SEB Antwerp - Abstract Book

ABSTRACT BOOK

SEB ANNUAL CONFERENCE

A ROOM WITH A ZOO

KONINGIN ASTRIDPLEIN 20-26

2018 ANTWERP, BELGIUM

08 JULY - 11 JULY 2025

SEBIOLOGY.ORG #SEBCONFERENCE SOCIETY

ANTWERP 2025

ANIMAL BIOLOGY ABSTRACTS

A1: MULTISCALE MUSCULOSKELETAL MECHANICS AND MODELING

ORGANISED BY: NICOLAI KONOW (UNIVERSITY OF MASSACHUSETTS LOWELL),

JANNEKE SCHWANER (KU LEUVEN)

A1.1 SPECIAL SESSION INTRODUCTION: MULTI-SCALE MEASUREMENTS AND MATHEMATICAL MODELING OF MUSCULOSKELETAL MECHANICS

Tuesday 8th July 2025 09:00

Nicolai Konow (University of Massachusetts Lowell, United States), Janneke Schwaner (Max Plank Institute for Intelligent Systems, Germany)

Nicolai_konow@uml.edu

Muscle, the principal motor propelling animal movement, is also a system typically invoked to exemplify hierarchically-organized biological systems. Traditionally, muscle studies have targeted multiple organizational scales, ranging from myoprotein structure-function relationships, via cell and tissue contractile mechanics, to mathematical modeling of intact musculoskeletal system function. However, studies across these disparate scales have typically been carried out in silos across the comparative, bioengineering, and healthcare fields and these siloed approaches have generally precluded crossscale understanding of how muscle functions. Taking 21st Century convergence-approaches, teams worldwide have recently begun making paradigm-shifting discoveries about how muscle’s crystalline-like ultrastructure achieves diverse and suitable performance-outcomes at the organ- and whole-organism- scales. These discoveries have uncovered emergent properties related to the hierarchical system composition that historically have evaded understanding in other multi-scale systems until trans-disciplinary approaches were adopted. The present Special Session aims to reach consensus about how convergence approaches in muscle studies are designed and carried out and foster global, transgenerational, and transdisciplinary synergy in ongoing and forthcoming multiscale studies of muscle function.

A1.2 MODELLING ENERGETICS ACROSS SCALES: FROM MOTOR UNITS TO MOVING ANIMALS

Tuesday 8th July 2025 09:00

t.dick@uq.edu.au

Skeletal muscles consume energy to power animal movement. Yet experimental tools that directly measure metabolic energy lack the spatial and temporal resolution needed to capture energy use across the range of movements that animals perform in nature. Physiologicallyinformed models offer a powerful alternative, simulating the energy required for force production and movement. However, existing models substantially vary in their predictions of in vivo energy consumption, highlighting the need for improved approaches to accurately characterize locomotor energetics. In this talk, I will showcase two areas of research whereby we aim to (1) create more accurate muscle models capable of capturing in vivo skeletal muscle energy use during voluntary contractions, and (2) develop whole-body predictive simulations of human and animal movement to establish mechanistic links between musculoskeletal form and locomotor energetics. Specifically, I will discuss ways in which we are combining experimental tools that capture physiological data spanning motor unit recruitment, fibre dynamics, joint kinematics and kinetics, and whole body metabolic cost together with computational models of single muscles and predictive simulations of whole animal locomotion. Our studies demonstrate how physiologically-informed muscle models can capture the contributions of contraction-specific motor unit properties and recruitment characteristics to in vivo energetic costs. We showcase how human predictive simulations scaled from the size of a mouse to an elephant demonstrate that legged movement is cheaper for larger animals per kg of body mass. Further we use simulations of hopping kangaroos to disentangle their ability to mitigate the extra energetic costs associated with faster hopping speeds.

Tuesday 8th July 2025 09:30

Taylor JM Dick (University of Queensland, Australia), Lauren Thornton (University of the Sunshine Coast, Australia), Lars D'Hondt (KU Leuven, Belgium), Friedl De Groote (KU Leuven, Belgium), Christofer Clemente (University of the Sunshine Coast, Australia)

Natalie Holt (UC Riverside, United States), Tyler Whitacre (UC Riverside, United States), David Labonte (Imperial College London, United Kingdom)

natalieh@ucr.edu

Skeletal muscle performance is attributed to work producing crossbridge interactions between the contractile proteins, actin and myosin. Myosin kinetics are through to underpin the isotonic force velocity relationship observed in skeletal muscle. Variation in maximum shortening velocity (Vmax ) is attributed to variation in myosin isoform and is thought to dictate organismal performance. However, Vmax varies in ways that cannot be explained by actin-myosin interactions, decreasing with decreasing muscle recruitment irrespective of the myosin isoform recruited. This effect of recruitment on Vmax has been suggested to be due to the physical properties of the muscle, such as mass, viscosity and elasticity, limiting its capacity to accelerate and so reach a myosin-defined Vmax . Here we determined the effect of recruitment on Vmax in 2 anuran plantaris muscles (cane toad and tree frog), with an ~40-fold difference in muscle mass, in vitro. If mass is an important determinant of Vmax , then we would expect a greater effect of recruitment in the larger muscle. There was a significant effect of recruitment on Vmax in both muscles (p< .005), and this effect was significantly greater in the larger cane toad muscle (p< .005). This has implications for the scaling of locomotor performance as the ratio between the force available for acceleration and mass to be accelerated systematically declines with increasing body size. Hence, larger species may be limited in their locomotor performance irrespective of the myosin isoform expressed, potentially explaining effects such as the scaling of maximum running speed.

A1.4 FILAMENTS REPEL WHILE MUSCLES PROPEL: A BIO-PHYSICAL EXPLANATION OF LATTICE SPACING

Tuesday 8th July 2025 09:45

Robert Rockenfeller (University of Koblenz, Germany)

rrockenfeller@uni-koblenz.de

The radial lattice spacing (LS) of actin and myosin filaments is a fundamental determinant of muscle force generation, yet its regulation remains an open question. While the assumption of volume constancy provides a phenomenological plausibility check, it lacks a mechanistic basis for LS changes during fiber contraction. We introduce a novel model demonstrating that electrostatic repulsion between charged filaments, governed by Debye-Hückel theory, dictates LS adaptations. Under the simple assumption of energy conservation, the model predicts LS variations across sarcomere lengths with remarkable accuracy, aligning closely with experimental data and outperforming traditional volume-based models.By explaining macroscopic muscle behavior with molecular interactions, the model offers deeper insight into the physics of muscle function. The refined understanding of LS dynamics enhances predictive capabilities in musculoskeletal modeling, with implications for physiology, biomechanics, and robotics. Adaptability to different muscle types further broadens its relevance, offering potential applications in understanding pathological conditions affecting sarcomere structure or the development of targeted drugs.Providing a first-principles explanation for LS regulation, this work challenges conventional assumptions and establishes a new foundation for multi-scale muscle research, from molecular mechanisms to whole-body movement.

A1.5 CONSEQUENCES OF THE FORCEVELOCITY RELATIONSHIP FOR THE ALLOMETRY OF MUSCULOSKELETAL PERFORMANCE

Tuesday 8th July 2025 10:00

David Labonte (Imperial College, United Kingdom) d.labonte@imperial.ac.uk

Animals vary vastly in size. With this size variation come potential changes in the key physical constraints they encounter, and the maximum locomotor performance they can achieve. Understanding the interaction between size, physical constraints and locomotor performance is a key task in comparative biomechanics, typically approached by invoking the parsimonious assumptions of geometric and physiological similarity. Notably absent from such textbook approaches is the explicit consideration of a key property of skeletal muscle, emerging straight from the molecular mechanism of contraction: muscle can shorten no faster than with characteristic maximum speed, at which its force output drops to zero. In this talk, I will address the effect of this force-velocity relationship on the allometry of musculoskeletal performance, and I will demonstrate that this challenges the key tenants of classic isometric scaling theory: during dynamic contractions across isometric musculoskeletal systems that vary in size, neither will maximum and average muscle forces be proportional to a characteristic area, nor will maximum work nor power output be proportional to a characteristic mass. Instead, the force-velocity relationship imposes size-specific deviations from classic scaling theory, which manifest, for example, in a non-trivial scaling of maximum running, flight or swimming speed. In contrast to the constraints considered in classic scaling theory, constraints imposed by the force-velocity relationship can be circumvented through nontrivial changes in musculoskeletal design, providing direct quantitiative predictions on mechanically optimal musculoskeletal design, and a fresh perspective on the functional significance of musculoskeletal gearing and of elastic elements in series with muscle.

A1.6 THE RELATIONSHIP BETWEEN MUSCLE STRUCTURE, FORCE GENERATION, AND MUSCLE FUNCTION

Tuesday 8th July 2025 10:15

Tobias Siebert (University of Stuttgart Motion and Exercise Science, Germany), Andre Tomalka (University of Stuttgart Motion and Exercise Science, Germany), Jörg Fehr (University of Stuttgart Institute of Engineering and Computational Mechanics, Germany), Norman Stutzig (University of Stuttgart Motion and Exercise Science, Germany), Matthew Millard (University of Stuttgart Motion and Exercise Science, Germany)

tobias.siebert@inspo.uni-stuttgart.de

Eccentric muscle contraction is a part of many activities but is poorly understood. Athletic activities such as jumping and running produce eccentric contractions. In addition, eccentric contractions occur during in-vivo experimental recreations of vehicle accidents. Lab experiments have improved the understanding of the mechanisms of eccentric contraction, and several models now include these mechanisms.

Experimental work shows that cross-bridge (XB) and non-XB structures within the sarcomere generate force during eccentric contraction. By using chemical cross-bridge inhibitors such as blebbistatin, it has become possible to measure experimentally the contributions made by XB and non-XB structures. These measurements make it clear that semi-active non-XB structures generate substantial force during eccentric contraction and that this force is primarily elastic. Several muscle models now include semi-active non-XB structures to reproduce experimental measurements of eccentric contraction more accurately. Most models use some variant of the sticky-spring hypothesis: during activation, a portion of the titin filament attaches to actin and, in doing so, appears to be stiffer during subsequent eccentric contractions. We are evaluating two models with a sticky-spring mechanism against our in-vitro experimental measurements. These models have applications beyond reproducing lab experiments, as our related in-vivo experiments show: the neck's muscles eccentrically contract during mechanical simulations of vehicle accidents. This line of research has the potential to touch many fields, ranging from muscle physiology to the relationship between muscle structure, force generation and function during various activities.

A1.7 IMPLICATIONS AND EVALUATION OF THE COOPERATIVE FUNCTIONS OF MYOSIN IN MUSCLE AND HEART CONTRACTION.

Tuesday 8th July 2025 14:00

Motoshi Kaya (University of Tokyo, Japan)

kaya@g.ecc.u-tokyo.ac.jp

We have analyzed the force generation dynamics of motor ensembles consisting of skeletal myosin or cardiac myosin, which are composed of 1 to approximately 20 molecules. Our findings reveal that cooperative force generation, which is unique to individual myosin molecules, plays a crucial role in their function. In addition, we have elucidated the molecular mechanism underlying this cooperative behavior. Interestingly, this cooperative force generation appear to be well suited to the contractile properties of skeletal and cardiac muscle. To quantitatively characterize this cooperative force generation, we applied information theory to evaluate mutual information and information efficiency. Our analysis suggests that as the number of myosin molecules increases from a few to about 30, inter-molecular information transmission becomes more efficient. In this talk, I will present these findings and discuss their implications.

A1.8 A GUINEA FOWL MUSCULOSKELETAL MODEL TO ANALYZE MUSCLE FORCES

Tuesday 8th July 2025 14:30

Marie J Schwaner (KU Leuven, Belgium), Lars D'Hondt (KU Leuven, Belgium), Robert Kambic (Hood College, United States), Stephan Gatesy (Brown University, United States), Monica A Daley (University of California Irvine, United States), Friedl De Groote (KU Leuven, Belgium) mariejanneke.schwaner@kuleuven.be

Muscles drive movements, but measuring muscle forces, lengths, and activations during movements is challenging, and experimental data is often limited to just a few muscles. Computational musculoskeletal models offer a way to estimate muscle states (length, force, activation) during movement. Here, we further developed an existing musculoskeletal model of the guinea fowl (Numida meleagris), a common animal model to study agile locomotion, to enable physiologically plausible simulations of the coordinated action of all muscles in dynamic movements. We used the model for inverse analyses of kinematics, kinetics, and muscle forces. We remodeled the existing one-legged muscle model of the guinea fowl to a bipedal model, including all major muscles of the limb, resulting in 48 actuators per limb. To improve computational efficiency, we reduced via points and wrapping surfaces while maintaining anatomical accuracy. We optimized tendon slack lengths for efficiency by minimizing activation squared across various motions. Tendon slack lengths are critical as they define a muscle's operational range but cannot be measured directly. Using inverse kinematics and dynamics, we estimated muscle-tendon lengths, moment arms, and muscle states (activation, fiber lengths, and forces). The model produced physiologically plausible estimates of muscle forces and inverse dynamics torques. Qualitatively we confirmed parameters with experimental data. Our dynamic model also supports predictive simulations, generating movement patterns without experimental data. Currently, we are using these simulations to explore how muscle mechanics and sensory feedback contribute to agile locomotion.

A1.9

FEATHERED BALANCE: THE ROLES OF MUSCLE ANTAGONIST ACTION DURING LOCOMOTOR PERTURBATIONS.

Tuesday 8th July 2025 14:45

Daniel Bartlett (Umass Lowell, United States), Brandon Reder (Umass Lowell, United States), Andrew A Biewener (Harvard, United States), Jonas Rubenson (Penn State, United States), Nicolai Konow (Umass Lowell, United States)

Daniel_Bartlett@uml.edu

Understanding how muscle contractions are coordinated to maintain stability and efficiency across varied locomotor tasks remains a key biomechanics challenge. Indirect evidence suggests that antagonist muscle co-activation stabilizes joints, but muscle force data remains limited, leaving the role of antagonist action in musculoskeletal energy transfer unresolved. We took a multi-scale approach, using Guinea fowl(Numida meleagris) to determine how an antagonist muscle pair generate and distribute energy during unsteady movement such as drop landings, slip–trip perturbations, and treadmill decelerations). We combined fascicle-scale (sonomicrometry), muscle-scale (tendon buckles, EMG) and musculoskeletal-scale (force plates, 3D motion capture) observations with center-of-mass analyses. Thereby, we captured a continuum of responses spanning from rapid perturbations to sustained decelerations. During drop landings, antagonist force and torque generation by tibialis anterior and lateral gastrocnemius facilitates controlled energy dissipation by adjusting limb stiffness to prevent joint collapse upon impact. Treadmill locomotion reveals antagonist torque overlaps at both toe-on and toe-off that manifest at low levels even during steady locomotion and increases during deceleration. Taken together, our direct, multi-scale measurements of antagonist muscle action indicate that co-contraction employs flexible mechanisms—adjusting timing and magnitude to perturbation severity—to foster robust, adaptable locomotion under diverse conditions. Thus, our study refreshes and refines traditional views of

antagonist action and provides a framework for bio-inspired robotics and intervention strategies for efficient yet stable movement.

A1.10 DON’T STRESS - HOW DIGITAL FLEXOR MUSCLES REDUCE METATARSAL BENDING MOMENTS DURING FAST LOCOMOTION OF EMUS AND TYRANNOSAURUS REX

Tuesday 8th July 2025 15:00

Pasha A Van Bijlert (Utrecht University Naturalis Biodiversity Center, Netherlands), Karl T Bates (University of Liverpool, United Kingdom), Knoek AJ Van Soest (Vrije Universiteit Amsterdam, Netherlands), Anne S Schulp (Utrecht University Naturalis Biodiversity Center, Netherlands)

pasha.vanbijlert@naturalis.nl

Locomotor abilities of extinct animals can be analysed by reconstructing the stresses on the skeleton, which impose functional constraints on locomotion. Previous work combined multibody dynamic simulations with Euler-Bernoulli beam theory to analyse the locomotion of Tyrannosaurus rex. Beyond speeds of 5.5-6.25 m/s, stresses on the metatarsals would exceed the yield strength of bone (~150-200 MPa), limiting T. rex to walking gaits. We have investigated this phenomenon further in T. rex and a modern functional analogue (emu, Dromaius novaehollandiae), using quasi-static analyses and predictive physics simulations. In both taxa, the moments of the digital flexor muscles and the ground reaction force (GRF) about the metatarsophalangeal joint are balanced, with digital flexor mechanical advantage (MA) of ~0.15. This allows computing the bending moments at the (tarso) metatarsus midshaft as a function of GRF. Our quasi-static analysis suggests that the digital flexors counteract bending moments induced by the GRF, and that the morphology of the non-avian theropod metatarsus further reduces stresses when MA is low. We have incorporated digital flexor and extensor muscles into musculoskeletal models of the emu and of T. rex (~7800 kg). Predictive simulations confirm the stress reducing effect of the digital flexors identified by quasi-static analyses: at the same relative muscle mass, we found true running gaits at speeds up to 10.75 m/s, with peak metatarsal stresses ~40 MPa. The stress-reducing effects of the digital flexors add grounded and aerial running to the feasible locomotor repertoire of an adult Tyrannosaurus rex.

A1.11 MAPPING MOLECULES TO MUSCLES: MASTICATORY MYOSIN EXPRESSION

AND MULTISCALE TUNING OF

Tuesday 8th July 2025 15:15

Robert J Brocklehurst (University of Massachusetts Lowell, United States), Nicholas LaFave (University of Massachusetts Lowell, United States), Varun Dhorajia (University of Massachusetts Lowell, United States), Prabath Meemaduma (University of Massachusetts Lowell, United States), Brandon Reder (University of Massachusetts Lowell, United States), Mattthew Gage (University of Massachusetts Lowell, United States), Jeffery Moore (University of Massachusetts Lowell, United States), Nicolai Konow (University of Massachusetts Lowell, United States)

robert_brocklehurst@uml.edu

An ancient masticatory isoform of myosin (MHC-M) is expressed in jaw muscles and hypothesized to be associated with increased force production in hard-biting vertebrates. However, how myosin expression and molecular properties cascade through the hierarchy of muscle functional organization and influence system-level outputs remains unclear. Rodents are a diverse clade that provides a powerful system for testing structure-function relationships across scales, by comparing species with different skeletal and muscle morphologies (sciuromorphs, hystricomorphs and myomorphs) that either express or lack MHC-M. We measure myosin transcript and protein expression patterns (SDSPAGE), intact muscle force-length data (in situ ergometry), muscle physiological cross-sectional area (gross dissections), and dynamic moment arms (ex vivo X-ray reconstruction of moving morphology). We then estimate incisor bite force using this multiscale dataset. Myosin expression data demonstrates exclusive MHC-M expression in jaw adductors, signaling a functional rather than a developmental origin. In situ force-length data demonstrate greater specific tension in muscles expressing MHC-M, and dissections show generally consistent patterns of relative muscle prominence across taxa. Muscle moment arms are highest in sciuromorphs, not all of which express MHC-M. Estimated bite forces are greatest in MHC-M expressing taxa, whereas some taxa that lack MHC-M retain high force outputs, indicating that similar system outputs are attainable in multiple ways across scales. Our results show selection for ecologically-relevant traits across muscle organizational scales in the rodent craniofacial system – from myosin expression to muscle moment arms - and our multiscale analysis unveils the complex functional relationships within biological systems.

A1.13 TISSUE ENGINEERING SKELETAL MUSCLE FOR REGENERATIVE MEDICINE AND ROBOTICS

Tuesday 8th July 2025 16:00

Ritu Raman (Massachusetts Institute of Technology, United States)

ritur@mit.edu

Human beings and other biological creatures navigate unpredictable and dynamic environments by combining compliant mechanical actuators (skeletal muscle) with neural control and sensory feedback. Disease or damage that impacts neuromuscular tissues thus has a severe negative impact on health, mobility, and quality-of-life, motivating the development of tissue engineered multicellular models of the motor control system. We have engineered optogenetic skeletal muscle actuators and shown that light can be used to non-invasively and precisely control muscle contraction, and moreover, that repeated light stimulation "exercise" can program tissue strength, endurance, and regeneration after trauma in vitro and in vivo. Leveraging these

tissues, we have interrogated how exercise programs crosstalk between muscle and other surrounding cells, such as peripheral nerves and vasculature, to better understand how mechanical and biochemical signaling can be manipulated in physiological and pathological states. In addition to applications of this work in disease modeling and regenerative medicine, we will also discuss how we use engineered muscle to power adaptive biohybrid robots that demonstrate a range of functional behaviors such as walking and gripping. This talk will cover the advantages, challenges, and future directions of using tissue engineered models to understand and manipulate the mechanics of biological motor control systems.

A1.12 EFFICIENT ELASTIC TISSUE MOTIONS INDICATE GENERAL MOTOR SKILL

Tuesday 8th July 2025 16:00

Praneeth Namburi (Massachusetts Institute of Technology, United States), Roger Pallarès-López (Massachusetts Institute of Technology, United States), Duarte Folgado (Fraunhofer Portugal AICOS, Portugal), Uriel Magana-Salgado (Massachusetts Institute of Technology, United States), Enya Ryu (Massachusetts Institute of Technology, United States), Armin Kappacher (Massachusetts Institute of Technology, United States), Hugo Gamboa (Fraunhofer Portugal AICOS, Portugal), Brian W. Anthony (Massachusetts Institute of Technology, United States), Luca Daniel (Massachusetts Institute of Technology, United States) praneeth.namburi@gmail.com

Insights into the general nature of motor skill could fundamentally change how we develop movement abilities, with implications for musculoskeletal well-being and injury. Here, we sought to identify indicators of general motor skill–those shared by experts across disciplines (e.g., squash, ballet, volleyball) during non-specialized movements (e.g., reaching for water). Identifying such general indicators of motor skill has remained elusive. Using ultrasound imaging with deep learning and optical flow analysis, we tracked elastic tissues (muscles and associated connective tissues) during a simple reaching task performed similarly by world-class athletes and regional-level athletes drawn from diverse disciplines, as well as untrained non-experts. We analyzed previously unexamined inefficiencies: transverse elastic tissue motions orthogonal to muscle fiber direction and physiological tremors, which are oscillations that do not contribute to the net work done by muscles. We discovered that world-class experts minimize both these inefficient motions compared to regional level athletes and non-experts. While regional-level athletes surprisingly showed similar inefficiencies to non-experts, they used elastic tissues more effectively, achieving equivalent movements with smaller actuationrelated tissue motions. We establish elastic tissue motion as a key indicator of general motor skill, expanding our understanding of elastic mechanisms and their role in general aspects of motor skill.

A1.14 TRADING OFF STABILITY, AGILITY AND EFFICIENCY OF MOVEMENT ACROSS A BROAD RANGE OF MUSCLE TENDON MORPHOLOGIES

Tuesday 8th July 2025 16:30

Laksh Kumar Punith (University of Michigan, United States), Gregory S Sawicki (Georgia Institute of Technology, United States)

lakshp@umich.edu

Animals care about multiple objectives, yet are stuck with one set of musculoskeletal parameters at a time. So, the question naturally arises, what values should they pick and what tradeoffs may they face? We cannot answer the first question as it is subjective, however we can attempt to answer the second. Here we focus on Achilles tendon stiffness – whose value in humans has been shown to maximize efficiency in walking and running. We ask how does changing Achilles tendon stiffness (1) affect efficiency, stability and economy of movement in a cyclic bouncy gait (e.g. hopping) and (2) how do they tradeoff. To answer that question, we built a mathematical model of human hopping which consists of a mass in gravity actuated by a muscle-tendon unit across a lever arm (representing the foot). The muscle is cyclically stimulated at 2.5Hz (preferred hopping frequency) to generate hopping and efficiency (ratio of mechanical work and metabolic cost), stability (average ratio of energy dissipated and energy injected by a change in ground height), and agility (maximum and minimum work possible by changing stimulation timing) were calculated. We find (1) Nominal achilles tendon stiffness (180000 N/m) had maximum efficiency, medium stability, and low agility ( positive work) and high agility (negative work). Additionally, increasing stiffness had no benefit except agility (positive work). However, decreasing stiffness trades off lower efficiency to gain higher agility (negative work) and higher stability – potentially explaining why older adults have lower tendon stiffness values despite the energetic burden.

A1.15 MUSCLE MASS AFFECTS THE SCALING OF FORCE PREDICTIONS FROM 1D HILL-TYPE MODELS DURING HUMAN MOVEMENT

Tuesday 8th July 2025 16:45

Ameur Latreche (Simon Fraser University, Canada), Ing-Jeng Chen (Simon Fraser University, Canada), Stephanie Ross (University of Calgary, Canada), Evie Vereecke (University of Leuven, Belgium), James Wakeling (Simon Fraser University, Canada)

ameur_latreche@sfu.ca

Muscle inertia should affect the mechanical output of muscle, with its effects being greatest at larger sizes, and greater accelerations. Muscle inertia is known to affect the mechanical output of isolated muscle preparations; however, its influence during natural, wholebody movement remains unclear. In this study, forces were compared between a traditional one-dimensional massless muscle model , and a muscle model in which muscle mass was distributed along its length. Kinematic and electromyographic data were collected from twenty

participants performing walking, running, hopping and sit-to-stand tasks, and muscle was geometrically scaled using factors of 0.1, 1 and 10. The results showed that muscles modelled at a scale factor of 10 exhibited significantly higher root-mean-squared errors (RMSE) in normalised time-varying forces, reaching up to 7.23% of maximum force for the vastus lateralis during running compared to a maximum RMSE of 0.31% for scales 0.1 and 1. Furthermore, tasks involving higher muscle accelerations, such as running and hopping, resulted in greater mass effects than lower-cadence activities. These mass effects were smaller than those we have previously predicted from 3D muscle models. These findings underscore the importance of accounting for muscle mass in larger muscles during rapid movements, and the need to account for complete 3D muscle deformations and dynamics when understanding muscle force and function.

A1.16 MUSCLE FIBRE TYPE DISTRIBUTION INFLUENCES WALKING BIOMECHANICS: A PREDICTIVE SIMULATION STUDY

Tuesday 8th July 2025 17:00

Torstein E Dæhlin (Simon Fraser University, Canada), Stephanie A Ross (University of Calgary, Canada), Nilima Nigam (Simon Fraser University, Canada), Freidl De Groote (KU Leuven, Belgium), James M Wakeling (Simon Fraser University, Canada)

torstein_eriksen_dhlin@sfu.ca

Muscle fibre type distribution may be influenced by clinical state and differs between individuals. For example, chronic heart failure patients experience a shift from fast to show fibres, while sprinters have a larger fraction of fast fibres than non-sprinters. However, in vivo changes in fibre type distribution are accompanied by alterations in other muscle properties, most notably size and strength, making it difficult to isolate their effects on movement. This challenge can be overcome using predictive simulations, which synthesize motion and control based on a performance criterion. This study investigated the impact of fibre type distribution on gait biomechanics using predictive simulations. We simulated walking (1.33 m/s) using the predictive simulation framework, PredSim. Ninety-two muscles were each represented by a Hill-type muscle model with two motor units containing all its slow and fast fibres, respectively. The baseline model used experimentally derived physiological cross-sectional area fractions for slow and fast fibres. These proportions were then varied from 6% to 96% slow fibres to assess their effects on walking biomechanics. Metabolic cost of transport gradually decreased (~26% in total) as the fractions of slow fibres increased from 6% to 96%. Spatiotemporal characteristics, joint angles, joint torques, and muscle coordination were similar in most conditions, excepting at the highest slow fibre fractions (>86% slow). While the latter effects were modest during walking, we hypothesize that fibre type composition may have greater impacts on more demanding tasks, such as running. Overall, these findings suggest that muscle fibre type composition meaningfully affects gait biomechanics.

A1.17 TITIN UNDERPINS RESIDUAL FORCE ENHANCEMENT, DEPRESSION, AND THE STRETCH-SHORTENING CYCLE EFFECT

Tuesday 8th July 2025 17:15

Anthony L Hessel (University of Muenster, Germany), Michel N Kuehn (University of Muenster, Germany) Anthony.hessel@uni-muenster.de

Skeletal muscle active tension is dependent on its history. When activated isometrically, tension can be predicted based on the sarcomeric length-tension relationship, where force is proportional to the overlap of the myosin-containing thick filaments and actincontaining thin filaments. Contrary to expectations, an active stretchhold leads to increased tension (residual force enhancement), active shorten-hold leads to less tension (residual force depression), and an active stretch-shorten-hold leads to less tension but not at the level of a pure shortening-hold (stretch-shortening cycle effect). The I-band titin spring is thought to be the primary driver of these history-dependent effects, hypothesized to be through a change in titin-based stiffness upon activation. Using small angle X-ray diffraction in combination with a novel mouse model that specifically cleaves 50% of I-band titin, we evaluated the relationship between titinbased force, history-dependent properties, and sarcomere protein order and orientation. Our results demonstrate that cleaving 50% of I-band titin reduces the history-dependent tension effects towards those expected under purely isometric conditions. Furthermore, each of the isometric or length-change conditions had unique structural signatures that help to explain differences in tension, which seem to be more related to changes in titin-based tension on the sarcomere and force transmission, and less dependent on changes to cross-bridge kinetics. An activation-dependent change in titin-based stiffness seems plausible but the mechanism that accounts for this remains to be deduced.

A1.18 THE MECHANICAL BEHAVIOUR OF APONEUROSIS: BRIDGING THE GAP BETWEEN STATIC ASSUMPTIONS

AND REAL-WORLD DYNAMIC CONTRACTIONS

Wednesday 9th July 2025 15:00

Stephanie A. Ross (University of Calgary, Canada), Christine Waters-Banker (University of Calgary, Canada), Andrew Sawatsky (University of Calgary, Canada), Timothy R. Leonard (University of Calgary, Canada), Walter Herzog (University of Calgary, Canada)

stephanie.ross1@ucalgary.ca

Aponeurosis acts as a surface for fascicles to attach to and facilitates transmission of forces across pennate muscle. Although aponeurosis is a continuation of tendon and shares many of the same material properties, its more complex structure and loading during contraction results in more non-uniform and multidirectional patterns of deformation. These patterns of deformation and their determinants have been described for highly controlled conditions such as constant length or constant load contractions. However, these static or steady-

state contractions likely do not lead to forces applied to aponeurosis and resultant deformations that reflect those that occur during in vivo movement. In this study, we aimed to address this gap by examining patterns of aponeurosis deformations in in situ rabbit medial gastrocnemius muscle under variable loading conditions. In particular, we determined the extent to which biaxial deformations are dictated by factors such as muscle force, length, and fascicle shortening during cyclic work-loop contractions that reflect the loading conditions that occur in vivo. These findings will not only bridge the gap between our understanding of aponeurosis behaviour from controlled to more realistic variable contractions, but will provide a suite of experimental measures from which to develop and validate more accurate representations of aponeurosis in advanced 3D muscle models.

A1.19 MATHEMATICAL MODELLING CONNECTS MUSCLE FUNCTION ACROSS SCALES OF ORGANISATION

Wednesday 9th July 2025 15:30

Sam Walcott (Worcester Polytechnic Institute, United States) swalcott@wpi.edu

In skeletal muscle, trillions of molecules organised in various substructures work together. The molecules sense and respond to each other in different ways. Understanding muscle function therefore requires understanding intermolecular coupling both within and between muscle's substructures. To do so, we use mathematical modelling to interpret our collaborators' experiments. Studying isolated, purified molecules allows us to understand how molecules apply forces on one another and the effects of those forces. We have developed models that describe measurements of single molecules, ensembles of ~10 molecules, and ensembles of ~100 molecules under a range of conditions. However, these models do not explain measurements from muscle cells (fibres). To understand this disconnect, we collected measurements from both isolated molecules and muscle fibres, under similar conditions. Our model describes the fibre measurements when we add thick filament activation, the phenomenon where inactive myosin molecules in thick filaments become activated when force is applied. This effect does not occur in molecular experiments, where molecules are not in thick filaments, and our model predicts our molecular measurements when we remove thick filament activation. General principles at the cellular scale might apply to larger scales. E.g., isometric force in a limb might be similar to a fibre. Our models, like most models, predict a linear relationship between metabolic cost and isometric force. Interestingly, our measurements in human subjects show a non-linear scaling, with metabolic cost rising as force to the ~1.6. This scaling likely arises from fibre recruitment, and demonstrates the difficulties in connecting muscle scales.

A1.20 DEVELOPING AND UTILISING MUSCULOSKELETAL MODELS

Lauren H Thornton (University of the Sunshine Coast, Australia), Lars D’Hondt (Katholieke Universiteit Leuven, Belgium), Friedl De Groote (Katholieke Universiteit Leuven, Belgium), Taylor J M Dick (University of Queensland, Australia), Christofer J Clemente (University of the Sunshine Coast, Australia)

Lauren.Thornton2@research.usc.edu.au

Kangaroo hopping is uniquely energetically efficient at slow speeds and small sizes, however, it is unknown how the locomotor performance of large or fast moving kangaroos compares to other animals. Hopping in giant kangaroos (>150 kg) may even be impossible or severely incumbered by tendon morphology. We built a musculoskeletal model of an average (27 kg) kangaroo and geometrically scaled it to various sizes between 10-650 kg. We implemented the models in a predictive simulation framework to generate hopping up to the maximum speed for each model. Contrary to expectations, tendon stress was not the predominant limit for either the maximum size or speed. Rather, maximum speed was limited by available muscle strength. Maximum speed declined with model mass as larger models were unable to support the increase in ground forces required to sustain higher speeds. Larger models also progressively lost the energetic advantage that small kangaroos appear to have over other mammals. The simulations predict that hopping consumes oxygen at a similar rate at slow and fast speeds, and –crucially– at the same mass-specific rate regardless of size. Other terrestrial species tend to decrease oxygen consumption with mass, leaving giant kangaroos at a competitive disadvantage. At larger sizes, hopping only becomes more energetically efficient than alternative gaits at progressively faster speeds. Together, these results suggest that poor energetic and speed performance may have contributed to the extinction of giant kangaroos.

A1.21

SMALL MOLECULES TARGETING THE THIN FILAMENT MODULATE CALCIUM SENSITIVITY AND REVERSE CARDIOMYOPATHY MOTILITY PHENOTYPES.

Wednesday 9th July 2025 16:00

Jeffrey R. Moore (University of Massachusetts Lowell, United States), Meaghan E Barry (University of Massachusetts Lowell, United States), Michael` J Rynkiewicz (Boston University Chobanian Avedisian School of Medicine, United States), Lauren` E Brown (Boston University, United States), Aaron B Beeler (Boston University, United States), Stuart Campbell (Yale University, United States), William Lehman (Boston University Chobanian Avedisian School of Medicine, United States), Balajee Ramachandran (Boston University Chobanian Avedisian School of Medicine, United States)

Jeffrey_Moore@uml.edu

Wednesday 9th July 2025 15:45

Cardiomyopathies can be categorized as either hypo- or hypercontractile, with varying severity depending on the underlying biophysical disruption. Approximately 35% of pathogenic mutations occur in sarcomeric thin filament proteins, including tropomyosin and troponin. To enhance the precision of therapeutic interventions, we investigated proof-of-concept small-molecule contractile modulators targeting the thin filament. Using a multiscale mechanochemical approach, we combined computational modeling with experimental

assays to assess cardiac muscle thin filament modulation. Computational screening of thousands of small molecules identified dozens of potential candidates with favorable Glide docking scores (-7.5 to -10.5 kcal/mol) at a binding site near the tropomyosin overlap region, adjacent to troponin T. Functional validation using myosin-based in vitro motility assays revealed that one compound from the Boston University Center for Molecular Discovery, ‘NCB1’, desensitized the thin filament to calcium with an EC50 of 128nM (DMSO pCa50: 6.17 ± 0.13; NCB1 pCa50: 5.88 ± 0.34) and appeared to reverse the calcium hypersensitivity of the hypertrophic cardiomyopathy-associated mutation, Tpm-E62Q (E62Q-DMSO pCa50: 6.32 ± 0.13; E62Q-NCB1 pCa50: 5.80 ± 0.30). Conversely, another small molecule, ‘NCB2’, increased calcium sensitivity and appeared to reverse the calcium hyposensitivity of a cardiomyopathy-associated mutation, Tpm-E54K (E54K-DMSO pCa50: 6.03 ± 0.13; E54K-NCB2 pCa50: 6.1 ± 0.30). To further assess therapeutic potential, these compounds are being tested in engineered heart tissue. Our approach of integrating computational screening with experimental validation at higher organizational scales, demonstrates the power of multiscale approaches and underscores the ability to modulate thin filament function pharmacologically and restore contractile balance in mutations associated with cardiomyopathies.

A1.22 MULTI-SCALE ASSESSMENT OF CONTRACTILE PROPERTIES FOR HUMAN STEM CELL DERIVED CARDIOMYOCYTES CONTAINING MYH7 DISEASEASSOCIATED MUTATIONS.

Wednesday 9th July 2025 16:15

Michael Regnier (University of Washington, United States), Kerry Kao (University of Washington, United States), Kalen Robeson (University of Washington, United States), Matthew Childers (University of Washington, United States) mregnier@uw.edu

The MYH7 gene, that encodes for β-myosin, is a hot spot for mutations that have been associated with hypertrophic or dilated cardiomyopathy. We have developed multi-scale experimental and computational approaches to study these mutations in human inducible pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) at the protein, myofibril, cell and tissue level. An example is the G256E mutation, which is associated with hypertrophic cardiomyopathy. Myofibril mechanics measurements demonstrated this mutation results in a greater amount of force production and the rate of force generation is increased while the rate of relaxation is decreased. Elevation of ADP affected relaxation of G256E myofibrils less that WT myofibrils, suggesting ADP release is slowed with the mutation. Stopped-flow kinetics analysis of myosinactin complexes verified a slower ADP release. Molecular dynamics (MD) simulations suggest the mutation, located in the transducer region of myosin, results in loss of hydrogen bonds between beta sheet strands that reduce signaling between the nucleotide binding pocket and myosin’s actin binding surface. MD simulations of myosinactin indicate changes in contact between the two proteins that may indicate more stable protein-protein6 interaction. This may provide the structure-based molecular mechanism of delayed relaxation and, perhaps faster force generation. Altered contractile properties at the myofibril level were persistent at the cell and engineered heart tissue level, with stronger contraction and decreased relaxation rate for the G256E mutation. Combined our multi-scale platform to assess the contractile and structural dynamics affected by mutations in sarcomere proteins provides a powerful approach to understand the molecular mechanisms of disease.

A1.24 CHARACTERIZATION OF MUSCLE PROPERTIES ACROSS SCALES: FROM SINGLE CROSS-BRIDGES TO IN VIVO HUMAN SKELETAL MUSCLES

Friday 11th July 2025 09:30

Walter Herzog (University of Calgary, Canada) wherzog@ucalgary.ca

History dependent muscle properties have been described since the early 1950s1 . History dependent properties refer to residual force depression and residual force enhancement, rFE, observed when an active muscle is shortened or stretched, respectively. Here, I will focus exclusively on rFE. rFE is typically measured as the increase in isometric force following active stretching of a muscle, compared to the corresponding isometric force not preceded by active stretching. Despite 75 years of research, the mechanisms underlying rFE remain unknown, although some initially proposed mechanisms have been unequivocally rejected. To identify the molecular events responsible for rFE, we have performed experiments ranging from single actinmyosin interactions using laser traps2 , to in-vivo human skeletal muscles activated voluntarily or by electrical nerve stimulation3 . Summarizing the results of these studies, it appears (i) that rFE is associated with an increase in force of passive structural proteins, (ii) that this increase in passive force is associated with titin, and (iii) that the increase in titin force is associated with an increase in titin stiffness. We speculate that titin stiffness is increased by binding of proximal titin segments to actin, thereby reducing titin’s free spring length, causing an increase in titin force when a muscle is actively stretched. We further speculate that titin-actin binding is regulated by the exposure of attachment sites on actin through the inward movement of tropomyosin upon strong cross-bridge binding.

1 Abbott & Aubert (1952). J Physiol. 117(1),77.

2 Mehta & Herzog (2008). J Biomech, 41(7),1611-1615.

3 Lee & Herzog (2002). J Physiol, 545(1),321-330.

A1.26 AXIAL

MUSCLE-FIBRE

ORIENTATIONS REMAIN CONSISTENTLY HELICAL DURING EARLY DEVELOPMENT OF ZEBRAFISH

Friday 11th July 2025 10:00

Noraly MME Van Meer (Experimental Zoology Group Wageningen University, Netherlands), Johan L Van Leeuwen (Experimental Zoology Group Wageningen University, Netherlands), Martin J Lankheet (Experimental Zoology Group Wageningen University, Netherlands)

noralymmevanmeer@gmail.com

The fast axial muscles of larval bony fish are essential for survival, powering rapid escape responses during this period of high predation pressure. Whereas the fast muscle fibres follow a pseudo-helical pattern in adult and juvenile teleosts, and a helical pattern in larval zebrafish (Danio rerio), the developmental timeline of this pattern has remained unclear. We studied muscle-fibre arrangements in a genetically modified line of larval zebrafish from 2-13 days post-fertilization (dpf). Using 3D fluorescent confocal microscopy, we quantified fibre

orientations throughout the body, by their frontal projection angle α and sagittal projection angle relative to the notochord. To evaluate whether the fibres follow helical trajectories and to understand how these trajectories change across ontogenetic stages, we fitted a model of circular, concentric helices to the fibre orientations. We show that after hatching at 2dpf, muscle-fibre directions already exhibit a helical pattern that tapers towards the tail. Both the fit’s quality and the change of model parameters over time show that the helical muscle-fibre architecture remains consistent during the first eleven days post-hatching, without signs of pseudo-helical deviations. The rate of change in projection angles with radial distance from the helix centre decreases towards the tail. This is most pronounced for younger larvae and decreases as the fish mature. For different developmental stages, the helix centres are positioned at corresponding, normalised locations along the notochord. Our results emphasize the early presence of a helical fibre arrangement in the development of the complex fast axial muscles in larval fish.

A1.25 PREDICTING MUSCLEFIBRE STRAINS IN THE SWIMMING MUSCULATURE OF 4 DPF LARVAL ZEBRAFISH

Friday 11th July 2025 10:15

Johan L Van Leeuwen (Experimental Zoology Group Wageningen University, Netherlands), Noraly MME Van Meer (Experimental Zoology Group Wageningen University, Netherlands), Martin J Lankheet (Experimental Zoology Group Wageningen University, Netherlands)

johan.vanleeuwen@wur.nl

The fast axial muscle fibres of teleosts generate fast starts and highspeed swimming motions. Anteriorly, these fibres are closely packed in a nested (pseudo-)helical arrangement. In zebrafish (Danio rerio), the helical pattern is already present at hatching and is modified in the larval, juvenile and adult stages. Theoretical studies suggested that this arrangement helps to reduce variation in muscle-fibre strain within transversal cross-sections. Here, we predict the strain distribution as a function of body curvature at seven locations along the axial muscles of 4 dpf (days post-fertilization) zebrafish. We obtained equidistant muscle-fibre orientations from previously measured fibre directions in four specimens. Strains were computed based on a bending-beam model at a series of seven transverse, ’virtual’ slices along the anterior 70% of the axial muscles. We examined effects of muscle-fibre orientation and added shear by comparing three cases: (1) counterfactual, longitudinal fibre orientations, (2) helical arrangement without added shear, and (3) helical arrangement combined with added shear. The latter resulted in the lowest relative strain variances (quantified by the coefficient of variation), which only marginally increased with lateral body curvature. Posteriorly, the highest variance was present. Our analysis indicates that the helical arrangement with added shear reduces the variance in muscle-fibre strains and it keeps strain rates within physiologically feasible limits during large bodycurvature fluctuations. This conclusion may be applicable to the larval stage of most bony fish, if the muscle-fibre arrangement observed in larval zebrafish is representative of the majority of teleosts.

A1.27 JOINT-LEVEL FORCE-VELOCITY PROPERTIES FOR ARBITRARILY COMPLEX MUSCULOSKELETAL MODELS

Friday 11th July 2025 10:30

Christopher T Richards (Royal Veterinary College, United Kingdom), Tiina Murtola (Royal Veterinary College, United Kingdom)

ctrichards@rvc.ac.uk

One goal of musculoskeletal modelling is to explain dynamic behaviour in terms of fundamental muscle properties, such as the force-velocity (FV) relationship. However, this is challenging because the complexity of anatomically realistic models (namely, their high degrees of freedom, DOF) often prohibits detailed analysis; the number of mechanical interactions is too large for thorough investigation. Consequently, we may struggle to explain “high-level” behaviours such as joint kinematics and forces in terms of muscle-level dynamics. To address this, we developed a descriptive and visual framework for presenting intricate musculoskeletal modelling data. We computed a “joint-fv” curve as the activation weighted sum of instantaneous FV states of all muscles within a total “joint-FV space”. We applied our framework to two previously published models: 1) A low-DOF human arm during reaching and 2) a high-DOF human knee during walking. In both cases, we found that the instantaneous shape of the joint-fv curve morphs depending on synergistic and antagonistic co-contraction. Additionally, we found broad similarities in joint-fv trajectories, despite the biomechanical, behavioural and anatomical differences between reaching/walking. Specifically, joints followed a clockwise trajectory through joint-FV space, except when in the presence of non-contractile forces (i.e. contacts or cross-joint interaction forces). Hence, we propose that joint-fv trajectories communicate not only how mechanical energy flows through joints, but also how this flow is governed by interactions among intrinsic muscle properties (activation, FV) and extrinsic properties (multibody dynamics and contact forces) during dynamic activity.

A1.28 SCALING SINGLE MOLECULE

BEHAVIOUR IN ORGANISED SYSTEMS TO CONVERGE ON A COMMON MECHANISM FOR HOW CMYBP-C MODULATES THE CARDIAC RESERVE IN SS-CARDIAC MYOFIBRILS

Friday 11th July 2025 10:45

Neil M. Kad (University of Kent, United Kingdom), Matvey Pilagov (University of Kent, United Kingdom), Sonette Steczina (University of Washington, United States), Ateeqa Naim (University of Kent, United Kingdom), Michael Regnier (University of Washington, United States), Michael A. Geeves (University of Kent, United Kingdom)

N.Kad@kent.ac.uk

Cardiac muscle contraction occurs when myosin from the thick filament binds to the thin filament in an ATP-powered reaction, regulated by calcium and myosin availability. Some myosin heads remain inactive, creating a reserve to meet variable heart demands. Understanding how molecular effects scale up to the sarcomere level is key to modelling

contraction. Using single-molecule imaging of fluorescent ATP, we identified active myosins in myofibrils, detecting three ATPase kinetics: a fast, non-specific ATP-binding state, and two slower states—DRX and SRX. DRX represents contraction-ready myosins, while SRX serves as a cardiac reserve with reduced ATPase activity. In porcine myofibrils we show that 50% of sarcomeric myosins exist in this reserve, with the D-zone containing the lowest proportion (44%). PKA phosphorylation of porcine cMyBP-C reduced SRX myosins by 16% in the C-zone, 10% in the P-zone, and increased them by 8% in the D-zone. Remarkably, human cardiac myofibrils from a hypertrophic cardiomyopathy (HCM) patient with an MYBPC3-c.772G>A mutation causing cMyBP-C haploinsufficiency recapitulated the same pattern. This reveals a key regulatory role for cMyBP-C for both porcine and human β-cardiac myosin thick filaments, with compensatory changes occurring in the D-zone due to altered cMyBP-C phosphorylation or deficiency. Single-molecule imaging within the sarcomere provides a multiscale view of myosin activation, highlighting localised cooperativity relevant to both normal and diseased conditions.

POSTER SESSIONS

Friday 11th

A1.23 CROSS-SCALE CONUNDRUM: SLOW MASTICATORY MYOSIN IN JAW MUSCLES THAT ARE BOTH FAST AND STRONG

Varun Dhorajia (University of Massachusetts Lowell, United States), Nicholas LaFave (University of Massachusetts Lowell, United States), Brandon Reder (University of Massachusetts Lowell, United States), Robert Brocklehurst (University of Massachusetts Lowell, United States), Prabath Meemaduma (University of Massachusetts Lowell, United States), Matthew Gage (University of Massachusetts Lowell, United States), Nicolai Konow (University of Massachusetts Lowell, United States), Sam Walcott (Worcester Polytechnic Institute, United States), Jeffrey Moore (University of Massachusetts Lowell, United States)

varun_dhorajia@student.uml.edu

Muscle function depends on a complex and deep hierarchy, where molecular-scale motor proteins drive movements that scale up to muscle and organism performance via intermediate scales. However, since these scales are typically studied in isolation, it is difficult to understand their interactions. To bridge this gap, we examined the rodent jaw musculoskeletal system, which varies in myosin isoform composition and skull morphology, and derived a multi-scale mathematical model to investigate how muscle function integrates across scales. We show that expression of a jaw-specific myosin, masticatory myosin (MHC-M), is associated with jaw-closing function in some rodents. Fascicles of gray squirrel superficial masseter (SM-GS) that express MHC-M produce ~1.6-fold greater tension (13.52 ± 4.0 N/g) compared to the MHC-II expressing rat superficial masseter (SMRt; 8.48 ± 1.09 N/g). Stronger SM-GS fascicles also produce ~1.8-fold faster peak shortening velocity (SM-GS = 72.78 ± 16.02 mm/s; SM-Rt = 40.63 ± 3.19 mm/s). By contrast, at the molecular scale, MHC-M propels actin at ~5-fold slower unloaded velocity (VACTIN = 0.8 ± 0.1 µm/

sec) compared to MHC-II (4.3 ± 1.4 µm/sec). The apparent disconnect suggests that intact muscle performance is influenced by factors beyond myosin velocity, including myosin’s propensity for weak binding and/or thick filament activation. Our latest multi-scale mathematical model successfully recapitulates muscle behavior across scales. Further refinements to the model will incorporate influences from additional factors, including thin filament regulation, extracellular matrix mechanics, and fascicle architecture, to ultimately connect myosin’s molecular action to in-vivo measurements of rodent bite performance. Funded by NSF 2217246.

A2: EXPERIMENTAL PALAEOBIOLOGY - BRINGING FOSSILS "BACK TO LIFE"

ORGANISED BY: JAMIE A. MACLAREN (UNIVERSITY OF ANTWERP), NARIMANE CHATAR (UNIVERSITY OF CALIFORNIA BERKELEY), SOPHIE REGNAULT (ABERYSTWYTH UNIVERSITY), PETER FALKINGHAM (LIVERPOOL JOHN MOORES UNIVERSITY)

A2.17 ANCIENT LIFE IN MOVING FLUIDS: USING COMPUTATIONAL FLUID DYNAMICS TO TEST FUNCTIONALAND

ECOLOGICAL HYPOTHESES IN FOSSIL

A2.18 ADDUCTOR MUSCLES IN GIANT AND NON-GIANT INSULAR LIZARDS (GENUS GALLOTIA): IS MUSCLE GROWTH LIMITLESS?

TAXA

Friday 11th July 2025 09:30

Imran Rahman (Natural History Museum London, United Kingdom)

imran.rahman@nhm.ac.uk

Palaeontologists have long been fascinated with how ancient organisms moved and fed, butit has proved difficult to address these questions in ways that allow specific hypotheses to betested. As a result, endeavours in the field are sometimes dismissed as unscientific ‘just-so’stories. However, the increasing availability of techniques for visualizing and analysingfossils digitally and in three dimensions has provided a framework for testing specifichypotheses in extinct taxa. One such method is computational fluid dynamics (CFD), a toolfor simulating flows of fluids and their interaction with solid surfaces. In this talk, I will presentcase studies of how CFD has been used to test functional hypotheses in fossil taxa,informing on the ecology and evolution of ancient organisms. I will also outline somepossible future directions in palaeontological CFD analyses, such as simulations acrosslarger spatial scales and coupling different physics models. Ultimately, I aim to show howCFD has the potential to form a key part of the palaeontologist’s toolkit for bringing fossils‘back to life’.

Friday 11th July 2025 10:00

Josep Fortuny (Institut Catala de Paleontologia Miquel Crusafont, Spain), Laia Garcia-Escolà (Institut Català de Paleontologia Miquel Crusafont, Spain), Arnau Bolet (Institut Català de Paleontologia Miquel Crusafont, Spain), Andrea Villa (Institut Català de Paleontologia Miquel Crusafont, Spain), Alejandro Serrano-Martínez (Institut Català de Paleontologia Miquel Crusafont, Spain), Penélope Cruzado-Caballero (Institut Català de Paleontologia Miquel Crusafont, Spain), Carolina Castillo-Ruiz (Institut Català de Paleontologia Miquel Crusafont, Spain), Jordi Marcé-Nogué (Universitat Rovira i Virgili, Spain)

josep.fortuny@icp.cat

The endemic genus Gallotia (Lacertidae) has representatives on each island of the Canary Archipelago (Spain) with living and extinct taxa of variable size ranging from few centimetres to close to one meter in length. Their diet can be omnivorous, insectivorous or herbivorous depending on the taxon, but reconstruction of diet in extinct taxa is challenging. Jaw muscles play a crucial role in feeding activities, providing clues to understand the feeding capabilities and potential food sources of extinct species. Herein, we present adductor muscle reconstructions in living and extinct taxa based on three different approaches: A) dissection and B) Dice (Diffusible Iodine-based Contrast-Enhanced) microCT scanner of Gran Canaria giant lizard specimens (Gallotia stehlini), and C) digital muscle reconstruction using the software Blender add-on Myogenerator based on 3D skulls derived from microCT scanners of all living and extinct species of the genus. The integration of these three methodologies allows for a precise 3D modelling of adductor muscles, enabling the estimation of the Physiological Cross-Sectional Area (PCSA) for each muscle across different taxa, and providing a groundwork for calculating muscle force—an essential parameter for biomechanical simulations. By analysing both extant and extinct taxa, our results suggest that while the largest specimens exhibit the most massive adductor muscles in absolute terms, these muscles are proportionally smaller and more elongated relative to those of smaller taxa. These findings offer new insights into the functional morphology and scaling patterns of muscle architecture across different closely related species.

A2.19 COMPARATIVE ANALYSIS OF MASTICATORY AND LOCOMOTOR BIOMECHANICS IN EXTINCT AND EXTANT LAGOMORPHS

Friday 11th July 2025 10:15

Amber P. Wood-Bailey (University of Liverpool, United Kingdom), Roger W. P. Kissane (University of Liverpool, United Kingdom), Philip G. Cox (UCL, United Kingdom), Nathan Jeffery (University of Liverpool, United Kingdom), Alana C. Sharp (University of Liverpool, United Kingdom)

woodbailey.ap@gmail.com

The cranium of rabbits and hares (Leporidae) is highly modified from other mammals including their closest relatives, pikas (Ochotonidae). They possess unique features including a fenestrated rostrum and posterior cranial bones, pronounced ventral facial tilting relative to the occipital bone, and an intracranial joint that is potentially the only instance of mammalian cranial kinesis. In mammals, a primary force driving cranial form is mastication. However, these unique traits have been linked to specialised cursorial and saltatorial locomotion and likely function to reduce weight, improve vision and dissipate kinetic energy during high-speed running. Previous work has assessed these traits within the contexts of lagomorph evolutionary history and extant leporid comparative morphology. However, the biomechanical function of these traits remains poorly understood. In recent work, we have utilised finite element analysis to assess the extent to which mastication and locomotion influence cranial form across leporid species displaying varying locomotor forms. Furthermore, we also assessed masticatory efficiency in the extinct lagomorph Palaeolagus to determine whether its intermediate cranial morphology (sharing traits with both Ochotonidae and Leporidae) translates to its mechanical efficiency. Palaeolagus almost certainly did not run at the speeds seen in modern leporids. Therefore, assessing Palaeolagus allows us to better differentiate the influences of mastication and locomotion on cranial form in lagomorphs. We found relationships between facial tilt, complexity of the intracranial joint, habitual locomotor form and the mechanical response of the cranium under loads simulating a deceleration force, revealing that high-speed running has likely influenced the evolution of leporid cranial form.

A2.20 THE HOLOCENE BROWN BEAR (URSUS ARCTOS L.) IN MOROCCO:

A STUDY OF ITS DIET BY ZOOMS AND ISOTOPIC ANALYSIS.

Friday 11th July 2025 10:30

Shaymae Iken (UDC, Spain), ABDELJALIL Bouzouggar (INSAP, Morocco), AURORA MARIA Grandal-d'Anglade (UDC, Morocco)

Shaymae_ik@hotmail.com

The North African brown bear, also called the Atlas brown bear, is a species now extirpated in Africa but which lived until the 19th century at least in northern Morocco, as reported by some historical sources. The classic description presents it as a bear of small size and a diet based on fruits and roots. The historical

citations may be doubtful, but its presence in sites is confirmed. Its skeletal remains, although scarce, are preserved in some cave sites along with a variety of mammalian fauna of Holocene age. In this work we have applied isotopic analysis of the skeletal remains of Atlas bears and other species in order to characterize their diet. The analyzed skeletal remains are from the cave sites of el Hammar and Hattab II, located in northern Morocco. In both sites, the bone remains are usually fragmented and therefore taxonomic identification based in morphology was only possible in a low percentage. However, the application of peptide fingerprint analysis of bone collagen known as ZooMS (Zooarchaeology by Mass Spectrometry) allowed us to broaden the faunal spectrum and the number of remains identified, including bears, mustelids, felines and several ungulates. The result of the isotopic analysis of the Atlas bear compared to contemporary carnivores and ungulates shows that the historical sources were correct, and that the diet of the African brown bear was mainly herbivorous.

A2.21 BITING THROUGH TIME: THE EVOLUTION OF CARNASSIAL FUNCTION IN CARNIVOROUS MAMMALS

Friday 11th July 2025 10:45

Narimane Chatar (University of California Berkeley, United States), Melvin Vankeslt (Université de Liège, Belgium), Alejandro Pérez Ramos (Universidad de Málaga, Spain), Tahlia I. Pollock (University of Bristol, United Kingdom), Davide Tamagnini (Sapienza Università di Roma, Italy), Margot Michaud (Institut Polytechnique UniLaSalle, France), Z. Jack Tseng (University of California Berkeley, United States)

Narimane.chatar@berkeley.edu

Multiple lineages of carnivorous mammals convergently evolved bladelike (carnassial) teeth, specialised for maximising nutrient extraction from prey, primarily through slicing flesh and tendon, but in some cases, also facilitating bone crushing. As the only living mammals with carnassial teeth, carnivorans persist as one of the most diverse mammalian orders in both body size and ecological adaptations. A key factor in their success may be the versatility of the lower carnassial, which balances slicing and crushing functions. We test this evolutionary innovation hypothesis using high-density 3D geometric morphometrics to quantify shape in the lower carnassial of 250 species (both extant and extinct) and 288 physical performance tests on a subset of teeth to measure slicing and crushing efficiency and their trade-offs, then interpolate form-function relationships across performance landscapes. Our results reveal that specialized bicuspid taxa excel in slicing, and while some teeth maximize the slicing performances at the expense of the crushing performances, some hypercarnivorous taxa with bicuspid lower carnassial still exhibit decent crushing abilities. Although most taxa occupy a functional compromise zone, a few appear optimized for both functions. By integrating shape and mechanical performance, we uncover evolutionary trade-offs and pathways shaping carnivoran dentition. Our findings highlight that true optimization of both slicing and crushing is rare, suggesting strong functional constraints in carnassial evolution. This work refines our understanding of carnivoran dental evolution and reveals the selective pressures that shaped their extraordinary dietary diversity.

A2.22

SELECTION

BY DROUGHT IN THE EARLY EVOLUTION OF PLANT VASCULAR NETWORKS

Friday 11th July 2025 11:30

Martin Bouda

(University of Hohenheim, Germany)

?

Plant hydraulics is a growing field that investigates links between the structure and the hydrodynamic function of plants, from cellular to ecosystem scales. Recently, a collaboration of plant hydraulic physiologists and palaeobotanists began re-examining the fossil record to identify the function of key elements of plant vascular structure at the time of their origin.Xylem conduits, which mediate water transport in vascular plants, are subject to blockage by vapour-phase embolism. Under drought, the uncontrolled spread of embolism through the xylem results in mortality through hydraulic failure. Vascular anatomy and morphology can facilitate or constrain embolism spread by affecting the connectivity of the xylem conduit network. Insofar as vascular structure affects the risk of hydraulic failure, it must be subject to selection by drought.Network analysis suggests that drought selection shaped the well-known trend of increasing vascular complexity with plant or organ size. Selection by hydraulic failure would thus have promoted the early diversification of primary vascular forms during the Silurian-Devonian Radiation of plant life onto land. The early Devonian emergence of secondary xylem (wood) conferred resistance to hydraulic failure on par with increasingly complex contemporaneous primary vascular anatomies. Woody growth was particularly effective at maintaining embolism resistance with increasing plant size, although the earliest known woods could not support hydraulically safe arborescent habit without further anatomical innovations. The ongoing reanalysis of the fossil record aims to reinterpret the function of emerging vascular structures with respect to hydraulic safety, ultimately setting the hydraulics of extant plants in a revised evolutionary perspective.

A2.23 THE RECONSTRUCTION OF AN EXTINCT JURASSIC SOUNDSCAPE

Friday 11th July 2025 12:00

Fernando Montealegre-Z (University of Lincoln, United Kingdom), Jun Jie Gu (College of Agronomy Sichuan Agricultural University, China), Thorin B. Jonsson (Institute of Biology Universitätsplatz 2 Karl-Franzens-University Graz, Austria), Charlie Woodrow (Department of Ecology and Genetics Uppsala University, Sweden), Emine Celiker (School of Engineering University of Leicester, United Kingdom), Daniel Robert (School of Biological Sciences University of Bristol, United Kingdom), Fuming Fuming Shi (College of Life Sciences Hebei University, China), Dong Ren (College of Life Sciences Capital Normal University, China)

fmontealegrez@lincoln.ac.uk

A prominent feature of biodiverse habitats is the acoustic landscape. Yet very little is known about the acoustic landscapes of extinct environments, for example of a Jurassic Forest. One problem is that recovering the real acoustic features of extinct tetrapods is challenging, as their vocal organs do not readily fossilize. Conversely, the stridulating organs present in the sclerotised cuticle of some arthropods do fossilise

well. For example, the stridulatory structures (a file, plectrum, and sound radiating membranes) in the forewings of male crickets and katydids are preserved in fossils, offering a unique opportunity to investigate species diversification and the acoustic landscapes of the past. Integrating experimental and numerical procedures, several katydid fossils (of nine species) were studied to recreate the acoustic landscape of the mid Jurassic (Inner Mongolia, China). Wing vibration and calling songs of these fossils were recovered and validated. Jurassic katydids used sharp pure-tones (musical) calls, which made localization by eavesdropping predators difficult. While 60% of these species communicate in the low audio range 5-7 kHz, one species exploited ultrasounds (>20kHz). Results imply that ultrasonic communication in insects was established long before the emergence of bats. The results extend current understanding of the Jurassic soundscape, revealing insect song and hearing diversity, but also highlighting the co-evolutionary pressures and constraints exerted by ultrasound sensitive eavesdropping insectivorous predators other than bats. Such arm race is proposed as one of the main pressures that boosted the evolution of the mammalian cochlea and the sophisticated ‘insect cochlea’ shown by living katydids.

A2.24

USING TAIL BIOMECHANICS TO INFORM THE EVOLUTION OF SLOW GAITS IN GIANT EXTINCT KANGAROOS

Friday 11th July 2025 12:15

Megan E Jones (University of Manchester, United Kingdom), Andrew Pask (University of Melbourne, Australia), David Potter (University of Melbourne, Australia), Katrina E Jones (University of Manchester, United Kingdom) megan.jones-15@postgrad.manchester.ac.uk

Pleistocene kangaroos reached much greater sizes than any living species (up to 250kg), raising questions about their locomotor abilities. Among living kangaroos, the larger species tend to adopt a pentapedal slow gait, using their tails as a fifth limb to support their bodies. However, the sthenurines (short-faced giant extinct kangaroos) are thought to have walked bipedally without using their tail. We examined the functional adaptations of kangaroo tails by comparing joint range of motion (ROM) and stiffness of pentapedal kangaroos (ROM n=7, stiffness n=5) with generalist hoppers (ROM n=3, Stiffness n=2) using mechanical testing of cadaveric specimens in an instron machine. In the proximal region of the tail, pentapedal species display both greater range of motion and greater stiffness in ventroflexion than non-pentapedal species, suggesting large but controlled movements during tail touch down. This experimental data was used to validate digital osteological range of motion (oROM) modelling in AutoBend, which was then applied to a variety of extant species, as well as giant extinct kangaroos. Estimates of oROM from AutoBend generally matched experimental data in terms of magnitude and overall patterns, however, we found that different modelling parameters were optimal for different vertebral joints. Preliminary modelling of extinct species suggests that sthenurines had a lower range of motion in ventroflexion than extant pentapeds, particularly in the sacrocaudal joint, supporting the idea that they may have adopted bipedal striding during slow gaits.

A2.25 TRACK MORPHOLOGY AND SEDIMENT PARAMETERS: MOTION RECOVERED FROM SUBSURFACE LAYERS ARE ROBUST TO CHANGES IN SUBSTRATE PROPERTIES

Friday 11th July 2025 12:30

Benjamin W Griffin (Liverpool John Moores University, United Kingdom), Tash L Prescott (Liverpool John Moores University, United Kingdom), Peter L Falkingham (Liverpool John Moores University, United Kingdom)

b.w.griffin@ljmu.ac.uk

Penetrative tracks preserve significant information regarding foot motion due to the increased interaction between the foot and the sediment. Using surface and subsurface track morphology of a fossil track, the motion used by extinct animals can be experimentally replicated via testable hypotheses of motion. However, track morphology varies with sediment consistency, potentially affecting the reliability of these reconstructed motions. While track morphology at the surface is well known to vary with substrate consistency, the effect on the more constrained subsurface morphology is poorly understood. Using Discrete Element Method simulations, we examined the variability of subsurface track morphology with changes to sediment consistency. Two model systems were utilized; a simple cylinder vertically indenting, and a dynamic, simplified foot for which motions were reconstructed using an early Jurassic penetrative dinosaur track. Increasing sediment friction (reducing ‘flowability’) resulted in higher and more extensive displacement rims throughout the track volume. Increased cohesion led to tracks remaining open at and below the original surface, rather than subsurface tracks infilling with sediment from above as was seen in lower cohesion traces. However, tracks exposed along subsurface layers had morphologies which were considerably more robust to changes in sediment properties than the true surface tracks. This provides confidence that foot motions recovered from penetrative tracks can be accurate regardless of sediment consistency at the time of track formation and may therefore offer more reliable information about foot motion than surface tracks.

A2.7 SHARP INSIGHTS: EXPLORING CONSTRAINTS ON POINTED TOOTH F ORM IN TETRAPODS

Friday 11th July 2025 12:45

Tahlia I Pollock (The University of Bristol, United Kingdom), Pablo S Milla Carmona (The University of Bristol, United Kingdom), Charlie Caldicott (The University of Bristol, United Kingdom), Philip C. J Donoghue (The University of Bristol, United Kingdom), Emily J Rayfield (The University of Bristol, United Kingdom), Alistair R Evans (The University of Bristol, Australia)

tahliaipollock@gmail.com

Conical teeth are near ubiquitous among tooth-bearing tetrapods and serve primarily as tools for puncturing food. Despite their simple shape, this tooth form exhibits a high degree of morphological variation, from stout human canines to needle-like snake fangs and the sharp bladed teeth of vampire bats. What generates and constrains this diversity?

The Power Cascade developmental model offers insights into growth and form in pointed teeth, while functional studies suggest that their morphology is closely tied to performance—balancing puncture ability and breakage resistance. Here, we combine this generative model with an optimality pipeline to reveal the limits on pointed tooth evolution. Using the Power Cascade model, we generated theoretical teeth that span the variation observed in tetrapods (slenderness, lateral compression, and curvature). Then via 3D geometric morphometrics, we integrated theoretical and empirical morphologies from 200+ tetrapod species into a combined morphospace. The Power Cascade model effectively captures empirical variation, with almost all empirical forms falling within the area of morphospace defined by the model. However, certain forms, such as robust, highly compressed teeth, are not explored empirically. Next, we quantified puncture performance and breakage resistance across a subset of the combined morphospace, using a Pareto algorithm to identify optimal forms. Preliminary results show that the most densely occupied regions—middling degrees of slenderness and curvature, and slight lateral compression—are optimal, reinforcing the idea that pointed tooth shape is functionally constrained. This combined theoreticalexperimental approach is a powerful framework for understanding how developmental and functional factors shape morphological diversity.

POSTER SESSIONS

Friday

A2.1 MORPHOLOGICAL CONVERGENCE AND DIVERGENCE IN LONG BONES OF CARNIVORAMORPHA (MAMMALIA) WITH A REASSESSMENT OF LOCOMOTOR HABITS OF

FOSSIL TAXA

Antonia R. M. Kaffler (Museum für Naturkunde Berlin, Germany), Apolline Alfsen (Museum für Naturkunde Berlin, Germany), John J. Flynn (American Museum of Natural History, United States), John A. Nyakatura (HumboldtUniversität zu Berlin, Germany), Brandon M. Kilbourne (Museum für Naturkunde Berlin, Germany)

kafflera@hu-berlin.de

Carnivoramorpha is a >60 Ma-old mammal group displaying a remarkable diversity in phenotypes, body sizes, and habitats, exhibiting diverse types of locomotion, which also evolved independently in several carnivoran lineages. However, the drivers of this diversification and the role of convergence in locomotor evolution remain unclear. In this study, we tested for morphological convergence in external traits of the humerus and femur of 105 fossil and extant species, including both stem Carnivoramorpha and crown Carnivora, to better understand what drove the exceptional diversification of this clade. The locomotor habits of extinct taxa were reassessed by comparing the morphologies of fossil and extant species in light of locomotor specialisations identified in extant taxa. Our findings reveal that morphological variation is more substantial in the femur than in the humerus, with the most pronounced distinction being between aquatic and non-aquatic species. Swimming-adapted taxa possess shorter humeri and femora with increased medial-

lateral mid-shaft diameters, while arboreal and scansorial species exhibit elongated bones with round mid-shafts. Semi-aquatic and semi-fossorial species occupy intermediate positions in morpho space. Among fully aquatic taxa, humeral and femoral morphology distinctly separates species employing different swimming modes, including wing-like forelimb propulsion, hindlimb propulsion, and a combination of both. Unexpectedly, stem carnivoramorphans share more morphological traits with extant species than with more closely related fossil crown taxa. These findings demonstrate that functional constraints and ecological pressures have shaped long bone morphology in a complex manner, influencing both lineage-specific and across-clade convergent adaptations.

A2.2 PRELIMINARY CONSTRUCTION OF A 3D DATASET OF FOSSILS OF TEMNOSPONDYLS

Andrea Prino (Comparative Zoology Institute of Biology Humboldt Universität zu Berlin, Germany), John A. Nyakatura (Comparative Zoology Institute of Biology Humboldt Universität zu Berlin, Germany), Florian Witzmann (Museum für Naturkunde Leibniz-Institut für Evolutions- und Biodiversitätsforschung Berlin, Germany), Lucrezia Ferrari (Staatliches Museum für Naturkunde Stuttgart, Germany)

andrea.prino@hu-berlin.de

Virtual 3D models of fossils are recognised to be of increasing importance in the study of biomechanics and functional morphology of extinct animals due to the growing number of available computational modelling approaches, potentially deep insights into musculoskeletal function, and implications for palaeobiological inferences. This is especially true when there is no satisfying extant analogue to the skeletal structure that is being digitised. Here we illustrate the 3D models of the pectoral girdle elements of four species of Temnospondyli (Gerrothorax pulcherrimus, Metoposaurus krasiejowensis, Lydekkerina huxleyi, and Mastodonsaurus giganteus), a group of fossil amphibians that lived from the Early Carboniferous to the Early Cretaceous, inhabiting different environments and ecological niches. The fossils of G. pulcherrimus and M. giganteus were digitised with a structured light scanner and photogrammetry, while a handheld surface scanner was used for M. krasiejowensis. L. huxleyi was scanned with microCT because of the sedimentary matrix surrounding the bones. These surface models are only the first ones of a 3D dataset that will comprise other Temnospondyli specimens, with the intention to cover most of their ecomorphological diversity. The dataset will be the basis for a 3D geometric morphometric analysis in order to build a 3D phylomorphospace. We aim to quantify the shape diversity between the pectoral girdle elements of Temnospondyli and investigate the correlation between morphology and ecological adaptation. Subsequently, this dataset will be leveraged in computational modelling approaches to further explore the form-function relationship of the pectoral region of Temnospondyli to gain insight into their locomotor mechanics.

A2.3 STILL USING MODERN UNGULATE ANALOGUES TO EXPLORE EQUID SIDETOE FUNCTION THROUGH AN ICONIC EVOLUTIONARY TRANSITION...

Jamie A MacLaren (University of Antwerp, Belgium), Anastasia Selini (University of Antwerp, Belgium), Joris Nouwen (Vrije Universiteit Brussel, Belgium), Leo R Cools (University of Antwerp, Belgium), Peter Aerts (University of Antwerp, Belgium)

jamie.maclaren@uantwerpen.be

The equid locomotor transition is one of the most iconic morphofunctional shifts in terrestrial mammals. Throughout their evolution, equids reduced their side-digits, with different phylogenetic clades exhibiting greater or lesser degrees of digit reduction. Over 80% of equid genera retained side-digits, despite many species coexisting with monodactyl equids for over 7 Ma. In this continuing study, we shed light on the functionality of the side-digits of extinct equids using an extant morphological bracket, comparing toe-ground interception across ecologically diverse ungulates with side-digits. Using high-resolution 3D surface scans, joint range-of-motion was estimated from osteological material of modern and extinct ungulate forelimbs. Distal limb rigs were built and analysed, rotating the third proximal phalange parasagittally at biologically realistic, regularly spaced intervals. Toe-to-ground interception for the side-digits was scored for the varying degrees of central digit extension (simulating high-performance actions), and under increasingly compliant substrates (mimicking different underfoot conditions). Our results demonstrate widespread functionality in the side digits of tridactyl equids, with significant differences found between earlier browsing forms (e.g. Anchitherium) and later grazing forms (e.g. Hipparion). High-performance actions, such as galloping or jumping/landing would have caused the side digits of almost all tridactyl equids to impact the substrate. Our work confidently refutes the notion of functional redundancy in equid side-digits. The extant morphological framework within which this study was conducted also provides a suite of potential extant analogues for verifying simulations of extinct equid locomotion, and thus paves the way for more integrative investigations involving in-vivo and in-silico locomotor kinematics.

A2.4 INVESTIGATING THE BIOMECHANICAL EFFICIENCY OF HORSE LIMBS THROUGH THEIR ICONIC DISTAL LIMB EVOLUTION.

Anastasia Selini (University of Antwerp, Belgium), Tim De Ridder (University of Antwerp, Belgium), Peter Aerts (University of Antwerp, Belgium), Jamie A. MacLaren (University of Antwerp, Belgium)

anastasia.selini@uantwerpen.be

Single-toed (monodactyl) equids (horses, zebras, asses) are the only surviving members of the family Equidae, despite living contemporaneously with three-toed (tridactyl) forms for c.15 Ma. Among the tridactyl forms, a trend of side-digit reduction is observed, raising the question about the energetic advantage of digit loss. The inertial load hypothesis describes the reduction (and eventual loss) of side-digits in equids as a means to minimize energetic cost during locomotion, linked to reducing inertial load (or moment of inertia,

MOI) of the limbs by minimizing their distal mass. In this study, we tested this hypothesis by estimating and comparing inertial loads of tridactyl equid limbs, both with and without side-digits. Additionally, we compared the results of the tridactyl and monodactyl equids, while accounting for differences in limb size, to investigate the effect of side-digit loss across equid evolution. MOI was calculated on soft tissue limb reconstructions created using 3D models of (fossil) bones. A validation analysis using 3D renders of cadaver specimens verified the predictability of these reconstructions. We demonstrate that the entire limb MOI with regard to the scapular rotation centre is significantly smaller without side-digits. However, the difference is very small, and its functional significance can be questioned. Sizecorrected MOI between monodactyl and tridactyl taxa suggest overall significant differences (monodactyl equids with lower MOI); however, distal limb mass comparisons (e.g. pastern segments) showed no signs of the effect of side-digits. Our results hint at limb segment allometry as a more notable influence on MOI reduction during horse evolution.

A2.5 WIDE IS THE GAPE THAT FEEDS – EXAMINING THE PHYSICAL CONSTRAINTS OF BITING IN CONICAL AND SABRE-TOOTHED FELIDS

Ilke Boutsen (University of Antwerp, Belgium), Eleesha Annear (University of Antwerp, Belgium), Tim De Ridder (University of Antwerp, Belgium), Jan Scholliers (University of Antwerp, Belgium), Jamie A. MacLaren (University of Antwerp, Belgium) ilke.boutsen@student.uantwerpen.be

Sabre-toothed cats (Felidae: Machairodontinae†) are considered to have wide gape angles compared to conical toothed cats (e.g. lions, leopards, etc.). Intuitively, a wider gape may have allowed for larger prey to be dispatched with a neck bite. In this study, we took an experimental approach using 3D-printed skulls to investigate maximum gape angles in African cats from the Pliocene-to-Holocene (including conical and sabre-tooth cats). We tested whether representative skulls could physically fit around the neck, upper throat, and muzzle of high-quality taxidermed models of potential prey items (including suids, gazelle, antelope and bovids, rhinocerotids, and proboscideans). To account for soft tissue restrictions on maximum gape, we conducted a comparative study on fully-fleshed and de-fleshed heads of house cats (Felis catus), leopard (Panthera pardus), and lion (P. leo), examining both maximum myological (fully fleshed) and osteological gape angles. Osteological gape angles were larger across the specimens; we therefore used the highest, lowest, and mean differences in angles between osteological and myological gape angles as a range of conservative correctionfactors for the gape angles of the 3D-printed skulls. Current results indicate comparable killing potential between medium-sized sabretooth cats (Dinofelis, Megantereon, Lokotunjailurus) and modern leopards and cheetahs. The extremely long sabres of Megantereon prevented the initiation of a killing bite on many medium and large ungulates, including adult alcelaphine, tragelaphine, and reduncine bovids (e.g. Kobus ellipsiprymnus). Finalising experimental results and applying prey-preference analyses will provide a more tangible range of prey which African sabre-tooths could have physically killed.

A2.6 PALEONEUROLOGICAL INVESTIGATIONS OF THE MIOCENE DUGONGS (MAMMALIA, SIRENIA) FROM KUTCH, WESTERN INDIA

Aatreyee Saha (Indian Institute of Technology Roorkee, India), Sunil Bajpai (Indian Institute of Technology Roorkee, India), Debarati Mukherjee (Indian Statistical Institute Kolkata, India)

aatreyee_s@es.iitr.ac.in

The sirenian fossil record extends over the past 50 million years beginning in the Eocene, and is well documented in the tropical and subtropical areas of the world, with a remarkable diversity in the Miocene. The simple brain morphology of sirenians have posed interesting questions in our understanding of their brain evolution, in contrast to the complex nervous systems of other marine mammals such as cetaceans which evolved and diversified in the same time interval. Studies on sirenian paleoneurology have been scant and suggest that their endocasts possess poorly developed gyrification, with small olfactory bulbs, long optic nerve stumps, broad trigeminal nerve stumps, ossified tentorium, bony falx cerebri and low encephalisation quotient. Here we describe two virtual endocasts of a Miocene dugongine from Kutch, western India: Bharatisiren indica. Based on micro CT scanning, we performed a study of the anatomical and aspects of these endocasts. Our data provide new insights into brain development of Miocene dugongs in the context of physiological changes and lissencephaly. Our study also examines the perioral vibrissae and small olfactory bulbs in dugongs, shedding light on changes in their foraging habits and the somatic sensory system.

A2.8 USING

THE ALLOSAURUS

JIMMADSENI SKULL STRUCTURE AS A PUZZLE PIECE TO FEEDING FUNCTION

Luisa Semerakova (University of Lincoln, United Kingdom), Gregory Sutton (University of Lincoln, United Kingdom), Iain Stott (University of Lincoln, United Kingdom), Manabu Sakamoto (University of Reading, United Kingdom), Jordi Marcé-Nogué (University of Rovira i Virgili, Spain), Stephan Lautenschlager (University of Birmingham, United Kingdom)

lsemerakova@lincoln.ac.uk

Cranial shape in extinct fossilised species provides a vital puzzle piece to our understanding of their feeding behaviour which cannot be observed in real time. The carnivorous theropod MOR693 Allosaurus jimmadseni fossil offers insight into its feeding function and the palaeo-ecology of the Late Jurassic geological period. A. jimmadseni possesses a distinctive cranial anatomy, displaying large fenestrae and a thin cranio-caudally elongated skull. The skull’s lightweight anatomy has led researchers to hypothesise a “puncture and pull” feeding behaviour, in which an animal captures prey with a puncture bite, and proceeds to tear with a pulling motion. Using 3D scans of the MOR693 skull and applying a finite element analysis, I obtained the maximum, average, and minimum total von Mises stress in the skull during different biting angles. My results report that the 0-30° bites (puncture) exhibited the highest stress values, while the 90° bite (pull) showed the lowest. A consistent decrease from a 0° to a 90° bite in the maximum, average, and minimum stress indicates that the skull experienced the least amount of stress during the pulling aspect of

feeding. Low-stress values suggest an evolutionarily advantageous feeding motion in this dinosaur, therefore it is reasonable to conclude that the A. jimmadseni utilised this feeding strategy. The results of this research present that the skull was likely adapted for a pulling dominant feeding behaviour rather than a puncture, further supporting the puncture and pull feeding hypothesis in the A. jimmadseni.

A2.9 FROM FUNCTION TO FORM : COMPUTING COLLATERAL LIGAMENT ATTACHMENTS

Mythili Damal Kandadai (Ghent University, Belgium), Ajay Seth (Delft University of Technology, Netherlands), Gerwin Smit (Delft University of Technology, Netherlands)

mythili.damalkandadai@ugent.be

In extinct and extant species, some insights on joint function can be gained using bone morphology. Models of joints tend to use tendons to control joint function, often giving little or no insight on the role of ligaments in controlling the range of motion of a joint. This study presents an algorithm to automatically compute ligament attachment sites for a flexion-extension joint using optimisation, given bone morphology and required range of motion. To start with, the focus is on the collateral ligaments of the human finger Distal Inter-Phalangeal (DIP) joint. The algorithm takes bone profiles and the required maximum flexion and extension angles as inputs. First, a grid of possible attachment sites is generated from the bone profiles. Using this grid, a discrete stage determines the best combination of attachment sites by minimising an objective function subject to a set of geometric constraints. This seeds the second stage– a continuous domain local optimisation which refines the attachment coordinates by minimising the error between required and computed range of motion. The algorithm’s outputs are attachment site coordinates of the two edges of a band of collateral ligaments capable of achieving the required range of motion. The outputs were verified by adding ligaments computed by the algorithm to an OpenSim simulation model and confirming that the required range of motion was achieved. In contrast to other published research, the algorithm presented here computes ligament attachment sites based on range of motion - deriving form from function rather than relating form to function.

A2.10

VISUALISING FOOT-SUBSTRATE INTERACTIONS

BENEATH THE SEDIMENT SURFACE USING μCT SCANNING.

Tash L Prescott (Liverpool John Moores University, United Kingdom), Benjamin W Griffin (Liverpool John Moores University, United Kingdom), Peter L Falkingham (Liverpool John Moores University, United Kingdom)

n.l.prescott@ljmu.ac.uk

In nature, animals commonly traverse across compliant, plastically deformable substrates, leaving tracks. Understanding the foot-substrate interaction can provide valuable insights into trackmaker anatomy, biology and behaviour, particularly for extinct animals where these are not directly observable. However, interpreting these interactions can be difficult, requiring the visualisation of both foot and internal substrate morphology, below the exposed surface. Previous work used X-rays to observe foot motions beneath the sediment surface, but sub-surface

sediment movement has remained challenging to observe. We used μCT to visualise sub-surface sediment structures, comprised of layered wet sand and clay particles, before and after indentation by a foot. There were challenges both in setting up the sediment (maintaining thin layers of fluid substrate in a confined area) and in visualisation (penetrating the wet sediment with X-ray and distinguishing between sediment layers with similar contrast). To address the visualisation issues, we explored various segmentation methods including machine learning and semi-automated (watershed transform) techniques. The machine learning algorithms required so much training as to be substantially slower than manual segmentation. However, the use of the watershed transform combined with manual painting, allowed discrimination of the layers, despite complications where the foot had penetrated and blended layers together. Nevertheless, the method promises to provide useful mechanistic information about the foot-sediment interaction and may prove particularly fruitful if expanded into 4D time-series scans.

A2.11 TESTING FUNCTIONAL DIFFERENCES IN PROBOSCIDEAN LIMB MORPHOTYPES UNDER COMPRESSION USING FINITE ELEMENT ANALYSIS

Nicolas Wagner (State Museum of Natural History Stuttgart, Germany), Narimane Chatar (University of California Berkeley, United States), Jesse Hennekam (Maastricht Science Programme, Netherlands)

nicolaswagner.university@gmail.com

Proboscideans (e.g. elephants, mammoths, and mastodons) include some of the largest known land mammals. Their limbs evolved a columnar structure and unique reorientation to withstand extreme vertical compression. Recent studies identified two distinct limb morphotypes—robust and gracile—independent of body mass, raising questions about their functional differences under compressive loads. To explore the functional implications of these morphotypes, we used finite element analysis (FEA) to simulate compressive forces on proboscidean humeri. Our results show that the broader, more robust morphotype resists compressive stress more effectively than the slimmer morphotype, suggesting functional specialisations in load-bearing strategies. While FEA is rarely applied to bone compression tests, our findings highlight its potential for investigating biomechanical adaptations in graviportal species. This study enhances our understanding of proboscidean limb evolution and establishes a methodological framework applicable to other large-bodied taxa, such as sauropod dinosaurs.

A2.12 CRANIAL LACERTID BIOMECHANICS THROUGH THE APPLICATION OF NANOINDENTATION

Laia Garcia-Escolà (Institut Català de Paleontologia Miquel Crusafont, Spain), Josep Fortuny (Institut Català de Paleontologia Miquel Crusafont, Spain), Jordi Marcé-Nogué (Universitat Rovira i Virgili, Spain)

laia.garcia@icp.cat

The genus Gallotia consists of lizards that are endemic to the Canary Islands, with both extant and extinct species with important size variability among the different species. We used nanoindentation to evaluate Young’s Modulus (E) across different cranial bones in G. stehlini, G. galloti, and G. atlantica. Results showed a relatively homogeneous distribution of mechanical properties throughout the skull and mandible. It also reveals that Young’s Modulus is influenced by size, with larger specimens exhibiting lower bone stiffness (higher E values). In consequence, it is feasible to estimate Young’s Modulus for extinct giant species (G. goliath and G. auaritae), enabling future studies on their cranial mechanics. To assess the consistency of E values, we integrated them into Finite Element Analysis (FEA) models of cranial loading during biting. The results indicated that localized variations in bone stiffness had minimal impact on overall biomechanical performance, supporting the assumption that E can be treated as homogeneous in FEA. This study enhances our understanding of skull material properties and ecological adaptations. It also provides a framework for inferring biomechanical traits in fossil taxa, revealing a correlation between skull elasticity and body size. Smaller species, such as G. atlantica, had more rigid skulls, whereas larger species, including G. goliath, exhibited greater elasticity, supporting a predominantly herbivorous diet and reduced predation pressure.

A2.13 FROM TAIL SWINGING TO WALKING: RECONSTRUCTING THE PREFERRED WALKING SPEED OF THE SAUROPOD DINOSAUR GIRAFFATITAN BRANCAI

Max Herde (Museum für Naturkunde, Germany), John A. Nyakatura (Humboldt-Universität zu Berlin, Germany), Pasha A. Van Bijlert (Utrecht University, Netherlands), Verónica Díez Díaz (Museum für Naturkunde, Germany)

john.nyakatura@hu-berlin.de

Sauropod dinosaurs were the largest terrestrial vertebrates that ever lived. Understanding their locomotor capabilities offers insight into how they moved and navigated their environment. However, the exact parameters of their gait kinematics, such as their preferred step frequency and walking speed, are largely undetermined. Animals past and present select gait kinematics close to the natural frequencies of relevant body parts, enabling resonance-based energy savings. Conversely, modelling the natural frequencies of relevant body parts may thus yield information about the optimal gait kinematics of extinct animals. Non-avian dinosaurs possessed massive tails, which contributed both actively and passively to their locomotor behaviour. Their tails were passively suspended by ligaments, forming a massspring system where the tail oscillated with each step as they walked. The natural frequency of the tail has previously been used as a proxy for their step frequency (Natural Frequency Method). Here, we will apply the Natural Frequency Method to estimate the energetically optimal step frequency and walking speed of the Late Jurassic sauropodGiraffatitan brancai. We have built a three-dimensional biomechanical model of the tail, where all vertebrae are connected by hinge joints and suspended by interspinous ligaments, using MuSkeMo within Blender. We introduce a new protocol where the natural frequency of tails can be analysed using the musculoskeletal simulation software OpenSim, allowing for drop-in replacement with other biomechanical tail models. If successful, the methodology can be expanded to other sauropods to explore how different tail morphologies affect sauropod gait kinematics.

A2.14 EXPLORING THE FUNCTIONAL MORPHOLOGY OF SAND DOLLARS THROUGH DEEP TIME TO THE PRESENTDAY USING 3D MODELLING AND COMPUTATIONAL FLUID DYNAMICS

Eleanor Wilson (University of Southampton, United Kingdom), Jeffrey Thompson (University of Southampton, United Kingdom), Imran Rahman (Natural History Museum, United Kingdom), Jorn Cheney (University of Southampton, United Kingdom), Neil Gostling (University of Southampton, United Kingdom)

e.wilson@soton.ac.uk

Sand dollars (Scutelloida) are a group of irregular echinoids characterised by highly derived morphologies adapted for burrowing and sediment feeding. They have a flattened body, short spines, and, in some species, lunules—perforations in the test unique to this group. Different hypotheses have been proposed to explain the function of lunules, including facilitating feeding, enhancing stability, aiding burrowing, or providing structural reinforcement. However, their impact on hydrodynamic performance remains largely understudied. An improved understanding of the function of the lunules in particular and sand dollar morphologies more generally is essential for reconstructing the environmental and evolutionary pressures shaping their form through time. This study will explore the relationship between sand dollar form and function by integrating geometric morphometrics with computational fluid dynamics (CFD). Using laser scanning and micro-CT imaging, 3D models have been constructed of 37 taxa ranging from the early Cenozoic to the present. These digital reconstructions are being used as the basis for a quantitative analysis of morphological variation and its impact on hydrodynamic performance. Morphometric analyses are being undertaken to characterise shape differences across the clade. In addition, CFD simulations will assess how these differences effect hydrodynamic performance in various environments. By quantifying the link between form and function, this research seeks to provide new insights into the biomechanical adaptations of sand dollars and their evolutionary responses to shifting ecological pressures. Moreover, these findings will contribute to a broader understanding of the importance of hydrodynamics in shaping the functional morphology and evolution of benthic marine invertebrates.

A2.15 THE FEEDING DEAD: SIMULATING EARLY TETRAPOD FEEDING

Daniel Schwarz (Stuttgart State Museum of Natural History, Germany), Rainer Schoch (University of Hohenheim, Germany) daniel.schwarz@smns-bw.de

Understanding the feeding behaviour and diet of early tetrapods, such as temnospondyl amphibians,is essential to understand their ecological roles, particularly during their transition from aquatic toterrestrial environments. A DFG-funded project, as part of a research unit focused on the life historystrategies of early tetrapods, aims to illuminate temnospondyl feeding strategies and dietary habitsby integrating ontogenetic, phylogenetic, and functional analyses. The research is organised into fivecomprehensive work packages. Firstly, the ontogenetic differences in various temnospondyl feedingapparatuses are examined using advanced µCT scanning, digital dissection,

retrodeformation, anddigital repairs to reconstruct key structures crucial for understanding their feeding mechanics.Secondly, distinct morphotypes reflecting the evolutionary and developmental biology oftemnospondyl feeding are identified using data compiled from the first work package. Thirdly, byapplying digital modelling techniques, we reconstruct probable aquatic feeding strategies associatedwith the identified morphotypes, providing insights into how these organisms might have fed in theiraquatic habitats. In the fourth work package, terrestrial feeding strategies are delineated bycorrelating morphotype data with contemporary studies on vertebrate feeding patterns, enablinghypotheses about their terrestrial adaptations. Finally, we synthesise fossil evidence with ourmorphotype analyses to reconstruct dietary specialisations, enhancing our understanding of thepaleoecology of temnospondyls. This multidisciplinary approach allows for a comprehensiveunderstanding of how temnospondyls adapted their feeding mechanisms across environments andontogeny, offering new perspectives on their life histories during pivotal evolutionary transitions.

A2.16 NICHE PARTITIONING AND FEEDING PERFORMANCE IN LATE CRETACEOUS MARINE REPTILES FROM THE WESTERN INTERIOR SEAWAY

Francesco Della Giustina (Evolution Diversity Dynamics lab UR Geology Université de Liège, Belgium), Valentin F Gaudichon (Institut des Sciences de l’Evolution de Montpellier Université de Poitiers-Montpellier, France), Romain Boman (Department of Aerospace and Mechanical Engineering Université de Liège, Belgium), Narimane Chatar (Department of Integrative Biology University of California, United States), Jamie A MacLaren (Functional Morphology Lab Department of Biology Universiteit Antwerpen, Belgium), Valentin Fischer (Evolution Diversity Dynamics lab UR Geology Université de Liège, Belgium)

fdgiustina@uliege.be

The coexistence of numerous sympatric predatory marine reptiles in the Western Interior Seaway (WIS), a vast inland sea that stretched across North America during the Late Cretaceous, suggests ecological partitioning within higher trophic niches. Many studies have focused on dental morphology as a proxy to infer feeding habits of aquatic tetrapods, but much more ecological insight may be gained through simulations of mechanical performances. Here, we conducted the first, large-scale, comparative study of WIS marine reptile jaw biomechanics, applying muscle-driven finite element analyses (FEA) on a dataset of high-resolution three-dimensional models of Santonian-Maastrichtian mosasaurids and polycotylid plesiosaurians. For comparative purposes, mosasaur jaws were modeled with a fused symphysis and immobile intramandibular joint, forming a single functional element. Muscle insertions were identified to reconstruct jaw adductor muscles and assess respective muscle and bite force. We used Metafor software to simulate realistic muscle traction dynamics during biting, including simulations at multiple opening angles and multiple biting locations. We recover clearly distinct biomechanical performances among the sample, notably between the slender-snouted mosasaurids (e.g., Clidastes) and polycotylids, and the robust-jawed mosasaurids (e.g., Prognathodon). By integrating jaw size, mechanical efficiency, and strain, we provide strong support for niche partitioning among these marine predators, as influenced by physical biting capabilities. Our results offer deeper insight into feeding ecologies in Late Cretaceous marine predators, and provide a unified protocol to assess niche partitioning in sympatric marine reptiles from well-sampled regions.

A3: FUNCTIONAL MORPHOLOGY OF LOCOMOTION AND FEEDING: A TRIBUTE TO PETER AERTS

ORGANISED BY: PAULINE PROVINI (MUSÉUM NATIONAL D'HISTOIRE NATURELLE), SAM VAN WASSENBERGH (UNIVERSITY OF ANTWERP)

A3.1 OVERCOMING CHALLENGES IN STUDYING FILTER-FEEDERS FOR BIO-INSPIRED FILTRATION

Wednesday 9th July 2025 09:00

Leandra Hamann (University of Bonn, Germany) lhamann@biob.uni-bonn.de

Suspension feeders, organisms that retain food particles from water, have recently become of interest to inspire engineered filtration systems aiming for higher efficiency, energy savings, and reduced clogging. Among the 35 known suspension feeding mechanisms, only a few have been explored in detail for a biomimetic transfer, and even fewer have progressed to successful prototypes, patents, and commercial products. Based on my research of invertebrate and vertebrate suspension feeders, I experienced several challenges during the identification, analysis and transfer of biological particle separation processes. For example, constraints such as availability, protection statuses, and size posed difficulties when examining organisms like flamingos, manta rays, and whale sharks. A significant challenge was encountered in analysing the role of mucus in particle adhesion and transport in ascidians. Flow tank experiments using artificial mucus demonstrated limited particle retention capabilities compared to natural mucus. Despite these obstacles, promising results were achieved with ram-feeding fish. By integrating morphological, behavioural, and fluid-dynamical analyses, a prototype filter was developed with a self-cleaning mechanism capable of retaining 97.5% of microplastic fibres in a controlled lab environment. These findings underscore the potential of the biomimetic approach not only to advance filtration technology but also to deepen our understanding of these organisms, thereby supporting their conservation

A3.2 HOW SPINAL CURVATURE AND MORPHOLOGY DRIVES HEAD MOTION

Wednesday 9th July 2025 09:00

ariel.camp@liverpool.ac.uk

The vertebral column of fish is a multi-function structure for feeding and swimming. Vertebral motion is hypothesized to vary with vertebral morphology across the spine, but these motions have been difficult to directly measure—particularly during feeding. How do different regions of the vertebral column contribute to head motion? We used X-ray reconstruction of moving morphology (XROMM) to measure vertebral motion in Commerson’s frogfish (Antennarius commerson): a fish with large craniovertebral motions and craniocaudal variation in vertebral shape. We examined vertebral bone and muscle anatomy with dissections, computed tomography, and magnetic resonance imaging. Vertebral motion was analysed using an existing XROMM dataset of craniovertebral motion in 17 strikes from 3 individuals. We fit Beziér curves to the approximate centre of mass of each vertebra (the centrum) to measure spinal curvature and calculated the distance between adjacent neural spines. The magnitude and direction of curvature varied across the vertebral column, as the neurocranium is elevated and translated rostrally. From head to tail, vertebrae 1-3 flex dorsally with the highest curvature, 5-8 extend ventrally, 9-15 flex dorsally, and 16-18 have small, variable motions. Neural spine translations show the distances between 1-5 reduce substantially, compared to the other vertebrae. Vertebra and axial muscle morphologies vary across the spine, sometimes corresponding to regions of higher curvature. Function, motion, and morphology vary across the frogfish spine: large, cranial rotations drive neurocranium elevation, while counter-rotations of more caudal regions translate the neurocranium. Thus, frogfish offer a useful system for understanding the functional morphology of craniovertebral motion.

A3.3 JIGGLING JAW JOINTS, TENDON SPRINGS OR STRINGS, AND FINNED FEEDING ON LAND: SCIENTIFIC INSPIRATION FROM THE BIOMECHANICS ADVENTURES OF PROF. PETER AERTS.

Wednesday 9th July 2025 09:30

Ariel L Camp (University of Liverpool, United Kingdom), Callum Vaudrey (University of Liverpool, United Kingdom), Tasha Prescott (Liverpool John Moores University, United Kingdom), Robert Rockenfeller (University of Koblenz, Germany)

Nicolai Konow (University of Massachusetts Lowell, United States)

Nicolai_konow@uml.edu

Professor Peter Aerts’ retirement will undoubtedly impact the insightful and prolific stream of biomechanical understanding our community has gleaned from his Antwerp laboratory. My contribution to Prof. Aert’s Festschrift highlights how his scholarly output formed both inspiration and key lessons for this upstart biomechanist. In his early work on jaw function in a small cichlid,Peter built a founding biomechanical understanding of the intramandibular joint. This shaped my PhD on the mechanics and ecosystem function of similar jaw joints in biting. Further research on how intramandibular joints shape jaw function, continued by others to this day, is starting to establish how biting shapes and rejuvenates some of the planet’s most important and imperiled ecosystems. In subsequent studies on gibbon locomotor biomechanics, Peter’s team carefully considered how tendon materials properties affect musculoskeletal function, in spring- or string-like ways. This work fueled my curiosity about how widespread elastic mechanisms might be in biomechanical systems. This thinking outside-the-box prompted paradigm-shifting discoveries of spring-driven motion in systems traditionally thought to lack them, including in small organisms, feeding systems, and systems for moving through fluid. In more evolution-focused studies, Peter’s team unraveled how aquatic vertebrates switch to terrestrial feeding. Their fish-focused findings continue to inspire my lab’s approaches to understand comparable transitions in salamanders.

A3.4 VERTICAL JUMPING PERFORMANCE IN HUMAN AND NON-HUMAN PRIMATES: AN EXAMPLE OF RELAXED SELECTION?

Wednesday 9th July 2025 09:45

François Druelle (ADES (UMR 7268) AMU-CNRS-EFS, France), Zoé Nowicki (Palévoprim (UMR 7262) CNRS-UP, France), Gilles Berillon (HNHP (UMR 7194) CNRS-MNHN-UPVD, France), Kristiaan D'Août (University of Liverpool, United Kingdom), François Marchal (ADES (UMR 7268) AMU-CNRSEFS, France), Pauline Provini (MECADEV (UMR 7179) MNHNCNRS, France)

francois.druelle@univ-amu.fr

Most non-human primates commonly exhibit exceptional jumping performance, particularly optimized for arboreal leaping. In contrast, humans appear more grounded, and arboreal leaping would represent an extremely risky behavior for them. This contrast raises two key questions: why do non-human primates possess such remarkable jumping abilities, and why did human primates lose this adaptation? In this presentation, we will review the leaping capabilities of primates, including their vertical jumping performance, drawing on various studies, notably those conducted by Prof. Peter Aerts. Using insights from functional morphology, we will explore the anatomical and biomechanical factors underlying the exceptional jumping performance of non-human primates, such as morphotype, lever arms, muscle properties, and muscle power. Finally, we will discuss when and why these capacities may have been reduced or lost in the human lineage, that is, how natural selection ceased to maintain this trait.

A3.5 MUSCLE-TENDON DYNAMICS AND TAIL-ASSISTED MANEUVERING IN THE AERIAL ESCAPE JUMPS OF DESERT KANGAROO RATS

Wednesday 9th July 2025 10:00

AMarie J Schwaner (Marie Janneke Schwaner, Netherlands), Stacey Shield (Cape Town University, South Africa), David C Lin (Washington State University, United States), Craig P McGowan (University of Southern California, United States)

mjschwaner@live.nl

Desert Kangaroo rats (Dipodomys deserti) use high, erratic vertical leaps—up to ten times their hip height—to evade predators like snakes. These impressive jumps challenge muscle power limits, and the rat's tail plays a key role in stabilizing and maneuvering during aerial escapes. Here, we focused on muscle-tendon dynamics during the jumping phase and the tail’s role in the aerial phase of escape jumps. The research towards their jumping performance, inspired by the Galago jumping studies by Peter Aerts, shows that even submaximal jumps require up to 340 W/kg of muscle power, suggesting maximal jumps need more power than muscles alone can provide. Kangaroo rats achieve this by using their Achilles tendon in two ways: (1) transferring energy from thigh and back muscles and storing elastic energy, while (2) decoupling muscle fascicle velocities from ankle flexion to optimize power production. In the aerial phase, kangaroo rats rotate their long tail along with their body. Previous research suggested the tail's primary role is balance, but we found total body reorientation to be independent of jump height, -distance, and aerial time: indicating that the tail is purposefully used for aerial reorientation. This is further emphasized by the tail's motion that mirrors the body’s angular momentum, and the animals re-orient their body in a "step-wise" manner with closely aligned tail segments. Current studies are exploring how kangaroo rats use their tail for aerial stability and maneuverability through computational simulations, validated by experimental data.

A3.6 AN INVERSE DYNAMICS ANALYSIS OF JUMPING IN THE CROWNED SIFAKA (PROPITHECUS CORONATA)

Wednesday 9th July 2025 10:15

Johan L Van Leeuwen (Experimental Zoology Group Wageningen University, Netherlands), Laura Verbeek (Experimental Zoology Group Wageningen University, Netherlands), Sander WS Gussekloo (Expeimental Zoology Group Wageningen University, Netherlands)

johan.vanleeuwen@wur.nl

Sifakas are a group of seven species of indriid lemurs of the genus Propithecus, which are native to Madagascar and well know for their striking vertical clinging and leaping abilities. These primates leap from tree-to-tree in their natural habitat and achieve jumping distances of up to ten meters. Despite a few kinematic studies, we still lack an inverse dynamics analysis of sifaka leaping that could show the power produced during take-off. To fill this gap, we made synchronized videorecordings from three different angles of leaping crowned sifakas (1 male and 1 female) in the primate park “Apenheul” (Apeldoorn, The

Netherlands). The animals were free to jump without any attached markers. Video footage was calibrated such that measurements in 3D space could be made using the DLT method. We were not allowed to make any direct body measurements, but body mass of each individual was provided by Zoo personnel. Using body mass, video footage, and (scant) morphological data from the literature of related sifaka species, and geometrical models, we estimated segmental dimensions, mass, and moments of inertia. Together with the motion records, these were used to estimate kinetic– and potential energy, take-off force and instantaneous power during take off. In absence of body markers and the Sifaka’s long hairs, we had to cope with relatively high errors. Estimated mass-specific powers were compared with maximum specific powers of vertebrate muscles from the literature to explore whether stored elastic energy is (partially) used to power the jump.

A3.7 THE EVOLUTION OF BIPEDALISM IN AUSTRALIAN AGAMID LIZARDS.

Wednesday 9th July 2025 11:00

Christofer Clemente (University of the Sunshine Coast, Australia)

cclement@usc.edu.au

The origin of bipedal locomotion in lizards is unclear. Earlier suggestions for a speed or endurance advantage were not supported, with speed being similar for bipedal strides, compared with quadrupedal strides, and the percentage of strides that each species ran bipedally, being negatively related to running endurance. Modelling studiesby Aerts et al.suggest bipedalism in lizards may be a consequence of a caudal shift in the body centre of mass, combined with quick bursts of acceleration, causing a torque moment at the hip lifting the front of the body. This model was supported with a significant acceleration threshold between quadrupedal and bipedal runs, and the percentage of bipedal strides that each species ran, being positively related to body size and the proximity of the body centre of mass to the hip. However, variation in morphology could only account for 56% of the variation in acceleration thresholds, suggesting that limb and tail dynamics have a significant influence on bipedalism. Our analysis revealed that angular acceleration of the trunk about the hip, and of the tail about the hip were both important predictors of extended bipedal running, along with increased temporal asymmetry of the ground reaction force profile. Together, these results show that bipedalism may have first arisen as a consequence of acceleration and a rearward shift in the BCOM, but subsequent linages have exploited this consequence to become bipedal more often, suggesting that bipedalism in lizards may convey some advantage.

A3.8 CONTRIBUTION OF THE STUDY OF BIRD BIPEDALISM TO THE UNDERSTANDING OF THE EVOLUTION OF SHAPE

Wednesday 9th July 2025 11:00

Anick Abourachid (Muséum National d'Histoire Naturelle, France)

abourach@mnhn.fr

The study of the evolution of form requires knowledge of the evolutionary history, selective pressures and structural constraints that have been imposed on organisms. In this context, the 10,000 species of crown birds are a very useful model. The evolutionary history of these dinosaurs is well documented in the fossil record, while the very high ecological diversity of present-day species provides information on selective constraints. The common body plan, imposed by specialisation in flight, provides a homogeneous structural framework. The highly conserved pelvic locomotor system has played a fundamental role in the evolution of birds, enabling them to colonise all continental, aerial and aquatic environments. The hind limbs are used for walking, and sometimes running or swimming. They are essential for taking off and landing. So birds use them in very different mechanical contexts. The study of the function of the pelvic system provides crucial information for identifying the properties that arise from the structure of the bird body and that have enabled their extraordinary radiation. It illustrates the contribution of functional morphology to our understanding of the evolution of shape.

A3.9 THE AGEING HUMAN HEEL PAD: ASSESSING MECHANICAL BEHAVIOUR IN THE LAB AND IN THE FIELD.

Wednesday 9th July 2025 11:30

Kristiaan D'Août (University of Liverpool, United Kingdom), Omar Elnaggar (University of Liverpool, United Kingdom), Adam Rowlatt (University of Liverpool, United Kingdom), Claire Brockett (University of Sheffield, United Kingdom), Alana Sharp (University of Liverpool, United Kingdom), Catherine Willems (HOGent, Belgium)

kristiaan.daout@liverpool.ac.uk

The human heel pad loses some of its shock absorbing properties during ageing. It is unclear whether this results from “wear and tear” or from the physiology of ageing itself. To help answer this question, we have studied the mechanical behaviour of the heel pad in populations reflecting a diversity of locomotor habits, footwear and substrate use: Europeans, Ju|’hoan traditional huntergatherers from Namibia, and Indian shod and barefoot volunteers. This work builds on seminal studies from the 1990s by Peter Aerts and collaborators on the mechanical properties of the heel pad. We have collected ultrasound images of the heel pad at different loads, Shore heel hardness, plantar pressures and impact acceleration during walking, and Digital Image Correlation-based plantar skin deformation. For the European population we have also obtained MRI foot scans for subsequent Finite Element Modelling. Our preliminary analyses indicate that the heel pad tends to get thicker with ageing and that in vivo deformation is greatest in the macrochamber. Shore hardness correlates weakly with dynamic heel pad elasticity. Skin thickness and heel pad behaviour differs between the populations studied.

A3.10

LEGS AS LINKAGES TO LEGS AS MACHINES… TOWARDS LEGS FOR ROBOTS?

Wednesday 9th July 2025 11:45

James Usherwood (The Royal Veterinary College, United Kingdom)

jusherwood@rvc.ac.uk

The actions of the major human leg muscles are well established. Anatomy, inverse dynamics and computer modelling allow muscles to be described as flexors and extensors, agonists and antagonists, and as motors, brakes and struts. However, the functions of these muscle actions remain unclear; we can describe what muscles do, but not necessarily why. Here, leg muscles, bones, and their connections, are viewed as links and joints of mechanisms and structures meeting the task of a vehicle, of weight support during translation, and the two fundamental demands of an effective machine: to avoid mechanical work, and to supply mechanical work economically. Human legs throughout a running stance are modelled as a sequence of linkages that predict muscle action and indicate the varying muscle functions within the integrated leg. Work avoidance is achieved with isometric muscles and linkages that promote a sliding of the hip over the ground contact. Work economy requires, for muscle with constrained power and a cost to activation, contraction over the whole of stance; this function is achieved by the hamstrings without disrupting the linkage geometries necessary for work avoidance. In late stance, the two functions occur simultaneously through coactivation of antagonistic biarticular muscles, providing one answer to Lombard’s paradox. Early application of these principles to a range of toy and human-scale models will be presented. These demonstrate the potential for bioconvergent linkages to facilitate work-avoidance, powering economy, and simplified control in engineered leg design.

A3.11 SWIMMING IN SNAKES: WHAT HAVE WE LEARNED SO FAR.

Wednesday 9th July 2025 12:00

Anthony Herrel (CNRSMNHN, France), Elizabeth Gregorio (PMMHCNRS, France), Vincent Stin (PMMHCNRS, France), Guillaume Fosseries (CNRS, France), Xavier Bonnet (CNRS, France), Ramiro Godoy-Diana (PMMHCNRS, France) anthony.herrel@mnhn.fr

With 4177 species snakes are one of the most diverse groups of vertebrates and have occupied nearly all ecological niches despite the lack of limbs. Interestingly, recent studies have shown that irrespective of their habitat use all snakes can swim. Moreover, many terrestrial species swim faster than semi-aquatic, fully aquatic and marine snakes. Yet, aquatic snakes are morphologically different, both in term of external body proportions as well as their musculo-skeletal system. This raises the question whether all snakes swim alike and whether possibly aquatic snakes are more efficient than non-aquatic species. To gain insights into this question we have been gathering data on the 2D and 3D kinematics of snake swimming and have been quantifying the 3D wake of swimming snakes using volumetric PIV. Our result show significant differences in the 3D kinematics of different snakes with some snakes of the genus Acrochordus signficantly flattening their boy medio-laterally which impavcts both the kinematics and the hydrodynamics of swimming. In doing so they appear to converge on marine snakes that show flattened bodies and tails.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A3.12 MORPHOLOGY DRIVES FUNCTIONAL PERFORMANCE VARIATION: THE CASE OF TRAP-JAW ANT MANDIBLES

Cristian L. Klunk (Technische Universität Darmstadt, Germany), Michael Heethoff (Technische Universität Darmstadt, Germany), Andrew Suárez (University of Illinois, United States), Joshua Gibson (University of Illinois, United States), Fredrick Larabee (University of Illinois, United States), Alexandre V. Palaoro (Universidade Federal do Paraná, Brazil), Rodrigo M.S. Feitosa (Universidade Federal do Paraná, Brazil)

klunkcristian@gmail.com

Trap-jaw ants are recognized for their generally elongated mandibles that snap at remarkable speeds, having evolved among nine genera and three subfamilies. Despite superficial similarities, mandible morphology varies considerably, potentially affecting bite performance. To investigate these effects, we measured functional traits — mechanical advantage, cuticle thickness, and second moment of area (I) — and conducted finite element analysis (FEA) simulating a strike bite on 3D mandible reconstructions of 25 species from eight genera and two subfamilies of trap-jaw ants. We performed Principal Component Analysis with the functional traits and FEA-derived stress values and hypothesized that species distribution in this multivariate space would reflect their phylogenetic relationships. Species mostly grouped with their generic relatives, except Anochetus and Orecthognathus, which showed broader distributions. The distribution of trap-jaw genera also resembled their phylogenetic relatedness, but Myrmicinae and Ponerinae subfamilies did not form distinct clusters, as was initially anticipated. FEA stress data were relevant for grouping species with more elongated mandibles, such as Acantognathus spp. and Strumigenys denticulata. Odontomachus spp. and Daceton armigerum clustered due to their higher values ofI normalised by cross-section shape. Strumigenys spp. with shorter mandibles grouped due to their high mechanical advantage, I corrected by mandible length, cuticle thickness, and the low-stress values they exhibited under bite loading. Although our results only partially support the hypothesis that mandible function aligns with the phylogenetic relationships of trap-jaw ants, they highlight the functional consequences of mandible morphological variation in the context of the outstanding strike impacts these ants are submitted to.

A3.13 ISLAND EVOLUTION IN MICE - EFFECTS OF DIET QUALITY ON THE MUSCULOSKELETAL SYSTEM OF THE MASTICATORY APPARATUS

Christine Böhmer (Kiel University, Germany), Levke Hansen (Kiel University, Germany), Ekaterina Gorshkova (Kiel University and Max-Planck-Institute Plön, Germany), Daniela E. Winkler (Kiel University, Germany), Anja Guenther (Universität Hildesheim and Max-Planck-Institute Plön, Germany)

cboehmer@zoologie.uni-kiel.de

Isolated environments such as islands can provide restricted dietary resources of varying quality. This has a major impact on evolution of island species, and can lead to rapid morphological adaptation, especially in small mammals. In order to understand the impact of diet quality on the masticatory apparatus in the model speciesMus musculus domesticus, we quantitatively analyzed the main masticatory muscles and the mandibular morphology in semi-natural populations kept on different diets for six generations. Individuals of the F5 generation raised on high quality (HQ) or standard quality (SQ) diets showed significantly higher muscle mass and larger anatomical cross-sectional area (ACSA) of theM. masseterand theM. temporalisin mice raised on SQ diet as compared to HQ diet. A trend towards more robust (i.e., sturdy) mandible morphology in SQ mice as compared to HQ mice was evident. The investigation of individuals of two F6 generations which were fed on a diet different from that of the precedent generation revealed that the diet switch from HQ to SQ resulted in increased muscle size, whereas the diet switch from SQ to HQ lead to decreased muscle size as compared to the respective control group. The mandible displayed limited differences in morphology. These findings suggest that within six generations, diet quality could be a selection factor for morphological traits in the mandible which may become epigenetically fixed. However, additional studies such as DNA methylation and histone modification are necessary to unravel the role of the epigenome in this context.

A3.14 HERBIVORY IN THE MARINE REALM: MORPHOPHYSIOLOGICAL ADAPTATIONS OF THE SALEMA PORGY (SARPA SALPA) TO SEAGRASS FEEDING

Christine Böhmer (Kiel University, Germany), Saskia Strehlau (Kiel University, Germany), Daniela E. Winkler (Kiel University, Germany), Harald Gruber-Vodicka (Kiel University, Germany)

cboehmer@zoologie.uni-kiel.de

Seagrass is ubiquitous in the sublittoral of the Mediterranean Sea, providing essential ecosystem services such as coastal protection, carbon sequestration and supporting biodiversity. Many animals use seagrass habitats for reproduction, refuge or foraging, but few directly feed on seagrass. A striking exception is the salema porgy (Sarpa salpa), one of the main macroherbivores in the Mediterranean, where adults predominantly consume seagrass. While the ecological role of herbivory on seagrass is clear, the morphophysiological adaptations to seagrass feeding in fish remain unknown. Here, we investigate morphological and physiological adaptations towards a seagrass rich diet inS. salpaby comparing it with non-herbivorous fish. We collect data on 1) force-producing capacity of the cranial muscles, 2) patterns of diet-tooth-interaction using dental microwear

texture analysis, 3) morphology of the digestive tract and 4) composition of the gut microbiome using DNA analysis. Next, we will measure biting performance and track mouth kinematics during feeding strikes ofS. salpausing a three-dimensional video system. We expect that the musculature of the feeding apparatus enables forceful bites to cut the plant tissue. The plant-tooth interaction should leave characteristic traces on the surface of the dental structures and likely will include characteristic scratches reflective of the tough food. As shown in other fish, we expect that the intestine inS. salpais longer compared to non-herbivorous taxa because of the low nutrient diet. Likewise, it is expected that the gut flora ofS. salpaexhibits a distinct composition sharing prominent microbial taxa found in other marine herbivores.

A3.15 ARBOREAL ADAPTATIONS CONSTRAIN THE MORPHOLOGICAL EVOLUTION OF THE RADIUS BONE IN PRIMATES AND CARNIVORANS.

Océane E.N. Cluzeau (KU Leuven, Belgium), Mallaury Rollet (Muséum national d’Histoire naturelle, France), Vivien Louppe (Naturhistorisches Museum der Burgergemeinde Bern, Switzerland), Sharon E. Holte (The Mammoth Site, United States), Margot Michaud (UniLaSalle, France), Anne-Claire Fabre (Naturhistorisches Museum der Burgergemeinde Bern, Switzerland)

oceane.cluzeau@kuleuven.be

The arboreal environment is a complex three-dimensional environment that presents functional challenges. Despite these challenges, many clades of tetrapods have colonised this environment independently. So far, only a handful of studies investigate the impact of living in trees on the morphology in a large macroevolutionary sample. Here, we investigate whether there is an effect of degree of arboreality on radius shape. To do so, we compared radius shape across arboreal and terrestrial species of carnivorans and primates. Radius shape is an interesting structure as it influences forearm movement and hand position, which are vital in arboreal environments. Our sample comprises 239 specimens belonging to 160 species and, is representative of the locomotor diversity of carnivorans and primates. We used 3D geometric morphometrics to quantify the shape of the radius. Comparative phylogenetic methods were applied to understand the influence of size, locomotion and evolutionary history of each clade on radial shape. Our results showed a significant impact of the locomotion and morphological similarities in the radial shape among species with similar arboreal locomotion. Furthermore, the morphological diversity of radial shapes in carnivorans and primates is low, in contrast to the high diversity observed in terrestrial species. This suggests that arboreal environments impose greater constraints on the radial morphology in carnivorans and primates, which is consistent with results obtained in other vertebrates.

A3.16 LEGS AS LINKAGES, LEGS AS MACHINES, LEGS AS TOYS… AND FOR ROBOTS?

James Usherwood (The Royal Veterinary College, United Kingdom)

jusherwood@rvc.ac.uk

Legs can perform many functions, but fundamentally their ‘purpose’ is to support body weight while the body travels. To do this effectively, the structures, mechanisms and actions of the legs should 1) avoid avoidable mechanical work demand, 2) allow economical supply of mechanical work, while 3) be simple and robust to control. Recent work considering ‘legs as linkages’ focuses on these roles. Sequences of isometric muscle actions result in a work-avoiding ‘sliding’ motion of the body over the foot (role 1); in the human, this would account for gluteus, then vastus, then rectus femoris (forming a 4-bar linkage) tensions. Given a limited peak muscle power, and a cost to muscle activation, work is provided economically (role 2) with muscles that contract over the entire stance; in running humans this would be the hamstrings that provide mechanical power without altering the work-avoiding geometries of role 1. And the sequence of linkages resulting in sliding (role 1) engage muscles through simple changes in geometry (role 3). Early application of these principles to a range of toy and human-scale models will be presented. These demonstrate the potential for bio-convergent linkages to facilitate work-avoidance, powering economy, and simplified control in engineered leg design.

A3.17 MICRO-CT IMAGING AND 3D RECONSTRUCTION OF MUSCLES IN THE BUCCAL MASS OF THE SEA SLUG (APLYSIA CALIFORNICA)

Chloe K Goode (University of Lincoln, United Kingdom), Steve M Rogers (University of Lincoln, United Kingdom), Hillel J Chiel (Case Western Reserve University, United States), Gregory P Sutton (University of Lincoln, United Kingdom) ChGoode@lincoln.ac.uk

The experimentally tractable nervous system of the of the sea slug (Aplysia californica) has long made its feeding apparatus a model system for studying the biomechanics and neural control of behaviour. When feeding, this herbivorous slug uses muscles (I1- I10) within its buccal mass (mouthparts) to protract and retract a toothed radula, allowing it to dexterously grasp, tear and swallow fibrous algae. Unlike the jaws of vertebrates, where muscles generate force by acting against rigid skeletal elements such as bone,Aplysiagenerates movement using only soft tissue. Biomechanical models of muscle action in the buccal mass during feeding are all based on a basic anatomical study from 1942, and thus a modern update is quite timely. In this study, we aimed to expand upon the anatomical works of Howells (1942), by using Micro-Computed Tomography (μCT) and 3D visualisation software (Dragonfly) to produce high resolution 3D digital reconstructions of muscle groups within the buccal mass.In total, 25 buccal masses ranging from 0.06 – 3.20g were imaged, at a minimum resolution of 7μm, using an iodine stain (0.5-3% w/v) to improve tissue contrast. This much improved anatomy allowed us to gain an insight into muscle action, by comparing the position of the muscles relative to the radula during the protraction (grasping) and retraction (swallowing) phase, as well as identifying new muscle groups not previously described. Finally, by comparing animals across a range of masses, we show how the buccal mass geometry scales with size.

A3.18 CAN GEOMETRIC MORPHOMETRIC PROFILING CORROBORATE WITH THE BEHAVIOURAL EFFICACY?

SWAPNANIL MONDAL (Ethophilia Research Foundation, India), Chayan Munshi (Ethophilia Research Foundation, India)

snilstudy@gmail.com

Prawns have a special appendage arrangement and specific body morphometrics that help to successfully execute swimming, walking, combat, grooming, and foraging. To study the fundamental morphological adaptation of its appendages, the freshwater prawn species Macrobrachium lamarrei is being selected as a model organism. Understanding of the geometric morphometric structure was primarily done using Scanning Electron Micrograph (SEM) images. The geometrical representations of the morphology were done using the digital graphical method. The effectiveness of the functioning of appendages was determined by spatial analysis of the morphological structures. The structural intricacies were evaluated in terms of geometrical formula, where these structures displayed complicated geometrical features. We have tried to formulate the body and appendage morphology to understand the efficacy in manifesting several robust behavioural tasks. The Macrobrachium lamarrei is a reliable model for studying morphological adaptative changes in invertebrates. Our study emphasises the structural distinctiveness and convolutions, which are designed with unique geometric patterns. To facilitate cross-organism comparisons across different ecological niches, we propose mathematical formulations that elucidate significant micro-morphological.

A3.19 HOOKED

(LOLIGO

ON

FISHING: HOW

SQUID

FORBESII) CATCH FISH USING SUCKER TEETH

Jan Severin Te Lindert (Wageningen University, Netherlands), Jonathan Huie (George Washington University, United States), Cassandra Donatelli (Chapman University, United States), Brett Klaassen van Oorschot (Eindhoven university, Netherlands), Sander Gussekloo (Wageningen University, Netherlands), Guillermo Amador (Wageningen University, Netherlands)

severin.telindert@wur.nl

Squid suckers have a unique morphology consisting of a rigid ring, often lined with sucker ring teeth. While, previous studies have hinted that these teeth play a role in gripping prey, this has not been tested. Here we studied the teeth morphology of Loligo forbesii and use silicone sucker models with 3D printed resin teeth to test the effect on pull off and friction performance. We tested the performance on three substrates: acryl (hard), silicone (soft) and gelatine (pierceable). Our results indicate that Loligo forbesi teeth enhance friction, hence avoiding prey slippage during prey capture and handling.

A4: KINEMATICS AND ROBOTICSSTATE OF THE ARTS KINEMATICS AND THEIR TRANSFER TO

ROBOTICS AND INNOVATIVE METHODS AND TECHNIQUES IN BIOMECHANICS

ORGANISED BY: SEBASTIAN KRUPPERT (UNIVERSITY FREIBURG), DANIELE LIPRANDI (UNIVERSITÄT GREIFSWALD), FABIAN PLUM (IMPERIAL COLLEGE LONDON), HENDRIK K BECK (IMPERIAL COLLEGE LONDON)

A4.14 ULTRAFAST FOURIER LIGHTFIELD MICROSCOPY REVEALS 3D RECOIL OF TINY ELASTIC STRUCTURE

Thursday 10th July 2025 09:00

Melody W Young (Duke University, United States), Clare Cook (Duke University, United States), Justin Jorge (Duke University, United States), Roarke Horstmeyer (Duke University, United States), Sheila Patek (Duke University, United States)

melody.young@duke.edu

In tiny biological systems, the storage and release of elastic energy during ultrafast movements is modulated by how structural materials deform in space and time. Trap-jaw ants deform their springy head capsules, a geometrically complex 3D structure, to power mandible strikes ranking among the fastest biological movements known. Visualizing deformation of these tiny, curved exoskeletons is challenging, requiring imaging tools to resolve micron-scale deformations across millimeter-scale structures (~2 mm, anterior–posterior) of strikes occurring in ~70 µs. To address this, we developed an ultra-high-speed Fourier light field microscope (FLFM) optimized for capturing real-time deformation of the trap-jaw ant head capsule with high spatial and temporal resolution. Our FLFM integrates an ultra-fast sensor (Photron E980S, achieves 1 MHz+ fps) with 3-6 array lenses to capture unique perspectives of the ant head capsule at 100,000 frames per second. White paint speckled on the ant heads provided optical features tracked using optical flow with sub-pixel precision in each perspective. A calibrated model of the optical system was then used to compute the 3D motion of the dots from the flow vectors. We resolved z-axis (in and out of the ant head capsule) recoil displacements averaging 33.3 ± 11.4 µm with a standard error of 2.5 μm— the first time such dynamic and distributed elastic recoil has been fully quantified in an ultrafast biological spring-latch system. This modular hardware and software approach can be adapted to other small-scale, high-speed systems, offering a new workflow for integrating high-speed imaging with 3D deformation analysis.

A4.15 AN INNOVATIVE FORCE SENSOR TECHNOLOGY MIMICKING DISTAL PADS’ FUNCTIONAL MORPHOLOGY TO STUDY THE EVOLUTION OF LOCOMOTION

IN ARBOREAL MAMMALS

Thursday 10th July 2025 09:00

Séverine L. D. Toussaint (CR2P UMR 7207, France), Artémis Llamosi (Inarix, France)

severine.toussaint@mnhn.fr

he ability to live in trees is a ubiquitous adaptation in mammals, but the specific mechanisms underlying the evolution of arboreal locomotion are variable among groups. For example, primates evolved in an arboreal context and acquired unique traits such as opposable first digits and nails instead of claws, which are still shared by the majority of extant species. However, the initial function of these specificities are still unclear. Studying the biomechanics of movements and forces exerted by the autopods during arboreal locomotion in primates and other arboreal mammals provides insight into the impact of the arboreal lifestyle on their morpho-functional adaptations. Here we developed an innovative force sensor technology that mimics the morpho-functional adaptation of distal pads of arboreal mammals. This patented technology measures the direction and intensity of contact forces, with a spatially resolved and dynamic resolution. Its design enables to make sensors of variable shapes and sizes and can be used in natural environments. We designed a version of this system in the shape of a branch to study the biomechanics of grasping during arboreal locomotion in various mammals in zoological parks. These data will notably allow to elucidate whether nails of primates allow them to apply more force compared to the claws of other mammals, by quantifying for the first time the variation of forces exerted by the different anatomical regions of the phalanges in those species. This technology and experimental methodology have multiple applications, ranging from biomechanics to haptics, health and robotics.

A4.16 SIMULTANEOUS MEASUREMENT OF TRIAXIAL GROUND REACTION FORCES ON A WALKING ANT’S LEGS.

Thursday 10th July 2025 09:30

Toshihiro Shiratori (Keio University, Japan), Hidetoshi Takahashi (Keio University, Japan) toshishiratori@keio.jp

In this study, a micro force plate array is proposed that can simultaneously measure the triaxial ground reaction force of each leg of a small insect such as an ant. The distinct role of each leg is crucial to understanding the ant's locomotion mechanism. Based on the interaction of each leg with the ground, the mechanical work performed by each leg and the energy consumed during movement can be calculated to elucidate the locomotion pattern that allows ants to maintain high speed with minimal energy expenditure. Previously, the ground reaction force of a single leg has been measured by a small force plate. Similarly, multipoint measurement by a force plate array are needed to measure the ground reaction forces of all feet simultaneously. However, conventional strain gauge-type force plates require large strain bodies, and their mechanical structure makes the implementation of multipoint force plates difficult. In addition, a biaxial micro force plate array using MEMS (Micro Electro Mechanical System) technology for measuring the ground reaction forces of ants has recently been proposed. However, the fabrication process was complex, and it is difficult to array densely. In this study, a triaxial micro force plate array utilizing the sampling moiré method, a camera based displacement measurement technique, and a prism was fabricated and evaluated. Using the fabricated device, the ground reaction force of each leg of Camponotus japonicus was measured, confirming that the device is capable of measuring triaxial ground reaction forces simultaneously.

A4.17 MAKING IT TURN: APPLYING BISON KINEMATICS TO SOFT ROBOTS

Thursday 10th July 2025 09:45

Joscha Teichmann (University of Freiburg exc livMatS Plant Biomechanics Group Freiburg, Germany), David Zimmermann (University of Freiburg exc livMatS Plant Biomechanics, Germany), Thomas Speck (University of Freiburg exc livMatS Plant Biomechanics, Germany), Sebastian Kruppert (University of Freiburg exc livMatS Plant Biomechanics, Germany)

joscha.teichmann@livmats.uni-freiburg.de

Soft robots are made from flexible, deformable materials that allow for gentle and adaptive interactions with their environment. They are often inspired by biological organisms to overcome specific challenges that conventional, rigid robots face. One of these challenges is operating in environments that are inaccessible or unsuitable for electronically controlled robots. However, most soft robots can still only walk in a straight line, without any mechanism to steer them. We present an approach inspired by Bos bison to steer a soft quadruped robot. By analysing a large video dataset of free-ranging American bison, we found that they bend their spines laterally while walking in curves and applied these findings to our recently developed quadruped soft walker

with parasagittal gait. We manoeuvred the walker around various obstacles and tested it for speed, load bearing capacity, and stability. Our results show how lateral bending can be used to steer quadruped robots. Although the robot can already carry more than 300 g, our analysis also suggests additional factors that contribute to steering in heavy animals, which we plan to implement. We expect our work to be a starting point for more sophisticated steering mechanisms for electronics-free, pneumatic soft robots.

A4.18 A BIOMIMETICS APPROACH TOWARDS UNDERSTANDING THE VENUS FLYTRAP’S TRAP MECHANICS

Thursday 10th July 2025 10:00

Maartje HM Wermelink (University of Freiburg exc livMatS Plant Biomechanics Group Freiburg, Germany), Renate Sachse (TUM Department of Civil and Environmental Engineering Chair of Structural Analysis, Germany), Thomas Speck (University of Freiburg exc livMatS Plant Biomechanics Group Freiburg, Germany), Falk Tauber (University of Freiburg exc livMatS Plant Biomechanics Group Freiburg, Germany)

maartje.wermelink@biologie.uni-freiburg.de

The Venus flytrap (Dionaea muscipula) has long intrigued plant enthusiasts and botanists alike with its rapidly closing trap. Its fast closure movement and well observable size render D. muscipula a textbook carnivorous plant. The leaf of D. muscipula evolved into the characteristic two-lobed trap that is hinged at the leaf’s midrib, leaving the enlarged petioles as the main photosynthetic organ. The closing motion of the trap is a rapid switch from the lobes’ concave open-state to their convex close-state, catching the prey within 100-500 ms after the trap was triggered. Consequently, the leaves can be characterised as bistable systems, possessing two low-energy states. The transition from concave to convex is initiated by changes in turgor pressure. The closing movement is accelerated by the release of stored elastic energy from prestresses in the concave state, leading to inversion of the bi-axial curvature of the lobes. By identifying the key aspects in the motion, we aim to translate this mechanism into a mechanical model system. We transferred geometrical characteristics such as dimensional ratios and the thickness gradient in the lobe of the Venus flytrap to the design of a 3D printed bistable actuator. This resulted in a trap lobe that is stable in both the concave and convex configurations and closes with a snap. By exploiting these characteristics, we aim to create an artificial Venus flytrap that closely mimics the kinetics and mechanical behaviour of its biological counterpart.

A4.19 COORDINATING LIMBS AND SPINE: (PARETO-) OPTIMAL LOCOMOTIONIN THEORY, IN VIVO, AND IN ROBOTS

Thursday 10th July 2025 10:15

Robin Maag (University of the Sunshine Coast, Australia), Robert Rockenfeller (University of Koblenz, Germany), Robert L. Cieri (University of British Columbia, Canada), Johanna T. Schultz (University of the Sunshine Coast, Australia), Christofer J. Clemente (University of the Sunshine Coast, Australia)

Robin.Maag@research.usc.edu.au

Among vertebrates, patterns of movement vary considerably, from the lateral spine-based movements of fish to the predominantly limbbased movements of mammals. Yet, we know little about why these changes may have occurred in the course of evolution. Lizards form an interesting intermediate group where locomotion appears to be driven by both motion of their limbs and lateral spinal undulation with the extent varying between species. To understand the evolution and relative advantages of limb versus spine locomotion, we developed an empirically informed mathematical model, as well as used in-vivo data to inform a robotic model. Furthermore we have compared predictions from the mathematical model to in-vivo data from running and climbing lizards and data collected with the robotic model. Our mathematical model showed that, if limbs were allowed to grow longer, movements of the spine did not enable longer strides, since spinal movements reduced the achievable range of motion of the limbs. Yet, in-vivo data shows lateral spine movement is widespread among diverse group of lizards. Our robotic model was able to explain this disparity, showing that increased movement of the spine was energetically favorable. Our robot model also revealed that stability decreased with increased spine and limb range of motion, detailing the trade-off between speed and stability. Overall, our robotic model found a Pareto-optimal set of strides—when considering speed, efficiency, and stability—requiring both spine and limb movement, which closely agreed with movement patterns among lizards.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A4.7 A HIERARCHICAL CLUSTERSEPARATION FRAMEWORK FOR ANALYSING FIBRE-BASED BIOLOGICAL MATERIALS

Daniele Liprandi (Universität Greifswald, Germany), Jonas O Wolff (Universität Greifswald, Germany) daniele.liprandi@uni-greifswald.de

Accurately distinguishing and classifying fibre types within composite bundles presents significant challenges, particularly for micro-scale fibres arranged in hierarchical structures. Biological fibre composites, such as spider silk or arterial walls, contain fibres that cannot be easily isolated, while their minimal mass makes characterisation through conventional techniques like mass spectroscopy, Raman spectroscopy, or proteomics time-consuming and, in some cases, impossible. In this work, we address this challenge by introducing a new method based on statistical classification and physically-constrained optimization. The approach exploits the ability of obtaining data both from the single fibres, e.g. through scanning electron microscopy, and

from the composite fibre network, e.g. mechanical properties. The fibre-dependent data are used to run a labelling procedure using Gaussian Mixture Models. We use this first composition of the fibre sub-populations, as the start of a Mixed-Integer Linear Programming (MILP), to further categorize fibres based on their linear phase behavior, their mechanical properties, and their biological constraints. This integrated methodology proves particularly valuable for natural materials, where multiple fibre types with distinct mechanical functions coexist within a single structure. Through testing, we demonstrate robust classification performance when combining geometrical and mechanical properties. This method successfully distinguishes between overlapping distributions and resolves ambiguities that pure statistical approaches cannot address. To facilitate adoption across disciplines, we provide our implementation as an open-source Python package. By applying this method to other biological fibre networks, we could improve our understanding of how fibre bundles are organised in nature, and how they reach their optimal mechanical performance.

A4.8 THE UNIQUE MUSCLE ARCHITECTURE OF THE SEAHORSE TAIL DEMYSTIFIED

Dries Marzougui (Ghent University, Belgium), Dominique Adriaens (Ghent University, Belgium), Francis Wyffels (Ghent University, Belgium)

dries.marzougui@ugent.be

Seahorses possess a unique tail muscle architecture that enables efficient grasping and anchoring onto objects. This prehensile ability is crucial for their survival, as it allows them to resist currents, cling to mates during reproduction, and remain camouflaged to avoid predators. Unlike in any other fish, the muscles of the seahorse tail form long, parallel sheets that can span up to eleven vertebral segments. Our study investigates how this distinctive muscle arrangement influences the mechanics of prehension. Through in-silico simulations validated by a 3D-printed prototype, we reveal the complementary roles of these elongated muscles alongside shorter, intersegmental muscles. Furthermore, we show that muscles spanning more segments allow greater contractile forces and provide more efficient force-to-torque transmissions. Our findings confirm that the elongated muscle-tendon organisation in the seahorse tail provides a functional advantage for grasping, offering insights into the evolutionary adaptations of this unique tail structure.

A4.9 GROUND REACTION FORCE MEASUREMENT OF DIAPHERODES GIGANTEA USING A TRANSPARENT THREE-AXIAL FORCE PLATE

Yukitake Nakahara (Keio University, Japan), Guillermo Amador (Wageningen University, Netherlands), Hidetoshi Takahashi (Keio University, Japan) nakaharayukitake@keio.jp

This study proposes a transparent force plate capable of simultaneously measuring the ground reaction force (GRF) and observing the contact geometry of the stick insect foot. It is well known that the dorsal footpad of the stick insect can

adhere to various surfaces, enabling it to support its own body weight when upside down even while being relatively large. As such, they have been used as a model organism in the fields of biomechanics and bioadhesion. For example, one study observed the contact of the footpad while pulling a stick insect off of a flat glass plate. While another study used measurements of GRF of stick insects to inform a model representing their locomotion. In this study, we propose a force plate that can simultaneously observe the footpad's contact geometry during locomotion and measure the GRF in 3D. The force plate is a device that can measure GRF and has been traditionally manufactured using electronic strain gauges. In this study, we designed and fabricated a transparent force plate using a camera and the sampling moiré (SM) method. The SM method measures the displacement of the force plate's supporting spring structure. Replacing the spring structure changes the force range and force resolution. Thus, a single setup can measure various types of animals. We measured the GRF of the stick insect Diapherodes gigantea during walking. During the experiment, the GRF and footpad contact geometry were observed for two conditions: walking locomotion and the defensive behavior of shaking to mimic swaying the leaves.

A4.10 UNLOCKING BISTABILITY: COMPUTATIONAL TOOL FOR THE SIMULATION OF DERMAPTERAN HINDWING FOLDING

Nele Binder (Westfälische Hochschule Westfälisches Institut für Bionik, Germany), Leone Costi (European Space Agency Advanced Concepts Team, Netherlands), Dario Izzo (European Space Agency Advanced Concepts Team, Netherlands), Tobias Seidl (Westfälische Hochschule Westfälisches Institut für Bionik, Germany)

nele.binder@outlook.de

The dermapteran hindwing is known for its bistable properties, resulting from the interplay of folding geometry and anisotropic distribution of resilin, a protein capable of storing elastic energy. These properties present compelling possibilities for the space industry, aiming to reduce weight and stowing volume of spacecraft by using minimal actuation to deploy structures like solar panels or satellite drag sails. Our research introduces a computational tool, built on top of the open source MuJoCo library, to simulate the biomechanics of wing folding. Initially focusing on the fan-folded area of the hindwing, we demonstrate a bistable system, including both a locked open state and a closing mechanism. This tool reproduces the dynamics of the dermapteran hindwing fan folding as a function of key design parameters. These parameters include geometry, mass, stiffness and actuation, allowing predictions on the structure’s behaviour across different scales. Results demonstrate successful closing within 90 seconds of wing structures with a radius of approximately 50 cm. Closing can be achieved by applying at torques of 20 Ncm locally in the centre of the radial fan. This leads to elastic energy release of tendons, with a stiffness of 30 N/cm, which are substituting the resilin found in the broadened vein patches. Consequently, the wing sections fold, representing a global deformation. The tool demonstrates successful upscaling of the small wing, while preserving the general properties of the bistable system. It serves as a foundation for further software development and engineering of biomimetic, deployable structures for the space industry.

A4.11 KESTREL MORPHING REVEALS STABILITY TAILORING AND AERODYNAMIC BENEFITS OF WING-TAIL COUPLING IN WIND-HOVERING FLIGHT

C Mario Martinez Groves-Raines (University of Bristol, United Kingdom), Shane Windsor (University of Bristol, United Kingdom), Simon Watkins (RMIT University, Australia), Abdulghani Mohamed (RMIT University, Australia) mario.grovesraines.2016@bristol.ac.uk

Actuation has been identified as a significant limiting factor for turbulence mitigation of aircraft. Turning to nature for inspiration enables an understanding of how highly agile birds can articulate their aerodynamic surfaces during precision flight conditions such as wind hovering. Such understanding can inspire morphing actuation that enable higher control authority and rapidity, improving flight performance in challenging scenarios. This paper, therefore, explores the effects of specific kestrel morphing motions using a high-fidelity morphing robot of a kestrel, which replicates predominant motions seen in real wind-hovering kestrels. Through comprehensive wind tunnel testing, the aerodynamic effects and stability implications of wing extension, tail spread, and tail incidence mechanisms are examined. The findings illustrate redundancy in control axes, enabling the birds to trim for stability through their area changing degreesof-freedom. The coupling of wing and tail extension, seen in real flight, not only facilitates improved lift generation but also effectively decouples lift and pitching moment axes, reflecting strategies observed in real kestrel flight. The remarkably low inertia of kestrels, extracted through CT scanning, is found to be an important contributor to the agility advantage of kestrels versus similar sized aircraft. This study highlights the significant potential of bio-inspired morphing, providing fresh perspectives on control strategies informed by nature's flight mechanisms.

A4.12 THE FORWARD KINEMATICS AND WORKSPACE GENERATION OF INSECT LEGS

Benedikt Josten (Kiel University Department of Functional Morphology and Biomechanics, Germany), Thies H. Büscher (Kiel University Department of Functional Morphology and Biomechanics, Germany), Stanislav N. Gorb (Kiel University Department of Functional Morphology and Biomechanics, Germany)

bjosten@zoologie.uni-kiel.de

The multifunctionality of insect legs, i.e. integrating different functions into a single structure, makes them fascinating models for biological and biomimetic research. Understanding and emulating their kinematic architecture offer valuable insights into the leg formfunction relationship and provide novel design concepts for bio-inspired robotic systems. In the present study, a workflow for reconstructing the 3D-workspace of insect legs (all the positions, which the leg tip can reach in 3D space) is proposed on the example of the desert locust Schistocerca gregaria and the dragonfly Anax imperator. The kinematic chain of one fore, middle and hind leg was defined following the Denavit-Hartenberg-convention, which considers the natural alignment of consecutive joint axes. The Denavit-Hartenberg-parameters were calculated based on the coordinate data of the joint articulations

obtained from reconstructed µCT-scans. The determination was performed in a custom R script, which can easily be modified to consider both mono- and multiaxial joints. The kinematic chain model was additionally supplemented with opening angle measurement data of individual leg segments, providing the necessary information to construct the 3D-workspace of the leg. This approach can be applied to any variation of arthropod appendages, providing a basis for broadscale quantitative, comparative analyses to further our understanding of the evolution of arthropod extremities and to potentially use this knowledge in robotic designs.

A4.13 REPRODUCTION OF KESTREL GUST-MITIGATION KINEMATICS WITH A ROBOTIC MORPHING WING

Matthew Penn (RMIT University, Australia), Mario Martinez Groves-Raines (University of Bristol, United Kingdom), Simon Watkins (RMIT University, Australia), Shane P Windsor (University of Bristol, United Kingdom), Abdulghani Mohamed (RMIT University, Australia)

s3545287@student.rmit.edu.au

Flight tests were conducted on Nankeen kestrels (Falco cenchroides) hovering in a wind tunnel to investigate their responses to discrete gusts. Gusts were generated using downstream rotating louvres, which modulated the strength of an updraught in which the birds could hover with wings fixed. Motion capture cameras recorded the kestrels’ kinematic responses during gust encounters. These gust responses were replicated using a robotic morphing kestrel wing and tail with three degrees of freedom: wing extension, tail spread, and tail pitch. The model was pre-programmed with movements imitating the birds’ gust responses, which were actuated in coordination with the gust generator. Measurements of the aerodynamic loads showed that the gust loads were effectively mitigated in the lift axis for both upward and downward step gusts. These findings highlight key degrees of freedom that could inform bioinspired gust mitigation strategies for small UAVs.

A4.1 PUFFERFISH AND THEIR ARMOURED SKIN DURING INFLATION: THE INTERACTION BETWEEN A SOFTHARD INTERFACE FOR SOFT-ROBOTIC APPLICATION

Rachel Tran (University of Liverpool, United Kingdom), Chiara Micheletti (Max Planck Institute of Colloids and Interfaces, Germany), Bahman Taherkhani (University of Southern Denmark, Denmark), Shahrouz Amini (Max Planck Institute of Colloids and Interfaces, Germany), Ahmad Rafsanjani (University of Southern Denmark, Denmark), Beth Brainerd (Brown University, United States), Samantha Gartner (Brown University, United States), Ariel Camp (University of Liverpool, United Kingdom)

rachel.tran@liverpool.ac.uk

In times of stress, pufferfish gulp water or air into their stomach to triple their body volume. This in turn drives their rigid dermal spines, embedded in their soft stretchy skin to rotate in effort to

deter predation. To gain insight on the contrasting properties of this surprisingly understudied interface, we thus implanted skin and spine markers into subjects, to acquire skin-spine kinematics during natural inflation via biplanar x-ray imaging and x-ray reconstruction of moving morphology (N= 6 inflations from 3 individuals). Stomach pressure was also recorded simultaneously. During natural inflation, peak pressures reached a median of 2.46 kPa (N= 11 trials) whilst inflation rates, estimated using a dynamic digital endocast, reached up to 0.517 cm3 /s for a maximum body volume of 140 cm3 . Meanwhile, spines elevated by up to 80° relative to the skin surface and longitudinal skin strain ranged between 1.1 – 1.5 in the midsagittal area. Spine elevation, skin strain and body volume generally plateaued as stomach pressure began to increase. Together with detail on skin-spine microarchitecture and micromechanics (e.g., collagen fibre arrangement in an unstretched vs stretched state and tensile tests), and advanced finite element modelling, we ultimately aimed to develop a soft robotic model. This robot will include repetitive inflation actuation and stretch sensing without risk of tearing. Alternative applications may include prosthetic and multi-material manufacturing.

A4.2 HOW BUMBLEBEES LAND ON RAPIDLY-MOVING FLOWERS: SENSORYMOTOR FLIGHT CONTROL OF LANDING ON SIDEWAY MOVING FLOWERS

Chenyao Wang (Experimental Zoology group Wageningen University, Netherlands), Vincent Van de Pas (Experimental Zoology group Wageningen University, Netherlands), Lana De Vries (Experimental Zoology group Wageningen University, Netherlands), Steffen Werner (Experimental Zoology group Wageningen University, Netherlands), Christophe De Wagter (MAVLab TU Delft, Netherlands), Florian Muijres (Experimental Zoology group Wageningen University, Netherlands)

chenyao.wang@wur.nl

Landing precisely is vital for flying animals. However, disturbances in outdoor environments always complicate the process. For bumblebees, dynamic gusts cause both unpredictable flower movements and displacements of foraging bumblebees, which necessitate a rapid compensation of perturbations with their sensory-motor control system. Here, we study how rapid flower movements affect the landing behavior of bumblebees (Bombus terrestris). Using stereoscopic highspeed videography, we track bumblebees landing on an oscillating flower mimic and model their landing kinematics with control theory. The result shows that bumblebees land on moving flower with rapid motor actions controlled using visual perception of the moving target. The proposed visual-motor control model shows that optical perception signals facilitate bumblebees tracking the moving flower and gaze control while landing. The model also suggests a surprisingly low sensory-motor delay (median 57.1 ms). Moreover, by examining in-flight time histories of roll angle and sideway-acceleration, the helicopter model for aerodynamics force production proposed based on fruit flies is proved as valid for bumblebee flights. These results lead to a more thorough understanding of insect flight control system and could facilitate bio-inspired tracking and landing algorithms for flying robots.

A4.3 A FEATHER-INSPIRED, ELECTROADHESIVE MECHANISM TO IMPROVE FLIGHT CAPABILITIES OF MORPHING WING UAVS

Amy

Jealous (University of Bristol, United Kingdom), Jonathan Rossiter (University of Bristol, United Kingdom), Shane Windsor (University of Bristol, United Kingdom)

amy.jealous@bristol.ac.uk

Fastening barbules are hook-like microstructures on the surface of a bird’s primary flight feathers which prevent separation of adjacent feathers during wing extension. As a result, they are thought to be important for improving bird flight performance at high angles of attack by helping to maintain a smooth aerodynamic surface. This ability would be very useful for morphing-wing uncrewed aerial vehicles (UAVs) which can adjust the shape of their wing to suit a variety of flight conditions. Some of these UAV wings are comprised of multiple feather-like segments which slide over one another. However, they lack this between-feather fastening. Because of this, they struggle in gusty flight conditions and when flying at high angles of attack; their wing segments flap apart creating gaps that air can pass through which prevents the wings from producing sufficient aerodynamic force to maintain flight. Taking inspiration from fastening barbules, we investigate an electro-adhesive mechanism with the aim to enable controllable fastening between wing segments. Electro-adhesion involves the application of high voltage to electrodes which causes them to adhere together, but as soon as this voltage is removed, adhesion is lost. This study measures maximum adhesion strength between two electrodes in multiple directions. Results from these tests will enable application of this mechanism to future morphing wing UAVs.

A4.4 A STRIKING DIFFERENCE: BIOMECHANICS OF A SPECIALIZED PREDATORY STRIKE – THE IMPALING HUNTING STRATEGY OF THE MOSS MANTIS HAANIA ORLOVI (INSECTA: MANTODEA)

Fabian Bäumler (Kiel University Department of Functional Morphology and Biomechanics, Germany), Stanislav N Gorb (Kiel University Department of Functional Morphology and Biomechanics, Germany), Sebastian Büsse (University of Greifswald Cytology and Evolutionary Biology, Germany)

fbaeumler@zoologie.uni-kiel.de

Fast motions play a crucial role in many biological processes, allowing organisms to capture elusive prey, escape predators, or navigate challenging environments with remarkable speed and precision. These rapid movements are especially vital in predator-prey interactions, often requiring a performance that exceeds the limits of pure muscle contraction alone, to fulfil the particularly high demands placed on the associated musculature and skeletal system. To overcome these limitations, specialized anatomical structures and biomechanical mechanisms are employed, often involving elastic energy storage, rapidly released through latch-mediated spring actuation (LaMSA) systems combined with optimized musculoskeletal gearing. These biological catapults are widespread in nature, enabling animals to achieve speeds and accelerations far beyond what muscle power alone

could produce. Although commonly known for their grasping-like predatory strike, which was until now reported to be purely muscle driven, a small group of mantodeans (praying mantises) reveals strong morphological and behavioural deviations. The highly transformed raptorial forelegs of Haania orlovi are moved in a ballistic high-speed motion (~1,6 ms), utilizing the spear-like reinforced distal spines of the tibia to impale their prey item. The system is mainly based on elastic energy storage in the deformed cuticle of the trochanter, presumably caused by co-activated contraction of the large extensor and flexor muscles of the coxa, with a calculated mechanical power output of more than 100.000 W/kg. It presents a very simple and compact power amplification system. Understanding the principles behind such highspeed movements provides insights into evolutionary adaptations of biological systems and may inspire new technological innovations.

A4.6 DIGITAL IMAGE CORRELATION FOR BIOMECHANICAL ANALYSIS OF PLANTS - APPLICATION EXAMPLES AND RECENT ADVANCES

Max D Mylo (Cluster of Excellence livMatS @ University of Freiburg, Germany)

max.mylo@livmats.uni-freiburg.de

Digital image correlation (DIC) is an optical measurement technique for non-contact, full-field displacement and strain analysis of surfaces. Since the advent of DIC algorithms in the 1980s, the technique has evolved and found applications in various disciplines beyond classical materials science. More recently, DIC has played a key role in improving our understanding of plant motion and complementing biomechanical analysis. However, the nature of plant systems, such as their complex geometry and multi-hierarchical structure, has also revealed some DIC limitations, which are being addressed in current work. Although stereo-camera setups are capable of three-dimensional surface analysis (3D-DIC), they cannot cover the entire object for complex structures such as the Hakea fruit. Using a rotatable sample stage with reference points, a system has been developed that can fully visualise the opening mechanism of the Hakea fruit using 360° DIC. Such drying movements can take several hours to days, severely limiting the efficiency of DIC measurements. Robot-controlled systems provide a versatile solution for synchronous high-throughput DIC analysis of multiple samples. In addition, more complex assumptions about the trajectory of optical paths allow analysis of the swelling motion of pine scales in water or through the windows of climate chambers. Furthermore, its sister technique, Digital Volume Correlation (DVC), extends the analysis into the interior of plant structures, further enhancing the informative value of biomechanical analyses. With these recent developments and the ability to directly compare and validate FE simulations, DIC has the potential to play an even greater role in future biomechanical analysi.

A5: OPEN BIOMECHANICS

ORGANISED BY: DAVID LABONTE (IMPERIAL COLLEGE LONDON), PAULINE PROVINI (MUSÉUM NATIONAL D'HISTOIRE

A5.1 AERODYNAMIC EFFECTS OF THE TRANSITION BETWEEN STROKES IN BIRD FLIGHT, WIND TUNNEL STUDY WITH A ROBOTIC WING

Tuesday 8th July 2025 09:00

Victor Colognesi (Lund University, Sweden), Christoffer Johansson (Lund University, Sweden)

victor.colognesi@biol.lu.se

How birds flap their wings, or their kinematics, vary between species, but also individual birds show variation between their wingbeats depending on the flight conditions. Understanding the aerodynamic effects of different wing kinematics can help us explain when and why birds select certain kinematics. A crucial aspect of flapping flight is the transition between successive up- and down-strokes. The pitching motion that occurs at these stages of the flapping cycle, and potential interactions between the wings, may have a large impact on the force production. This is well known for hovering flight but has not been extensively studied in forward flight.

In this presentation, we discuss experiments that were conducted using a robotic, flapping wing in a wind tunnel. The wing kinematics used different timings for the pitching motion in relation to the transition between strokes, and the flapping motion was centered around different mean elevation angles. By measuring the flow behind the wing and analyzing the obtained velocity field, we computed the aerodynamic forces produced by the flapping robot. Our results show that these understudied kinematic parameters affect the absolute and relative production of lift and thrust in flapping flight. Notably, since they have different impacts on the horizontal and vertical forces, they could explain differences in flapping strategies observed in birds at different speeds and in different conditions. The results of this research can thus contribute to understanding bird flight, but also to the design and control of flapping drones.

A5.2 BURROWING PERFORMANCE IN MOLES: A BIO-INSPIRED STUDY FROM BIOLOGICAL TO MECHANICAL JOINT

Tuesday 8th July 2025 09:00

NATURELLE)

Estelle Klein (Muséum National d'Histoire Naturelle, France), Céline Houssin (Muséum National d'Histoire Naturelle, France), Arnaud Delapré (Muséum National d'Histoire Naturelle, France), Damien Chablat (Nantes Université Ecole Centrale de Nantes, France), Mathieu Porez (Nantes Université Ecole Centrale de Nantes, France), Raphaël Cornette (Muséum National d'Histoire Naturelle, France)

estelle.klein@mnhn.fr

Bio-inspiration has led to the development of technical solutions by replicating principles or structures observed in living organisms to create more efficient machines. In turn, these robots can serve as scientific tools to study animal locomotion.

In this context, subterranean animals like moles exhibit a distinct morphology adapted to their specialized lifestyle. Being strictly fossorial, mole species are particularly interesting for studying burrowing performance and adaptations. Our main goal is to explore the relationship between morpho-functional patterns and burrowing performance in moles species while developing a bio-inspired project that integrates and utilizes our biological data. To deepen our understanding, we will design a bio-inspired "mole robot."

Here we present the first step in the transition between biology and mechanics, focusing on the joint level. To achieve this, we conducted anatomical dissections to accurately describe the musculoskeletal characteristics of moles. These results enabled us to precisely define the insertion zones of the muscles and joints in the forelimbs. These biological joints were then translated into mechanical counterparts to design the kinematic chain of the mole robot. Our original data provide a concrete illustration of a crucial step linking biology and robotics.

A5.3 ON THE FILTER-FEEDING BEHAVIOUR OF THE BAMBOO FAN SHRIMP (ATYOPSIS MOLUCCENSIS)

Tuesday 8th July 2025 09:30

Pim G. Boute (University of Groningen, Netherlands), Francis M. Moore (University of Groningen, Netherlands), Maximilian Simon (University of Groningen, Netherlands), Antoine M.P. Deleersnijder (University of Groningen, Netherlands), Eize J. Stamhuis (University of Groningen, Netherlands)

p.g.boute@gmail.com

Filter-feeding organisms strain suspended particles from the water using various mechanisms. Bamboo fan shrimp (Atyopsis moluccensis) are freshwater crustaceans (Decapoda) which filter with basket-like setae fans attached to their first two pairs of pereiopods. Captured particles are brought to their mouthparts by contraction of the fans and subsequent retraction of the pereiopod. Currently, factors determining

the filter-feeding behaviour of bamboo fan shrimp are unknown. On shrimps in a semi-natural aquarium environment, we quantified (i) the effect of flow speed on the filter-feeding mode (active or passive) and filtration activation threshold (both in absence of particles) as well as (ii) the effect of food and non-food particles (of about equal size) on fan contraction and cleaning. In both experiments, shrimps were recorded using videography to analyse the filter-feeding behaviour afterwards. The results indicate that the filter-feeding activity depends on the speed of the oncoming flow. Furthermore, responses to food particles were different compared to non-food particles, where fan morphology seems to play a role. We discuss our findings in the context of flow characteristics, setae morphology, mechano- and chemoreception, contraction stimuli, intraspecific variation, and fan shrimp ecology.

A5.4 FATIGUE INDUCED MICROCRACKS IN LOCUST EXOSKELETONS

Tuesday 8th July 2025 09:45

Christoph Bruns (Hochschule Bremen - City University of Applied Sciences, Germany), Susanna Labisch (Hochschule Bremen - City University of Applied Sciences, Germany), Jan-Henning Dirks (Hochschule Bremen - City University of Applied Sciences, Germany)

cbruns@ext.hs-bremen.de

The cuticle exoskeleton of insects is evolutionarily very successful and extremely versatile, so that insects can be found in a wide variety of habitats. When running, jumping or flying, the exoskeleton of insects is exposed to high dynamic loads. To withstand these loads, the exoskeleton must be very robust and avoid or deal with fatiguerelated damage. However, the strategies that insects use to cope with dynamic loads are still poorly understood. Previous studies have focused on the static mechanical properties of the cuticle and neglected its responses to dynamic loading.

To better understand how insect exoskeletons withstand cyclic loading and how potential fatigue-induced microcracks propagate in the cuticle, we performed biomechanical tests on the tibia of locusts (Locusta migratoria) to simulate realistic loading conditions and to induce microdamage. Advanced imaging techniques (X-ray tomography, scanning electron microscopy and light microscopy) were used to analyze fatigue-induced damage and structural adaptations in the cuticle. In this talk, first results of this ongoing research project, such as the S-N curve and three-dimensional crack paths, will be presented and insights into the fatigue properties of insect exoskeletons will be given.

A5.5 WHAT DETERMINES THE PITCH OF A BEE’S BUZZ?

Tuesday 8th July 2025 10:00

Charlie Woodrow (Uppsala University, Sweden), Mario Vallejo-Marin (Uppsala University, Sweden)

charlie.woodrow@gmail.com

The characteristic buzz of bees, produced by their indirect (thoracic) flight muscles, has been extensively studied in the context of flight. In particular, many studies have investigated how the wingbeat frequency

is influenced by abiotic factors such as air density, temperature, and humidity but is primarily constrained by biomechanical factors such as resonance of the thorax and the need to generate lift. However, these same muscles also produce vibrations in non-flight contexts, including communication, defence, and buzz-pollination. During these behaviours, the wings are decoupled from the system, providing a more direct route to assessing the determinants of muscle contraction frequency. Interestingly, mass-dependence is absent in non-flight buzzing, suggesting that other factors dominate when the wings are removed from the system. Here, we summarise multiple experiments on wild and lab-reared bumblebees to explore these factors. In particular, we demonstrate the role of thorax temperature in determining muscle biomechanics, and show that exposure to heavy metals, which interfere with calcium signalling, can reduce contraction frequency. We highlight that studying non-flight vibrations in bees provides valuable insights into asynchronous muscle function, offering a rich avenue for future research.

A5.6 INVESTIGATING THE MORPHOLOGICAL STRUCTURE OF THE HIGHLY ADAPTABLE MEDITERRANEAN MEDICINAL LEECH (HIRUDO VERBANA) SUCKERS

Tuesday 8th July 2025 10:15

Peter Kappel (Botanical Garden TU Darmstadt, Germany), Simon Poppinga (Botanical Garden TU Darmstadt, Germany) peter.kappel@tu-darmstadt.de

The Mediterranean medicinal leech (Hirudo verbana) possesses two suckers for attachment and locomotion: a posterior one at the rear and an anterior one that forms around the mouth. Both are used for attachment, whereas the anterior one is also used for feeding. The soft, muscular suckers are highly versatile in their attachment capabilities, allowing the leech to adhere to a wide range of surfaces, from smooth and airtight to rough and even porous, both underwater and on land. When faced with a non-airtight surface to which it cannot attach by suction, the leech can attach via secondary mechanisms, such as clamping, locking and spacing. In addition, the mucus secreted by the leech's integument provides wet adhesion. Unlike conventional technical suction cups, Hirudo verbana places its suckers on a surface from the inside to the outside, a method that considerably reduces the dead volume to be evacuated and, consequently, the energy required for suction. A deeper understanding of the functional morphology of leech suckers therefore has great biomimetic potential to improve the adaptability, energy efficiency and thus sustainability of technical suckers widely used in industrial automation. We are using biomechanical methods as well as imaging techniques such as histology and µCT to study the morphological structure of the sucker to eventually determine the form, function and relationship of the sucker's connective and muscular tissues.

A5.7 FROM BONES TO BEHAVIOUR: INVESTIGATING THE FUNCTIONAL MORPHOLOGY OF HOMINOID PRIMATES

Tuesday 8th July 2025 14:00

Evie E Vereecke (KU Leuven, Belgium), Timo Van Leeuwen (KU Leuven, Belgium), Oceane EN Cluzeau (KU Leuven, Belgium), Mythili Damal Kandadai (KU Leuven, Belgium), Julia Van Beesel (KU Leuven, Belgium)

Evie.Vereecke@kuleuven.be

Functional morphology has been central to my academic training, beginning with my Master’s and PhD under Peter Aerts. Throughout my work, I have explored form-function relationships in the locomotor system of hominoid primates, focusing on hands, feet, and more recently, the shoulder. The overarching goal is to understand how the musculoskeletal system adapts to different locomotor and postural behaviours, providing key insights into human evolution. Hominoids, our closest relatives, are particularly valuable for this purpose. A major strength of our research is the integration of detailed morphological analyses with biomechanical experiments, made possible through collaborations with European zoos. Our group studies muscle architecture via dissections, analyses 3D muscle shape and paths using surface scanning, and investigates 3D bone shape through CT scanning and geometric morphometrics. Joint kinematics are assessed in cadaver experiments using optical motion tracking. Our recent work on great ape shoulders (Pongo n=3; Gorilla n=2; Pan n = 4) shows that orangutans exhibit exceptionally high glenohumeral mobility but have similar shoulder muscle properties compared to other great apes. When compared to humans, the supraspinatus of great apes seems functionally distinct. The next phase involves developing musculoskeletal models to test scenarios that cannot be studied experimentally. Given ethical restrictions on primate research, computational modelling presents a unique opportunity to investigate form-function relationships and shed light on key adaptations in our evolutionary history.

A5.8 X-RAY ANALYSIS OF THE FILTERFEEDING MECHANISM OF WILD DUCKS (ANAS PLATYRHYNCHOS)

Tuesday 8th July 2025 14:00

Lukas Hageneder (University of Antwerp, Belgium), Sam Van Wassenbergh (University of Antwerp, Belgium)

lukas.hageneder@uantwerpen.be

Wild ducks (Anas platyrhynchos) forage for food at the water's surface by a behaviour known as dabbling. However, the precise mechanics of this feeding process remain poorly understood. Theoretical models have suggested the involvement of cross-flow filtration, with small vortices forming across the lamellae of the upper and lower beak, but these flow patterns have yet to be experimentally validated. This study seeks to address this gap by providing the first experimental quantifications of the cranial kinematics and hydrodynamics during dabbling in wild ducks. Using a high-speed biplanar X-ray system, we captured particle trajectories alongside the movement of the beak and tongue during filter feeding, and reconstructed these movements in 3D space through X-ray Reconstruction of Moving Morphology (XROMM).

Our results were then compared with existing hypotheses proposing that food particles are temporarily retained within vortices in the lamellae and subsequently scraped off by the tongue. To investigate this, we analysed the vorticity of particles near the lamellae. We also explored the suction mechanism by comparing our kinematic data with a theoretical model of piston-like bulges, which are believed to generate suction. Our findings revealed that the internal cavity formed

by the beak cannot be approximated as a fixed cylindrical shape, and that tongue movements are far more complex than previously assumed. Furthermore, we assessed the efficiency of particle suction across various particle sizes, providing a more nuanced understanding of the feeding process in wild ducks.

A5.9 SWALLOW THOSE WORDS: SOUND PRODUCTION IN THE ATLANTIC CANARY (SERINUS CANARIA) USING BIPLANAR CINERADIOGRAPHY

Tuesday 8th July 2025 14:30

Kelsey T. Stilson (Muséum national d'Histoire naturelle, France), Pauline Provini (Muséum national d'Histoire naturelle, France)

kelsey.stilson@mnhn.fr

Avian sound production has historically focused on the syrinx, the evolutionary analogue of the mammalian vocal cords. However, as any human opera singeror pop star knows,vocalisationis acombination of sound production, amplification, filtering, and muscle control. Recent studies have shown that some of these same core principles of sound production are likely true for Aves as well. A literature search revealed that it is yet to be fully understood how exactly avian anatomical structures and muscle motor commands produce the range of avian vocalizing despite decades of careful anatomical, histological, and, more recently, neurophysiological research. To study the anatomical componentsof sound production in Aves, we used the biplanar cineradiographic system at the Muséum national d’Histoire naturelle in Paris to visualize the movement of the internal anatomical structures in the Atlantic Canary (Serinus canaria). We simultaneously recorded biplanar x-ray videos and audio data of the canary’s vocalisations, including both communication calls and birdsong. We observed significant motions of the beak, the tongue, the larynx and the trachea, as well as overall posture of the animals correlated to sound production. Other oral behaviours such as breathing, eating, clearing of the palate after eating, and preening were recorded as well. The animal was able to quickly switch between behaviours and used many of the same movements for different behaviours. Thus, the anatomical definitions of classic behaviours, such as birdsong, are likely to expand as these newer methods of looking at biological behaviours, including biplanar cineradiography, are developed.

A5.10 THE BIOMECHANICS OF CAMPANIFORM SENSILLA: A FUNCTIONAL INTERPRETATION OF STRAIN SENSING ON INSECT WINGS

Tuesday 8th July 2025 14:45

Myriam J Uhrhan (Imperial College London, United Kingdom) myriam.uhrhan18@imperial.ac.uk

Insect wings undergo continuous deformation during flight, caused by the interplay of aerodynamic, inertial, and elastic forces on the wing. Beyond lift production, insect wings are sensory organs, equipped with a high number and diverse array of sensors. Together with flow sensors,

strain sensing campaniform sensilla (CS) rapidly encode complex wing states. In this study, we explore the activation mechanism of CS and how their sensitivity can be mechanically fine-tuned in the dragonfly wing, through a series of finite element analyses.

First, we examine the functional morphology of individual CS, supporting the pinching hypothesis as the primary mechanism for exciting the associated neuron. Next, we focus on the specific sensor morphology of dragonfly wing CS and the impact of their local environment on sensing properties. Specifically, we investigate how the presence of a bump structure near CS conveys direction selectivity and how the CS field configurations (e.g. density, sensor-to-sensor distance, and orientation) affect individual CS strain perception. Finally, we present a high-fidelity wing base model that emphasizes the significance of sensor location on the activation sequence. Our finding suggests that single CS-bumps on dragonfly wings fire during spanwise bending, while sensilla fields at the wing base monitor loading patterns associated with different flight modes. This detailed biomechanical analysis supports the wing deformation encoding scheme we proposed based on electrophysiological data in a separate study.

A5.11

BALLISTIC SEED DISPERSAL: HOW THE SQUIRTING CUCUMBER PREPARES FOR THE PERFECT SHOT

Tuesday 8th July 2025 15:00

Helen Gorges (Kiel University Department of Functional Morphology and Biomechanics, Germany), Mieke Brinkhaus (Kiel University Department of Functional Morphology and Biomechanics, Germany), Thies H Büscher (Kiel University Department of Functional Morphology and Biomechanics, Germany), Stanislav N Gorb (Kiel University Department of Functional Morphology and Biomechanics, Germany)

hgorges@zoologie.uni-kiel.de

The squirting cucumber (Ecballium elaterium, Cucurbitaceae) exhibits unique mechanical adaptations for explosive seed dispersal. As soon as the fruit is ripened, it explodes due to turgor pressure and ejects its seeds and fluid several meters away. For this mechanism, the fruit requires specialized structural adaptations. This study elucidates the plant’s morphological changes during fruit ripening and seed ejection using micro-CT imaging, 3D-modelling and high-speed videography. 3D-reconstruction showed seeds arranged in six longitudinal rows inside the fruit, attached to vascular bundles on the hilum. During ripening, the fruit prepares for the explosion with straightening of the fruit stem and increasing the angle between stem and fruit to 53°, which comes close to the perfect theoretical angle for the ballistic parabola of 50° without considering air resistance. As the fruit explodes, the seeds, which are shot out of the fruit one after the other and exit the fruit smoothly due to the fruit’s ejected mucus, reach ejection speeds of 10-13 m/s and distances up to 12 m.

The results provide new insights into the structure and mechanical properties underlying the explosive seed dispersal mechanism of the squirting cucumber. The data provides a starting point for elaborated computational analyses and translation to bioinspired engineering.

A5.12 AGE-RELATED SENESCENCE OF AVIAN VOCAL PERFORMANCE

Tuesday 8th July 2025 15:15

Nicholas W. Gladman (University of Liverpool, United Kingdom), Lucas M. Dal'Ava (São Paulo State University, Brazil), Coen P. H. Elemans (University of Southern Denmark, Denmark)

N.W.Gladman@liverpool.ac.uk

Ageing of the vocal system typically takes the form of an inverted U-shaped relationship, where peak vocal performance is achieved in early adulthood before declining with progressive age. These changes likely reflect changes in the underlying physiology and neurological performance. Phonation involves the precise coordination of both respiratory and vocal musculature, with advanced age typically leading to weaker respiratory muscles and slower vocal muscles; where respiratory muscles support vocal strength and endurance, while vocal muscles support more refined vocal control. Here, we investigated the impact of advanced age in zebra finches (Taeniopygia castanotis), analysing age-related changes at both the physiological and wholeanimal levels. We measured the contractile properties of vocal and respiratory muscles of young (≤2 years) and old (≥5 years) male birds, as well as acoustic analyses of songs from animals throughout their lifetime to capture vocal changes over time. We found the respiratory muscles of older animals showed significant declines in force and power output when compared to younger animals, accompanied by significant increases in muscle speed with advanced age. Vocal muscles, however, showed no significant changes with age, suggesting vocal and respiratory muscles age differently. These changes at the musclelevel were detectable at the whole-animal level, with the source level of song declining as age increased. Taken together, our data suggest advanced age is associated with weakening of the respiratory muscles in birds, impacting vocal performance. Despite this, vocal muscle performance is maintained suggesting, while songs become softer, the complexity is not impacted by advanced age.

A5.74 THE EFFECT OF WING FLEXIBILITY ON INSECTS’ AERODYNAMIC PERFORMANCE

Tuesday 8th July 2025 16:00

Roi Gurka (Coastal Carolina University, United States), Ori Stearns (Tel-Aviv University, Israel), Kiruthika Sundararajan (Coastal Carolina University, United States), Dana Melamed (Tel-Aviv University, Israel), Gal Ribak (Tel-Aviv University, Israel)

rgurka@coastal.edu

The aerodynamic performances of aerial organisms are primarily controlled by the wings’ kinematics and morphology. Lift and thrust are generated by the complex kinematic motion for various planform shapes. In insects, the wings are flexible, elastically deforming under loads experienced during flapping. The adaptive value of this flexibility was tested using a revolving wing set-up. We chose to study the wing flexibility of the beetleBatocera rufomaculata. A suite of measurement tools was utilized to characterize the wing elasticity and its impact on the wing-fluid interaction. These include measuring the aerodynamic

loads as function of wing size for various Angles-of-Attack (AoA) using force balance, estimating the wing elasticity through digital imaging and characterize their morphological structures through mCT as well as perform PIV experiments at the downwash region of the wings under rotation. We show that the wing flexibility suppresses the reduction in lift coefficient that is expected to occur with a reduction of wing size. Moreover, the scaling of wing flexibility with size is intra-specifically tuned through changes in wing-vein cross-section, resulting in smaller wings achieving proportionally larger chordwise deformations compared to larger wings, when loaded with aerodynamic forces. These elastic deformations control the separation of flow from the wing as a function of AoA, as evidenced by the turbulence activity in the flow-field directly beneath the revolving wings. The study underlines the contribution of flexibility to control the flow over insect wings through passive wing deformations without the need for input or feedback from the nervous system.

A5.14 THE ART OF FILTER FEEDING: INSIGHTS INTO THE FEEDING MORPHOLOGY AND ECOLOGY OF DABBLING DUCKS

Tuesday 8th July 2025 16:00

Laila Kestem (Muséum national d'Histoire naturelle, France), Pauline Provini (Muséum national d'Histoire naturelle, France), Anick Abourachid (Muséum national d'Histoire naturelle, France)

laila.kestem@mnhn.fr

As part of the Nature4Nature project “Inspired to Integrate: Filtering Nature's Diversity for Nature-friendly Implementations“, this study explores filter-feeding morphology in dabbling ducks for bioinspiration. Dabbling ducks, comprising approximately 70 species, exhibit diverse feeding morphologies and ecological adaptations. However, the relationship between their distinct filtering structures and dietary preferences remains poorly understood, particularly regarding the morphology of soft tissues and keratinized structures. These structures, including the lamellae on the upper and lower beak and the lingual papillae, are integral to filter-feeding on the water’s surface. This project aims to establish clear links between filtration behaviour, diet, and filtering apparatus morphology in dabbling ducks. Using CT-scans of 25 phylogenetically diverse duck specimens and macro photography of 13 dissected tongues, we conducted morphometric analyses to quantify filtering structure variations. Online databases such as Avonet were used to supplement ecological information, including dietary compositions and foraging behaviour. Comparative studies correlated the morphological variations with the ecological data, shedding light on how different filtering structures adapt to various dietary preferences and ecological niches. Our data suggest convergent evolution of tongue morphology for filter-feeding. This research will provide novel insights into dabbling duck filter-feeding mechanisms and the ecological drivers of their morphological diversity. This knowledge will provide new perspectives for the subsequent abstraction of the filter morphology and mechanism for the development of a bioinspired design performing a filter function.

A5.15 THE ALLOMETRY OF CUTTING EFFICIENCY IN ATTA CEPHALOTES LEAF-CUTTER ANTS.

Tuesday 8th July 2025 16:30

Olivia K Walthaus (Imperial College London, United Kingdom), Finn Wagner-Douglas (Hochschule Bremen, Germany), Lina Rhmari-Tlemcani (Imperial College London, United Kingdom), Frederik Puffel (Imperial College London, United Kingdom), David Labonte (Imperial College London, United Kingdom)

l.walthaus20@imperial.ac.uk

Leaf-cutter ants are the dominant herbivores of the Neotropics, responsible for an astonishing 15% of defoliation. To enable foraging on this industrial scale, extreme worker polymorphism has evolved, with associated task-specialisation. Central to this foraging behaviour is cutting - if an ant cannot cut into a leaf, it cannot harvest the plant fragments needed to sustain the colony's fungus gardens. To generate the considerable forces necessary to cut leaves, ants use large mandible closer muscles incurring significant energetic penalties; leaf-cutting is thus not only mechanically challenging but also metabolically costly. The ratio between the mechanical work output and the metabolic expenditure defines the efficiency of the process. Are all worker sizes equally efficient leaf-cutters?

To assess cutting efficiency across the polymorphic workforce of Atta cephalotes, we measured the mechanical power output and metabolic demand of leaf-cutting using PDMS pseudoleaves. Metabolic power, measured via flow-through respirometry, increased with worker size but was independent of pseudoleaf properties, suggesting that ants of all sizes exert maximum effort regardless of cutting difficulty. Mechanical power, estimated from measured cutting force and speed, was driven by pseudoleaf toughness and thickness, not mandible size. Cutting speed increased with worker size but plateaued for larger workers. This led to a local maximum in cutting efficiency, with intermediate-sized workers being the most efficient. Our model predicts this optimal size based on leaf traits, enabling field hypothesis testing.

A5.16 TIME-DEPENDENT ATTACHMENT PROPERTIES OF POLLEN

GRAINS IN ANEMOPHILOUS PLANTS TESTED BY THE MASS CENTRIFUGATION METHOD

Tuesday 8th July 2025 16:45

Martin Becker (Christian-Albrechts-University Kiel Department of Functional Morphology and Biomechanics, Germany), Stanislav Gorb (Christian-Albrechts-University Kiel Department of Functional Morphology and Biomechanics, Germany)

mbecker@zoologie.uni-kiel.de

The process of pollen release, transfer and capture is the most critical step in reproduction of higher plants and requires several steps of detachment and reattachment of pollen grains to different surfaces. As a response to their specific biotic or abiotic factors, pollen grains have developed strong variability of size, shape and surface microstructure, which affects their adhesion properties in a specific manner and

contributes to the pollination syndrome of a plant. However, despite decades of research and a great public awareness, the adhesion forces have rarely been measured directly.

In the present study, we used a mass centrifugation setup with glass as a standard substrate, to characterize time dependent adhesion properties of pollen grains from four anemophilous species and compared them to the results of previous studies. Our results show strong differences in adhesion between species studied in fresh and aged state, which can be related to their respective pollination ecology. We discuss the species-specific adhesive properties of pollen grains in order to collect a broad set of quantitative data about adhesion properties of pollen grains and to understand their role in the process of pollination. The methodological aspects of the study are also discussed and centrifugation method is suggested as a standard approach for this kind of experiments.

A5.17 CONVERGENT EVOLUTION OF MECHANISMS FOR FAILURE- AND WEARPREVENTION IN CHONDRINID RADULAE

Tuesday 8th July 2025 17:00

Wencke Krings (University of Leipzig, Germany), Stanislav N. Gorb (Kiel University, Germany), Bernhard Hausdorf (Leibniz Institute for the Analysis of Biodiversity Change, Germany)

wencke.krings@uni-hamburg.de

The radula, consisting of rows of teeth embedded in a chitinous membrane, is a distinctive molluscan adaptation for gathering and processing food. Among molluscs, this organ displays remarkable diversity in its morphology, material composition, and mechanical properties, depending on the characteristics of the preferred food or/and the substrate to which the food is attached (e.g., sand, stone, or wood surfaces). In this study, we investigate radular morphology using scanning electron microscopy, material composition via energy-dispersive X-ray spectroscopy, and mechanical properties through nanoindentation in six stylommatophoran gastropod species of the family Chondrinidae. Three of these species feed exclusively from rock surfaces, while the other three feed from mixed surfaces.

In addition to morphological differences — rock-scraping feeders have fewer number of denticles — we found that the rock-scraping feeders possess either higher calcium or silicon content in their tooth surfaces. These features are likely adaptations to reduce structural failure and wear. In contrast, the mixed-substrate feeders exhibit teeth with a higher number of delicate denticles and lower content of the aforementioned elements. Furthermore, the teeth of solidsubstrate feeders were harder and stiffer (Young’s modulusE: 8–12 GPa; HardnessH: 0.9–1.3 GPa) compared to those of mixedsubstrate feeders (E: 5–8 GPa;H: 0.4–0.7 GPa). Harder and stiffer teeth likely serve as a mechanism for failure and wear prevention. The rock-scraping feeders do not form a clade within the Chondrinidae indicating that the radular morphologies, material compositions, and mechanical properties characterizing these specialists are the result of convergent evolution.

A5.18 STRUCTURED AIRFLOWS FACILITATE COMPLEX SOARING BEHAVIOURS FOR ENERGY EFFICIENT URBAN FLIGHT

Tuesday 8th July 2025 17:15

Freddie Turner (University of Bristol, United Kingdom), Arthur Richards (University of Bristol, United Kingdom), Shane Windsor (University of Bristol, United Kingdom) freddie.turner@bristol.ac.uk

The air is a dynamic medium. Wind interacts with terrain and obstacles to create complex flows, consisting of updrafts, shear and turbulence on a variety of scales. While these flow effects represent challenges to the designers of small robotic aircraft, birds are known to utilise them to reduce their energetic costs; rising air can be used to offset sink in gliding flight, while wind gradients (nonuniformities in a flow) can result in airspeed increases when the air is accelerated past the bird. This work investigates the use of energy harvesting flight strategies in the complex airflow structures of urban environments. Trajectory generation techniques from optimal control theory were used to derive energy-harvesting manoeuvres for a gull-sized aircraft within computational fluid dynamics models of urban wind fields to evaluate the effect of the wind conditions and environment’s geometry on the energy which could be gained. Our results showed that the wind structures created by buildings could be utilised to substantially extend flight endurance, with both rising air and wind gradients used in the optimised trajectories for energy extraction. Findings from this work could provide insight into the flight strategies of urban birds and enhance the energy efficiency of future aerial robots.

A5.20 CRUSHERS AND GRASPERS: DIVERSIFICATION OF A MUSCULOSKELETAL SYSTEM TOWARD TWO OPPOSITE FUNCTIONAL OPTIM

Wednesday 9th July 2025 15:00

Yuri Simone (University of Antwerp, Belgium), Anthony Herrel (CNR Paris, France), Renaud Boistel (University of Poitiers, France), Arie Van der Meijden (Cibio-Biopolis, Portugal) yurisimone1@gmail.com

When selective pressures for different functions act simultaneously on a structure, morphological diversification can be shaped by adaptation toward distinct functional optima. Systems may evolve along a performance gradient, optimizing different aspects of function in response to ecological demands.

We investigated two scorpion species representing the morphological extremes of chela (pincer) shape. Scorpion chelae exhibit remarkable morphological diversity associated with ecological roles, and their performance varies along a force-velocity continuum. To explore how structural and muscular adaptations shape performance, we developed a biomechanical model integrating synchrotron microtomography, muscle architecture, and performance data.

Our findings reveal that these species exhibit distinct structural and muscular arrangements, each optimized for a different performance outcome. The short-fingered species maximize closing force through

increased mechanical advantage and longer sarcomeres, enhancing muscle contraction efficiency. In contrast, the slender-chela species optimizes closing velocity through muscle orientations that favor rapid acceleration. While additional functional demands likely influence these designs, one morphology appears specialized for quickly capturing prey, while the other seems to be adapted for prey crushing. These divergent performance optima may have played a key role in shaping the trophic ecology of scorpions and influencing the evolution of their venom.

A5.19 THE INFLUENCE OF POLLEN AGING ON ADHESIVE PROPERTIES OF POLLEN GRAINS IN INSECT POLLINATED PLANTS

Wednesday 9th July 2025 15:00

Simon Züger (Kiel University Department of Functional Morphology and Biomechanics, Germany), Stanislav N. Gorb (Kiel University Department of Functional Morphology and Biomechanics, Germany)

szueger@zoologie.uni-kiel.de

Pollination is a fundamental biological process ensuring genetic diversity through sexual reproduction in many plants. For successful pollination, the pollen must be transported from the male parts of a flower (anther) to the female part (stigma) by wind, water and different animal species. Insect pollination has co-evolved with flowering plants (angiosperms) and contributed to their success and high recent diversity. To ensure successful pollination, pollen grains undergo several cycles of attachment and detachment and possess specific adaptations for this purpose in shape, size, surface microstructures, and presence/ absence of the pollenkitt. Although it is known for some plant species that the release mechanisms of anthers and the interaction between pollen and stigma are species-specific, quantitative measurements of adhesion forces are still lacking for the majority of plant species. To better understand these processes and the influence of different abiotic and biotic factors on pollen adhesion, we suggest a standardised method using a mass centrifugation setup and an inert, non-adhesive standard substrate (glass). Using this setup, we investigated adhesion properties of pollen from four zoophilous species and the influence of pollen aging on their pull-off forces. Additionally, we compared time dependent adhesion in pollen aged either on the substrate or on the anthers.

A5.21 VARIATION IN PULMONARY AIRWAY MORPHOLOGY IN CETACEANS FACILITATES

AIR STORAGE DURING DIVING AND RAPID VENTILATION

Wednesday 9th July 2025 15:30

Robert Cieri (University of British Columbia, Canada), Marina Piscitelli-Doshkov (University of British Columbia, Canada), Merryn Tawhai (Auckland Bioengineering Institute, New Zealand), Robert Shadwick (University of British Columbia, Canada)

bob.cieri@gmail.com

The pulmonary systems of Cetaceans are the largest in evolutionary history and tell a fascinating story about adaptation to marine life. Challenges to lung design in cetaceans include extreme body size, the repeated collapse and reinflation of lungs due to external pressure during diving, and extreme ventilatory dynamics due to exceptionally short breaths and high tidal volumes. Using morphological analysis of pulmonary airways segmented from computed tomography (CT) scans of inflated lungs from 13 species, we show that airway morphology differs substantially from terrestrial mammals and varies among cetacean species. Among cetacean lung airways, a greater Strouhal diameter ratio (the degree of diameter decreases along branching generations) is associated with deep-diving, and a lower Stouhal diameter ratio is associated with fast ventilation in a phylogeneticallyinformed analysis. This suggests that changes in airway tree geometry represent a trade-off between the need to store lung gas in the primary airways during diving may be a more important selective pressure than maximizing flow rates. By using computational fluid dynamics simulations built using one-dimensional tree-growing algorithms to extend the pulmonary tree down to the acini, we show that branching angles and diameter ratios evolved to enable extremely fast and short ventilation in cetaceans. Combining our airway sophisticated models with traditional measurements and LiDAR/photogrammetry models of lung anatomy from species which are too large to CT scan, we can perform an allometric analysis of airway shape and size in cetaceans and simulate how breathing works in the largest lungs of all time.

A5.86 THE COMPARATIVE BIOFLUIDMECHANICS OF DIPTERA FLIGHT

Wednesday 9th July 2025 15:45

Florian T Muijres (Wageningen University, Netherlands), Camille Le Roy (Wageningen University, Netherlands), Ilam Bharathi (Wageningen University, Netherlands), Thomas Engels (Aix-Marseille Université CNRS, France), Stanislav Gorb (University of Kiel, Germany)

florian.muijres@wur.nl

Two-winged insects (Diptera) are a highly-diverse group of insects, possess specialized flight motor systems, and exhibit a wide range of flight styles. The wingbeat frequencies in this group vary dramatically, from 40 Hz in craneflies to 1000 Hz in mosquitoes. Despite this, the role of evolutionary diversification in shaping the biofluidmechanics of their flight remains largely unexplored. Here, we studied hovering flight in 47 Diptera species, spanned their complete phylogeny and size range. For each species, we used stereoscopic high-speed videography to quantify hovering flight kinematics, and modelled aerodynamics using Computational Fluid Dynamics. From this, we determined per species their in-flight aerodynamic force production, aerodynamic power requirements, and aeroacoustic sound production. We used μCT to image flight muscle morphology and estimate flight power availability. Our findings show that relative wings size scales inversely with body mass, allowing tiny Diptera to produce sufficient aerodynamic forces for weight support. Furthermore, for most Diptera, mass specific aerodynamic power requirement for flight scales positively with body mass, adhering to physical scaling laws. However, closelyrelated craneflies and mosquitoes are exceptions to these trends. Craneflies, with their unusually large slow-beating wings, exhibit relatively efficient flight strategies. In contrast, mosquitoes and midges demonstrate highly inefficient flight mechanics, while producing enhanced aeroacoustic sound. These Diptera also possess exceptionally large flight motor musculature. Sexual selection might thus have

caused mosquitoes to trade off flight efficiency for enhanced sounds production, required for in-flight mate-selection. Other Diptera might balance flight efficiency and maneuverability, as their flight styles differ that of craneflies.

A5.23 ROBOTICS CONTRIBUTION TO THE UNDERSTANDING OF PASSIVE BIPEDALISM IN BIRDS, BALANCE AND STABILITY EXPLAINED BY TENSEGRITY

Wednesday 9th July 2025 16:00

Idriss Pelletan (Museum nationale d'Histoire naturelleCNRS, France), Roxane Vimbert (Nantes Université - École Centrale Nantes - IMT Atlantique - CNRS, France), Christine Chevallereau (Nantes Université - École Centrale Nantes - IMT Atlantique - CNRS, France), Mathieu Porez (Nantes Université - École Centrale Nantes - IMT Atlantique - CNRS, France), Anick Abourachid (Museum nationale d'Histoire naturelleCNRS, France)

idriss-clement.pelletan@mnhn.fr

All birds have a remarkably efficient balance. This is particularly evident in their ability to maintain an upright posture when resting or sleeping. Unlike humans lineage, the different parts of the pelvic apparatus are not aligned perpendicular to the ground, so they cannot be held upright by the compressive force of gravity. Our previous work has shown, using robotic simulation, that birds with this flexed posture can passively maintain a bipedal position via a tensegrity system. We use our previous model and vary its geometric parameters according to four bird species (Zebra Finch, Mallard, Egret and Macaw) representing different leg proportions. We check the generalisation of our model by applying it to the four species. For each case, we determine the requirements to reach a stable equilibrium. Based on our results, we propose a new model to simulate a wide range of avian pelvic limb proportions and determine the associated stability zone, i.e. the area in which the Centre of Mass (COM) can evolve while maintaining balance. The aim is to compare, describe and identify the parameters that allow the bipedal equilibrium to be maintained in a stable passive manner. We have also identified new features in the maintenance of postural balance, such as the bony and supra-tendinous bridges located on the distal part of the tibiotarsus. Our results provide a better understanding of how birds maintain a stable bipedal posture, as well as providing elements for the future development of bipedal robots.

A5.24 COMPARATIVE AERODYNAMICS OF DIPTERA FLIGHT

Wednesday 9th July 2025 16:15

Ilambharathi Govindasamy (Wageningen University and Research, Netherlands), Camille Le Roy (Wageningen University and Research, Netherlands), Thomas Engels (AixMarseille Université CNRS, France), Stanislav Gorb (University of Kiel, Germany), Florian Muijres (Wageningen University and Research, Netherlands)

ilam.govindasamy@wur.nl

Diptera, one of the most abundant insect groups, represent 15% of animal diversity and exhibit remarkable flight capabilities powered by unsteady aerodynamics and specialized muscles. We investigated the in-flight aerodynamics, aeroacoustics, flight muscle ratio and elastic storage of 47 Dipteran species, covering their full phylogenetic diversity and size range. Our findings show that while derived Dipteran groups maintain conserved flight mechanics, craneflies achieve efficient flight with large, slowly flapping wings, while mosquitoes and midges rely on high-frequency, low-amplitude wingbeats that demand greater power. The flight muscle ratio also follows this trend.

The air friction in low Reynolds number strongly affects the lift-drag ratio in fruitflies and smaller insects, but mosquitoes have larger drag compared to other flies of same Reynolds number. This is due to high friction forces associated with strong rotational motion over flapping motion at low flapping amplitudes. This inefficient flight style, however, enhances sound production efficiency driven by frequency. We also explored the role of elastic energy storage in these species and found diminishing returns for power savings. Even in larger Diptera, some elastic storage is sufficient to minimize power. Furthermore, elastic storage inversely scales with inertial power, highlighting the importance of inertial power in larger species. Overall, our findings indicate that the ancestral groups like craneflies, and mosquitoes/midges exhibit divergent flight mechanics adapted to their ecology, whereas derived Diptera evolved narrow aerodynamic strategies that likely balance flight efficiency and agility. Future studies on Dipteran flight agility will provide deeper insights into the evolutionary trade-offs.

A5.62 OPPORTUNISTS IN THE MARINE REALM: ARE DIETARY SPECIALIZATIONS REFLECTED IN THE FEEDING APPARATUS OF GREY SEALS AND HARBOR SEALS?

Thursday 10th July 2025 09:00

Christine Böhmer (Kiel University, Germany), Anne C. Erichsen (Kiel University, Germany), Julia Schaar (Kiel University, Germany), Friederike Schulz (Kiel University, Germany), Elisabeth Steinbach (Kiel University, Germany), Daniela E. Winkler (Kiel University, Germany), Charlotte B. Thøstesen (The Fisheries and Maritime Museum Esbjerg, Denmark) cboehmer@zoologie.uni-kiel.de

During the land-to-sea transition, pinnipeds underwent an evolutionary shift in emphasis of craniomandibular function from prey processing to prey capture. Additionally, pinnipeds are opportunistic feeders and show flexibility in feeding strategy. They capture prey as efficiently as possible, which may require them to switch between prey types depending on their availability. This challenges the identification of form-function relationships and the reconstruction of the feeding strategy in fossil seals. Here, we investigate two sympatric phocid species from the Northern Sea: the Harbor seal (Phoca vitulina) and the Grey seal (Halichoerus grypus). Although they show disparate tooth morphology (multicusped vs. conical teeth), their diet is relatively similar (mainly fish) as well as their foraging behaviour (pierce feeding). In order to identify similarities and differences between both species and how the respective anatomical features correlate to each other, we obtained

quantitative data on the craniomandibular morphology, the masticatory musculature and the microscopic dental surface wear. The latter stemming from contacts between food and exogenous material with the teeth during feeding. Our analysis showed that P. vitulina primarily consumed hard structures, whereas H. grypus primarily fed on softer food particles. P. vitulina has a relatively shorter craniomandibular morphology suggesting a higher bite force as compared to H. grypus. Likewise, some muscles reveal characteristics that facilitate a wider gape in P. vitulina. Overall, our results show that the anatomy of the feeding apparatus in our specimens relates to differences in food composition with P. vitulina having a larger diet diversity as compared to H. grypus.

A5.63 NEED FOR SPEED: ARE JAW MUSCLE FASCICLE LENGTH AND PCSA DIFFERENT IN SPECIES VARYING IN SINGING CAPACITIES?

Thursday 10th July 2025 09:00

Jana De Ridder (Ghent University, Belgium), Sam Van Wassenbergh (Antwerp University, Belgium), Dominique Adriaens (Ghent University, Belgium)

jana.deridder@ugent.be

A bird’s beak has several functions, from feeding and drinking to singing, leading to a compromise in morphology. Adaptive evolution in relation to feeding ecology is an important driver in beak shape and size. To crack hard seeds, several species evolved a strong beak. Singing on the other hand is an important factor in sexual selection. Females usually prefer more complex songs and high trill rates, reached by fast beak movements. This leads to a trade-off between strong and fast beaks. The biomechanical principles underlying this force-velocity trade-off are, however, still unclear. In a first step to fill this knowledge gap, the anatomy of the jaw muscles was compared for a series of estrildid and fringillid finches varying in beak morphology and singing capacities. Using manual dissections, muscle fascicle lengths were measured and physiological cross-sectional area (PCSA) was calculated. Fascicle length and PCSA indicate the specialization of a muscle in either speed or force. As expected, the closing muscles are well developed in the strong biting species, but the imbalance with the opener muscles also increases. Conversely, for fast singers, a smaller imbalance between opening and closing is expected to facilitate singing. The weak correlations between metrics for singing performance and muscle architecture indicate that other factors are more important in determining song trill rates.

A5.64 FUNCTIONAL MORPHOLOGY OF SEAHORSE TAIL PREHENSION: SCAFFOLDED FROM MICROSCOPICAL AND μCT ANALYSIS

Thursday 10th July 2025 09:30

Danial Forouhar (Ghent University, Belgium), Dominique Adrians (Ghent University, Belgium), Francis Wyffels (Ghent University, Belgium)

danial.forouhar@ugent.be

Seahorses and pipehorses exhibit prehensile capabilities, using their tails to grasp onto objects or anchor themselves. This adaptation is facilitated by unique musculoskeletal structures, including large gaps between bony plates,specialised joints, and a distinct hypaxial muscle architecture. The prehensile tail actuates through active and passive mechanisms, yet little is known about its detailed muscle organisation, muscle-skeletal attachments, and force transmission arrangement. This study investigates the musculoskeletal organisation of the seahorse tail using dissection, microscopic imaging, 3D reconstruction, and contrast-stained micro-computed tomography (µCT). We examine the organisation of hypaxial muscle fibres andunique organisation of parallel running tendon sheets in relation to the bony plates and vertebral column. The hypaxial muscle complex is enclosed in a thin connective tissue layer, forming a long "muscle sac"partially detached from the skeleton. Yet, its forces are transferred to the skeleton via parallel myosepta, extending diagonally over multiple segments, while the attachment architecture of the myosepta to the vertebrae and muscle sac remains unclear. By integrating µCT data with dissections, we visualise the muscletendon sheet sandwich structure, verify its attachments, and its role in controlled grasping. These findings enhance our understanding of force transmission in seahorse tails and provide insights for bioinspired robotics, particularly in semi-soft robotics and semi-flexible actuators.

A5.65 KINEMATICS AND KINETICS OF TRIPEDAL LOCOMOTION IN CANINE AMPUTEES

Thursday 10th July 2025 09:45

Zoe T Self Davies (Harper Keele Veterinary School, United Kingdom), James R Usherwood (Royal Veterinary College, United Kingdom)

z.davies@hkvets.ac.uk

The bipedal and quadrupedal gaits of mammals are largely wellcharacterised within the literature; however, with no true, naturally occurring tripedal gaits, locomotion on three legs is not well understood. Understanding of tripedalism is valuable for research in both veterinary rehabilitation and robotics, where limb-loss may be encountered. Limb amputation is not uncommon in small animal veterinary medicine, following trauma or neoplasia; as such, there is a population of domestic tripedal mammals in the form of canine amputees, providing a unique perturbation into the study of locomotion. The aim of this study was to investigate whether 3-legged dogs use distinct limb sequences which could be determined as gaits, with clearly defined kinematics and kinetics. Data were collected from 12 canine amputees (6 forelimb and 6 hindlimb amputees) moving at a range of speeds. At higher speeds, three-legged dogs use a three beat gallop-like gait. Forelimb amputees use a rotary-like gallop whereby the hindlimb ipsilateral to the remaining fore is always the leading limb, whereas, hindlimb amputees use both rotary- and transverse-like sequences, varying the lead within the forelimb pair. At low speeds two strategies are observed: approximately constant-period single-limb cycles, resulting in the single limb striking more than once per cycle and the loss of consistent hind-fore phasing; or very high period single limb cycles that maintain hind-fore phasing but require either very high hops, or kinetics approaching an inverted pendulum run. Here, we present kinematic and kinetic data across speeds during tripedal locomotion.

A5.47 HILL'S HYPERBOLIC RELATION: THERE'S MORE (MECHANICS) TO IT THAN MEETS THE (PHENOMENOLOGICAL)

Thursday 10th July 2025 10:00

Michael Günther (Universität Stuttgart, Germany)

s7gumi@uni-jena.de

Well known to biomechanists, A.V. Hill formulated in his iconic paper in 1938 that the relation between a muscle fibre's contractile force and its shortening rate of length change (velocity) is of hyperbolic character; a phenomenological derivation based on quantitative measurands of extraordinary quality. First, I reflect in this talk on the conditions under which this relation was formulated, namely, steadystate (nearly constant rate and activity) contractions. Apart from the limit case of near-isometric contractions, such steady-state condition are practically non-existent in animals' everyday movements, in which usually muscle fibres contract with changing activities against both compliant appendages (e.g. tendons) in series and even accelerated body parts. I next refer to experiments on rapid force changes, in which it has been shown that fibres still show hyperbolic force-velocity relations, even if analysed under non-steady-state conditions, then reaching higher contractions rates. I eventually point to the fact that theory (actually, reductionist mechanical models) can indeed explain why hyperbolic force-velocity characteristics of fibres can be observed in a probably broad range of conditions far beyond steady-state. This is because the observations are likely rooted in the structural properties of a cross-bridge, its mechanical element arrangement including compliance and (force-dependent) damping. Also, both the microscopic idea of protein friction and simple thermodynamic considerations based on the idea of discrete cross-bridge states (the core of Huxley-type sliding filament modelling) are consistent with force-dependent damping, which is probably a mechanical key to understand the hyperbolic force-velocity relation.

A5.67 HEMODYNAMIC MECHANISM OF DISSIPATION OF MUSCULAR ENERGY IN HOVERING HAWKMOTHS

Thursday 10th July 2025 10:15

Kostya Kornev (Clemson University, United States), Artis Brasovs (Clemson University, United States)

kkornev@clemson.edu

Understanding the dynamics of blood flow and fuel delivery to the flight muscles of hovering hawkmoths is critical for evaluating the energy budget of these most energy-demanding organs. Flying hawkmoths significantly increase the body temperature and concentration of the lipoprotein nanoshuttles that deliver fuel from the fat body to the muscles. These changes directly affect blood viscosity and the dynamics of blood circulation. Using data on blood viscosity in resting hawkmoths (Sphingidae) and analyzing the structure of flight muscles from X-ray tomography data, we developed a series of models providing estimates of the drag forces exerted by the flowing blood on contracting muscles, pointing on important connection of muscular action with hemodynamics. We show that the flowing blood is able to deform muscle and hence this nontrivial coupling of blood flow and muscular

contraction/relaxation leads to a viscoelastic reaction of the thorax. This work was partially supported by NSF grants IOS 2014664 & 2422802. [1] Brasovs A, Palaoro AV, Aprelev P, Beard CE, Adler PH, Kornev KG. 2023 Haemolymph viscosity in hawkmoths and its implications for hovering flight. Proc. R. Soc. B 290: 20222185

A5.68 EVALUATION OF CAVITATION EFFECT ON IMPACT MITIGATION DURING UNDERWATER PLUNGE OF BOOBIES

Thursday 10th July 2025 11:00

Yoshinobu Inada (Tokai University, Japan), Mitsuhiro Mori (Tokai University, Japan), Hiroshige Matsuoka (Kyoto University, Japan)

inada@tokai.ac.jp

When boobies find prey in the ocean while flying, they dive steeply and plunge headfirst into the water at nearly 100 km/h to catch food. This study aimed to clarify how they protect their bodies from the significant impact upon entry. Based on CT images of the booby’s head, we created a life-sized head model and developed a launching device to achieve an entry speed of nearly 80 km/h and conducted plunge experiments. High-speed cameras captured the moment of impact, and acceleration sensors measured the forces involved. The results showed that the faster the entry speed, the more cavitation bubbles formed around the head. Additionally, we confirmed that these bubbles might help reduce the impact of the plunge.

A5.69 THE EVOLUTION OF CRANIOMANDIBULAR SKELETON ENABLES THE APPEARANCE OF EXTREME FEEDING AND NESTING BEHAVIORS

Thursday 10th July 2025 11:00

Ghislaine Cardenas Posada (University of Kiel, Germany), Christine Böhmer (University of Kiel, Germany)

gcardenasposada@gmail.com

Understanding how animal structure evolves to respond to natural selection while accommodating exceptional behaviors is a major goal in evolutionary biology. In birds, one of the most impressive and innovative behaviors is the pecking that woodpeckers perform. Woodpeckers can access wood boring larvae, build a safe nesting strategy in tree cavities, and communicate efficiently by pecking. While there is considerable research on the mechanisms and morphological traits that have emerged to support the pecking behavior of woodpeckers, little is known about how variation in behavioral phenotypes relates to variation in cranial morphology. The overarching goal of this proposal was to investigate how the morphology of the craniomandibular apparatus varies across woodpecker species and how it relates to variation in behavioral traits associated with their pecking behavior. To do this, we took µCT scans from the head of specimens loaned from several museums across Europe and obtained scans from open databases like Morphosource and Morphobank. Using this data, we quantified several traits of internal and external morphology of the craniomandibular apparatus of woodpeckers. Based

on information obtained from the literature we categorized species based on whether they are primary or secondary cavity nesters and whether they are extractive foragers or gleaners. Using representatives of 20 genera, we then ran phylogenetic comparative analysis to explore the coevolution of both morphological and behavioral traits. We find significant morphological variation across the family and a strong correlation with behavioral phenotypes.

A5.70 THE CONTROL OF TARGETED JUMPS IN PRAYING MANTISES

Thursday 10th July 2025

11:30

Girish Kumar (National Centre for Biological Sciences, India), Sanjay P Sane (National Centre for Biological Sciences, India)

girishkumar@ncbs.res.in

To locomote across their discontinuous habitats, arboreal insects must overcome challenges such as path gaps, changing inclines and various textures that can affect traction. Insects such as praying mantises and katydids jump across leafy substrates to scale the gaps. To perform such targeted jumps, the insect must first orient itself towards the target, estimate the target distance and angle, and then jump with the appropriate take-off speeds and angles to land. Before making a targeted jump, mantises estimate the target distance using motion parallax via a behaviour called ‘peering’. Because the distance is estimated before jumping, we hypothesise that mantises modulate take-off speed and angle to ensure a proper landing. To test this hypothesis, we developed a behavioural assay consisting of a launch platform on which the mantis was placed and a target platform positioned at variable distances and angles. We filmed the jumps of the praying mantis (Hierodula spp.) nymphs with a single high-speed camera and tracked the body parts to obtain take-off speed and angle. The jumps of praying mantis nymphs, which lack wings, can be modelled as projectiles. Although there are infinite combinations of speeds and angles in principle to reach the target, our results indicate that mantises use a combination in which they control take-off speed with the target distance and the take-off angle with the target angle. Mantises achieve the modulation in take-off speeds by changing their acceleration while keeping the duration of acceleration constant. Together, our results provide insights into mantises achieving targeted jumps.

A5.71 DESICCATION, TANNING AND DEPOSITION: FIRST INSIGHTS INTO WOUND HEALING IN LOCUSTS (LOCUSTA MIGRATORIA)

Thursday 10th July 2025 11:45

Jonas J Unterholzner (Hochschule Bremen - City University of Applied Sciences, Germany), Jan-Henning Dirks (Hochschule Bremen - City University of Applied Sciences, Germany)

Jonas.Unterholzner@hs-bremen.de

Insects are one of the most evolutionary successful groups, thriving in nearly all ecosystems on Earth due to their versatility. This makes insect cuticle one of the most abundant biological materials. Despite their relatively high resistance to mechanical stress, insects constantly

face the risk of injury in their daily lives. In case of an injury, they must protect themselves from dehydration and pathogen invasion by sealing the wound. Given the relatively short life cycle of most insects, it remains unclear whether proper wound healing is ontogenetically beneficial. To investigate this, we developed a precise method for making small incisions through the tibial epidermis of mature locusts (Locusta migratoria). From a macroscopic perspective, wound darkening appears to increase over time, likely due to desiccation and tanning. Additionally, we performed microCT scans to better understand the wound closure process. Our findings show that cuticle thickness increases during healing, but it remains unclear whether this results from a directed deposition of new cuticle or simply the accumulation of haemolymph proteins to facilitate closure. To explore this further, we analysed multiple time points to compare different stages of healing. The talk will present the first results of this ongoing research and offer insights into the general wound healing processes in locusts.

A5.72 FORELIMB MOTION AND RECIPROCATION MEDIATE AERODYNAMIC CONTROL IN A GLIDING LIZARD

Thursday 10th July 2025 12:00

Erik A Sathe (University of Oslo, Norway), Robert Dudley (University of California Berkeley, United States)

e.a.sathe@ibv.uio.no

Aerial locomotion has evolved repeatedly in arboreal lineages. Many of these organisms lack wings yet have considerable control over their speed and trajectory while airborne. Forelimb activities and body postures can provide pathways for aerodynamic control in wingless taxa that can nonetheless glide. The flat-tailed house gecko (Hemidactylus platyurus) is one such arboreal organism that has been shown to engage in directed aerial descent. However, the active role of their limbs has not yet been explored. We characterized limb and body kinematics of H. platyurus descending in a vertical wind tunnel so as to determine biomechanical consequences of forelimb movements during controlled aerial behavior. We hypothesized that active movement of the forelimbs while gliding in this posture can be used to control body orientation and aerodynamic force production. We used MATLAB software to digitize and reconstruct the geckos’ movements in three dimensions as well as to estimate their velocities and accelerations using the first and second derivatives of a quintic spline smoothing algorithm, respectively. Geckos mostly assumed a stereotypical skydiving posture but intermittently would flex the body ventrally as the forelimbs were retracted posteriorly. Shoulder retraction, spinal column flexion, and subsequent translational velocity in the vertical and cranial directions were positively correlated; body pitch correlated positively with vertical acceleration and negatively with horizontal acceleration. Such alteration of body posture with simultaneous forelimb displacement thus modulates the directions and magnitudes of aerodynamic forces, suggesting aerodynamic function for limb displacement and reciprocation in the absence of wings.

A5.73 NO TORQUE-FREQUENCY TRADE-OFF WILL SLOW ME DOWN: BIOMECHANICS OF HIGH-FREQUENCY FINGER MOVEMENTS

Thursday 10th July 2025 12:15

Cas Jorissen (Universiteit Antwerpen, Belgium), Sam Van Wassenbergh (Universiteit Antwerpen, Belgium) cas.jorissen@uantwerpen.be

The vertebrate body contains many lever systems operated by antagonistic muscle pairs. Some are involved in tasks with potentially conflicting mechanical demands. To better understand these demands, insight into the biomechanical basis of performance trade-offs is needed. Humans use their fingers for tasks requiring high static forces (e.g. gripping) or fast, repetitive movement (e.g. typing, playing musical instruments). The flexor muscles can be disproportionally stronger than the extensor muscles for individuals excelling in gripping, resulting in a large antagonistic torque imbalance. This imbalance may affect rapid finger movement, as fully activating the flexor muscles would inevitably lead to delayed or slowed finger extension while the powerful flexors are relaxing. Hence, a torque-frequency trade-off is expected. We measured the maximal torque output of the index finger during both flexion and extension in 137 individuals to assess the torque imbalance. High-speed videos of standardised index finger oscillations are used to quantify maximal frequency, and surface-EMG provides comparative data on activation patterns. In contradiction to our hypothesis, we found a positive correlation between static finger torque and frequency output, meaning that stronger people can also produce higher frequencies. Notably, the duration of flexion movements decreases with increased finger torque. Our results, therefore, show no torque-frequency trade-off in rapid finger movements in humans. The implications for other multifunctional lever systems, such as bird beaks, will be discussed.

A5.13 TESTING THE GEARBOX HYPOTHESIS OF INSECT FLIGHT

Friday 11th July 2025 09:30

Sanjay P Sane (National Centre for Biological Sciences Tata Institute of Fundamental Research, India), Abin Ghosh (National Centre for Biological Sciences Tata Institute of Fundamental Research, India), GS Girish Kumar (National Centre for Biological Sciences Tata Institute of Fundamental Research, India)

sanjay.sane@gmail.com

Flying insects flap their wings at very rapid rates and yet very precisely. For instance, flies, bees and beetles beat their wings at frequencies of a few hundred cycles per second because the muscles powering their flight possess a property called delayed stretch activation. In these insects, stretch activation combines with indirect muscle architecture to generate a thoracic resonance enhancing wingbeat frequencies approximately tenfold. These insects could hence miniaturize - a key factor in their evolutionary success. How do thoracic vibrations convert into precise and coordinated wing movements? At the junction of the wing and thorax, the wing hinge consists of three structures - the Pleural Wing Process (PWP), the Radial Stop (RS) and the Pterale C

(Pt-C). The PWP is a grooved gearbox-like structure which mechanically interacts with RS. This interaction is hypothesized to be crucial for amplitude modulation in flies, allowing them to make sharp turns during aerial maneuvers. Alternatively, wing modulation may be primarily driven by the steering muscles. We tested the gearbox hypothesis by selectively ablating the PWP and observing its effect on free-flight maneuvers. Even after gearbox ablation, flies can make sharp yaw turns, indistinguishable from the unablated controls. We also imaged the wing hinge in a set of diverse flies and observed that the gearbox structure are not conserved in diverse flies although they can conduct intricate maneuvers. Thus, the gearbox structure may be of secondary importance as compared to the steering muscle activation in modulation of amplitudes.

A5.75 STICKING ON TIME –INVESTIGATING THE BIOMECHANICS OF TENTACLE ATTACHMENT IN CUTTLEFISH

Friday 11th July 2025 09:45

Alexander Koehnsen (Wageningen University and Research, Netherlands), Jesse Hopstaken (Wageningen University and Research, Netherlands), Johan L Van Leeuwen (Wageningen University and Research, Netherlands), Sebastian Henrion (Wageningen University and Research, Netherlands), Remco Pieters (Wageningen University and Research, Netherlands), Guillermo J Amador (Wageningen University and Research, Netherlands)

alexander.koehnsen@wur.nl

Decapod cephalopods (cuttlefish and squid) are well known for their tentacle strikes during hunting. The tentacles are modified arms that rapidly extend to grasp prey. Each tentacle consists of an extensible stalk and a terminal club, which is equipped with suckers for attachment. This prey capture method comes with several challenges. The tentacle clubs have to be extended fast enough for the prey not to escape, their position and orientation has to be correct for the suckers to make contact, and the suckers have to actually attach by generating suction pressures. All of this happens within less than 40 milliseconds. Here, we describe the 3D kinematics of tentacle strikes of the dwarf cuttlefish Sepia bandensis combined with the club movements during attachment to a flat surface. Tentacle strikes follow a distinct sequence, beginning with an initial positioning phase, followed by rapid extension. As the extension nears completion while reaching the prey, the clubs unfurl lateral fins and adjust their orientation for contact, while the tips of the clubs remain connected and the stalk buckles upon contact. Our research may provide a foundation for exploring decapod hunting strategies, contributing to a broader spectrum of investigations concerning the behavioural ecology, neuromechanics, and biomechanics of cephalopods. Additionally, understanding the deployment of soft appendages with potentially passive suckers might help us design fast and versatile bioinspired gripping devices.

A5.76 RUNNING GRACEFULLY IN ARMOUR: A TRADE-OFF BETWEEN OSTEODERM PROTECTION AND MOBILITY IN A CORDYLID LIZARD.

Friday 11th July 2025 10:00

Eleesha Annear (University of Antwerp, Belgium), Simon Baeckens (University of Antwerp, Belgium), Chris Broeckhoven (University of Antwerp, Belgium), Peter Aerts (University of Antwerp, Belgium), Raoul Van Damme (University of Antwerp, Belgium)

eleesha.annear@uantwerp.be

Osteoderms, bony elements within the dermis of a disparate set of vertebrates like reptiles and amphibians, are often associated with protective functions. The graceful crag lizard Hemicordylus capensis exhibits an unusual intraspecific variation in osteoderm expression. Individual osteoderms can have elongated or discoid shapes, be keeled or not, and their total volume can vary between 0 and 80 mm3 per individual lizard. We hypothesise that this variation reflects local shifts in the balance between the protective benefits and costs (reduced mobility) of osteoderm expression and morphology, with animals heavily invested in osteoderm-based protection experiencing reduced flexibility and impaired climbing performance. To test this idea, we combined high-speed video footage of climbing lizards and micro-computed tomography to assess the influence of osteoderms on mobility. Our results indicated that osteoderm expression did not directly constrain climbing performance through reduced flexibility. Instead, we found an indirect effect: individuals with higher osteoderm expression exhibited shorter stride lengths, leading to significantly slower climbing speeds. Furthermore, osteoderm morphology played a key role, with lizards exhibiting high volumes of discoid osteoderms climbing significantly slower than those with similar volumes of elongated osteoderms. These findings suggest that while osteoderms do not rigidly limit body flexibility, they impose functional trade-offs by reducing stride-length and climbing performance depending on their osteoderm morphology. Our study highlights the complex interplay between osteoderm protection and locomotion, demonstrating that osteoderm variation in H. capensis likely reflects ecological and functional trade-offs rather than serving purely as a protective mechanism.

A5.77 A NEW STATE-OF-THE-ART COMPUTATIONAL BIOMECHANICS WORKFLOW TO ELUCIDATE THE KINETIC NATURE OF LIZARDS DURING BITING

Friday 11th July 2025 10:15

Jordi Marcé-Nogué (Universitat Rovira i Virgili, Spain), Laia Garcia-Escolà (Institut Català de Paleontologia Miquel Crusafont, Spain), Andrea Villa (Institut Català de Paleontologia Miquel Crusafont, Spain), Arnau Bolet (Institut Català de Paleontologia Miquel Crusafont, Spain), Wencke Krings (University of Leipzig, Germany), Alejandro SerranoMartínez (Institut Català de Paleontologia Miquel Crusafont, Spain), Stanislav Gorb (Kiel University, Germany), Penélope Cruzado-Caballero (Universidad de La Laguna, Spain), Carolina Castillo-Ruiz (Universidad de La Laguna, Spain), Josep Fortuny (Institut Català de Paleontologia Miquel Crusafont, Spain)

jordi.marce@urv.cat

The vertebrate skull faces a crucial challenge: balancing the need to protect critical regions (such as the brain) while enabling effective food processing. To evaluate the cranial kinesis of the Gran Canaria giant lizard (Gallotia stehlini), we created a new state-of-the-art workflow that improves previous computational models in the field in terms of complexity and reliability. We combined a musculoskeletal model using Multibody Dynamic Analysis (MDA) with Finite Element Analysis (FEA) and optimization methods using genetic algorithms in forward dynamics to model biting behaviour under different biting configurations. The skull model was generated using micro-computed tomography, and adductor muscles were reconstructed to create the musculoskeletal model. This model allowed for the optimization of bite force to infer the muscle forces used as input in the FEA model. Both the musculoskeletal and FEA models were tested under three independent kinetic configurations: akinesis, streptostyly, and amphikinesis. FEA models incorporated cranial sutures using contact elements and heterogeneous material properties derived from nano-indentation experiments. This approach allowed for a confident evaluation of how different kinetic and suture configurations balance the two conflicting roles of protecting important areas and chewing and processing food. Results show that streptostyly reduces stress in key areas of the skull and mandible, helping to prevent damage, while akinetic and amphikinetic configurations have higher stress levels, making them more likely to fail. Additionally, experiments of biting force in living specimens confirms that models featuring streptostyly most closely approach in-vivo measured forces.

A5.78 UNVEILING THE SECRETS OF LEAF UNFOLDING: NEW INSIGHTS FROM PELTATE SPECIES SYNGONIUM PODOPHYLLUM AND PILEA PEPEROMIOIDES

Friday 11th July 2025 10:30

Michelle Modert (University of Freiburg, Germany), Tom Masselter (University of Freiburg, Germany), Thomas Speck (University of Freiburg, Germany)

michelle.modert@biologie.uni-freiburg.de

Leaf unfolding is a critical process in plant development. Yet, despite the remarkable diversity of leaf-bearing plants, the underlying mechanisms driving this process remain poorly understood. Most studies focus on predictive models under varying conditions but often lack a comprehensive biomechanical perspective. Peltate leaves, unlike typical foliage leaves that unfold via creases, often emerge in a ‘rolled-up’ state, making their unfolding particularly intriguing.

This study explores the distinct unfolding dynamics of two model species: Syngonium podophyllum and Pilea peperomioides. S. podophyllum unfolds asymmetrically, with its two halves opening successively, driven primarily by upper epidermal cell expansion. In contrast, P. peperomioides unfolds symmetrically, with its two halves opening simultaneously, while undergoing significant morphological changes including lateral growth of the lamina and coordinated cell proliferation and expansion in the upper and lower epidermal layers. While the underlying mechanisms remain complex, factors such as cell wall elasticity, turgor pressure, and microfibril orientation seem to play key roles in the unfolding of P. peperomioides leaves. By shedding light on the process of peltate leaf unfolding, this presentation aims to deepen our understanding of and inspire new perspectives in leaf development research.

A5.79 THE LOCOMOTORY PROFILING OF FRESHWATER PRAWNS: A BIOPHYSICAL APPROACH

Friday 11th July 2025 10:45

Ishika Pal (Ethophilia Research Foundation, India)

chayanbio@gmail.com

Animal locomotion is a key action in the prey-predation interaction and is widely acknowledged as one of the most significant factors in the evolutionary success of any species.Macrobrachium lamarrei, a freshwater prawn species is unique to study movement biophysics and its corresponding physiology. Intricate locomotory patterns and biomechanical approaches make this species an excellent model to understand complex biomechanical process of movement. The organism is capable of extreme fast swimming because to its specific morphometrics. Videographic analysis of the study organism (Macrobrachium lamarrei) was done to understand clearly the biomechanical manifestations of superfast movement pattern. The biophysical movement profiling was done calculating essential locomotory parameters like velocity, acceleration and swimmeret strokes. Using the effectiveness of swimmerets and pereiopods,Macrobrachium lamarreidemonstrates the collaborative effort of swimming and walking. Extremely quick swimming is possible because of the organism's unique body posture and profoundly flexible abdomen. The biophysiological process of the superfast movement is supported by the array of short and long muscles. According to our hypothesis, the prawns efficiently process a deep angular structure using their abdominal divisions and gain potential energy to provide push for their rapid swimming. We have named this movement as catapulting movement. This study aimed to elucidate the possible mechanisms of superfast movement of freshwater prawns (Macrobrachium lamarrei), which corroborates the efficacy of locomotory profiling substantiating the evolutionary success of the prawn’s species.

A5.80 WAKE ANALYSIS OF A ROBOTIC AVIAN WING WITH MOULT GAPS IN FLAPPING FLIGHT

Friday 11th July 2025 11:30

Daniele Certini (Lund University, Sweden), Christoffer Johansson (Lund University, Sweden), Anders Hedenström (Lund University, Sweden)

daniele.certini@biol.lu.se

Birds regularly moult their feathers when they are worn from use such as mechanical wear damage due to UV exposure or accidents. Moulting generates temporary, generally symmetric, wing gaps, which can reduce flight performance by altering aerodynamic forces, lift and drag. Birds can compensate for some of these effects through mass loss, enlarged flight muscles, and adaptive wing morphing. To circumvent compensatory modulation by the birds, we performed experiments with a biohybrid robotic wing in a state-of-the-art wind tunnel. The biohybrid robotic wing, resembling a jackdaw, enables precise control over flapping kinematics, pitching, and wing folding behaviours while closely approximating avian wing morphology. We replicated the moult gaps observed in a jackdaw previously studied in gliding flight by selectively removing feathers on the robotic wing. Stereo particle image velocimetry was employed to characterise the wake structure and quantify changes in vorticity production and distribution due to feather loss across a range of kinematics and flight speeds. By linking wake dynamics to kinematic parameters, we aim to elucidate how naturally occurring moult gaps and wing damage influence aerodynamic performance. Our findings provide insight into how birds mitigate the aerodynamic costs of moult through behavioural and physiological adaptations, helping to explain why moult often coincides with specific phases of the annual cycle. Understanding these compensatory strategies sheds light on how birds maintain flight efficiency despite temporary losses of the wing surface. Beyond avian flight, these findings could inform strategies for mitigating the effects of wing damage, particularly in micro aerial vehicles.

A5.81 INTRODUCING THE MONKEY GRASSHOPPER,

A SPRING-POWERED JUMPER

WITH THE ABILITY TO CONTROL ITS LINEAR VELOCITY

Friday 11th July 2025

11:30

Shannon L Harrison (Shannon Harrison, United Kingdom), Gregory Sutton (University of Lincoln, United Kingdom), Charles D Deeming (University of Lincoln, United Kingdom)

shannonharrisonh1@gmail.com

Jumping represent one of the most widely used modes of locomotion in the animal kingdom. However, this does not mean that the characteristics of jumps are universal; there are many different ways in which jumps are powered (actuated). In orthopterans there are two main methods of actuation; direct muscle actuation and latch mediated spring actuation. It has previously been suggested that spring actuated systems provide propulsive power to an animal, which in turn generates incredibly fast jumps. Clown hoppers (Eumastacidae) are a group of south American grasshopper which use their spring actuated laterally projected legs to achieve jump speeds of up to 3.1 m/s. Similar to the muscle actuated group of arboreal orthopterans (Phlugidini), the clown hopper will perform targeted jumps, although the level of control which they employ is less fine tuned. When clown hoppers are presented with 3 different overhead target heights (50 mm, 75 mm and 100 mm), there was a significant difference between the linear velocity (m/s) at take-off with jump speed increasing as target height increases. However, whilst there was a generalised decrease

in angular velocity (rad/s), this was not significant suggesting that whilst the hoppers can control the extent to which the spring in their legs powers the jumps (represented by the proportionate change in speed of the jumps), the ability to control jump rotation at different heights remains obscure.

A5.82 VARIATION IN HYDRODYNAMIC PERFORMANCE AMONG BOXFISH CARAPACE SHAPES

Friday 11th July 2025

12:00

Merel Van Gorp (Universiteit Antwerpen, Belgium), Igor Bij de Vaate (Rijksuniversiteit Groningen, Netherlands), Pim G. Boute (Rijksuniversiteit Groningen, Netherlands), Simon Baeckens (Universiteit Antwerpen, Belgium), Eize J. Stamhuis (Rijksuniversiteit Groningen, Netherlands), Michael E. Alfaro (University of California Los Angeles, United States), Sam Van Wassenberg (Universiteit Antwerpen, Belgium)

merel.vangorp@uantwerpen.be

The clade of boxfish (Ostraciidae and Aracanidae) are reef-dwellingfish that share a unique feature, the carapace. The body of Ostraciidae is completely covered by a bony shell of fused hexagonal plates. In Aracanidae, the carapace also covers the body, but is not completely closed at the caudal peduncle for some of the species. The carapace provides protection against predators, but its shape also defines their hydrodynamic characteristics. Among the many extant species, shapes vary between boxes with major lateral keels, over wedges with dorsal and ventrolateral keels, to more disc-like shapes with major dorsoventral keels. Here, we studied how hydrodynamic performance differs among twenty-nine species of boxfish. Drag forces and pitch and yaw moments were calculated using computational fluid dynamics simulations based on 3D laser-scans of museum specimens, which were all digitally rescaled to the same carapace volume. Up to 40% difference was observed between boxfish species with the lowest drag force and those with the highest drag force. We determined that Aracanidae have a significantly higher drag force than Ostraciidae. Additionally, we found a strong positive correlation between drag force and frontal-projected area and a negative correlation between drag force and carapace length. The strong variability in drag force related to the degree of axial compression of boxfish shapes, together with the relatively high coefficients of drag in boxfish in general, suggests that weak selection pressures on drag-reduction are common in this group.

A5.83 MECHANICS OF BACKWARD SWIMMING IN MOSQUITO LARVAE

Friday 11th July 2025 12:15

Karthick Dhileep (University of New South Wales Canberra, Australia), Fang-Bao Tian (University of New South Wales Canberra, Australia), John Young (University of New South Wales Canberra, Australia), Joseph C.S. Lai (University of New South Wales Canberra, Australia), Sridhar Ravi (University of New South Wales Canberra, Australia) k.dhileep@unsw.edu.au

Aquatic locomotion in invertebrates is notable, as many display unique kinematics that diverge from those seen in vertebrates. These deviations raise fundamental questions about the evolution and effectiveness of these gaits, as well as the underlying physical mechanisms. The potential benefits of these gaits provide further incentive for their study, particularly for artificial underwater swimmers. In this study, we focus on one such gait displayed by mosquito larvae. In response to a threat, mosquito larvae undergo large amplitude undulatory bending of their bodies. Unlike their low amplitude forward swimming counterparts such as fishes, this large amplitude bending results in backward swimming, with the tail leading the body. To understand this unique gait, high-speed filming of the backward gaits of mosquito larvae was conducted. Through marker-less tracking, key kinematic and dynamic parameters of locomotion were quantified and analysed. Additionally, the flow field around the larvae was determined through particle image velocimetry analysis. The results revealed that extensive body bending leads to distinctive body dynamics supported by strong vortical flow structures and hydrodynamic forces. This results in increased rotations of the body, aligning the larvae nominally orthogonal to the swimming direction and propelling them with the tail in the lead. Compared with forward swimming, the backward gaits produce higher swimming speeds, ideal for escape responses.

A5.84 COMPUTATIONAL HYDRODYNAMIC ANALYSIS OF SUCTION-FEEDING IN A GIANT SALAMANDER (ANDRIAS, CRYPTOBRANCHIDAE)

Friday 11th July 2025 12:30

Matheo López-Pachón (Universitat Rovira i Virgili, Spain), Jordi Marcé-Nogué (Universitat Rovira i Virgili, Spain), Josep Fortuny (Institut Català de Paleontologia Miquel Crusafont Universitat Autònoma de Barcelona, Spain), Ryoko Matsumoto (Kanagawa Prefectural Museum of Natural History, Japan)

matheo.lopez@urv.cat

Suction-feeding is a method of prey capture in fluids by sucking the prey into the predator's mouth. This highly specialised mechanism has been employed by various taxa, including the salamander group Cryptobranchidae, since the Jurassic period. Modern salamanders of the genus Andrias have preserved this feeding strategy without significant morphological changes since the Oligocene. Understanding the biomechanics of suction-feeding is valuable for analysing the physical and morphological mechanisms that support it, as well as its influence on the evolution of feeding strategies in aquatic amphibians, given that suction-feeding has proven to be a highly successful mechanism.

In this study, we developed a two-dimensional Computational Fluid Dynamics (CFD) model of suction-feeding based on micro-CT scans of a first-generation hybrid Andrias davidianus x Andrias japonicus from the Okayama region, Japan. Transient CFD simulations were conducted using unstructured dynamic meshes, along with an overset approach, which allows bidirectional interaction between the prey and the surrounding fluid. Translation and rotation movements of the skull and lower jaw were implemented, also considering surface deformation. Additionally, the depression of the hyoid was considered. The inertial properties of the dynamic mesh were defined according to data from previous studies on Chinese giant salamander (Andrias davidianus). Variables such as prey position, size, and weight were parameterised. The results reveal that cranial geometry, the hyoid

apparatus, and prey properties play a crucial role in generating negative pressures that facilitate feeding.

A5.85 STRUCTURAL, MECHANICAL AND CHEMICAL ADAPTATIONS OF AROLIUM UND EUPLANTULAE IN THE STICK INSECT MEDAUROIDEA EXTRADENTATA

Friday 11th July 2025 12:45

Julian Thomas (Kiel University Department of Functional Morphology and Biomechanics, Germany), Alexander Kovalev (Kiel University Department of Functional Morphology and Biomechanics, Germany), Esther Appel (Kiel University Department of Functional Morphology and Biomechanics, Germany), Thomas Schmitt (Würzburg University Department of Animal Ecology and Tropical Biology, Germany), Zsolt Karpati (Würzburg University Department of Animal Ecology and Tropical Biology, Germany), Thies H. Büscher (Kiel University Department of Functional Morphology and Biomechanics, Germany), Stanislav N. Gorb (Kiel University Department of Functional Morphology and Biomechanics, Germany)

jthomas@zoologie.uni-kiel.de

Stick and leaf insects (Phasmatodea) rely on two distinct types of smooth cuticular attachment pads on their tarsi to attach and move on diverse substrates: the pretarsal arolium, which is mainly specialized to generate adhesion, and the tarsal euplantulae, which are mainly responsible for providing friction. Both pads produce fluid secretion in the contact area to support their respective functions. These pads work in a complementary manner, allowing the insects to adapt their attachment strategy to the substrate properties. However, a comparative study of structural and mechanical properties, as well as chemical composition of adhesive secretion of arolium and euplantulae is lacking in the literature.

Here, we aim to bridge this gap and present a comprehensive analysis of both types of attachment pads by integrating ultrastructural analysis (histology, light microscopy), mechanical characterization (atomic force microscopy), and chemical profiling (gas chromatography-mass spectrometry).

Our results reveal that the adhesion-specialized arolium possesses a loosely-distributed fibrous ultrastructure, lower elastic modulus, and higher pull-off forces. It also secretes a larger volume of adhesive fluid, enriched with methyl-branched hydrocarbons. In contrast, the friction-optimized euplantulae exhibit a densely-distributed fibrous ultrastructure, higher elastic modulus, lower pull-off forces, and produce fluid with fewer amount of methyl-branched hydrocarbons. These structural, mechanical, and chemical adaptations underline the complementary roles of the two pad types in insect attachment. Our findings provide a better understanding of structure-function relationships in both types of pads, with potential inspirations for biomimetic design in soft robotics and adhesive technology.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A5.25 THREE-DIMENSIONAL AND ANISOTROPIC ESCAPE STRATEGIES OF MOSQUITO REVEALED BY SWATTING ROBOT

Taito Koeda (Chiba University, Japan), Seiya Shimakawa (Chiba University, Japan), Yuuki Kato (Chiba University, Japan), Hao Liu (Chiba University, Japan), Toshiyuki Nakata (Chiba University, Japan)

23wm4151@student.gs.chiba-u.jp

Animals exhibit escape behaviours as a defence against predators. In this study, we investigated the escape behaviour of mosquitoes when threatened by hosts such as humans and other animals. While previous studies have examined escape behaviours in various animals, most have focused on two-dimensional stimulus-response relationship, overlooking the complexity of three-dimensional behaviours. To address this gap, we developed a mosquito-swatting robot and an experimental arena where both the direction of the stimulus and the mosquitoes’ initial position can be controlled in three-dimensional space. Using this setup, we observed the mosquitoes’ three-dimensional and anisotropic escape strategies. Our results confirmed that the swatting robot effectively induces the mosquito escape behaviour. Detailed observations of their escape manoeuvres revealed the critical role of leg thrust in take off and a mechanism that compensates for their inherent low manoeuvrability. Additionally, we found that the relative direction of the gravity strongly influences the time taken for mosquitoes to escape. In the case where mosquitoes collided with the robot piston during escape, acceleration was 3-4 times higher than normal, suggesting passive escape mechanism by collision. Our methodology provides new insights into mosquito escape behaviour and may contribute to novel physical control strategies for mosquito management.

A5.26 THE EFFECT OF MOSQUITO ANTENNAL MORPHOLOGY ON ODOUR MOLECULE CAPTURE.

Seiya Shimakawa (Chiba University, Japan), Taito Koeda (Chiba University, Japan), Chihiro Fukui (Chiba University, Japan), Daigo Terutsuki (Shinshu University, Japan), Hao Liu (Chiba University, Japan), Richard J. Bomphrey (Royal Veterinary College, United Kingdom), Toshiyuki Nakata (Chiba University, Japan)

sei.general.acct1@gmail.com

Female mosquitoes detect host odours using olfactory receptors on the flagellum of their antennae. However, it is unclear how well antenna morphology is adapted to capture odour molecules. In this study, we measured Culex pipiens antenna geometry using microscope images and performed computational fluid dynamic analyses on an idealised three-dimensional model. The flow around the antennae was used to

simulate the particle motion of odour molecules, and thereby test the effect of fibrillae length on odour molecule capture rate. Results suggest that the fibrillae hinder the movement of odour molecules toward the olfactory receptors on the flagellum and increase the aerodynamic drag on the antenna. The increase of drag increases the cost of flight but may enhance sensitivity to sounds, which is important for mosquito reproduction. This finding indicates a potential trade-off between olfactory and auditory functions in mosquito antennae.

A5.27 DARWIN’S FINCH JAW MUSCLE ARCHITECTURE AND KINEMATICS IN RELATION TO BITING SPECIALIZATION

Irene Montanez-Rivera (University of Antwerp, Belgium), Cas Jorissen (University of Antwerp, Belgium), Kiyoko Gotanda (Brock University, Canada), Jaime Chaves (San Francisco State University, United States), Anthony Herrel (Muséum National d'Histoire Naturelle, France), Sam Van Wassenbergh (University of Antwerp, Belgium)

irene.montanezrivera@uantwerpen.be

It is assumed that the force-velocity trade-off of beak movement had implications for song divergence, mating dynamics and ultimately the process of speciation in Darwin’s finches. Species with higher bite forces to crack larger seeds have evolved songs characterized by slower beak movements, while finches with slender beaks produce more complex songs involving more rapid movements. To gain insight into the biomechanical principles behind this force-velocity trade-off we investigated, based on contrast-enhanced CT, the geometrical characteristics of jaw depressor and adductor muscles in four finch species: the warbler finch, the small tree finch, and the small and medium ground finches. We found that pennation structure was fairly conserved, but for the medium ground finch, PCSA and moment arms increased by >10% for both the adductors and depressor in our sample. These preliminary data, integrated with beak kinematical parameters acquired from field recordings of high-speed videos, such as, open-close frequencies, amplitude, and velocities will provide new insights into the biomechanics behind the divergence in beak movement capacity in Darwin’s finches.

A5.28 EFFECTS OF WING COLORATION ON FLIGHT PERFORMANCE OF LONGDISTANCE FLYING SEABIRDS

Yoshinobu Inada (Tokai University, Japan), Kei Fukuoka (Graduate School of Tokai University, Japan)

4CEMM082@tokai.ac.jp

This study focuses on the wing coloration of long-distance flying seabirds, many of which exhibit a characteristic black-and-white wing pattern, with a notable tendency for black wingtips. Since black surfaces absorb more solar radiation than white surfaces, they tend to heat up, thereby warming the surrounding air. This temperature difference can affect the airflow around the wing and its wake, potentially altering aerodynamic characteristics. In this study, a 3D-printed experimental model based on a NACA airfoil was developed, incorporating an internal heater to investigate the effects of wing surface temperature variation on the surrounding airflow. Wind tunnel experiments and

oil flow visualization tests were conducted to analyze how surface heating affects boundary layer properties and flow separation. The experimental setup featured a film heater embedded inside the wing, enabling continuous heating to better simulate the flight conditions of birds. The results showed that the lift-to-drag ratio improved within a specific range of angles of attack. This suggests that surface heating altered boundary layer characteristics and helped suppress flow separation. These findings indicate that optimizing wing coloration and surface heating could contribute to improving the flight efficiency of long-distance flying seabirds, and thus applicable to the development of high efficiency aircraft wings.

A5.29 QUANTIFICATION OF THE

DYNAMIC

RESPONSE

(PITCH) OF A REPLICA BARN OWL (TYTO ALBA) UNDER ATMOSPHERIC DISTURBANCE WITH AN ACTIVELY CONTROLLED TAIL.

Zhaohua Zeng (University of cambridge, United Kingdom), Simon Watkins (Royal Melbourne Institute of Technology, Australia)

zz545@cam.ac.uk

A novel biomimetic approach to understanding the aerodynamic and stabilizing functions of the barn owl’s tail is presented. A full-size, 3D-printed replica of a barn owl configured in a natural gliding posture with an actuated, movable tail was designed and manufactured for controlled wind tunnel experiments. Aerodynamic forces—including lift, drag, and pitching moments—were systematically measured over a range of angles of attack and tail pitches, with the results calibrated against established literature. Analysis revealed that although the tail contributes only marginally to overall aerodynamic efficiency, it plays a critical role in generating stabilizing pitching moments, particularly under small perturbations. Wind tunnel tests further assessed the tail’s effectiveness in supplying stabilizing moments, showing that for minor disturbances, tail actuation maintains pitch stability at a low energetic cost. To further elucidate the barn owl’s dynamic behavior in pitch, a simplified differential equations model was developed to simulate its response to gust-induced and other disturbances; the effects of disturbance frequency were also evaluated. Owing to the bird’s low moment of inertia, even minimal tail actuation produced significant stabilizing effects without compromising efficiency. Thus, the study indicates that pairing a low-moment-ofinertia airframe (like the birds' body) with an active stability augmentation system may reduce or eliminate the need for a large horizontal stabilizer, thereby enhancing both aerodynamic agility and structural efficiency. These findings provide novel insights into the aerodynamic control strategies of gliding birds and offer promising design principles for the development of bio-inspired aerial vehicles.

A5.30 BONE MICROSTRUCTURAL PATTERNS IN THE STYLOPODIA OF RODENTS

Jan Wölfer (Humboldt-Universität zu Berlin, Germany), Oliver B. Berg (Humboldt-Universität zu Berlin, Germany), Marlene Bleich (Humboldt-Universität zu Berlin, Germany), Nunik Christen (Humboldt-Universität zu Berlin, Germany), Moritz Deckwerth (Humboldt-Universität zu Berlin, Germany), Dennis Fischer (Humboldt-Universität zu Berlin, Germany), Lea Gresens (Humboldt-Universität zu Berlin, Germany), Gopithan Kulanathan (Humboldt-Universität zu Berlin, Germany), Maria Rein (Humboldt-Universität zu Berlin, Germany), John A. Nyakatura (Humboldt-Universität zu Berlin, Germany)

jan.woelfer@hu-berlin.de

Rodents comprise around 40% of mammalian diversity, have convergently evolved various lifestyles, and span a body mass range of four orders of magnitude. Hence, they constitute an insightful taxon for studying ecomorphological diversification. Much research has been conducted on postcranial adaptations to different locomotor behaviours; however, the biomechanical properties of bone microstructure remain understudied. We are currently analysing the epiphyseal trabecular network and the cross-sectional properties of the diaphysis of rodent stylopodia from hundreds of species to identify signals related to locomotor habits, body mass, and phylogenetic inertia. We use µCT data to extract parameters from the trabecular network, such as bone volume fraction (BVTV; bone volume per total epiphyseal volume), mean trabecular thickness (TrTh), and connectivity density (ConnD; trabecular number per area), as well as from crosssections along the diaphysis, such as cross-sectional area (CSA) and second moment of area (SMA). Preliminary results from selected clades suggest a common scaling pattern across rodents. With increasing body size, BVTV only slightly increased, driven by a relative increase in ConnD, while TrTh decreased in proportion. These differences might be associated with proportionally higher epiphyseal stresses in larger rodents. However, CSA and SMA tended to either relatively decrease, increase, or remain in proportion to body size depending on the clade. Locomotor behaviour appeared to have a negligible effect on CSA and SMA. However, epiphyseal BVTV varied across different behaviours. Notably, these differences were solely driven by TrTh in mouse-like rodents, but also by ConnD in squirrel-like rodents, suggesting cladespecific adaptive strategies.

A5.32 REINFORCED LATTICES IN NATURE – BIOINSPIRATION FOR LARGE-SCALE WOVEN STRUCTURES IN CONSTRUCTION MATERIALS

Hannah G.J. Berndt (Wageningen University and Research, Netherlands), Guillermo J Amador (Wageningen University and Research, Netherlands), Steffen Werner (Wageningen University and Research, Netherlands)

hannah.berndt@wur.nl

The building and construction sector is responsible for 37% of global greenhouse gas emissions. Historically, the effort of decarbonizing buildings was mainly centralized around post-construction operations, like cooling, heating and electric systems. The New European Bauhaus

has launched funding around new goals: sustainable urban design, lifestyle and architecture. AlgoLoam, a project funded by the European Innovation Council, aims to develop a new modular internal wall satisfying these new principles. The wall solution will be made of loam and enforced with an algorithmically generated, biodegradable, 3D fiber reinforcement inspired by naturally occurring structures. Our part of the AlgoLoam mission is to design the 3D fiber reinforcement. The aim of this design is to create a weavable geometry with excellent mechanical characteristics in terms of resistance to compression, tension, bending and torsion with minimal material use. Fungal mycelium will be taken as biological inspiration, as mycelium has excellent mechanical properties while being lightweight. Mycelium has been a popular bio-based, composite material in research and development, but a deep understanding of the functional mechanics of hyphal geometries is still missing. We aim to better understand the complex hyphal geometries and through investigating how the mycelium adapts its growth and hyphal morphology under different environmental conditions and applied mechanical loads.

A5.34 COMPARATIVE MUSCLE ARCHITECTURE IN (SEMI-AQUATIC) MUSTELIDS AND SUBSEQUENT STEPS TO IDENTIFY MUSCULOSKELETAL ADAPTATIONS FOR AQUATIC LOCOMOTION

Tim De Ridder (University of Antwerp, Belgium), Leonard Dewaele (Institute of Natural Sciences, Belgium), Jamie A. MacLaren (University of Antwerp, Belgium), Sam Van Wassenbergh (University of Antwerp, Belgium)

tim.deridder@uantwerpen.be

Semi-aquatic mammals have evolved adaptations for aquatic locomotion, an activity which differs greatly from terrestrial locomotion due to the denser and more viscous medium. Furthermore, semiaquatic species cannot fully specialise since they need to balance their adaptations to fit their needs in both environments. Mustelids provide a valuable model for studying the evolution of such adaptations, as the group encompasses a wide range of aquatic specializations. Previous studies on their skeletal limb anatomy suggest a correlation between increased robustness and the higher biomechanical demands of swimming. To meet the elevated force requirements of swimming, we hypothesize that skeletal changes are accompanied by modifications in muscle architecture, specifically an increase in force-generating potential in distal limb muscles. To investigate this, we conducted manual dissections to measure muscle mass, fascicle length, pennation angle and to calculate the physiological cross-sectional area (PCSA). PCSA and fascicle length serve as indicators of specialization for either high force generation or increased contraction speed, providing a quantitative insight into muscle performance potential. The next phase is to link these anatomical adaptations to specific functional demands of aquatic (and terrestrial) locomotion. Future steps involve gathering kinematic data of terrestrial and aquatic locomotion in live animals and modelling these locomotor patterns. By integrating anatomical and functional data across a gradient of aquatic specialization in mustelids (fully terrestrial ferrets < infrequently aquatic minks < habitually aquatic otters), this study aims to enhance our understanding of the evolution of aquatic locomotion in mustelids and, more broadly, in mammals.

A5.35 CONTRACTILE PROPERTIES OF JAW MUSCLES CONTRIBUTE TO FORCE-VELOCITY TRADE-OFF IN BEAK MOVEMENTS OF SONGBIRDS

Maja Mielke (University of Antwerp, Belgium), Coen P. H. Elemans (University of Southern Denmark, Denmark), Nicholas W. Gladman (University of Liverpool, United Kingdom), Anthony Herrel (Muséum national d’Histoire naturelle CNRS, France), Falk Mielke (Research Institute for Nature and Forest, Belgium), Sam Van Wassenbergh (University of Antwerp, Belgium)

maja.mielke.bio@mailbox.org

Birds rely on their beak as a versatile, multi-functional tool during various behaviours. Depending on a bird’s ecology, a beak may be specialised for producing high bite forces (e.g., to break down hard food items) or fast oscillation rates (e.g., to produce elaborate birdsong). Previous studies indicated that high bite force and fast beak movements oppose one-another, suggesting a force-velocity trade-off. However, the underlying mechanisms contributing to this trade-off in songbirds have not been studied in detail. We hypothesise that the contractile properties of the avian jaw muscles, specifically their normalised rates of force rise during contraction and force decay during relaxation, are a limiting factor for maximal beak oscillation rates. To test our hypothesis, we measured the tetanic, isometric half-contraction and half-relaxation times of beak opener and beak closer muscles in a weak biting (canary) and a hard biting (Java sparrow) songbird in vitro. We observed that, in the harder biting species, both muscle types are slower in contraction and relaxation. Furthermore, within both species, beak closer muscles were slower in contraction and relaxation compared to beak opener muscles. We conclude that muscles which are adapted to high force production need more time to contract and relax compared to muscles producing low maximal forces. These findings suggest that the contractile properties of avian jaw musculature may contribute to the observed force-velocity trade-off in songbird beak movements. Our results further suggest that the muscles involved in forceful biting may contain a greater proportion of slow, fatigue-resistant fibres.

A5.36 THE BIOMECHANICAL AND EVOLUTIONARY ALLOMETRY OF MAXIMUM RUNNING SPEED IN SPIDERS (ARANEAE)

Shreyas Kuchibhotla (Imperial College London, United Kingdom), Elizabeth Bane (University of Florida, United States), David Labonte (Imperial College London, United Kingdom), Jonas O Wolff (Universität Greifswald, Germany), Vincent Jackel (Universität Greifswald, Germany)

svk21@ic.ac.uk

Spiders are incredibly diverse and prolific predators, and stand out among terrestrial animals in their use of both muscular and hydraulic movement actuation. Size-dependent constraints on musculoskeletal and hydroskeletal performance dictate biomechanical limits on the allometry of running speed. However, the large evolutionary timescales in spiders have engendered significant diversity associated with niche specialisation, particularly in leg morphology - an equally important consideration. In order to better understand the role of each of these factors in determining spider locomotor performance, we (i) quantified the relationship between body mass and maximum

sustained running speed for over 100 species from over 50 families, covering seven orders of magnitude in body mass; (ii) evaluated the effects of cephalothorax and limb proportions on normalised running speed; and (iii) contextualised both shape and performance variation in a comparative phylogenetic framework. Preliminary analysis of the mass-speed relationship suggests a pattern that follows predictions from physiological similarity theory. However, there exists considerable scatter about the fitted trendline, likely reflecting ecological specialisation and phylogenetic history that mask the variation corresponding to biomechanical scaling effects.

A5.37 BIOMIMETIC MODELS REVEAL THE SCALING PRINCIPLES AND MORPHOLOGICAL ADAPTATIONS OF CUTTLEFISH SUCKERS

Baowen Zhang (Wageningen University Research, Netherlands), Brett Klaassen van Oorschot (Wageningen University Research, Netherlands), Yoerick Lankhof (Wageningen University Research, Netherlands), Guillermo Amador (Wageningen University Research, Netherlands)

baowen.zhang@wur.nl

Cuttlefish suckers, distributed along their arms and tentacles, exhibit remarkable size variations, ranging from tens of micrometers to tens of millimeters in diameter. Previous studies have found a unique powerlaw relationship between sucker diameter and attachment stress: smaller suckers generate disproportionately higher attachment stresses. However, the underlying mechanisms driving this relationship remain poorly understood. In this study, we developed a biomimetic model to elucidate this phenomenon. By simplifying the morphology of cuttlefish suckers, we designed and fabricated a series of bio-inspired artificial suckers with diameters ranging from 3 mm to 36 mm. The attachment performance of these suckers was systematically measured in both water and air, including pull-off force, displacement, and pressure. Our results show that the biomimetic suckers replicate the power-law relationship observed in natural cuttlefish suckers, suggesting a shared attachment mechanism. Furthermore, our model provides insights into the morphological adaptations of cuttlefish suckers, particularly asymmetric sucker designs and stiff internal tissues. By uncovering the biomechanical principles underlying cephalopod sucker attachment, this study motivates the design of next-generation artificial grippers with enhanced adaptability and robustness.

A5.38 THE INFLUENCE OF PLANT PROPERTIES, ANT BODY SIZE, AND TEMPERATURE ON CUTTING SPEED IN LEAF-CUTTER ANTS

Nina Dorsch (Imperial College London, United Kingdom), Olivia Walthaus (Imperial College London, United Kingdom), Dilanka Deegala (Imperial College London, United Kingdom), Frederik Püffel (Imperial College London, United Kingdom), David Labonte (Imperial College London, United Kingdom) nrd24@ic.ac.uk

The foraging habits of leaf-cutter ants shape Neotropical rainforests: around 15% of measured defoliation can be attributed to leaf-cutter

ants. Leaf harvesting at such an industrial scale is only ergonomically possible if ants can cut leaves quickly. Leaf-cutter ant workers may vary by more than two orders of magnitude in size, and may forage on hundreds of plant species that vary in toughness – how do both factors influence cutting speed? To gain a more thorough understanding of the biomechanical determinants of cutting, we employed a suite of custom-built set-ups to measure four key factors—cutting speed, the maximum isometric bite force, the force necessary to cut thin sheets with ant mandibles, and maximum mandible closing speeds—each across the worker size range. A simple biomechanical model, based on the theory of physiological similarity and informed by the measured parameters, accurately predicts the allometry of cutting speed across a range of both synthetic and natural leaves. The model also suggests that environmental temperature fluctuations will change the cutting speed allometry quantitatively, but not qualitatively, because temperature affects the kinetic energy but not the work capacity of muscle. To test these predictions, we will measure cutting speed, maximum bite force, and mandible closing speeds in a controlled environmental chamber. With a validated and predictive model at hand, we hope to gain deeper insight into the biomechanical underpinnings of one of the most important ecological interactions in the Neotropics.

A5.39 ALLOMETRY OF LEG MUSCULATURE IN ATTA VOLLENWEIDERI LEAF-CUTTER ANTS

Melissa R.M. Tan (Imperial College London, United Kingdom), Brendon E. Boudinot (Senckenberg Institut Naturmuseum Germany, Germany), Frederik Püffel (Imperial College London, United Kingdom), Adrian Richter (Senckenberg Gesellschaft für Naturforschung, Germany), Thomas Van de Kamp (Karlsruhe Institute of Technology, Germany), David Labonte (Imperial College London, United Kingdom) melissa.tan19@imperial.ac.uk

Leaf-cutter ants are key ecosystem engineers, accounting for around 25% of herbivory in the Neotropics. Their success is partly due to the efficient organization of traffic along long foraging trails, with a length on the order of hundreds of metres, enabling rapid transport of leaf fragments back to the nest. Smooth traffic flow facilitates this process, and is achieved despite the fact that trail traffic composition is complex. Traffic consists of polymorphic ants carrying variable loads, presumably leading to a variation in preferred and maximal speeds, and associated organisational complexity. How do load-carrying capacity and locomotor performance vary with size? One way to address this question is to examine the scaling of leg musculature, as these muscles both drive forward motion and support load-bearing.

We conducted a detailed allometric study of the primary leg musculature, using synchrotron-based µCT scans of worker legs across the size range (0.5-57.3 mg). CT scans were segmented to obtain muscle volumes, and a custom-written fibre-tracing algorithm was used to reconstruct muscle anatomy in 3D, permitting extraction of the physiological cross-sectional areas, and the fibre lengths and pennation angles of all individual muscle fibres. Preliminary allometric analysis suggests positive allometry of limb segment muscle volume, mirroring results for the mandible closer muscle. Thus, larger leafcutter ant workers appear to be specialised for heavy mechanical labour. These findings provide a mechanical basis for future large-scale studies exploring how the ants adapt foraging trail traffic to ensure efficient load transport despite a heterogeneous traffic composition.

A5.40 REGIONAL VARIATION IN THE MASTICATORY MUSCLE OF RABBITS (ORYCTOLAGUS CUNICULUS)

Nicholas W. Gladman (University of Liverpool, United Kingdom), Graham N. Askew (University of Leeds, United Kingdom), Karl T. Bates (University of Liverpool, United Kingdom), Roger W. P. Kissane (University of Liverpool, United Kingdom)

N.W.Gladman@liverpool.ac.uk

Muscle-driven movements of the jaw are key to important behaviours, such as feeding. Jaw muscle anatomy and behaviour is therefore expected to show adaptive variation across species that vary in diet and trophic ecology. In the rabbit, a generalist herbivore, one of the key drivers of this process is the superficial masseter muscle, this large fan-shaped muscle plays an important role in elevating the mandible and moving it forward to enhance chewing. Here we investigate if this large muscle shows regional variation in function using an X-ray Reconstruction of Moving Morphology (XROMM) based approach. To achieve this, computer-based locators were placed along points of the mandible and maxilla and connected using straight lines, mimicking the bone insertion points of the superficial masseter. From these estimates of fibre strain were calculated. These data were validated against direct measures of fibre strain change, measured using flouromicrometry while rabbits fed on a variety of food types. Taken together, these data reveal a gradient of muscle strains from the dorsal to ventral of the superficial masseter; where strains associated with more ventral positions were approximately 10% higher than those in more dorsal positions of the muscle. The functional implications of these variations in the strain across the muscle remain largely unexplored, but may reflect compartmentalisation of muscle function, such as dorsally located fibres that undergo less shortening being more important in force generation while more ventrally located fibres undergoing greater strains enabling greater displacements needed for masticatory behaviours.

A5.41 ON THE COMPLEX CONTACT MECHANICS OF CUTTLEFISH SUCKERS

Guillermo J Amador (Wageningen University, Netherlands), Jan Severin Te Lindert (Wageningen University, Netherlands), Alexander Koehnsen (Wageningen University, Netherlands), Brett Klaassen van Oorschot (Wageningen University, Netherlands), Tabo Geelen (Wageningen University, Netherlands), Sander W.S. Gussekloo (Wageningen University, Netherlands)

guillermo.amador@wur.nl

Cuttlefish rely on arrays of suckers lining their arms and tentacles to capture prey. Given their importance in hunting, the suckers must be capable of providing secure attachment onto various substrates. The rim of a sucker, which provides sealing in order to generate suction pressures, exhibits arrays of stiff microstructures (papillae) and viscoelastic mucus. We find that the papillae enable secure attachment to rough substrates, especially when the roughness amplitude matches the geometry of the papillae. The roughness of the exoskeletons of shrimp and crab and scales of teleost fish, the typical prey for cuttlefish, lies within this range, hinting at a potential morphological adaptation. The mucus on the suckers was found to be highly viscous and shear

thinning, with the viscosity decreasing from 50 to 20 centipoise as shear rate increases from 0 to 2000 Hz. On the other hand, the mucus found throughout the rest of the body has a viscosity of 5 centipoise that does not change with shear rate. These differences in viscoelastic properties hint at a possible specialisation of the sucker mucus. Our findings shed light on the functional morphology of cuttlefish suckers and inform the design of versatile bio-inspired suction cups.

A5.42 PROPRIOCEPTION IN MOTION: OCTOPUS ARM FUNCTIONAL NETWORK OF PROPRIOCEPTION

Letizia Zullo (IRCCS OSPEDALE POLICLINICO SAN MARTINO, Italy), Beatrice Pistolato (Istituto Italiano di Tecnologia and University of Genoa, Italy), Orel Benita (Hebrew University of Jerusalem, Israel), Janina L Röckner (Istituto Italiano di Tecnologia and University of Genoa, Italy), Nir Nesher (Ruppin Academic Center, Israel), Tal Shomrat (Ruppin Academic Center, Israel), Binyamin Hochner (Hebrew University of Jerusalem, Israel), Letizia Zullo (IRCCS Ospedale Policlinico San Martino, Italy)

letizia.zullo@hsanmartino.it

The octopus, with its eight long and flexible arms, is an example of highly efficient motor behavior reached in an animal lacking any rigid structure. The octopus uses unique strategies to cope with the complexity arising from its hyper-redundant appendages, including the hierarchical organization of the motor system and the rather autonomous arms.

One important and rather underinvestigated topic is role of proprioception in octopus motion.

Here we studied their existence and functional role of muscle proprioceptors in the arm motion using techniques confocal microscopy, proteomics, biomechanics and electrophysiology. Proteomic analysis and confocal imaging reveled the massive presence and very organized distribution of piezo mechanosensitive ion channels along muscle cells. These are densely innervated from neurites branching from neurons of the arm nervous system.

We then performed step-stretch biomechanical experiments and demonstrated, for the first time, how stretch is coded into afferent responses apparently proprioceptive. We also show that muscles manifest intrinsic mechanisms of stretch-induced contraction independent from the sensory innervation.

Our results point to the existence of a double mechanism of control of muscle activation, one resembling a spindle-like mechanism of proprioception, and a second one present at the muscle circuit level. These may be involved in arm reflex motion like sucker and arm withdrawal response, but also in more complex behaviors. This study represents the first assessment of muscle proprioception function at a lower level control of the arm and open the way to further investigate its role in both autonomous and complex motion.

A5.43 COVERT FEATHER DEFLECTION PATTERNS DURING PERCHING OF HARRIS’ HAWKS

Griffin Emter (University of Bristol, United Kingdom), Jasmin CM Wong (University of Bristol, United Kingdom), Shane Windsor (University of Bristol, United Kingdom)

vy21011@bristol.ac.uk

The covert feathers on the top surface of birds’ wings have been observed to deflect upwards at high angles of attack, such as when a bird is landing. This is thought to be a form of passive high-lift device, and artificial versions on rigid aircraft model wings have found aerodynamic performance enhancements including increased maximum lift, increased post-stall lift, and reduced pitching moments. However, there has been surprisingly little research quantifying the spatial and temporal patterns of how covert feathers deflect on birds in flight. This study used high-speed video measurements to characterise covert feather deflections during perching manoeuvres by Harris’ Hawks (Parabuteo unicinctus), and explored how covert feather behaviour changed depending on their location on the wing and the phase of flight. Characteristic patterns of activation were identified and compared to experiments in the literature to draw conclusions on the aerodynamic performance enhancements birds may be gaining from covert feather deflection, and how this could be applied to future covert feather inspired flap designs.

A5.44 BEHAVIOUR AND MORPHOLOGY: EXPLORING

THE

VALUE OF TRABECULAR ARCHITECTURE IN PREDICTING HUNTING TYPES IN CARNIVOROUS MAMMALS

Levi Dethlefs (Humboldt University Berlin - Nyakatura-Lab for Comparative Zoology, Germany), Jan Wölfer (Humboldt University Berlin - Nyakatura-Lab for Comparative Zoology, Germany), John A. Nyakatura (Humboldt University BerlinNyakatura-Lab for Comparative Zoology, Germany)

levi.dethlefs@student.hu-berlin.de

Feeding ecology of carnivorous mammals is highly diverse. It is generally accepted, however, that most species primarily employ one of three hunting strategies: pursuit predation, pounce/pursuit predation, or ambush predation.

This study explores the possibility of leveraging trabecular morphology in the distal humerus as a predictor for predation strategies in carnivorous mammals. Degree of Anisotropy (DA), connectivity density and bone volume fraction of 18 different species of Carnivora and the recently extinct Thylacine (Thylacinus cynocephalus) as a representative of carnivorous marsupials are investigated using ORS Dragonfly. Anisotropy was computed using both the mean intercept length (MIL) and the star volume distribution (SVD). Discrepancies between the outcomes using these two methods are highlighted and discussed. We present the first dataset of trabecular bone morphology for major carnivoran clades and recover DA as the most important predictor of hunting type. Our data enables us to clearly differentiate between ambush predators such as lions and tigers and pounce and pursuit predators such as foxes or wolves and cheetahs. Our results further suggest an ambush-like behaviour in the extinct thylacine. However,

the discrepancies between the two methods of computation invite further investigation and discussion about fundamental principles in the computational analysis of anisotropy in trabecular bone; critical to comparison across studies.

A5.45 DO HINGE-LIKE JOINTS REALLY AID IN MORE EFFICIENT LOCOMOTION?GROUND REACTION FORCES AND BONE MICROSTRUCTURE IN CURSORIAL MAMMALS

Adrian Scheidt (Humboldt University Berlin, Germany), Jan Wölfer (Humboldt University Berlin, Germany), John A Nyakatura (Humboldt University Berlin, Germany)

a.scheidt@hu-berlin.de

Mammals with a cursorial lifestyle exhibit elongated distal limb bones and generally more hinge-like joints in the limbs. Elongated limbs and other cursorial traits have been shown to reduce locomotion costs, but the role of hinge-like joints has not been examined independently. Hinge-like joints stabilize the limb against sideways excursion and restrict movement to a single (parasagittal) plane. Thus, it has been suggested that this enhances locomotor efficiency, due to a reduction of required muscular joint control. However, this assumption has not been explicitly tested in relation to hinge-like joints, independent of other cursorial adaptations. Here, we first aim to assess the hinge-like nature of elbows in mammals of various locomotor types. We will quantify the restriction to a single axis of rotation in the humero-radial joint of cursorial species by measuring and comparing the osteological range of pronation and supination. Next, we evaluate locomotor efficiency during steadystate locomotion by comparing in vivo ground reaction forces (GRF) in the same species. We expect cursorial species to exhibit relatively lower medio-lateral forces. This will indicate how efficiently GRF are channeled unidirectionally in the fore-aft direction during steady-state locomotion. Additionally, to determine whether increased hinge-like morphology corresponds to more unidirectional stresses on elbow bones, we will analyze anisotropy in the trabecular structure of the humerus, ulna, and radius. We expect cursorial species to exhibit lower anisotropy. This study contributes to the understanding of the interface of form and function in mammalian cursorial locomotion.

A5.46 EVALUATING INTER- AND INTRASPECIFIC VARIABILITY IN THE STRESS RESISTANCE OF THE CARNIVORAN HUMERUS USING FEA MODELLING

Oliver B Berg (Humboldt-Universität zu Berlin, Germany), Antonia Kaffler (Museum für Naturkunde Berlin, Germany), John A Nyakatura (Humboldt-Universität zu Berlin, Germany)

bergoliv@hu-berlin.de

Carnivora are a diverse group of mammals exhibiting specializations to different lifestyles and locomotor types. While humeral shape differences have been demonstrated to reflect such specializations, the extent to which they translate into performance differences remains

underexplored. Furthermore, intraspecific differences in performance have not been assessed. The aim of this project is to investigate the relationship between humeral shape and variability in bone stress resistance among carnivorans.

To test this, we examined a minimum of five specimens from three species with distinct locomotor specializations (cursorial, aquatic, semiarboreal) using comparative finite element analysis. Each humerus was subjected to three loading scenarios simulating strains experienced during terrestrial locomotion, swimming, and climbing.

We expect that interspecific variability in performance is substantially greater than intraspecific variability. Additionally, we expect each species to perform best - exhibiting the lowest bone strains in the models - in loading scenarios that correspond to its typical lifestyle.

A5.48 THE FINCH FORMULA: DECODING FLAP-BOUNDING TACTICS DURING FLIGHT TRAINING

Jasmin CM Wong (University of Bristol, United Kingdom), Clementine Bodin (McGill University, Canada), Sarah C Woolley (McGill University, Canada), Shane P Windsor (University of Bristol, United Kingdom)

jasmin.wong@bristol.ac.uk

Small birds use a distinct pattern of intermittent flight known as ‘flapbounding’, distinguished by alternating phases of rapid flapping and tucked-wing ballistic movement. Previous theoretical and experimental studies suggest that this behaviour reduces energetic costs or regulates horizontal velocity during long flights. However, we observed zebra finches using flap-bounding even during short perch-to-perch flights. Furthermore, individuals converged on a consistent flight path with training, initiating the bound at a specific point in their trajectory. To investigate what objectives are driving this learned behaviour, we developed an analytical model of flap-bounding and applied a gradient-free optimisation method to test multiple hypothesized objectives: minimising energy, minimising flight time, minimising or maximising bounding duration, minimising bounding velocity, and minimising landing deceleration. By comparing the optimised trajectories to experimental data, our results suggest that the learned trajectory is not dictated by a single objective but instead represents a compromise among competing performance goals. While future work will refine the analytical model with more complexity, these findings demonstrate that during short flights, zebra finches choose trajectories that balance multiple, potentially contradictory, goals.

A5.49 CLINGING TO LIFE: DEVELOPMENTAL AND BIOMECHANICAL INSIGHTS INTO EARLY EUROPEAN MISTLETOE (VISCUM ALBUM) ATTACHMENT

Max D Mylo (Cluster of Excellence livMatS @ University of Freiburg, Germany), Luiza Teixeira-Costa (Work group on Wildness Vrije Universiteit Brussel, Belgium), Lukas Wiese (University of Freiburg, Germany), Thomas Speck (Plant Biomechanics Group @ University of Freiburg, Germany)

max.mylo@livmats.uni-freiburg.de

Establishing a secure connection to a substrate is vital for plant growth, particularly for species like mistletoes that live off the ground and depend on host trees for water and nutrients. Although adult plant attachment has been extensively studied, mechanical strategies during early development remain largely unexplored. We investigated the early host attachment process of the European mistletoe (Viscum album L.) at the seedling stage. By integrating germination experiments, microtomography, histological analysis, and biomechanical testing, we focus on three primary attachment structures: the seed coat, hypocotyl, and holdfast. The viscin layer—a sticky coating on the seed—provides initial adhesion to the host. As the seedling develops, the hypocotyl extends and flattens against the host, forming a holdfast that secures the seedling and helps in penetrating host tissues. Tensile tests to failure reveal that all three structures involved withstand almost equal forces in the early developmental stages, all being markedly greater than the seedling's own weight. Within months, an endophytic network emerges, interlocking with the host bark to create a stable connection that supports water transport and enhances mechanical attachment by about a factor of four. After the initial mechanical equilibrium of the tissues involved, the holdfast becomes the main responsible for adhesion, while the viscin attachment diminishes and the cotyledons eventually detach from the seed coat. The hypocotyl facilitates this transition between viscin- and holdfast-mediated attachment. Our findings highlight the essential early-stage mechanisms of mistletoehost interaction that lay the foundations for an enduring relationship that will last for decades.

A5.50 ASSESSING THE ROLE OF BARBS AND SUBSTRATE PROPERTIES ON INSERTION AND EXTRACTION FORCES IN WORKER HONEYBEE STINGERS

Yuvan Kamalakanthan (UNSW Canberra, Australia), Fiorella Ramirez-Esquivel (UNSW Canberra, Australia), Sridhar Ravi (UNSW Canberra, Australia)

y.kamalakanthan@unsw.edu.au

Insect ovipositors and stingers have extensive variation in their morphology depending on the substrate they penetrate or probe. From an engineering perspective, stingers are micro penetration devices capable of penetrating a substrate and delivering a package. Understanding the role played by the microstructures and substrate property on the insertion and extraction forces will enable us to design efficient bioinspired micro needles and transdermal medical patches.

Quasi-static insertion and extraction experiments on honeybee stingers were conducted on artificial homogeneous substrate(humimic) and fibrous chicken muscle. The force required to remove the stinger from the fibrous substrate was 3 times more than that of in the homogenous substrate due to the rearward facing barb making it harder to pull out. The barbs, in addition to helping the stinger anchor, were found to significantly reduce the insertion forces. The increased stress concentration at the site of the barbs can contribute to the decreased insertion force. Stingers with barbs were found to require one-third the insertion force in humimic and half the insertion force in the fibrous substrate, compared to modified barbless stingers. In biomedical applications, a reduced insertion force would translate to less pain and less tissue damage. Higher extraction forces could be beneficial in designing mechanically adhering patches.

A5.51 RANGE OF MOTION OF THE ELBOW JOINT ACROSS A SAMPLE OF EXTANT XENARTHRANS

Charlotte Koeber (Humboldt-Universität zu Berlin, Germany), Adrian Scheidt (Humboldt-Universität zu Berlin, Germany), John A. Nyakatura (Humboldt-Universität zu Berlin, Germany)

koeberch@hu-berlin.de

The shape of articular surfaces within the humero-ulnar joint has been linked to allowing and/or preventing of specific mobilities. This joint thus enables functions that are needed for varied locomotor behaviors. To offer deeper insight into the form-function relationship, joint mobility should be studied, as it bridges the joint morphology with its function.

Composed of the three lineages, Xenarthra are closely related and yet differ notably in way of life. While armadillos are fossorial and specialized in digging, sloths live strictly arboreal. Anteaters exhibit differing degrees of arboreality, specializing further in opening and foraging nests of termites and ants. Accommodation to each behavior reflects in distinctive morphologies and locomotion.

We here quantitatively compare the mobility of the humero-ulnar joint of two armadillos, two sloths and three anteaters, adding the red panda as an outgroup taxon. The use of automated range of motion analysis allows the use of all six degrees of freedom, as well as limitation by two viability criteria (overlap- and separation threshold).

We expect the highly arboreal sloths and the silky anteater to exhibit greater mobility, reflecting the necessity to bridge gaps in a highly variant and discontinuous habitat. In contrast, we expect much more constraint mobility in more terrestrial and digging species. We further predict that differences in digging strategies will lead to distinct patterns of joint mobility. Such differences once established for extant species could also be used for paleobiological inferences of extinct taxa. Overall, we aim to illuminate the form-function relationship in joints more closely.

A5.52 BUILDING STEREOTYPICAL MOTION THROUGH SYNCHRONOUS ACTIVATION OF ANTAGONISTIC MUSCLES IN THE OCTOPUS ARM

Letizia Zullo (IRCCS OSPEDALE POLICLINICO SAN MARTINO, Italy), Janina L Röckner (University of Genoa and Istituto Italiano di Tecnologia, Italy), Janina L Röckner (University of Genoa and Istituto Italiano di Tecnologia, Italy), Beatrice Pistolato (University of Genoa and Istituto Italiano di Tecnologia, Italy)

letizia.zullo@hsanmartino.it

Octopus arms are muscle hydrostats capable of large variety of motions from autonomous reflex action to complex tasks. Movement in muscle hydrostat is determined by the contraction of specific set of muscles or by co-contraction of antagonistic muscles.

Here we studied the pattern of activation of arm antagonistic muscles (longitudinal and transverse) during arm extension and withdrawal reflex stereotypical motion.

We performed electromyography of the antagonistic muscles on a whole arm ex-vivo preparation and used the DeepLabCutTM markerless

pose estimation to reconstruct the kinematics of the arm motion. Arm extension was triggered through electrical stimulation of the arm nerve cord and induced a specific sequence of motor response (i) An initial arm extension, (ii) a delayed arm shortening and, (iii) a second extension shortly after.

A similar activation patterns was observed in the two muscles. However, a difference in their activation level was observed. Longitudinal muscles showed the highest activity right after the stimulus and before the arm shortening (i). The transverse muscles showed two picks of activation, one immediately after the stimulus (i), and one delayed during the second elongation (iii).

The withdrawal reflex was elicited by pinching the arm tip, causing the arm to twist and retract toward its base.

A similar electromyography pattern was found in both muscles. Interestingly, the difference in their activation strength and duration might reflect their role in various phases on motion.

This study further complements our understanding of octopus arm motion and offer insights into hydrostatic limbs movement building blocks.

A5.53 OPTIMAL WING DESIGN FOR AUTOROTATING AERIAL VEHICLE INSPIRED BY SAMARA FRUIT OF DIPTEROCARPACEAE FAMILY

Haruki Hiro (Tokai University, Japan), Yoshinobu Inada (Tokai University, Japan)

4CEMM081@tokai.ac.jp

This study aims to create an autorotating winged aerial vehicle inspired by the samara fruit of the Dipterocarpaceae family. The samara fruit of Dipterocarpaceae can fly through autorotation after detaching from a branch. Its design may be optimized to carry more nutrients and achieve longer flight durations. Therefore, in this study, we attempted to optimize the wing shape for maximum thrust and flight duration using QMIL, a propeller design software developed by Dr. Mark Drela, and compared it with the actual wing shape of the samara fruit. A genetic algorithm was employed as the optimization method. PyAutoGUI in Python was used for the automated execution of the genetic algorithm and QMIL. The lift coefficients at 0%, 50%, and 100% positions from the wing root were used as optimization parameters. As a result, we confirmed that the propeller shape maximizing thrust and flight duration closely resembled the wing shape of the Dipterocarpaceae samara fruit. According to this result, we plan to develop an autorotating winged aerial vehicle based on the calculated optimal design.

A5.54 ENERGY LANDSCAPES AND THE OPTIMAL TUNING OF LAMSA SYSTEMS

Charles A C Brook (Imperial College London, United Kingdom), Natalie C Holt (University of California Riverside, United States), David Labonte (Imperial College London, United Kingdom)

cb1121@ic.ac.uk

Latch Mediated Spring Actuated (LaMSA) mechanisms enable some of nature’s most powerful motions, but maximal performance requires

“tuning” between the geometric and material properties of the elastic spring, and the physiological and anatomical parameters of the loading muscle. Here, we use the conservation of energy to show that the efficacy of a generalised LaMSA system depends, to first order, on two dimensionless numbers: the physiological similarity index Γ – the ratio between the muscle’s kinetic energy and work capacities – and the dimensionless stiffness, Ξ - the ratio between spring and effective muscle stiffnesses. Together, these two numbers span a complex threedimensional energy landscape, delineating regions where latching is beneficial or detrimental to system performance compared to direct muscle actuation. Ideal latching, achieved for Ξ close to unity, can only convey an advantage when Γ < 1/2, making it less attractive for larger animals. For Ξ < 1, the muscle is displacement-limited, and for Ξ > 1 it is force-limited; in both cases, the spring-muscle system is “mistuned”, resulting in a more extreme upper bound on Γ for latching to be beneficial. We show that further performance reductions due to force-length properties of muscle can be avoided by shifting the optimal muscle length away from the muscle resting length, as is indeed observed in some animals that rely on elastic energy storage to power movements.

A5.55 EVOUTION AND ALLOMETRIC SCALING OF JUMPING PEFORMANCE IN ORTHOPTERANS

Ronja Eilhardt (University of Greifswald, Germany), Jonas O. Wolff (University of Greifswald, Germany)

ronjaeilhardt@t-online.de

Jumping performance is a key locomotor trait that is shaped by both evolutionary processes and allometric laws. It acts as predominant mode of locomotion in grasshoppers, locusts, crickets and katydids, thus playing a critical role in behaviors such as predator evasion, mate search, and navigation through complex environments. In this study, we aimed to explore how jumping performance scales allometrically and evolved across different Orthopteran lineages differing in their ecological niches. By comparing 12 Caelifera and 7 Ensifera species in a phylogenetic comparative framework, we investigated how jump kinematics vary with body size, jump actuation mechanisms, and ecological adaptation. Specifically, we assessed parameters such as maximum and mean take-off velocity, acceleration, jump height and distance, as well as jump-off force and power, while considering the influence of body mass. Preliminary results indicate that Caelifera exhibit higher jumping performance with lower body mass compared to Ensifera. We conclude that evolutionary pressures related to habitat and ecological function drives variations in jumping performance across species, with allometric scaling differing between taxa.

Keywords: Jumping performance, Allometry, Locomotor traits, Orthopteran taxa, Locomotion evolution.

A5.56 FROM STRUCTURE TO MOTION: ANATOMICAL AND MORPHOLOGICAL CHANGES DURING LEAF UNFOLDING IN SYNGONIUM PODOPHYLLUM

Michelle Modert (University of Freiburg, Germany), Thomas Speck (University of Freiburg, Germany), Tom Masselter (University of Freiburg, Germany)

michelle.modert@biologie.uni-freiburg.de

The mechanisms underlying leaf unfolding remain largely speculative and are often based on mathematical models. Notably, peltate leaves, which 'unroll' rather than unfold via creases, have received little attention. Here, we investigate the unfolding process of peltate leaves in Syngonium podophyllum, analysing anatomical and morphological changes to uncover the driving mechanisms. Our findings reveal that unfolding occurs successively in the two leaf halves and is driven by cell expansion rather than proliferation. Throughout unfolding, leaf width remains nearly constant, and Young’s modulus is low, indicating a flexible lamina. Once unfolding is complete, the lamina stiffens, with secondary venation playing a key role in structural reinforcement. Initially, the stiffness of secondary veins is comparable to the lamina, but after unfolding, it increases significantly and becomes the main support for the entire leaf structure. The lamina is stiffest parallel to secondary venation, which indicates prevailing external loads in this direction. Unfolding leaves generate forces in the millinewton range, which we propose are strong enough to overcome the resistance of surrounding foliage. Successful unfolding allows the plant to compete for sunlight in dense vegetation.

A5.57 A HIGH-QUALITY DIET EARLY IN ADULTHOOD IS NECESSARY FOR INSECTS TO INCREASE EXOSKELETON PUNCTURE RESISTANCE

Noraly MME Van Meer (Entomology and Nematology Department University of Florida, United States), Christina M Salerno (Entomology and Nematology Department University of Florida, United States), Elizabeth G Bane (Entomology and Nematology Department University of Florida, United States), Christine W Miller (Department of Zoology University of Cambridge, United Kingdom), Walter Federle (Department of Zoology University of Cambridge, United Kingdom)

noralymmevanmeer@gmail.com

Arthropods rely on exoskeletal cuticle for protection and stabilization of the body. Yet, new research shows that the exoskeleton’s structural integrity can depend on external factors, including nutrition during early development. However, we do not yet know if the exoskeleton can recover from low-quality nutrition in early adulthood. Furthermore, it is unknown if the puncture resistance of cuticle decreases after a shift to a low-quality diet. To answer these questions, we used the leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae). N. femorata preferentially feed on cactus fruit, but fruit availability varies seasonally. Males compete for fruit by kicking and grappling one another with their spiny hind legs. Injuries, including puncture, are common. Previous work shows that diet impacts exoskeletal thickness and puncture resistance: bugs fed a high-quality diet (cactus pad with fruit) have thicker exoskeletons and increased puncture resistance relative to those on low-quality diet (cactus pad). In this study, adult male N. femorata were kept on four different diet treatments for 28 days, including two switch diets. We used a penetrometer to measure puncture resistance of the dorsal abdomen. We found that a highquality diet provided in the first week of adult life was essential for building cuticle with high puncture resistance. Moreover, females, but not males, showed evidence of partial recovery from a poor start in adult life once high-quality nutrition was provided. Finally, we did not find evidence that a switch from a high-quality to a low-quality diet one week into adulthood resulted in decreased puncture resistance.

A5.58 SEXUAL DIMORPHISM AND COMBAT BEHAVIOR IN ARTIODACTYLS: INSIGHTS FROM MORPHOLOGICAL DIFFERENCES AT THE CERVICOTHORACIC BOUNDARY

John A Nyakatura (Humboldt-University of Berlin, Germany), Oskar Beck (Humboldt-University of Berlin, Germany), Min-Yi Lam (Humboldt-University of Berlin, Germany), Jan Wölfer (Humboldt-University of Berlin, Germany)

john.nyakatura@hu-berlin.de

Many artiodactyl lineages have evolved elaborate headgear involved in male-male combat behavior. Since females typically do not engage in such behavior, it can be expected that this is reflected in sexual dimorphism within the affected structures. Moreover, the various behaviors impose drastically different loadings on the body. For example, ramming combat behavior exerts extreme compressive forces on the skull and cervical vertebrae, whereas the wrestling behavior of male cervids involves entangling the antlers and, apart from pushing, sudden pulls to unbalance the opponent. This should result in tensile forces specifically on the spinous processes of the first thoracic vertebrae, where the ligamentum nuchae inserts. In this study, we used imaging-based 3D quantitative analysis of shape (geometric morphometrics) and internal structure of the first thoracic vertebra to test (a) whether combat behavior is reflected in morphological differences between sexes at the cervico-thoracic boundary and, if present, (b) whether these differences are present in a species that uses ramming (mouflon) and in a species that uses wrestling (red deer). A comparative dataset was assembled using the collections of several natural history museums. The identification of sexual dimorphism due to behavioral differences between males and females adds complexity to the inference of function from form in fossil taxa with limited preserved material. In turn, such sex-specific morphological differences offer the possibility for deep insights into behavior from established osteological correlates.

A5.59 MORPHO-FUNCTIONAL STUDY OF BIRDS' VOCALIZATIONS: LINKING ANATOMY, ACOUSTICS, AND PHYLOGENY

Nyniane Steinkampf--Pellecuer (Museum national d'Histoire naturelle, France), Pauline Provini (Museum national d'Histoire naturelle, France)

nyniane.steinkampf-pellecuer@mnhn.fr

Birds are known for the great diversity of vocalizations they can produce. This is made possible by their unique vocal organ, the syrinx, located at the tracheobronchial junction. This organ varies in shape, size and configuration depending on the taxonomy. However, there is no simple relationship between its anatomy and the vocalization that is produced. Indeed, the sound is further modulated by the upper vocal tract: trachea, larynx, oropharyngeal-esophageal cavity (OEC), beak and tongue. The effect of these organs on the sound has been studied only for a few groups, and rarely from an integrative point of view. To investigate the role of each structure of the upper vocal tract on the acoustic characteristics of the vocalizations, we selected a sample of 10 taxonomically diverse species from 8 orders, with

various vocalizations and anatomies. We used CT-scan of collections specimens from the Muséum national d’Histoire naturelle of Paris or from the online database Morphosource, to segment the syrinx, trachea, larynx, hyoid skeleton, and skull of these species. Measurements were done on the obtained 3D models (e.g., dimensions of the syrinx, length of the trachea, dimensions of the larynx, volume of the beak etc.). These parameters were linked to the acoustical characteristics of the vocalizations extracted from recordings of the MNHN collections (e.g., duration, fundamental frequency, dominant frequency, vocal performance). By conducting comparative phylogenetic analyses, we tested the correlation between these anatomical and acoustical parameters. We showed that the syrinx, trachea, larynx, and beak all have an influence on the vocalization.

A5.60 AERODYNAMIC EFFECTS OF SLOTTED WING TIPS IN AVIAN FLIGHT – A NUMERICAL STUDY

Yosuke Yamamoto (Chiba University, Japan), Hao Liu (Chiba University, Japan), Toshiyuki Nakata (Chiba University, Japan)

yamamotoyousuke@chiba-u.jp

The wing tips of birds are formed by a series of primary feathers. When birds such as raptors are gliding, their primary feathers spread vertically and horizontally, and form slotted wing tips. Although the wing tip slots have been proposed to improve aerodynamic performance, the effects of the three-dimensional angles of the feathers and the advantages of wing tip slots remain unclear due to the high degrees of freedom feather positioning at the wing tip. In this study, we modeled the bird wings as a set of rectangular wings, following previous experimental studies, and evaluated their aerodynamic performance by two- and threedimensional numerical simulation and optimization. We compared the performance of the slotted wings with those without slots and found that the slotted wings weaken wing tip vortices, enhancing the lift-to-drag ratio. Gapped wingtips can generate aerodynamic forces near the wingtips, which are ineffective for aerodynamic force generation due to wingtip vortices in normal wings. Combined with their lightweight nature, these features have the potential to improve maneuverability. These results offer insight into the evolution of avian wing morphology and inform the design of flying robots.

A5.61 MATHEMATICAL DESCRIPTION OF ABSTRACTED FILTER FEEDING FISH MOUTH GEOMETRY FOR FLUID MECHANICAL INVESTIGATIONS

Albert J Baars (City University of Applied Sciences Bremen, Germany)

albert.baars@hs-bremen.de

Various fishes gain food by passive filtering of water. Remarkable of these filter systems is the non-clogging filter behaviour. To understand the filter mechanism a deeper insight into the flow topology is crucial. The geometry of mouth, gill domain, outer shape of the fish and the Reynolds number take influence on the topology and the filtered volume flow. In this work main components of the filter relevant fish geometry are recognized and abstracted. The shape of these components and their arrangement in space are described by mathematical functions.

This enables systematic investigations. By variation of geometrical parameters and the Reynolds number the effect on the flow topology and the filtered volume flow can be examined using computational fluid dynamics and/ore experimental techniques. In subsequent steps the filter behaviour will be considered.

A5.66 COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF FLOW TOPOLOGY AND PRESSURE DROP OF GILL RAKERS IN SUSPENSION-FEEDING FISH

Hiva Hormozi (Hochschule Bremen City University of Applied Sciences, Germany), Albert J. Baars (Hochschule Bremen City University of Applied Sciences, Germany)

hiva.hormozi@hs-bremen.de

Gill rakers play a crucial role in the filtering of suspension-feeding fishes. They seem to function similarly to a sieve, guiding particles toward the esophagus or collecting particles while influencing the filtered volume flow through hydrodynamic pressure drop. However, the relationship between gill raker morphology, onflow orientation relative to the rakers, hydrodynamic pressure drop, and flow topology is not yet fully understood. To investigate this, we have developed an abstract gill raker model with various geometrical parameters to represent rakers of different filter-feeding species. This study employs computational fluid dynamics (CFD) simulations using OpenFOAM to examine the effects of raker shape, onflow velocity orientation, and Reynolds number (50–1500) on flow topology and pressure drop. The simulated velocity fields are analyzed in terms of characteristic flow patterns and their interactions and are discussed in relation to particle filtration.

A6: COMPARATIVE ENDOCRINOLOGY

ORGANISED BY: CHRISTIAN TUDORACHE (LEIDEN UNIVERSITY), ERIN FAUGHT (LEIDEN UNIVERSITY)

A6.1 MINERALOCORTICOID AND GLUCOCORTICOID RECEPTOR HETERODIMERS DRIVE DISTINCT CORTISOL-INDUCED STRESS RESPONSES

Wednesday 9th July 2025 09:00

Marcel Schaaf (Radboud University, Netherlands)

marcel.schaaf@ru.nl

The steroid hormone cortisol plays a crucial role in our response to stress, influencing various physiological systems, including the brain and immune system. These effects are mediated by two receptors: the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). Both function as ligand-activated transcription factors, binding as homodimers to response elements in target genes. While MR and GR have been shown to form heterodimers, the physiological significance of MR/GR heterodimerization remains largely unexplored. In recent studies, we have demonstrated that MR/GR heterodimerization is essential for specific cortisol-driven effects on behaviour and immune function. To investigate this, we developed mutant MRs and GRs that could selectively form homo- or heterodimers and we expressed these receptors in zebrafish larvae from an MR/GR double knockout line. Behavioral analysis revealed that cortisol-induced hyperactivity occurred only under conditions of MR/GR heterodimerization. Similarly, cortisol’s inhibition of macrophage migration during inflammation also depended on heterodimer formation. To identify molecular targets of the MR/GR heterodimers, we next performed RNA-sequencing. Our findings showed that the heterodimers regulate distinct gene expression patterns. For example, genes involved in glutamatergic signalling were regulated, which was confirmed by CRISPR/Cas9-mediated gene editing of a response element in the gene encoding the metabotropic glutamate receptor 3, which abolished the cortisol-induced hyperactivity. In summary, our research establishes the physiological relevance of MR/GR heterodimerization in vivo, highlighting its central role in eliciting cortisol-induced responses to stress.

Peter C. Hubbard (Centro de Ciências do Mar, Portugal), Samyar Ashouri (Centro de Ciências do Mar, Portugal), Adelino V.M. Canário (Centro de Ciências do Mar, Portugal)

phubbard@ualg.pt

During reproduction of the Mozambique tilapia (Oreochromis mossambicus), chemical communication mainly relies on urinary steroidal glucuronides (sex pheromones) that dominant males release to prime the final ovulation in pre-ovulatory females and increase reproductive readiness. However, the role of steroids in chemical communication in females has received less attention. Here, we aimed to determine whether 17β-estradiol 3-glucuronate released by pre-ovulatory females functions as a reproductive signal towards males. We investigated the preference of focal males to visual, chemical (female conditioned water), and a combination of both stimuli from pre-ovulatory or post-spawning females, and 10−9 M 17β-estradiol 3-glucuronate. Compared to the control zone, where no stimuli were present, males were more responsive (time spent near the stimuli, digging behaviour, and urination frequency) in the visual and visual + chemical zones than in the chemical-only zone. Males preferred pre-ovulatory to post-spawning female-conditioned water. Interestingly, the time spent by focal males near the source of 17β-estradiol 3-glucuronate was similar to pre-ovulatory conditioned water. However, there was no significant difference in digging and urine pulses in response to 17β-estradiol 3-glucuronate compared to the control group. We suggest that male tilapia recognise the ovulation status of females using visual and chemical cues, and 17β-estradiol 3-glucuronate is part of the pheromone released by pre-ovulatory females to communicate their reproductive status. This study received Portuguese national funds from FCT - Foundation for Science and Technology through projects UIDB/04326/2020, UIDP/04326/2020 and LA/P/0101/2020.

A6.3 WHAT STEROID HORMONES CAN TELL US ABOUT ROSS SEALS (OMMATOPHOCA ROSSII)

Wednesday 9th July 2025 09:45

Tshepiso L Majelantle (University of the Witwatersrand, South Africa), Trevor McIntyre (University of South Africa, South Africa), Andre Ganswindt (University of Pretoria, South Africa), Marthan Bester (University of Pretoria, South Africa), Horst Bornemann (Helmholtz-Zentrum für Polarund Meeresforschung, Germany), Mia Wege (University of Canterbury, New Zealand)

t.majelantle@hotmail.com

Ross seals (Ommatophoca rossii) spend most of their year foraging pelagically and only haul out in dense consolidated sea ice for a brief period. The Ross seal is one of the least studied of the Antarctic icedependent pinnipeds. Here, we aimed to find out what information we can get from steroid hormones (progesterone, testosterone, and cortisol) measured in hair (males=7, females=14) and serum (males=7, females=13) samples intermittently collected from Ross seals in die Lazarev Sea, Antarctica, between 2016 and 2023. Sex of the animal can be correlated with 85% accuracy using progesterone to testosterone hormone concentrations ratios measured in serum. Sex correlation accuracy in hair samples was lower at 70% using the same progesterone to testosterone hormone concentrations ratios. Thereafter, Ross seal sex could be predicted from samples for two unknown individuals, which turned out to be males. The testosterone and progesterone concentrations in serum and hair were not significantly linked to body length in males and females respectively. Thus, the hormones cannot be used to estimate age of assumed mature Ross seals. Finally, the results suggest that hair likely cannot be used as a historical marker of stress, and reproduction as there was no significant difference in hair glucocorticoid, progesterone, and testosterone hormone concentrations between new and old hair sampled during moult. These are the first ever measurements of steroid hormone, testosterone and progesterone concentrations for one of the rarest Antarctic seal species and aim to serve as a baseline for future research to build on.

A6.4 ENHANCED CORAL CALCIFICATION INDUCED BY IN VIVO INJECTION OF HUMAN HORMONES

Wednesday 9th July 2025 10:00

Clémence Forin (Centre Scientifique de Monaco, Monaco), Denis Allemand (Centre Scientifique de Monaco, Monaco), Sylvie Tambutté (Centre Scientifique de Monaco, Monaco), Philippe Ganot (Centre Scientifique de Monaco, Monaco) clemence.forin@laposte.net

Calcification is the process by which corals build biomineral structures through the deposition of calcium carbonate on secreted organic matrix molecules. Despite advances at the cellular and physiological levels, the mechanisms controlling coral calcification remain elusive. This gap is primarily due to limitations in available techniques for these organisms. To overcome these challenges, we developed an alternative methodology using in vivo injection of exogenous molecules in octocorallian, one subclass of Anthozoa (Cnidaria) which produces minute biominerals called sclerites. In search of candidate factors potentially influencing calcification, we conducted a primary screening which allowed us to identify a potent candidate, stimulating calcification in both the soft coral Sarcophyton sp. (order Malacalcyonacea) and the precious coral Corallium rubrum (order Scleralcyonacea). Combining imaging analyses with ELISA assays, we characterized its hormonal pathway and quantified its effects on calcification. From methodology development to hormone screening, our research led us to focus on a well-known hormone in vertebrate, though barely studied in invertebrates, particularly anthozoans. Additionally, we established an ecological link between dietary iodine and coral calcification. Our study highlights the importance of marine food webs in these processes and opens new perspectives on the evolution of hormonal pathways.

A6.5 BALANCING RISK AND RESOURCES: ANTIPREDATOR RESPONSES IN A DESERT LIZARD

Wednesday 9th July 2025 10:15

Mihir Joshi (Indian Institute of Science, India), Maria Thaker (Indian Institute of Science, India) mihirm@iisc.ac.in

Non-consumptive effects, in addition to direct consumption, are recognized in shaping not just prey biology but also population dynamics, community structure and ecosystem function. One such effect is increase in energy expenditure due to glucocorticoid mediated stress response. Such prey, therefore, should preferentially seek out food rich in carbon to fuel the elevated energetic needs. We tested this prediction in herbivorous spiny-tailed lizards in Jorbeer conservation reserve in northwestern India, where they inhabit patches that are either abundant or poor in plant biomass. Additionally, the cattle carcass dumping ground inside the reserve attracts hordes of opportunistic carnivores/scavengers, creating a high-risk habitat for these lizards inside the reserve and a relatively low-risk habitat outside. We first measured the antipredator behaviour to confirm that these lizards perceived the predator presence as risky. We then collected blood samples to measure circulating glucocorticoid levels and field observations to measure the carbon:nitrogen ratios of their intakes across four treatments – high and low resource patches inside and outside the reserve. We found that although the lizard antipredator behaviour varied in response to both risk and resources, glucocorticoid levels remained unchanged across patch types. The elemental composition of lizard diets also remained unchanged across treatments, indicating that their physiology was unaffected by either risk or resources. Overall, although food resources and predator presence interact to influence anti-predator behaviour and opportunity costs, it does not translate to changes in either stress response or nutritional intakes in spiny-tailed lizards.

A6.6

STRESS, ANXIETY AND BEHAVIOUR IN ZEBRAFISH (DANIO RERIO) LACKING FUNCTIONAL EXPRESSION OF ONE OR BOTH SERT PARALOGUES

Wednesday 9th July 2025 11:00

Kathleen M Gilmour (University of Ottawa, Canada), Michael Tea (University of Ottawa, Canada), Yihang K Pan (University of British Columbia, Canada), Steve F Perry (University of Ottawa, Canada)

kgilmour@uottawa.ca

Studies using fluoxetine to inhibit the serotonin transporter (Sert) have implicated serotonin in regulation of the stress axis and behaviour in zebrafish. However, zebrafish have two Sert paralogues that differ in the brain regions in which they are expressed. To take advantage of this opportunity, CRISPR/Cas9 technology was used to generate single and double Sert paralogue knockout lines. Baseline and stress-induced cortisol levels were similar across genotypes. In an open-field test, only sertab-/- fish spent significantly more time in the centre of the arena, indicative of lower levels of anxiety-related behaviour. Thus, the anxiolytic effects of fluoxetine likely reflect inhibition of both

Serta and Sertb. However, in the novel tank diving test, which is also used to assess anxiety-related behaviour, sertab-/- and sertb-/but not serta-/- fish largely remained in the upper third of the tank. Video-monitoring of fish in their holding tanks over 24 h revealed that sertb-/- fish rarely left the top third of the tank, consistent with the ‘surfacing’ behaviour that has been attributed to serotonin toxicity. Thus, surfacing behaviour is likely triggered by elevated serotonin levels in brain areas that express sertb. Although the pathways underlying surfacing behaviour remain to be determined, sertb-/- fish responded to a shadow predator stimulus by diving, suggesting that surfacing behaviour is not linked to the absence of a fear response.

A6.7 URBANIZATION AND ACUTE STRESS DO NOT INFLUENCE SLEEP EXPRESSION IN LIZARDS

Wednesday 9th July 2025 11:30

Nitya P. Mohanty (Muséum national d'histoire naturelle, France), Paul-Antoine Libourel (Centre d'Ecologie Fonctionnelle et EvolutiveCNRS, France), Dhanya Bharath (Indian Institute of Science, India), Mihir Joshi (Indian Institute of Science, India), Maria Thaker (Indian Institute o f Science, India)

nitya.mohanty@gmail.com

Animals can sleep variably, with substantial flexibility in sleep duration and distribution, in response to ecological conditions. However, robustly quantifying sleep variation, across individuals and populations, is challenging in small animals such as lizards. Using recently developed miniature loggers, we recorded sleep in 19 wild-caught individuals of the Peninsular rock agama lizard (Psammophilus dorsalis). First, we validated the use of electrooculogram (EOG) as a proxy for sleep in lizards by comparing it to diel variation in arousal response. We then compared three populations each from urban and rural environments, for EOG-derived sleep parameters (sleep duration, and bout frequency, duration, and interval), and behaviourally-measured sleep intensity (latency to arousal). Finally, we simulated a predation attempt that induced acute stress in these individuals and tested for changes in sleep response by population type. Lizards slept mostly at night, with a total sleep time of on average 11.7h, typically in 60 min bouts separated by 8 min of wake state. Sleep characteristics did not differ between urban and rural lizards, though daytime sleep bouts were shorter and more consolidated in urban lizards. Contrary to evidence from mammals, acute stress did not impact sleep, overall or with respect to populations; therefore, a greater diversity of animal taxa must be investigated to determine how sleep varies across populations and in response to ecological stressors. In robustly measuring sleep-wake patterns in small vertebrates at a population level, our study paves the way for quantifying sleep responses over longer time periods, in mesocosms and in the wild.

A6.8 ANNUAL CYCLICITY AND CORRELATION OF ONTOGENETIC BONE GROWTH WITH HORMONAL AND PHYSIOLOGICAL STATES IN THE RED DEER

Wednesday 9th July 2025 11:45

Carmen Nacarino-Meneses (Institut Català de Paleontologia Miquel Crusafont (ICP-CERCA), Spain), Walter Arnold (Research Institute of Wildlife Ecology, Austria), Gabrielle Stalder (Research Institute of Wildlife Ecology, Austria), Meike Köhler (Institut Català de Paleontologia Miquel Crusafont (ICP-CERCA), Spain)

carmen.nacarino@icp.cat

Bone histology is a widely used tool for reconstructing physiological, hormonal and environmental conditions in extant and extinct vertebrates, but nothing is hitherto known about how tissue types and lines of arrested growth (LAGs) correlate with physiological and hormonal levels, or with environmental and biological characteristics. We designed a fluorochrome labelling experiment for an ontogenetic series of 13 red deer individuals to calibrate bone tissue types and LAGs in the femora with plasma IGF1 levels, heart rate, photoperiod and life history events (e.g., weaning) over a maximal period of 3 years for each individual. We found a strong correlation between bone growth and plasma IGF1 levels. Photoperiodic oscillations of plasma IGF1 levels and heart rate follow the same trajectory, although somewhat decoupled. Both also show an “autumn plateau” coinciding with the rut. This plateau is however not recorded in bone apposition rate. Notably, both daily bone apposition and plasma IGF1 values drop after weaning and recover 4 weeks after, while daily bone accrual does not increase with plasma IGF1 values during terminal gestation. As predicted by the disposable soma theory of ageing, we observed that plasma IGF1 decreases from young-to-old deer. There is also an interesting difference between hand raised (with nutrient-powered milk) and hind-raised calves, also predicted by ageing theories. All in all, our results help to better understand how bone histology correlates with biological and physiological characteristics, setting the stage for further experimental research in this area.

A6.9 OLFACTORY SIGNALLING IN LUSITANIAN TOADFISH: A KEY TO REPRODUCTIVE SUCCESS?

Wednesday 9th July 2025 12:00

Diana Gonçalves (Centro de Ciências do Mar do Algarve, Portugal), Zélia Velez (Centro de Ciências do Mar do Algarve, Portugal), Teresa Modesto (Centro de Ciências do Mar do Algarve, Portugal), Peter Hubbard (Centro de Ciências do Mar do Algarve, Portugal)

dsgoncalves@ualg.pt

Teleost fishes use olfaction to detect natural chemical compounds – odorants - belonging to several different classes. These odorants can be released by conspecifics or other species enabling fish to navigate, locate food, identify predators, and recognize conspecifics. The Lusitanian toadfish (Halobatrachus didactylus) is a bottom-living

species that uses acoustic communication during the reproduction season; reproductive males vocalize to attract females to their nest and take care of the nest and the eggs, after reproduction. As other teleosts, the toadfish has a well-developed olfactory system. Recent data showed that the toadfish has high olfactory sensitivity (as assessed by the electro-olfactogram - EOG) to a range of amino acids and intraspecific body fluids, particularly intestinal and accessory glands fluids, with quantitative differences between those from reproductive and non-reproductive males. In this study, we focused on the intestinal fluid (IF) from males. Using solid-phase extraction and preparative HPLC, we fractionated the IF collected from reproductive and nonreproductive males; 31 fractions from each were obtained and their olfactory activity was assessed by EOG. Cross-adaptation experiments with bile acids as adapting solutions indicated that the olfactoryactive fractions likely contain bile acids or share olfactory receptors with them; however, those from reproductive males are qualitatively different from those from non-reproductive males. This suggests a role for these odorants – likely bile acids – in reproduction.

A6.10 EFFECT OF ELEVATED TEMPERATURE ON GONADAL MATURATION

The rapid warming of the Arctic regions may have serious impact on cold-acclimated Arctic species. Polar cod (Boreogadus saida) is a key species in the Arctic food web, with a high biomass and an important prey item for larger fish, seabirds and marine mammals. Although the effect of warming on reproduction is crucial in assessing the vulnerability of a species to climate change, little is known about the impact of warming on the reproduction cycle of polar cod. To study the influence of elevated temperatures on gonadal growth, female B. saida were incubated for six months at a control temperature of 0°C and at elevated temperatures of 3°C and 6°C from August 2022 to February 2023. Magnetic resonance imaging (MRI) to follow the gonad development was applied on a subsample of female individuals from October 2022 to January 2023. Gonadal volume and oocyte diameter were determined from MR images. Histological samples of gonads were taken to determine maturation stages at three sampling points (December, January and February) covering the spawning season. Initial results show that elevated temperature leads to a delay in gonad maturation. Fish at control temperatures reached maximum gonadal volume and most mature gonads in December, whereas females at 3°C showed continued development and females at 6°C showed only small gonads and did not reach the spawning capable stage during the experimental period. Our results indicate a trade-off between reproductive investment and maintenance costs at higher temperatures.

A7: STRESS AS A DRIVER OF NEURAL PLASTICITY: FROM BRAINS TO BEHAVIOUR

ORGANISED BY: KATHLEEN M. GILMOUR (UNIVERSITY OF OTTAWA),

SARAH L. ALDERMAN (UNIVERSITY OF GUELPH)

A7.1 HOW EARLY LIFE STRESS SHAPES THE ZEBRAFISH BRAIN: THE ROLE OF GLUCOCORTICOIDS

Wednesday 9th July 2025 15:00

Helen Eachus (Aston University, United Kingdom), Min-Kyeung Choi (University of Exeter, United Kingdom), Anna Tochwin (University of Exeter, United Kingdom), Johanna Kaspareit (University of Exeter, United Kingdom), May Ho (University of Exeter, United Kingdom), Soojin Ryu (University of Exeter, United Kingdom)

h.eachus@aston.ac.uk

Exposure to early life stress (ELS) can profoundly alter neurodevelopment, with lasting consequences for behaviour and health. Glucocorticoids (GCs), the primary stress hormones, are key mediators of these effects, yet their role in shaping neurodevelopmental trajectories remains incompletely understood. Using an optogenetic zebrafish model, our recent work demonstrates that elevated GC levels during development drive region-specific changes in neurogenesis, particularly within the hypothalamus, a highly stress-sensitive brain region. ELS initially accelerates hypothalamic progenitor proliferation and growth, leading to precocious behavioural maturation. However, this early adaptive plasticity is followed by impaired differentiation, progenitor depletion, and a decline in neurogenic capacity. These neurodevelopmental alterations may contribute to more systemic long-term changes in brain function, which are potentially linked to long-term impaired feeding behaviour, reduced growth, and shortened lifespan. Understanding how stress hormones shape neurodevelopment is critical for elucidating the origins of stress-related disorders and may inform strategies to mitigate their impact.

A7.2 THE EFFECT OF ENDOCRINE DISRUPTING COMPOUNDS ON NEURODEVELOPMENT IN ZEBRAFISH EARLY LIFE STAGES

Wednesday 9th July 2025 15:30

Ellen Vandeputte (University of Antwerp, Belgium), Lucia Vergauwen (Zebrafishlab and ECOSPHERE University of Antwerp, Belgium), Dries Knapen (University of Antwerp, Belgium)

Ellen.Vandeputte@uantwerpen.be

Global interest in studying the effects of endocrine disrupting compounds (EDCs) on neurodevelopment, causing developmental neurotoxicity, has grown. Research in mammals has identified EDCinduced impaired neurodevelopment as an adverse outcome (AO) targeting cochlear function, cognition, learning and memory. Research on fish however typically focuses on other adverse effects (e.g. swim bladder inflation, eye development). The present study therefore aims to determine the impact of EDCs on zebrafish early life stages by analyzing the mammalian AOs, cochlear function and learning and memory. Cochlear function was assessed via the lateral line (LL) system, a neurosensory system that senses water motion and pressure gradients. The functional units of the LL are neuromasts and contain hair cells (HCs), which are similar to HCs in the cochlea. Zebrafish embryos were exposed to EDCs for 5 days, after which the number of HCs and total neuromasts were counted. Targeted exposure windows and gene transcript levels were used to gain more detailed mechanistic understanding of observed effects. Learning and memory is studied via a forced turn larval T-maze behavioral assay. Zebrafish larvae exhibit spontaneous alternation behavior (SAB, i.e. the animal’s tendency to alternate turn direction in consecutive turns). By closing one arm of the T-maze, the animal should choose to explore the other arm on the next trial. This requires proper memory. Zebrafish embryos were exposed to a positive control and EDCs, after which SAB was assessed. Overall, this work aids in determining to which extent EDCs can affect neurodevelopment in zebrafish.

A7.3 EFFECTS OF ENVIRONMENTAL COMPLEXITY ON NEURAL DEVELOPMENT IN ZEBRAFISH

Wednesday 9th July 2025 15:45

Sarah L Alderman (University of Guelph, Canada) alderman@uoguelph.ca

An animal’s environment can have a profound influence on neural phenotype, particularly during early development. Although this phenomenon is well-appreciated, it is at odds with laboratory practices for zebrafish, where embryos are maintained in water alone during the entire period of brain development and often beyond. We asked whether adding environmental complexity during early development impacts the neural phenotype of zebrafish. Fertilized eggs were allocated to petri dishes with water alone (barren) or supplemented with small multicoloured Lego bricks (complex). A suite of physiological, behavioural, and morphological end points was quantified after 5 days of rearing in these conditions. Following an acute stressor (2 min agitation), larvae reared in barren dishes elicited a characteristic increase in whole body cortisol, whereas cortisol content in larvae reared in complex dishes was unchanged. A vibrational startle response assay revealed that larvae from complex dishes habituated sooner to the repeated stimulus than larvae reared in barren dishes. A light:dark assay revealed that the freezing response to sudden illumination was diminished in larvae from complex dishes relative to larvae from barren dishes. Cell proliferation in the telencephalon—a key brain region for regulating behaviour—was quantified in larvae to explore a potential mechanism for the observed behavioural differences. Our results are consistent with the proneural responses observed in adult zebrafish housed with environmental enrichment: reduced stress responsiveness, startle response, and anxiety-like behaviour. Taken together, this study demonstrates how a simple modification to zebrafish rearing may benefit the brain and behaviour of a popular animal model.

A7.4 NEUROPHYSIOLOGICAL AND BEHAVIOURAL INSIGHTS INTO SWIMMING CHOICE OF JUVENILE ATLANTIC SALMON

Wednesday 9th July 2025 16:00

Martina Bellio (Norwegian University of Life Sciences, Norway), Marco A Vindas (Norwegian University of Life Sciences, Norway), Ruth Newberry (Norwegian University of Life Sciences, Norway), Lynne Sneddon (University of Gothenburg, Sweden)

martina.bellio0@nmbu.no

Atlantic salmon (Salmo salar) exhibit active swimming behaviour throughout most of their life cycle, effectively serving as a form of sustained exercise with the potential to influence physiological regulation and neurobiological processes; notably, exercise in mammals has been associated with improved stress coping and pain management; the extent to which similar mechanisms operate in fishes, along with the underlying neurophysiological processes, remains to be elucidated. To investigate this, we examined the swimming behaviour of juvenile salmon in a “choice arena” where individuals selected between calm and flowing water zones (0.5–1.8 body lengths per second; BL/s). By testing

different size groups, we assessed how exposure to water flow affects swimming behaviour and its potential neurophysiological effects. Our findings reveal a size-dependent pattern in flow selection, with larger individuals showing a strong preference for higher velocities (≥ 1.6 BL/s), while smaller fish divide their time between moderate currents (1.4–1.6 BL/s) and calm areas, i.e. a behavioural pattern incorporating intermittent rest periods between active swimming bouts. This may indicate a size-dependent energetic trade-off, with larger fish benefiting from station-holding behaviours in fast-flowing habitats, while smaller individuals appear to conserve energy by limiting prolonged flow exposure. Importantly, fish with access to flow exhibited lower plasma cortisol levels, suggesting lower stress reactivity. Preliminary neurochemical analyses revealed distinct monoamine activity patterns in the telencephalon and hypothalamus. Ongoing region-specific analyses aim to further elucidate the neurobiological mechanisms by which swimming choice influences stress resilience and pain coping strategies, in region-specific neuronal areas.

A7.5 THE EFFECTS OF TEMPERATURE AND SLEEP DISRUPTION ON SOCIABILITY AND METABOLISM IN THE TRINIDADIAN GUPPY, POECILIA RETICULATA

Wednesday 9th July 2025 16:15

Helena Norman (University of Glasgow, United Kingdom), Safi K Darden (University of Exeter, United Kingdom), Mike M Webster (University of St Andrews, United Kingdom), Jan Lindstrom (University of Glasgow, United Kingdom), Shaun S Killen (University of Glasgow, United Kingdom) helenanorman24@gmail.com

Sleep is a fundamental neurophysiological and behavioural state, observed ubiquitously across the animal kingdom. While the function of sleep remains elusive, its importance is evident through the deleterious effects of sleep deprivation. In fish- an understudied taxon in the context of sleep behaviour and ecophysiology- sleep deprivation has been linked to impaired cognition, altered movement, and reduced predator avoidance responses. As ectotherms, fish are particularly vulnerable to climate change, with increased temperatures and hypoxia associated with a plethora of behavioural and physiological changes. However, the impact of climate-related stressors on sleep in fish is largely unexplored. The present study aimed to address this gap by investigating: 1) how temperature changes influence sleep behaviour; 2) the effects of altered sleep on subsequent daytime activity, sociability, and metabolism; and 3) whether temperature modulates consequences of sleep deprivation. Using Trinidadian guppies (Poecilia reticulata), we implemented six experimental treatments: at 24°C and 28°C, fish experienced either no physical disruption, nighttime physical (sleep) disruption, or daytime physical disruption. To assess the effects of temperature on sleep behaviour, fish were filmed at night, and sleep patterns were quantified through video analysis. The following day, fish were placed in sociability assays, and we assessed behavioural changes using video-tracking software. Subsequently, we conducted intermittent-flow respirometry, to measure standard metabolic rate (SMR) and explore metabolic patterns following sleep alterations. This study represents the first investigation into the effects of climaterelated stressors on sleep in fish and the potential repercussions of sleep alterations in the context of a changing environment.

A8: ANIMAL RESPONSES TO A CHANGING WORLD: WHAT ABOUT COGNITION?

ORGANISED BY: LISANDRINA MARI (UNIVERSITY OF JYVÄSKYLA), ALYCIA VALVANDRIN (UNIVERSITY OF TURKU)

A8.2 FISH MINDS IN TROUBLED WATERS

Thursday 10th July 2025 09:00

Tyrone Lucon-Xiccato (University of Ferrara, Italy), Gaia De Russi (University of Ferrara, Italy), Elia Gatto (University of Ferrara, Italy), Elena Frigato (University of Ferrara, Italy), Georgiana Andrei (University of Ferrara, Italy), Annalaura Mancia (University of Ferrara, Italy), Monia Perugini (University of Teramo, Italy), Gil Rosenthal (University of Padova, Italy), Elena Maggi (University of Pisa, Italy), Stefano Cannicci (University of Firenze, Italy), Cristiano Bertolucci (University of Ferrara, Italy)

tyrone.luconxiccato@unife.it

Evidence is becoming overwhelming that human activities are driving environmental alterations from multiple perspectives, including chemical, ecological, and physical changes. These environmental alterations can have profound impacts on animals, particularly from a physiological standpoint. However, the cognitive system of animals is highly susceptible to both external environmental influences and internal physiological states, suggesting that cognition could also be significantly affected by these alterations. Here, I present a recent set of studies on freshwater teleost fish, the most endangered group of vertebrates, exploring whether and how anthropogenic stressors affect cognition. Various chemical alterations in aquatic environments induce neurotoxicity, directly impairing cognitive function. Microplastics, although indirectly, also impair cognitive functioning. Physical disturbances, such as light pollution, influence cognitive phenotypes, especially during early development. Lastly, ecological changes, such as the introduction of non-native species, affect cognitive variability through hybridization. All these findings converge on the same conclusion: although more challenging to observe, most anthropogenic stressors significantly impair cognition in fish. These cognitive disruptions should be recognized as major contributors to fitness reduction in altered environments, as cognition governs most adaptive behavioral responses. Considering cognition in future studies will likely reveal that the impact of human activities on animals is greater than previously believed.

A8.3

DOES TIMING MATTER? THE IMPACT OF HYPOXIA AT DIFFERENT DEVELOPMENTAL STAGES ON FISH COGNITION

Thursday 10th July 2025 09:30

Alycia VALVANDRIN (University of Turku, Finland), Camille ROCHON (University of Turku, Finland), Luisa BERMEJO-ALBACETE (University of Turku, Finland), Katja ANTTILA (University of Turku, Finland), Amélie CRESPEL (University of Turku, Finland)

alycia.valvandrin@utu.fi

Low oxygen concentration in the water, known as hypoxia, occurs naturally but is expected to become more frequent and severe due to current global changes and anthropogenic pressures. Organisms can adjust to a change in their environment via plasticity, but the timing of this plasticity has been overlooked, especially in ecophysiology aspects such as cognition. Cognition, referring to the ability of animals to make decisions, is essential for successful foraging, anti-predatory responses, and many other key functions linked directly to survival. Hypoxia, for instance, may modify different aspect of cognition, like the problem-solving and/or learning/memorizing cognition, what is then crucial to study in the current context of global changes. To address this question, we exposed three groups of three-spined stickleback Gasterosteus aculeatus to different hypoxia regimes: a control group that has always been in normoxia (>90% of O2 throughout the day), a group that has always been exposed to fluctuating hypoxia (>90% of O2 during the day and 30% of O2 during the night to mimic more natural conditions), and a group that has been in normoxia until 4 months-old, and then exposed to fluctuating hypoxia. Their problem-solving and learning/memorizing cognition were assessed using a decision-making and a detour test with an increase of complexity, leading to a reward. Assessing the impact of hypoxia at different developmental stages on cognition provides important insights on the capacity of fish to deal with their changing environments, primordial for predicting the global response of an organism to environmental changes.

A8.4 IMMEDIATE LOSS AND SUBSEQUENT RECOVERY OF OLFACTION IN BROWN TROUT (SALMO TRUTTA) EXPOSED TO NATURAL DISSOLVED ORGANIC CARBON

Thursday 10th July 2025 09:45

Lauren Zink (University of British Columbia, Canada), Molly Tilley (University of Lethbridge, Canada), Ilan Ruhr (University of Salford, United Kingdom), Matthew J Bogard (University of Lethbridge, Canada), Steve Wiseman (University of Lethbridge, Canada), Chris M Wood (University of British Columbia, Canada) lauren.zink@zoology.ubc.ca

Fish rely on olfactory perception to mediate a range of crucial lifehistory behaviours such as predator avoidance, navigation, and foraging. Multiple researchers have noted that dissolved organic carbon (DOC) protects against branchial and olfactory toxicity caused by aquatic contaminants; however, the mechanism by which DOC is protective of olfaction is unknown. The concentrations of DOC in natural waters are increasing in many ecosystems worldwide, driven by a number of factors, including land use changes, climatic shifts, and recovery from acid deposition; therefore, it is important to assess how DOC concentrations alter fish physiology. By exposing brown trout to 10 mg/L natural DOC derived from maple leaves, we have established that the gill and olfactory epithelia respond independently to DOC. We observed a hyperpolarization of the gill, which was consistent regardless of whether the exposure to DOC was acute (a 5-minute pulse) or sustained (48 hours). We then assessed the olfactory acuity of the same group of fish using electro-olfactography (EOG), which entailed exposing the fish to the same DOC, while simultaneously presenting them with a mixture of two odourants, L-alanine and TCA, that stimulate olfactory sensory neurons and produce a measurable electrical potential. Despite the presence of the odourants, we observed an immediate loss of olfactory acuity with the pulse exposure of DOC, but olfaction recovered under sustained DOC exposure. This presentation will explore the immediate loss of olfactory acuity and subsequent recovery from immunohistochemical, histological, physiological, and behavioural perspectives to discern mechanistic to population-level effects (NSERC Discovery).

A8.5 THE DARK

SIDE

OF LIGHT: DISRUPTED NATURAL LIGHT DARK CYCLES UNDERMINES PERSONALITY DEPENDANT VARIATION IN ACTIVITY

PATTERNS OF MIGRATORY THREESPINED STICKLEBACK

Thursday 10th July 2025 10:00

Danielle Crowley (Institute of biology Leiden University, Netherlands), Hossein Alami (Institute of biology Leiden University, Netherlands), Hans Slabbekoorn (Institute of biology Leiden University, Netherlands), Christian Tudorache (Institute of biology Leiden University, Netherlands)

d.crowley@biology.leidenuniv.nl

Natural light-dark cycles (LD) are key in regulating daily and seasonal rhythms in migratory species. As a predictable environmental cue, light can entrain the biological clock to the external environment. This steers the synchronisation of behavioural and physiological cycles with biological events, which benefits survival and reproduction. Such dependency on LD raises concerns for the impact of artifical light on the timing of natural rythms, as with increasing light pollution the entrainment of the biological clock may be distrupted. Additionally, individual personality type may influence the response to - and ability to cope with light pollution due to discrepency in clock rythmicity and timing of activity (day or night active). In this study we tested the impact of artifical light on the activity patterns of migratory stickleback and the link between personality and responsiveness to LD. We used emergence tests, to determine variation in personality and multiple-day open-field tests to relate consistent behavioural tendencies to disturbance effects from artifical light exposure. We quantified daily activity patterns under LD and under constant dim light (LL). Under LD, we found individual variation activity timing but that all fish were rythmic. However, under LL we found that the rhythm of all fish were distruped and there was a suppresion of activity. Additionally, we found that different personality types drove divergent strategies in both level and timing of activity under LD and LL. Though under prolonged LL this was neutrulised and all individuals showed a decrease in activity and no difference in activity timing.

A8.6 DOUBLE TROUBLE: HOST BEHAVIOUR INFLUENCES AND IS INFLUENCED BY CO-INFECTION WITH PARASITES

Thursday 10th July 2025 10:15

Maryane Gradito (Deakin University, Australia), Frédérique Dubois (Université de Montréal, Canada), Victoria Thelamon (Université de Montréal, Canada), Daniel WA Noble (Australian National University, Australia), Sandra A Binning (Université de Montréal, Canada)

s224705124@deakin.edu.au

Parasitised animals can differ dramatically in terms of their behaviour and cognitive performance from uninfected conspecifics. Yet, the causal direction of this relationship remains unclear: do parasites alter host behaviour/cognition, or do consistent differences in behaviour/ cognition make hosts more susceptible to infection? We tackled these questions using wild-caught pumpkinseed sunfish (Lepomis gibbosus) to investigate the relationships among parasitism, behaviour and cognition. In a first study, we used fish body condition as a proxy for health status to help reveal correlations between parasites and host traits (i.e., exploration, boldness, cognition). Only individuals in relatively lower body condition displayed a negative relationship between parasite density and exploratory behaviours. However, there was no correlation between aversive learning, a measure of cognitive performance, and infection. Our results showed that body condition is important to consider when studying infection in wild populations as some patterns are only apparent when body condition is taken into consideration. In a second study, we measured exploration, activity, boldness and body condition before and after a semi-experimental infection using lake mesocosms where sunfish were naturally exposed to parasites. We found that behaviour strongly influenced infection susceptibility: bolder and less active fish acquired a higher density of parasites during the infection period. Following infection, fish body

condition decreased with increasing cestode density, and activity decreased with increasing trematode density, suggesting that coinfection negatively impact hosts. These results highlight that two mechanisms may simultaneously operate: initial host behaviour influences their risk of infection, and infection alters the behaviour of infected hosts.

A8.7 HIGH-FAT HIGH-SUGAR DIETS AND THEIR EFFECTS ON THE GUT MICROBIOTA AND COGNITION OF FERAL PIGEONS (COLUMBA LIVIA DOMESTICA)

Thursday 10th July 2025 11:00

Camille A. Troisi (Université de Rennes, France), Joël White (Université Toulouse III, France), Anne-Sophie Benoiston (Université Toulouse III, France), Audrey Ghidizzi (Université Toulouse III, France), Lucie Moreau (Université Toulouse III, France), Coralie Drack (Université Toulouse III, France), Marina Papadopoulou (University of Tuscia, Italy), Luc Lens (Gent Universiteit, Belgium), Frederick Verbruggen (Gent Universiteit, Belgium)

camille.troisi@univ-rennes.fr

In the lab, diet has been found to greatly influence cognition, particularly during development. Specifically, high-fat high-sugar (HFHS) diets reduce learning and memory. One of the processes through which this occurs is the gut-brain axis, where the gut-microbiome influences how animals make decisions, such as during spatial exploration and navigation. In urban environments, species such as pigeons are often exposed to HFHS diets. In this study, we provided a HFHS diet and a control diet for 4 weeks to two groups of young racing pigeons, after which they all received the control diet (n=96). During treatment, the two groups did not differ in their gut-microbiota diversity, but from week 5 onwards young pigeons exposed to the HFHS diet had a higher gut-microbiota diversity than those raised on the control diet. When individuals were trained to return to their home loft, unlike what we predicted, individuals on the HFHS diet were (1) faster at finding the home loft, (2) faster at learning, (3) explored less and were (4) less cohesive and coordinated than individuals in the control group. Diet induced gut-microbiota diversity changes could explain behavioural differences in both social and individual navigation.

A8.8 LIKE FATHER, LIKE SON? EFFECTS OF PATERNAL EXPOSURE TO HEAVY METALS ON OFFSPRING EMOTIVITY AND COGNITIVE PERFORMANCE IN JAPANESE QUAIL (COTURNIX JAPONICA)

Thursday 10th July 2025 11:30

Lisandrina Mari (University of Jyväskylä, Finland), Lea Hipolite (University of Jyväskylä, Finland), Suvi Ruuskanen (University of Jyväskylä, Finland)

lisandrina.m.mari@jyu.fi

memory and learning, with strong potential to disrupt their cognitive abilities. In birds, cognitive performance has been positively linked to reproductive success and lifespan – as such, lead exposure represents a critical concern to their survival. However, we lack knowledge on how 1) ecologically-relevant lead concentrations affect avian cognition, and 2) whether parental exposure can induce effects visible in offspring. In this study, we exposed captive male Japanese quails (Coturnix japonica) to an ecologically relevant dose of lead and mated them to non-exposed females to produce an offspring generation. At three weeks of age, offspring were exposed to the same lead dose for two weeks. We monitored offspring growth and emotivity with a tonic immobility test before, during, and after exposure. In addition, after exposure, we assessed the offspring cognitive performance with an inhibitory control task, in which birds had to successfully detour a transparent barrier to access a food reward. Our results bring important insights into how metal pollution across generations affects the behavioral and cognitive performance of birds, with important implications for their capacity to adapt to a changing world.

A8.9 EFFECTS OF ARTIFICIAL LIGHT-AT-NIGHT ON METABOLIC AND BEHAVIOURAL RESPONSE TO SIMULATED STIMULI IN REEF FISH

Thursday 10th July 2025 11:45

Izzy C Tiddy (University of Glasgow, United Kingdom), Suzanne C Mills (EPHE, French Polynesia), Manuel Vidal (Aix Marseille Universite, France), Riccardo Beldade (Pontificia Universidad Catolica de Chile, Chile), Shaun S Killen (University of Glasgow, United Kingdom)

isabelle.tiddy@glasgow.ac.uk

Stressors such as artificial light-at-night (ALAN) affect both terrestrial and aquatic systems and are often associated with increased infrastructure and development. Coral reefs, which are often close to areas of rapid coastal development, are therefore prone to significant exposure to these stressors, however, the metabolic and behavioural effects of ALAN on coral reef fish are somewhat understudied. In this study, we used virtual reality (VR) to visually simulate exposure to various cues in two reef fish, Amphiprion chrysopterus and Dascyllus trimaculatus. Behavioural data was collected during and after exposure to a sandy environment (baseline) and simulated stimuli (conspecific, heterospecific, and predator) in fish previously exposed either to ALAN or to ambient light levels (control). In addition, for A. chrysopterus, metabolic and activity data were collected during and after exposure to a simulated predator. In behavioural trials, ALAN-exposed fish tended to be less risk averse, showing greater tendency to approach heterospecifics and predators. In behavioural trials in A. chrysopterus, ALAN-exposed fish were more active when exposed to a baseline stimulus but did not show an activity increase in response to stimuli, while control fish increased activity level. In respirometry trials, activity level was significantly reduced in both control and ALAN-exposed A. chrysopterus when exposed to a predator cue. Metabolic rate, however, was reduced significantly more in control compared with ALAN-exposed fish, during and after exposure. ALAN-exposed fish overall appear to be less responsive to predator cues, possibly due to higher metabolic demand associated with increased nocturnal activity leading to greater risk-taking.

A8.10 “DECODING LOBSTER “BRAIN”: EFFECTS OF ANAESTHESIA AND TEMPERATURE ON ELECTRICAL ACTIVITY OF SUPRAESOPHAGEAL GANGLION AND CONSCIOUSNESS STATUS IN HOMARUS AMERICANUS”

Thursday 10th July 2025 12:00

Luca Pettinau (Department of Animal Health and Welfare Wageningen University Research, Netherlands), Rodrigo Lorenzo (Institut de Ciències del Mar - CSIC, Spain), Henny Reimert (Department of Animal Health and Welfare Wageningen University Research, Netherlands), J.M.C.D. Meijer (Wageningen Technical Solutions Wageningen University Research, Netherlands), Hans Van de Vis (Department of Animal Health and Welfare Wageningen University Research, Netherlands), Guiomar Rotllant (Institut de Ciències del Mar - CSIC, Spain)

luca.pettinau@wur.nl

A fundamental dilemma in crustacean neuroscience is the lack of clear indicators of consciousness and sentience. Electroencephalography (EEG) and Visual Evoked Responses (VERs) are used to study neural activity associated with sensory processing, anaesthesia and consciousness in vertebrates, however, few studies applied these in vivo methods in crustaceans. Decapod crustaceans have a metameric nervous system with ganglia that control each respective body segment. The supraesophageal ganglion (SG) is the first ganglion of the nervous system and it integrates sensory and motor information. Like the brain in vertebrates, SG is speculated to have a prominent role in consciousness and awareness, although we lack empirical data. To explore this, at first we examined the SG’s electrical activity of American lobsters (Homarus americaus) under Eugenol (75 ppm) anaesthesia using EEG and VERs to flash-lights, recording before, during, and during recovery from anaesthesia (for 10 min each, and 20 min recovery). In a second experiment, EEG and VERs were measured during a thermal ramp (1°C * 5 min-1 ) to assess how temperature changes affect neural excitability and consciousness in these ectothermic animals. These results provide novel insights into characterization of the EEG and VERs in decapod crustaceans and could contribute to the ongoing discussion on whether these species exhibit neural dynamics associated with consciousness and awareness. This study expands our understanding of crustacean neurophysiology in response to anaesthesia and environmental challenges. This work was co-funded by the European Union’s Horizon Europe Project 101136346 EUPAH.

A8.11 DECISION-MAKING PERSPECTIVES OF ZEBRAFISH (DANIO RERIO)

Thursday 10th July 2025 12:15

Upama Das (Ethophilia Research Foundation, India), Guruprasad Garain (Patha Bhavana Visva Bharati University, India), Chayan Munshi (Ethophilia Research Foundation, India)

chayanbio@gmail.com

Locomotory activities in fish are thought to be a good behavioral marker for assessing neuro-ethological plasticity, and they are often used in ecotoxicological and pharmaceutical studies. Zebrafish (Danio rerio) are an excellent model for studying cognitive biology owing to their notable sensitivity to external stimuli as it is known that the sensitivity of zebrafish is reflected in its movement characteristics. Even microenvironmental disruption can have a considerable impact on this fish's locomotory biomechanics. We designed an experimental model system to critically understand the decision-making ability of zebrafish adults, where we have focused on the basic concept of foraging and the probabilities of finding the easiest or fastest trajectory to find the food source. Additionally, our objective is to find the possibility of avoiding complicated trajectories to reach the food source quickly. Our work aims to promote zebrafish as a "species in the spotlight" with the intent to further comprehend the neuroethological perspectives of movement biology.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A8.1 EFFECTS OF ARTIFICIAL LIGHT-AT-NIGHT ON THE DIURNAL RISK-TAKING BEHAVIOUR OF A GREGARIOUS REEF FISH

Izzy C Tiddy (University of Glasgow, United Kingdom), Shaun S Killen (University of Glasgow, United Kingdom), Suzanne C Mills (EPHE, French Polynesia)

isabelle.tiddy@glasgow.ac.uk

Artificial light at night (ALAN) is increasingly present in both terrestrial and aquatic systems and has been found to influence physiological and behavioural traits in wild animals in a range of habitats. In coral reef ecosystems, increasing human pressure often leads to more coastal infrastructure and boat traffic, resulting in an increase in ALAN exposure for reef organisms. Here, we aimed to investigate the effects of chronic ALAN exposure on social behaviour and risk-taking in a gregarious coral reef fish, Dascyllus trimaculatus. Wild fish were collected from sites containing both ALAN-exposed and control (ambient light levels) anemones around Moorea, French Polynesia. Fish underwent a three-chamber shoal choice test to assess diurnal sociability, followed by an emergence test to assess diurnal risk-taking behaviour. Activity levels were measured during both tests. No effect of ALAN exposure was found on daytime social behaviour or activity level. ALAN-exposed fish were, however, found to take less time to emerge from an anemone after a chase stimulus compared with control fish. The differences in risk-taking may be due to direct effects of ALAN exposure on risk-taking behaviour, or selective mortality of more risk-averse individuals, both potentially driven by increased nighttime activity levels during ALAN exposure. Increased nighttime activity may lead to increasing metabolic needs, driving increased risk-taking, or could lead to more risk-averse fish facing an increased risk of starvation or reduced growth. Our study adds to the existing literature and provides the first evidence that chronic ALAN exposure increases risk-taking behaviour in a marine fish.

A9: GOING BEYOND DEATH: UNDERSTANDING ECOLOGICALLY AND PHYSIOLOGICALLY RELEVANT IMPACTS OF ENVIRONMENTAL TOXICANTS AND INNOVATING FOR A SUSTAINABLE FUTURE: MITIGATING THE ENVIRONMENTAL RISKS OF HIGH-TECH SOLUTIONS AND POLLUTION OSMOREGULATION AND ENERGY USE

ORGANISED BY: AMELIA MUNSON (SWEDISH UNIVERSITY OF AGRICULTURAL SCIENCES), ROSA FREITAS (UNIVERSITY OF AVEIRO), LAETITIA MINGUEZ (UNIVERSITÉ DE LORRAINE), JEHAN-HERVÉ LIGNOT (UNIVERSITY OF MONTPELLIER)

A9.19 HIGH CO2 AND HIGH O2 AS POLLUTANTS IN INTENSIVE AQUACULTURE: ACID-BASE PHYSIOLOGY ILLUMINATES NEPHROCALCINOSIS, A FISH WELFARE CHALLENGE OF IMMENSE ECONOMIC COST

Tuesday 8th July 2025 09:00

Chris M. Wood (University of British Columbia, Canada), Cameron Emadi (University of British Columbia, Canada), Colin J. Brauner (University of British Columbia, Canada), Thi Hong Gam Le (University of Bergen, Norway), Harald Kryvi (University of Bergen, Norway), Elsa Denker (University of Bergen, Norway), Marius Takvam (University of Bergen, Norway), Tom Ole Nilsen (University of Bergen, Norway) woodcm@zoology.ubc.ca

Nephrocalcinosis (“kidney stones”) is a painful disease with an immense impact on the welfare of salmonids in aquaculture. In Norway, it affects approximately 190 million smolts annually, with 30 million of those dying. Economic losses are about US$140 million annually. We have developed a model of its cause based on acidbase physiology. Under intensive aquaculture, especially in RAS,

high PCO2 builds up in the water, often accompanied by high PO2 . CO2 equilibrates into the blood, and CO2 excretion is retarded. Additionally, high PO2 causes further CO2 retention. High PCO2 builds up internally, depressing pH (“respiratory acidosis”) in the plasma and pre-urine. Ca, Mg, inorganic phosphate, and ammonia concentrations also rise during acidosis. Fish gradually compensate by building up [HCO3 - ] (“metabolic base”) via ion-exchange mechanisms (Cl- /base, Na+ /acid) on the gills, thereby restoring plasma and preurine pHs to normal as long as water conditions remain unchanged. However, when fish are transferred to water with lower CO2 and O2 during standard aquaculture operations (e.g. grading, tank-cleaning, vaccination, shipping etc.), PCO2 in the plasma and pre-urine drops almost instantaneously, whereas high [HCO3 - ] persists for several hours. Thus, pH and [HCO3 - ] are simultaneously very high (“metabolic alkalosis”) in the plasma and pre-urine, together with other precursors (Ca, Mg, phosphate, ammonia) of the precipitates. An ideal chemical environment for nucleation and growth of kidney stones is created. We will report results of in vitro, in vivo, and field trials in support of this model, and recommend steps that can be taken to minimize the problem.

A9.2 TEMPERATURE MATTERS: ACUTE AND LATENT TOXICITY OF DILUTED BITUMEN TO DEVELOPING SALMON IS POTENTIATED BY A MODEST INCREASE IN WATER TEMPERATURE

Tuesday 8th July 2025 09:30

Todd E Gillis (University of Guelph, Canada), Derin Calik (University of Guelph, Canada), Anthony P Farrell (University of British Columbia, Canada), Chris Kennedy (Simon Fraser University, Canada), Sarah L Alderman (University of Guelph, Canada)

tgillis@uoguelph.ca

Bitumen, a heavy crude oil, is used globally for petrochemicals and road surfacing. In Canada, the Trans Mountain Pipeline carries >140 million liters of diluted bitumen (dilbit) per day from the oilsands in Edmonton to Vancouver. Along the way, it traverses the Fraser River Watershed, one of the largest salmon producing systems in the world. To examine the influence of environmental temperature on the response of coho salmon (Oncorhynchus kisutch) to dilbit exposure we incubated embryos from fertilization to swim-up at ambient temperature (Ta) or Ta + 3 °C while exposing them to one of three environmentally relevant concentrations of dilbit (0, 0.3, 1.0 μg/L total PAC). The aerobic capacity of the salmon was measured at swim-up using a hypoxia challenge. Fish exposed to 1.0 μg/L initial PAC demonstrated a 25% reduction in hypoxia tolerance and a 1020% increase in mortality and this response was magnified by 40% and 18%, respectively, in fish incubated at Ta + 3 °C. Consequences of dilbit exposure persisted after 6 weeks of depuration in clean water, but were greatest in fish exposed to dilbit at elevated temperature: additional 20% mortality and 30% decrease in mass relative to controls, and a 20% reduction in hypoxia tolerance. Relatively lower induction of Phase I biotransformation and greater tissue PAC content in warm-exposed coho suggests reduced PAC metabolism as a mechanism for the observed potentiation. Thus, seasonal fluctuations and baseline increases in water temperature from climate change can exacerbate the adverse effects of oil spills on developing fish.

A9.3 SWIMMING IN MEDICATED WATERS: UNDERSTANDING AND MITIGATING

Tuesday 8th July 2025 09:45

Eli Thoré (University of Namur, Belgium), Michael G Bertram (Swedish University of Agricultural Sciences, Sweden), Tomas Brodin (Swedish University of Agricultural Sciences, Sweden) eli.thore@unamur.be

The widespread use of pharmaceuticals leads to their introduction into natural environments worldwide. While some pharmaceuticals cause acute toxic effects in wildlife, such as mass mortality or reproductive failure, the majority are present in concentrations too low to be overtly toxic. However, these low concentrations can induce subtle behavioural changes in wildlife, potentially leading to significant ecological consequences. The last few decades have seen a

surge in behavioural ecotoxicology research, driven by methodological and technological innovations that allow for the collection of highresolution behavioural data in both laboratory and field settings. Despite these advancements and our increased understanding of the ecological risks posed by pharmaceuticals, this knowledge is seldom integrated into chemical regulation frameworks. This presentation highlights the necessity of incorporating behavioural ecotoxicology findings into regulatory practices to better protect wildlife and their ecosystems.

A9.4 SUBLETHAL YET SIGNIFICANT: HOW POLLUTANTS AND WARMING IMPACT FRESHWATER INVERTEBRATES AND ECOSYSTEM FUNCTIONING

Tuesday 8th July 2025 10:00

Claire Duchet (University of South Bohemia, Czech Republic), Julie Verheyen (University of Leuven, Belgium), Eve Soltane (University of South Bohemia, Czech Republic), Michael A Figueroa-Sanchez (University of South Bohemia, Czech Republic), Kateřina Grabicová (University of South Bohemia, Czech Republic), Robby Stoks (University of Leuven, Belgium), David S Boukal (University of South Bohemia, Czech Republic)

cduchet@prf.jcu.cz

Freshwater ecosystems face growing threats from chemical pollution and climate warming. However, their combined effects on freshwater invertebrates remain poorly understood, particularly the mechanisms linking (sub)individual responses to broader ecological impacts. To fill this gap, we assessed the effects of environmentally realistic concentrations of pharmaceutical contaminants (PhACs) and warming on freshwater invertebrates in outdoor mesocosms. We explored the physiological responses of Asellus aquaticus (Isopoda) and Cloeon dipterum (Ephemeroptera) in winter and summer, revealing seasonal differences in sensitivity: in winter, PhACs reduced energy availability and increased oxidative damage, while in summer, they boosted energy levels but reduced the population size. These physiological and populationlevel changes translated into ecosystem-level effects, including reduced leaf litter decomposition and altered insect emergence. Building on these findings, we investigated the effects of a PhACand-pesticide mixture and warming to examine how sublethal effects of environmentally realistic pollutant mixtures cascade to population and ecosystem levels. Preliminary insights suggest that interactions between chemical stressors and warming drive unexpected shifts in zooplankton population size and structure, reinforcing the need to move beyond mortality-based assessments toward more ecologically relevant endpoints. Our results highlight the vulnerability of aquatic invertebrates to warming in combination with low levels of pollution, demonstrating cascading impacts from individuals to ecosystems. These findings emphasize the need for integrative approaches to assess and mitigate the ecological consequences of emerging contaminants in a changing climate.

A9.1 THE HEAT AND THE HAZARD: COMBINED EFFECTS OF PFAS AND TEMPERATURE ON SHEEPSHEAD MINNOW PERFORMANCE

Friday 11th July 2025 09:30

Margot Grimmelpont (University of Connecticut, United States), Maria Rodgers (North Carolina State University, United States), Anika Agrawal (University of Connecticut, United States), Jacqueline Baron (University of Connecticut, United States), Dan Bolnick (University of Connecticut, United States), Sylvain De Guise (University of Connecticut, United States), Milton Levin (University of Connecticut, United States), Kat Milligan-McClellan (University of Connecticut, United States), Jessica Brandt (University of Connecticut, United States)

margot.grimmelpont@gmail.com

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants that bioaccumulate and cause harmful effects to organisms. Despite their widespread presence, few studies have investigated how environmental factors influence PFAS toxicity. This study assessed the combined effects of warming scenarios and PFAS mixtures on the metabolic and swimming performance of sheepshead minnows (Cyprinodon variegatus). Fish were exposed to a mixture of PFOS and PFOA (target concentration: 100 ng/ mL, consistent with the US EPA’s Aquatic Life Criteria for chronic exposures) under three temperature conditions (24°C, 26°C, and 28.5°C). Metabolic variables (SMR – standard metabolic rate, MMR – maximum metabolic rate, AS – aerobic scope) and critical swimming speed (Ucrit) were measured after 28 days of exposure. Results revealed a significant interaction between temperature and PFAS on AS, with fish exposed to PFAS showing lower AS at 28.5°C compared to those in PFAS-free water. This reduction in AS was attributed to a decrease in MMR at 28.5°C (though not statistically significant), while SMR remained unchanged. Ucrit followed a similar trend to AS and MMR but was not statistically significant. As Ucrit is closely linked to aerobic metabolic performance, these findings suggest that energydemanding compensatory mechanisms induced by the temperaturePFAS interaction may have been prioritized over swimming effort. Impairments to AS, a proxy for individual fitness, could reduce overall fish performance, potentially affecting growth and reproduction. Overall, this study suggests that PFAS-induced impairments to AS may be exacerbated under future climate scenarios, posing a significant threat to the health of ecosystems.

A9.20

THE EFFECTS OF POLYCYCLIC AROMATIC COMPOUND EXPOSURE ON CARDIAC THERMAL TOLERANCE OF LARVAL AND

Isabelle Anne Ferron (University of New Brunswick, Canada), Danielle Philibert (Huntsman Marine Science Center, Canada), Benjamin De Jourdan (Huntsman Marine Science Center, Canada), Matthew Gilbert (University of Alaska Fairbanks, United States), Ben Speers-Roesch (University of New Brunswick, Canada)

isabelleferron216@gmail.com

Ocean warming resulting from natural or anthropogenic processes require ectothermic species, such as fishes, to be able to sustain higher energetic costs. This can be particularly challenging when additionally faced with environmental threats such as oil spills. Crude oil contains a complex mixture of polycyclic aromatic compounds (PAC), which can have negative effects on marine species such as cardiac impairment in fishes. Because the heart plays a central role in sustaining energy demand during warming, PAC-induced cardiac perturbations could have detrimental impacts on the fish’s warming tolerance. I am investigating the physiological impacts of acute (24 hr) PAC exposure (methylnaphthalene, naphthalene, phenanthrene) on cardiac thermal tolerance in larval and juvenile lumpfish (Cyclopterus lumpus), an ecologically and economically important cold-water fish. Thusfar, I found that juvenile lumpfish are resistant to relevant levels of naphthalene and phenanthrene, whereas methylnaphthalene reduced peak heart rate (fH ) and the temperature of peak fH and cardiac arrhythmia. Understanding the combined effects of oil exposure and warming can help us better predict the severity of oil spills in our changing climate and their impact on marine fishes.

A9.21 LITHIUM BIOACCUMULATION AND TOXICITY: THE INFLUENCE OF LI/NA RATIO AND LITHIUM SALTS.

Friday 11th July 2025 10:15

Laurine Mathé (Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC) - Université de lorraine., France), Camille Grossard (Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC) - Université de lorraine., France), Laeticia Minguez (Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC) - Université de lorraine., France), Laure Giamberini (Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC) - Université de lorraine., France)

laurine.mathe@univ-lorraine.fr

Friday 11th July 2025 10:00

Lithium (Li) is a valuable metal with industrial applications, primarily used in Li-ion batteries for electric vehicles (89% of lithium production). The industry uses a variety of lithium forms, including lithium hydroxide, carbonate, chloride, and bromide. Nowadays, the majority of ecotoxicological studies assess lithium toxicity with lithium chloride (LiCl), followed by lithium carbonate (Li2CO3), and finally lithium hydroxide (LiOH). However, no studies have directly compared the toxicity of various lithium salts based on the release of their respective counter-ions after lithium dissolution in water. Nonetheless, these counter-ions are important to consider because they will alter the environmental physicochemical conditions as well as the physiology of bivalves, potentially affecting lithium bioaccumulation and toxicity. On the other hand, Sodium (Na) has the ability to compete with lithium. Thus, variations in environmental salinity may influence the toxicity of lithium released during mining and industrial activities. Global changes can also cause salinity

fluctuations in freshwater ecosystems (heavy rain reduces salinity, while drought increases salinity), potentially altering lithium toxicity. In this study, we compared the biological impact of lithium hydroxide and lithium carbonate on a freshwater organism (Dreissena polymorpha) exposed to different lithium concentrations and salinities (i.e., different Li/Na ratios). Bioaccumulation and several biomarkers associated with important physiological functions were assessed after 7 and 21 days. The findings will help us decide whether to consider lithium speciation or treat it as a single entity when assessing its toxicity, as well as how salinity may influence risk assessments.

A9.22 EVALUATING THE RELATIVE CONTRIBUTION OF TOXIC METALS TO REDOX HOMEOSTASIS IN FREE-RANGING ROE DEER

Friday 11th July 2025 10:30

Amandine Herrada (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), Benjamin Rey (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), Jean-François Lemaître (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), François Débias (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), Emmanuelle Gilot-Fromont (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), Marie-Laure Delignette-Muller (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), Gilles Bourgoin (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), Sonia Saïd (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), Maryline Pellerin (Office Français de la Biodiversité Direction de la Recherche et de l'Appui Scientifique, France), Nadia Crini (Université Marie et Louis Pasteur Laboratoire Chronoenvironnement, France), Clémentine Fritsch (Université Marie et Louis Pasteur Laboratoire Chrono-environnement, France), Renaud Scheifler (Université Marie et Louis Pasteur Laboratoire Chrono-environnement, France), Jean-Michel Gaillard (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France), Pauline Vuarin (Université Claude Bernard Lyon 1 Laboratoire de Biométrie et Biologie Evolutive, France)

amandine.herrada@univ-lyon1.fr

Redox homeostasis, i.e. the balance between oxidative damage and antioxidant defences, is essential for maintaining overall physiological function. Its disruption may lead to oxidative stress, affecting cellular function, promoting ageing, and increasing disease susceptibility. Toxic metals (e.g. lead, cadmium, mercury) can impair redox homeostasis by promoting pro-oxidant production and/or altering antioxidant defences. While the adverse effects of acute toxic metal exposure on redox homeostasis are well documented, especially in the lab, the effects of low-level exposure in natural populations remain poorly understood. Here, we investigated the relationship between toxic metal exposure and redox status in roe deer (Capreolus capreolus), while considering the potential modulatory effects of essential metals (e.g. selenium, zinc) and climate (i.e. rainfall, temperature). Toxic and essential metals were measured in hair samples from individuals inhabiting two contrasting environments in France, alongside plasma oxidative stress biomarkers.

Using linear mixed-effects models, based on integrative metal exposure indexes calculated through multivariate analyses (i.e. PCA), results revealed that low levels of toxic metals significantly contributed to oxidative stress. Rising toxic metal burdens were associated with increased oxidative damage on both lipids and proteins, and increased total non-specific antioxidant capacity, but decreased enzymatic and non-enzymatic antioxidants. Essential metals and climatic variables played only minor roles in modulating these effects. Overall, these findings highlight the implications of low-level toxic metal exposure for oxidative stress in natural populations, and underscore the need to investigate the broader consequences of environmental contaminants on wildlife health and population dynamics.

A9.23 BEHAVIOUR TO THE BONE: LINKING SKELETAL MINERALIZATION TO BEHAVIOUR IN LARVAL ZEBRAFISH (DANIO RERIO)

Friday 11th July 2025 10:45

Diana W. M. Hofman (Radboud University, Netherlands), Fernanda Ormel (Radboud University, Netherlands), Javi S. Lopez (Radboud University, Netherlands), Juriaan R. Metz (Radboud University, Netherlands), Wilco Verberk (Radboud University, Netherlands), Peter H. M. Klaren (Radboud University, Netherlands)

diana.hofman@ru.nl

Human activities release increasing amounts of chemical contaminants into aquatic environments, raising concerns about their impact on wildlife. Many pollutants act as endocrine disruptors, interfering with hormone-regulated processes essential for growth, reproduction, and development. In fish, such disruptions affect skeletal formation, muscle function, and neural signaling, all of which also affect behaviour. While chemical exposure is indeed known to alter fish behaviour, such as reducing responses to light-dark stimuli, it remains unclear whether these effects stem from skeletal changes or physiological disruptions. To address this, we study how altered skeletal mineralization affects zebrafish swimming behaviour. Using larval zebrafish (Danio rerio), a well-described animal model for skeletal development, we first manipulated calcium availability during early development to induce either increased or decreased bone mineralization. Larvae raised in low-calcium conditions lacked bone mineralization and moved less in 24-hour observations. In light-dark transition assays, they also failed to respond properly. Since calcium is critical for bone formation, muscle contraction, and neural signaling, we extended our study to F0 knockout larvae. F0 knock-outs of enpp1 (promotes mineralization by generating inorganic pyrophosphate) and entpd5a (inhibits mineralization by hydrolyzing nucleotide triphosphates) were generated and validated using genotyping, skeletal staining, and elemental analysis. Swimming behaviour was quantified at 5 days post-fertilization using automated tracking. Even at this early stage, altered mineralization resulted in reduced locomotion. We anticipate that a better understanding of the effect of skeletal mineralization on behaviour will allow for a more thorough understanding of the effect chemical pollutants have on fish behaviour.

A9.24 IN THE SEARCH OF SUBLETHAL BIOMARKERS: METABOLOMIC AND LIPIDOMIC PROFILING OF ARCTIC COPEPODS FACING OCEAN ACIDIFICATION AND PYRENE POLLUTION

Friday 11th July 2025 11:30

Lauric Feugere (MEEP lab Department of Biology Chemistry and Geography University of Quebec at Rimouski, Canada), Khuong Van Dinh (Department of Biosciences University of Oslo, Norway), Amalie M. B. Gravelle (Department of Biosciences University of Oslo, Norway), Katrine Borgå (Department of Biosciences University of Oslo, Norway), Haakon Hop (Norwegian Polar Institute Fram Centre Tromsø, Norway), Piero Calosi (MEEP lab Department of Biology Chemistry and Geography University of Quebec at Rimouski, Canada), Nadjejda Espinel-Velasco (Department of Biosciences University of Oslo, Norway)

feugla01@uqar.ca

Historically relatively sheltered from human disturbance, Arctic regions now face increasing threats from expanding maritime routes and industrial activities. These pressures add to existing environmental stressors, raising concerns about the conservation of fragile polar ecosystems, which are particularly vulnerable to cumulative impacts such as ocean acidification (OA) and widespread pollution. Combined stressors may cause unpredictable non-additive effects on marine ectotherms. Furthermore, by using traditional approaches limited to whole-organism levels, such as metabolic rates and mortality, we have overlooked sublethal, early-signals of physiological failure occurring at the cellular level. Therefore, we aimed at exploring the molecular responses of a key Arctic zooplankton species to different environmentally-realistic doses of a toxic polycyclic aromatic hydrocarbon under an OA scenario. For this purpose, the metabolome and lipidome of field-collected copepodid IV specimens of the copepod Calanus glacialis were profiled after two and ten days of exposure within an orthogonal design of four pyrene concentrations (0, 10, 100 and 200 nM) and two levels of OA (ambient and low pH). Multivariate analyses evidence an interaction between OA and pyrene contamination over time, albeit pyrene is a major driver. OA seemingly shifts the metabolomic dose response to pyrene compared to ambient pH. Further integrative analyses will help to decipher the functional consequences of such molecular alterations, to identify earlysignals of physiological failure. Implementing multilayer knowledge from such multifactorial experimental approaches will be critical in improving our ability to predict the fate of Arctic species in future, more disturbed polar oceans.

A9.25 MOLECULAR APPROACHES UNRAVEL THE IMPACT OF FOOD QUALITY AND LIGHT ON THE PHYSIOLOGY OF DAPHNIDS

Friday 11th July 2025 12:00

Izabela Malgorzata Antepowicz (Dublin City University, Ireland), Anne Leung (Dublin City University, Ireland), Emma Rowan (Dublin City University, Ireland), Katie O’Rourke (Dublin City University, Ireland), Xiaofei Yin (University College Dublin, Ireland), Lorraine Brennan (University College Dublin, Ireland), Konstantinos Grintzalis (Dublin City University, Ireland)

izabela.antepowicz3@mail.dcu.ie

In aquatic ecosystems, the growth and physiology of species are profoundly influenced by trophic interactions and environmental conditions, especially light and food sources. Daphnids, commonly known as water fleas, have a central role in freshwater ecosystems due to their wide distribution, crucial position in food webs, and sensitivity to environmental changes. In this study, we focused on the impact of food quality and light conditions on lifespan, growth, reproduction, and metabolic responses of daphnids. Frozen algae food is a less nutritious source that led to slower growth, reduced reproduction, and induced metabolic restrictions, while deprivation of light induced distinct metabolic changes, suggesting disruptions in circadian rhythms. These changes point to potential impacts on broader ecological interactions and metabolic efficiency. Our research highlights the importance of food quality and light in shaping aquatic organisms’ physiology, providing insights into the ecological and metabolic processes that govern freshwater species. The study’s results could inform broader ecological models and risk assessments, emphasising the interconnectedness of environmental factors on aquatic species' health and ecosystem dynamics.

A9.26 REVEALING HIDDEN

RISKS: IN VITRO ANALYSIS OF PFAS HAZARDS IN MYTILUS GALLOPROVINCIALISGILLS AND DIGESTIVE GLAND

Friday 11th July 2025 12:15

Marta B Cunha (University of Aveiro, Portugal), Alessandro Nardi (Università Politecnica delle Marche, Italy), Ana M Gil (University of Aveiro - CICECO, Portugal), Rosa L Freitas (University of Aveiro, Portugal)

martacunha@ua.pt

Per- and polyfluoroalkyl substances (PFAS), widely used in industries and consumer products, often contaminate marine environments, posing potential risks to wildlife and humans. Their bioaccumulation and toxicity have led to global concern, particularly with the emergence of short-chain PFAS as alternatives to restricted legacy compounds. However, limited information exists on their environmental fate and toxicity, necessitating further research on their effects on marine organisms, particularly bivalves. This study investigates the toxicity of six PFAS (short-chain: PFHxA, 6:2 FTA; long-chain: PFUnDA, PFDoA, PFTriDA, PFTeDA) in the digestive gland (DG) and gills (G) of Mytilus galloprovincialis, a key bioindicator, through in vitro exposure. To understand early toxicity mechanisms, biochemical responses related to oxidative stress and neurotransmission were assessed. The results indicated organ-specific effects, with the DG demonstrating heightened sensitivity to PFHxA, evidenced by a reduction in total antioxidant capacity. Conversely, PFTriDA exhibited a propensity to induce cellular damage at elevated concentrations. Gills exhibited a heightened response to PFDoA and PFTeDA, manifesting

as the inhibition of antioxidant enzymes resulting in oxidative stress. Additionally, PFHxA and PFTriDA were observed to exert neurotoxic effects through the inhibition of acetylcholinesterase. Among all compounds, 6:2 FTA was the least toxic, while PFHxA was the most toxic. These findings highlight the complexity of PFAS toxicity and the need to assess short- and long-chain compounds to establish safe environmental thresholds. M. galloprovincialis proves to be a valuable bioindicator, reinforcing the need for regulatory measures to mitigate PFAS pollution while providing insights into organ-specific toxicity and environmental exposure pathways.

A9.27 IMPACTS OF IONIZING RADIATION ON REPRODUCTIVE PROCESSES IN FUKUSHIMA TREE FROGS: TRANSCRIPTOMIC AND FUNCTIONAL INSIGHTS

Friday 11th July 2025 12:30

Léa Dasque (ASNR, France), Nathalie Mondy (Université Claude Bernard Lyon 1 CNRS ENTPE Villeurbanne France, France), Jean-Marc Bonzom (ASNRPSE-ENVLECO, France), Sandrine Frelon (ASNRPSE-ENVLECO, France), Olivier Armant (ASNRPSE-ENVLECO, France)

lea.dasque@asnr.fr

The Fukushima nuclear accident in 2011 led to significant radioactive contamination of the environment, resulting in chronic exposure to ionizing radiation (IR) for local wildlife. This chronic exposure raises critical concerns about its impact on biodiversity and particularly on the physiological mechanisms relative to species reproduction, that is one of the most radiosensitive fitness endpoints in non-human biota. Laboratory experiments have demonstrated that IR impact reproduction on both vertebrate and invertebrates and that male gametes appear particularly vulnerable to genotoxic stressors. In addition, in Fukushima, DNA lesions were detected in the male germ cells of exposed mice. Also, tree frogs in the Chernobyl exclusion zone exhibit, 30 years after the nuclear acc high mutation rates, reduced population sizes and decreased body condition indices that collectively suggest population decline and reproductive challenges. This study examines, during the breeding season, IR impact on the reproductive traits of male Japanese tree frogs (Dryophytes japonicus), a sentinel species. Transcriptomic analyses of gonadal tissues, sperm count/motility, and testosterone levels were performed. Frogs from contaminated sites show an increased gonadosomatic index correlated with higher sperm concentrations, while testosterone remains stable. The D. japonicus reference transcriptome was sequenced and assembled; ~9000 genes were detected in the dataset. Clustering and differential expression analyses reveal site-specific patterns, and dose-response analysis highlights around 10% genes significantly modeled with DRomics pipeline, enabling benchmark dose determination. Functional enrichment is underway to identify the most radiosensitive biological processes and analyse datas regarding phenotypic findings, resulting in an integrated overview on their reproductive ability.

A9.28 EFFECTS OF MICROPLASTIC FIBRE INGESTION ON FOOD CONSUMPTION, ENERGY STORES AND REPRODUCTION IN A CRICKET, GRYLLODES SIGILLATUS

Friday 11th July 2025 12:45

Jane E Allison (Carleton University, Canada), Fouzia Haider (Carleton University, Canada), Émile Vadboncoeur (Carleton University, Canada), Serita Fudlosid (Carleton University, Canada), Jennifer F Provencher (Environment and Climate Change Canada, Canada), Heath A MacMillan (Carleton University, Canada)

janeallison@cunet.carleton.ca

Microplastics (1-1000 µm) have become a pervasive pollutant in the environment. Microfibers, from synthetic textiles, are the dominant microplastic form in terrestrial and aquatic systems, agricultural runoff, and atmospheric samples. These tiny fibres are ingested by biota, including omnivorous insects like crickets, but their impacts on physiology and fitness remain unclear. In the lab, female crickets (Gryllodes sigillatus) chronically exposed to high concentrations of polyethylene terephthalate microfibers have smaller thoraces and abdomens compared to crickets fed a “clean” diet. We hypothesized that the effects on growth, particularly reductions in abdomen size, are reflective of reduced energy available for growth and reproduction. Here we quantified food consumption during development, stored energy (total lipid, carbohydrate and protein) at adult emergence and egg production at one week post adult eclosion, corresponding with reproductive maturity in this species. Consumption declined on plastic diets compared to a “clean” diet, however, this did not influence adult body mass, nor the number of eggs produced by mature females. Eggs in plastic-exposed females varied in size compared to controls, possibly signalling a delay in maturing eggs. Our results suggest crickets may be compensating for the impact of ingested plastics on growth and reproduction in a laboratory setting, but we caution that more pronounced effects may occur under more realistic environmental conditions, like food scarcity. Given the high likelihood that crickets encounter and ingest microplastics in the wild, this study provides a starting point to understand the impact of this exposure for both individuals and populations of wild insects.

POSTER SESSIONS

Friday 11th July 2025

18:00-20:00

A9.6 HOW ZEBRAFISH HANDLE THEIR NITROGENOUS WASTE: DETERMINING THE SKIN-TO-GILL TRANSITION OF RHESUS GLYCOPROTEINS

Wouter Mes (Radboud University, Netherlands), Robin Haanen (Radboud University, Netherlands), Arslan Arshad (Radboud University, Netherlands), Tsutomu Nakada (Shinshu University, Japan), Maartje AHJ Van Kessel (Radboud University, Netherlands), Marnix Gorissen (Radboud University, Netherlands)

wouter.mes@ru.nl

Excretion of nitrogenous waste is essential for all animals, and the type of waste is largely determined by water availability. Adult teleostean fish excrete ammonia primarily via their gills, which adds to water pollution in intensive aquaculture, and can impact fish health. Larval fish initially produce urea and shift to ammonia excretion after hatching, first via the skin, then via the gills. We studied the transition from cutaneous to branchial ammonia excretion. We investigated the expression and localization of ammonia transporters (rhesus glycoproteins) in zebrafish up to 8 days post-fertilization (dpf) and coupled these data to measurements of nitrogenous waste excretion and expression of marker genes for osmoregulation and urea production. We discovered a differential change in rhesus glycoprotein localization: Rhag and Rhbg translocate to gill filaments before 5 dpf, while Rhcgb translocates to the gills between 5 and 6 dpf and is localized in ionocytes. These findings indicate two pathways of ammonia excretion that transition independently, which is corroborated by correlating gene expression and developmental stage: post-hatch larvae up to 6 dpf show increased rhag, rhbg and rhcga expression, while 7-8 dpf zebrafish show increased expression of rhcgb and osmoregulatory marker Na+ /H+ -exchanger 3b. Expression of the uncharacterized rhcgl1 gene increased in a similar pattern, hinting towards involvement of additional rhesus glycoproteins in ammonia excretion. Our research suggests two distinct ammonia excretion pathways in zebrafish, and their relative contributions to ammonia excretion, as well as effects of environmental factors (e.g., pH and environmental ammonia) are subject of our future studies.

A9.7 DIETARY-DRIVEN VENOM PLASTICITY IN SCORPIONS: IMPLICATIONS FOR CONSERVATION PHYSIOLOGY AND EX SITU MANAGEMENT

Mouad Mkamel (University Hassan Ii Of Casablanca, Morocco), Zineb Agourram (University Hassan II Of Casablanca, Morocco), Nouhaila El Fenni (University Hassan II Of Casablanca, Morocco), Assya Lamaizi (University Hassan II Of Casablanca, Morocco), Anass Kettani (University Hassan II Of Casablanca, Morocco)

contact@mkamelmouad.com

Sustainable scorpion venom sourcing is crucial for research, yet wild harvesting raises ecological concerns. Captive breeding offers a promising alternative, but optimising venom yield and toxicity requires a deeper understanding of the factors influencing venom production. This study investigated the impact of a mealworm-based diet on venom toxicity in four lethal scorpion species: Androctonus mauretanicus, Buthus mardochei, Androctonus australis, and Androctonus amoreuxi. Scorpions were maintained on a mealworm diet, and venom was extracted electrically. Lethality (LD50) was assessed using mice, zebrafish, and Artemia, enabling a comparative analysis across vertebrate and invertebrate models. Results revealed significant plasticity in venom toxicity, with increased LD50 values observed across all species fed mealworms compared to scorpions fed a standard wild insect diet. These findings suggest that a mealwormbased diet reduces venom potency. This diet-induced venom modulation has implications for conservation physiology, suggesting a potential mechanism for mitigating human-wildlife conflict through controlled venom potency. It also informs ex situ management practices, facilitating safer handling and venom extraction procedures. Furthermore, utilising alternative models like zebrafish and Artemia reduces reliance on mammalian models, aligning with best practices for ethical research. Future research should elucidate the physiological mechanisms underlying venom plasticity and explore optimised dietary strategies for sustainable venom production.

A9.8 OLFACTORY SENSITIVITY OF FISH AND BIVALVES TO WASTEWATER TREATMENT PLANT EFFLUENTS

Diana Gonçalves (Centro de Ciências do Mar do Algarve, Portugal), Ana Rato (Centro de Ciências do Mar do Algarve, Portugal), Antons Basovs (University of Latvia, Latvia), Zélia Velez (Centro de Ciências do Mar do Algarve, Portugal), Teresa Modesto (Centro de Ciências do Mar do Algarve, Portugal), Peter Hubbard (Centro de Ciências do Mar do Algarve, Portugal)

dsgoncalves@ualg.pt

The detection of natural odorants is vital for marine animals. Although this sense can be affected by acidification and heavy metals, the potential of chemical pollutants, such as pharmaceutical compounds, to act as odorants themselves is unknown. Wastewater treatment plants (WWTP) are the principal source of micropollutants in European waters. We evaluated the olfactory sensitivity of two bivalves - carpet clam ( Ruditapes decussatus ),oyster( Magallana gigas ) and two fishes - Lusitanian toadfish (Halobatrachus didactylus) and gilthead seabream (Sparus aurata) to WWTP effluents. All species reside in the Ria Formosa, a lagoon in the south of Portugal that receives the effluents from several WWTPs. The olfactory sensitivity was assessed by the electro-osphradiogram (bivalves), electro-olfactogram (toadfish), or multi-unit recording from the olfactory nerve (seabream). All four species were able to detect the WWTP effluents down to 1:1000. Higher responses were evoked by C18 filtrates than their respective eluates, especially in bivalves, suggesting that the odorants are mostly polar compounds. The most abundant drugs found in the Ria Formosa (caffeine, carbamazepine, atenolol, erythromycin and diclofenac), evoked responses in fish, but not bivalves, even at 1 mM. However, concentrations in Ria Formosa are much lower than the detection thresholds. Our findings suggest that marine animals can detect compounds in WWTP effluents; whether these odorants can

interfere with the detection of natural odorants – ‘olfactory disruption’ – remains to be tested.

A9.9 EVOLUTIONARY ECOLOGY OF POLLUTANT TOLERANCE IN URBAN DAPHNIA

Felix Mende (Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany), Justyna Wolinska (Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany), Luc De Meester (Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany)

felix.mende@igb-berlin.de

Urban areas are expected to grow in the future and are sources of increased stress and health risks for ecosystems and people alike. The functionality of urban pond ecosystems is threatened by the potential influx of numerous pollutants from different sources, e.g. insufficiently treated wastewater and urban runoff. Especially synthetic organic chemicals, such as pesticides and vehicle-related compounds pose a threat to urban freshwater systems, as they can persist in the water cycle and affect aquatic organisms. Daphnia have recently become a promising model system for urban evolution studies. Their fitness, grazing abilities and species composition have been shown to be influenced by urban stressors, affecting the top-down control of (toxic) phytoplankton blooms. Yet the effect of urbanisation-associated pollution on the evolutionary adaptation of urban Daphnia magna populations to urbanisation is mostly unknown. Here, we expose Daphnia magna clones from different populations along an urbanisation gradient to the tire wear chemical 1,3-Diphenylguanidine. By quantifying the acute tolerances of individual clones, we are able to assess the genetic variation in tolerance to urbanisation-associated pollution not only between clones, but also between different populations along an urbanisation gradient. Thus, our study will aid in determining the threat of urban pollutants to pond ecosystems and quantify to what extent Daphnia magna populations genetically adapt to this threat.

A9.10 ZEBRAFISH (DANIO RERIO): A QUICK AND VERSATILE PRECLINICAL MODEL TO SCREEN EFFECTS OF ENDOCRINE-DISRUPTING CHEMICALS (EDCS).

Jolie Smeets (Radboud University Nijmegen, Netherlands), Nikita Toločkovs (Radboud University Nijmegen, Netherlands), Sterre Gon (Radboud University Nijmegen, Netherlands), Juriaan R. Metz (Radboud University Nijmegen, Netherlands), Peter H.M. Klaren (Radboud University Nijmegen, Netherlands), Marnix Gorissen (Radboud University Nijmegen, Netherlands)

jolie.smeets@ru.nl

A particularly concerning group of environmental contaminants are endocrine-disrupting chemicals (EDCs) that can interfere with the endocrine system by mimicking or blocking endogenous hormones. Disruption of hypothalamus-pituitary-axes (HP-axes) can lead to

serious health problems, e.g., thyroid malfunctioning (HPT-axis), interference with reproduction (HPG-axis), impaired stress response (HPI-axis), as well as (neuro)behavioural changes. As a rule, organisms are continuously exposed to multiple EDCs simultaneously, since EDCs deriving from cosmetics, packaging, pesticides, food, and other everyday products, end up in the environment. This urges the need to assess the physiological impact of EDC mixtures and to understand the mechanisms and targets affected. The zebrafish (Danio rerio) is a particularly suitable preclinical model to assess these toxicological effects for several reasons. Firstly, their rapid development can be easily non-invasively monitored due to its transparent body. Secondly, the zebrafish is a vertebrate species with a surprisingly high degree of homology to humans with respect to organ systems, physiology, genomics, and behaviour. Indeed, the model can be used to understand molecular mechanisms and targets given its fully annotated genome, ease of genomic manipulation, as well as a wide array of already available transgenic reporter lines of hypothalamuspituitary-axes biomarkers, and well-characterised behavioural assays. Together, these provide valuable insights into molecular mechanisms and natural behaviour, survival, and reproductive success, all of which are highly relevant for understanding the impact of EDCs. In this study, we assess the impact of various EDC mixtures on the HPaxes of zebrafish from a molecular, physiological, and behavioural point of view.

A9.11 THE EFFECTS

OF A PFAS (TRIFLUOROACETIC ACID, TFA) ON THE PHYSIOLOGY OF MEDITERRANEAN GREEN CRABS, CARCINUS AESTUARII.

Jehan-Hervé Lignot (UMR MARBEC, France), Marie Houede (University of Montpellier, France), Maxence Boissonade (University of Montpellier, France)

jehan-herve.lignot@umontpellier.fr

The effects of an acute exposure at sublethal concentrations to trifluoroacetic acid (TFA), a pollutant belonging to the PFAS family, were analysed using Carcinus aestuarii collected from Mediterranean lagoons presenting different levels of pollution. The goal was to evaluate crab response to pollution and potential differences based on the site of origin. Analyses of C. maenas did not show significant differences in morphometric parameters in the hepatopancreas (B-cell vacuolization rate, vacuole surface, epithelium thickness), neither between populations nor according to pollution levels. In contrast, analyses of C. aestuarii populations exposed to TFA revealed a dosedependent effect to pollution, leading to increased mortality, altered hemolymph osmolarity, and significant histopathological changes such as gill lamellae dilations and necrotic lesions. This study highlights the negative impact of TFA on Carcinus aestuarii and underscores the necessity to implement strict environmental regulations related to PFAS to protect marine coastal biodiversity.

A9.12 HEAD REGENERATION IN PLANARIANS AS A SENSITIVE, SUB-LETHAL ECOTOXICOLOGICAL ENDPOINT

Bruna S. Silva (CESAM Department of Biology University of Aveiro, Portugal), Susana Loureiro (CESAM Department of Biology University of Aveiro, Portugal), João L.T. Pestana (CESAM Department of Biology University of Aveiro, Portugal)

bruna.ssilva@ua.pt

Sensitive and reliable parameters are needed to address and compare sublethal toxicity of emerging contaminants. Bisphenol A (BPA) is an endocrine disrupter with estrogenic effects present in many products, including plastics, food packaging, and thermal receipts. Over the years, growing evidence showed that BPA negatively affects humans and wildlife, manifested especially through development and reproductive effects. BPA is considered a substance of very high concern under REACH legislation, and less toxic alternatives are needed. Using the freshwater planarian Girardia tigrina, known to be sensitive to many environmental contaminants, our goal was to assess the toxicity of BPA, and several of its alternative compounds (BPA F, BPS-MAE, and BPZ). We evaluated effects of the different compounds on planarian head regeneration after decapitation, as an indicator of toxicity. Decapitated planarians were exposed to four concentrations (0.16-0.4-1-2.5 mg/L) of our contaminants, and after 48 hours photographed to assess blastema area. Also, time for regeneration of photoreceptors and auricles was assessed for 10 days. Results revealed that all compounds reduced blastema area and delayed photoreceptors/auricles regeneration in planarians. BPA F and BPZ proved to be more toxic than BPA delaying and even inhibiting regeneration at lower concentrations. BPS-MAE revealed to be the less toxic alternative tested, since despite delaying head regeneration, especially auricle regeneration, it never completely inhibited it. Ongoing work addressing effects on sexual reproduction and on biochemical markers will further validate results and head regeneration endpoints as early warning indicators of stress and fitness in freshwater planarians under chemical exposure.

A9.13 THE MUSCLE AS AN ORGAN OF EXTRACELLULAR ACID-BASE REGULATION IN THE RAINBOW TROUT EXPOSED TO ALKALINE ENVIRONMENTS.

Michael P Wilkie (Department of Biology Wilfrid Lauier University, Canada)

mwilkie@wlu.ca

Many freshwater lakes are undergoing alkalization due to eutrophication caused by global climate change. Fishes exposed to such condition may develop a respiratory alkalosis, characterized by higher arterial blood pH (pHa) and corresponding drops in arterial PCO2 (PaCO2 ). Yet, pHa stabilizes after several hours due to a counterbalancing metabolic acidosis. We hypothesized that the source of metabolic acid (H+ m) used to stabilize pHa was the white muscle (WM), due to its high glycolytic capacity. Accordingly, cannulated rainbow trout (Oncorhynchus mykiss) were exposed to pH 9.5 for 48h during which blood was collected (control, 8h, 24h, 48h) for measurement of blood acid-base status, followed by WM collection for intracellular pH (pHi), glycogen and lactate measurement. A pronounced respiratory alkalosis, characterized by an increase in pHa from pH 7.83 to pH 8.00, was observed at 8 h but stabilized thereafter, despite continual declines in PaCO2 . Stabilization of pHa was due to a corresponding metabolic acid load (∆H+ m) of ~ 4 mM,

accompanied by a 2.5-fold rise in plasma lactate. After 48h, WM pHi increased by 0.1 pH units. Notably, WM glycogen decreased by 25%,with a corresponding 3-fold increase in lactate. Metabolic acid budget analysis revealed that WM experienced a ∆H+m deficit of ~ 1.5 µmol g-1 wet tissue, compared to a ∆H+m surplus of 0.6 µmol g-1 in the plasma, which originated in the WM. We conclude that the WM uses glycolysis to generate metabolic acid to buffer increases in extracellular pH when fish experience respiratory alkalosis due to higher water pH.

A9.14 THE EFFECT OF SALINITY AND SHORE HEIGHT ON THE ENERGY STORES OF THE BEADLET SEA ANEMONE ACTINIA EQUINA

Amanda A Wiesenthal (University of Rostock, Germany), Pascal Lüder (University of Rostock, Germany), Jack Thomson (University of Liverpool, United Kingdom)

Amanda.wiesenthal@uni-rostock.de

The intertidal zone is a challenging habitat because it is highly dynamic and organisms must cope with several abiotic factors such as extreme temperatures, UV radiation, periodic air exposure or the mechanical force of waves. Extreme heat and sun radiation can lead to evaporation from rock pools and consequently increase the salinity, while heavy rain introduces freshwater to the habitat and decreases salinity in rock pools. The beadlet sea anemone, Actinia equina, is found on coasts of the northeast Atlantic and Mediterranean Sea. During low tide individuals at high shore heights either become emerged or sit in rock pools (intertidal zone), while individuals at low shore heights remain submerged (sublittoral zone) in sea water. Thus, intertidal individuals periodically experience extreme conditions. We hypothesised that intertidal individuals are more tolerant to extreme salinities, and therefore deplete their energy stores less than sublittoral individuals under hypo- or hyperosmotic conditions. To test this hypothesis, Actinia equina were collected from the intertidal and sublittoral zones on the coast of Heligoland in the North Sea and exposed to one of seven different salinities (17, 22, 27, 32, 37, 42, 47) for at least 5 days. Subsequently, protein, lipid, carbohydrate and glycogen content were determined in tentacle and oral disc, column and pedal disc tissue. While salinity affected the protein and lipid content, carbohydrate and glycogen content were determined by shore height with intertidal individuals having consistently higher concentrations. There was, however, no conclusive evidence that intertidal individuals depleted their energy stores less than sublittoral individuals.

A9.15 A SYSTEMS APPROACH TO UNDERSTAND AND PREDICT POLLUTION

Emma Rowan (Dublin City University, Ireland), Anne Leung (Dublin City University, Ireland), Katie O'Rourke (Dublin City University, Ireland), Xiofei Yin (University College Dublin, Ireland), Lorraine Brennan (University College Dublin, Ireland), Konstantinos Grintzalis (Dublin City University, Ireland)

emma.rowan4@mail.dcu.ie

The ongoing rise in the global aging population, coupled with the excessive use of various resources, has significantly exacerbated environmental challenges, with the increased detection of pollutants in surface waters. This situation poses serious risks to aquatic ecosystems and human health. While various analytical techniques are employed in water monitoring to identify contaminants, the analytical methods employed are often inadequate for providing early predictions or to fully capture underlying mechanisms for the observed effects in the ecosystem. This limitation highlights the need for more comprehensive approaches to pollution assessment. Consequently, there is a growing support form effect-based methods that assess the responses of key species, such as daphnids, to pollutants. Daphnids are critical freshwater organisms that serve as valuable indicators of ecosystem health. In the context of New Approach Methodologies, they provide significant advantages due to their alignment with the principles of the 3Rs (Reduce, Refine, Replace) and their similar toxicity responses to more complex organisms, enhancing the application from phylotoxicological studies. Our research focuses on the impact of a range of commonly encountered pollutants, including pharmaceuticals, heavy metals, and industrial chemicals, on daphnid physiology. By integrating phenotypic endpoints, such as growth and reproduction, with metabolic fingerprints, we aim to provide deeper mechanistic insights into the actions of these pollutants. Ultimately, identifying metabolic disruptions can yield more sensitive assessment metrics, allowing us to capture the mechanisms of action more accurately. This enables timely predictions of pollution hotspots, facilitating proactive management strategies to mitigate environmental damage before it becomes irreversible.

A9.16 ATMOSPHERIC PARTICULATE MATTER AFFECTS THE EARLY DEVELOPMENT PARAMETERS OF FISH

Carolina Fernandes De Angelis (Federal University of São Carlos, Brazil), Michelly Pereira Soares (Federal University of São Carlos, Brazil), Israel Luz Cardoso (Federal University of São Carlos, Brazil), Iara Souza Costa (Federal University of São Carlos, Brazil), Daniel Wunderlin (Universidad Nacional de Córdoba, Argentina), Magdalena Monferrán (Universidad Nacional de Córdoba, Argentina), Marisa Narciso Fernandes (Federal University of São Carlos, Brazil), Ines Domingues (University of Aveiro, Portugal), Cléo Alcantara Costa Leite (Federal University of São Carlos, Brazil) carolinafdeangelis@gmail.com

The settleable part of atmospheric matter (SePM) produced by iron ore processing can cross-contaminate the aquatic environment. SePM is a complex mixture of particles, including metals and metallic nanoparticles, capable of causing critical sublethal damage to aquatic biota. Accordingly, this investigation analyzed the potential damage of multiple SePM levels (SL - 0.0, 0.095, 0.171, 0.309, 0.556, and 1.0 g·L-1 , 96 hours) to the early development of fish using a highly representative toxicological model, the zebrafish, Danio rerio. Although mortality was not affected, SePM impacted multiple levels of biological organization. SePM anticipated hatching to 24h (SL 0.309, 0.556, and 1.0); caused morphological alterations (especially tail bending – SL 0.095 and pericardial edema – SL 0.171); and changed heart rate (6 % decrease – SL 0.171, and 8.75% increase – SL 0.309 and 0.556). Moreover, SePM contamination caused a general reduction of the ability to buffer reactive oxidative species (SL 0.095, 0.171, 0.556, and 1.0), LPO levels were similar in all SL. LDH was reduced (SL 0.095, 0.171, 0.556, and 1.0), while AChE activity and locomotor behavior were unaffected. These early

impacts may directly affect fish development and the survival of natural fish populations. This was the first investigation to examine SePM effects on early fish development and underscored the need for a comprehensive assessment of the SePM problem, especially addressing long-term development under SePM contamination and potential transgenerational effects.

A9.18 IMPLICATIONS OF HEAVY METAL EXPOSURE FOR MALE REPRODUCTIVE PERFORMANCE IN WILD ROE DEER POPULATIONS

Pauline VUARIN (Laboratoire de Biométrie et Biologie Evolutive UMR 5558 CNRS-UCBL, France), Benjamin REY (Laboratoire de Biométrie et Biologie Evolutive UMR 5558 CNRS-UCBL, France), Amandine HERRADA (Laboratoire de Biométrie et Biologie Evolutive UMR 5558 CNRS-UCBL, France), François DEBIAS (Laboratoire de Biométrie et Biologie Evolutive UMR 5558 CNRS-UCBL, France), Nadia CRINI (Laboratoire Chrono-Environnement UMR 6249 CNRSUFC, France), Clémentine FRITSCH (Laboratoire ChronoEnvironnement UMR 6249 CNRS-UFC, France), Renaud SCHEIFLER (Laboratoire Chrono-Environnement UMR 6249 CNRS-UFC, France), Jean-François LEMAITRE (Laboratoire de Biométrie et Biologie Evolutive UMR 5558 CNRS-UCBL, France), Sonia SAID (Office Français de la Biodiversité, France) pauline.vuarin@univ-lyon1.fr

Heavy metals such as cadmium, lead or mercury, raise concerns for wildlife. While their reproductive toxicity has been thoroughly reported in the lab, its implications for free-ranging animals remain under-studied. Actually, it is likely that in natural populations, most animals are exposed to low doses of heavy metals throughout their life. However, whether such chronic exposure affect their reproductive performance remains to be tested. In this study, we investigated whether heavy metal exposure was related to sex hormone levels, primary and secondary sexual traits in European roe deer (Capreolus capreolus). To do so, we measured hair and liver concentrations of various toxic metals, faecal testosterone metabolites (FTM), testes mass and antler length on 71 hunted males from various locations in France. Cadmium, cobalt, nickel and lead were detected in most samples. Based on linear (mixed effects) models, we found that cadmium, and to a lesser extent cobalt liver concentrations, were negatively associated to absolute testicular mass, a proxy of sperm production and thus fertilization success. However, antler length was not related to metal exposure, despite its contribution to male competitiveness for female access. FTM levels were not related to metal exposure either, although sex hormones play a major role in underlying physiological and behavioral adjustments for seasonal breeding. Overall, our findings suggest that heavy metal exposure affects male testicular function in a wild ungulate, and such alterations are expected to have lasting fitness consequences.

A10: RIDING THE WAVE: INSIGHTS

INTO PLASTIC AND EVOLUTIONARY ANIMAL RESPONSES TO TEMPERATURE CHALLENGES

ORGANISED BY: NEAL DAWSON (UNIVERSITY OF GLASGOW), FRANCISCO RUIZ-RAYA (UNIVERSITY OF GLASGOW), MATTHEW BRACHMANN (UNIVERSITY OF GLASGOW)

A10.1 TEMPERATURE ADAPTATION SHAPES THE EVOLUTIONARY DYNAMICS OF MITONUCLEAR

INTERACTIONS

Tuesday 8th July 2025 09:00

Florencia Camus (University College London, United Kingdom)

f.camus@ucl.ac.uk

Metabolism lies at the core of life-history theory, and the ability to adapt to fluctuating environmental conditions is key for survival and fitness. Temperature is a pervasive ecological stressor, influencing metabolic rate, development, and energy allocation. Mitochondria play a central role in temperature adaptation by regulating energy transduction and intermediary metabolism, directly impacting growth and reproduction. However, oxidative phosphorylation (OXPHOS) is uniquely vulnerable, as it depends on coordinated expression of mitochondrial (mt) and nuclear (n) genomes, which face distinct evolutionary pressures. Temperature fluctuations challenge this mitonuclear balance, exacerbating intergenomic incompatibilities. Here, I provide evidence that mitonuclear interactions shape metabolic efficiency and resource allocation in response to temperature variation in Drosophila melanogaster populations. Using coevolved and admixed mitonuclear genotypes, I show that temperature stress amplifies mitonuclear mismatches, delaying development, altering metabolism, and reducing fitness. To uncover mechanisms, I will present RNA-Seq data on mitonuclear coexpression under thermal stress, linking genomic regulation to physiological traits. Results indicate that intergenomic epistasis cascades from cellular bioenergetics to organismal performance, with climate change intensifying these incompatibilities and increasing fitness breakdown risks in hybrid populations. Understanding mitonuclear contributions to temperature adaptation is crucial for predicting evolutionary responses to climate change and identifying genetic pathways buffering metabolic stress.

A10.2 MITOCHONDRIAL COI EVOLUTION AND THERMAL PLASTICITY IN VENOM PRODUCTION: ADAPTIVE RESPONSES TO CLIMATE STRESS IN MOROCCAN SCORPIONS

Tuesday 8th July 2025 09:30

Zineb Agourram (Faculty of Science Ben M’Sick., Morocco), Nouhaila EL FENNI (Faculty of Science Ben M’Sick., Morocco), Assya LAMAIZI (Faculty of Science Ben M’Sick., Morocco), Anass KETTANI (Faculty of Science Ben M’Sick., Morocco), Mouad MKAMEL (Faculty of Science Ben M’Sick., Morocco) zinebag2000@gmail.com

Climate change amplifies thermal extremes, challenging ectotherms like scorpions to deploy adaptive strategies across evolutionary and plastic timescales. This study integrates mitochondrial phylogenomics and captive thermal experiments to dissect how Moroccan scorpions reconcile genetic divergence with phenotypic plasticity under thermal stress. Using 50 mitochondrial COI sequences from 32 species, a high-resolution phylogeny reconstructed via Maximum Likelihood analysis revealed two ecologically distinct clades: desert species (Androctonus and Buthus) with heat-adapted COI haplotypes and forest species (Scorpio) harbouring cold-tolerant variants. The hybrid oasis genus Hottentotta bridged these clades, displaying transitional COI signatures and intermediate venom plasticity. Under controlled thermal regimes mimicking native habitats, desert species produced threefold more venom at 30°C compared to forest species, correlating with mitochondrial ATP6/ND4 pathway efficiency under heat stress. Temperature emerged as the primary predictor of venom output via Random Forest regression, explaining 85% of variance, while humidity and nutrition played secondary roles. Critical thermal thresholds were identified: scorpions entered hibernation below 20°C, while venom synthesis surged above 30°C, prioritising immediate survival over energy reserves. By linking COI divergence to thermal plasticity, this work demonstrates how scorpions balance ancient genomic constraints with rapid responses to climatic variability. These dual strategies—evolutionary adaptations in COI haplotypes and phenotypic flexibility in venom

production—highlight mechanisms for resilience in warming ecosystems. Our findings propose COI biomarkers for predicting thermal tolerance in conservation programmes and advance ecocontextualised venom bioprospection for biomedical innovation.

Keywords: Mitochondrial COI, Thermal Adaptation, Venom Plasticity, Climate Resilience, Experimental Biology.

A10.3 ENERGIZED AND EFFICIENT: DIGESTIVE EFFICIENCY AND MITOCHONDRIAL PHENOTYPE UNDERLIE THE RAPID EVOLUTION OF A FASTER PACE-OF-LIFE IN A RANGE-EXPANDING SPECIES

Tuesday 8th July 2025 09:45

Sarah Jorissen (KU Leuven, Belgium), Nicolas Pichaud (Université de Moncton, Canada), Steven Van Belleghem (KU Leuven, Belgium), Janne Swaegers (KU Leuven, Belgium), Robby Stoks (KU Leuven, Belgium)

sarah.jorissen@kuleuven.be

As global warming progresses, organismal pace-of-life (POL) traits evolve in response to shifting climates. A new hypothesis states that, apart from the food digestive metabolism, the mitochondrial phenotype (efficiency and density) contributes to POL-variations across thermal regimes. We investigated the thermal evolution and plasticity of the POL and its underlying mechanisms by making use of the southward range expansion of the damselfly Ischnura elegans, from France into warmer regions of Spain. Alongside the ancestral French region, we studied two Spanish regions: a ‘new edge’ region founded 10 years ago (Salamanca) and an ‘old edge’ region founded 70 years ago (Murcia-Alicante). In a common garden experiment, larvae and adults from all regions were exposed to French and Spanish summer temperatures. Our results confirmed that the old edge region evolved a faster POL than the ancestral region when exposed to Spanish temperatures. As hypothesized, the old edge individuals had higher mitochondrial and digestive efficiencies supporting their evolved fast POL. Additionally, the larvae and adults showed higher mitochondrial densities, further sustaining this pace. In contrast, the new edge region showed unexpectedly maladaptive traits, exhibiting a slower POL than the ancestral region when exposed to Spanish temperatures. These individuals increased their food intake, likely prioritizing energy allocation toward repair mechanisms to cope with thermal stress. Our findings suggest that the traditional POL framework, which links food intake to fast POL traits, may require refinement as we show for the first time that the mitochondrial phenotype is a driver of the POL during thermal evolution.

A10.4 THE IMPACT OF SHORT-TERM TEMPERATURE FLUCTUATIONS ON WHOLE-BODY METABOLISM AND MITOCHONDRIAL FUNCTION

Tuesday 8th July 2025 10:00

Maria Correia (University of Jyväskylä, Finland), Charli Davies (University of Jyväskylä, Finland), Antoine Stier (Université de Strasbourg, France), Suvi Ruuskanen (University of Jyväskylä, Finland)

magomesc@jyu.fi

Environmental temperature affects organisms’ physiology, behaviour and reproduction with costs for fitness and survival. Under climate change, extreme weather events are predicted to increase in frequency and intensity, yet it is not well known how organisms adjust to these rapid variations. Short-term fluctuating temperatures can alter an endotherms’ thermoregulatory capacity, which can be influenced by energy metabolism. On the organismal level, metabolic rate can vary with rapid temperature variations, especially outside the thermoneutral zone, and at the cellular level, mitochondrial function adjusts to meet energy demands. We investigated if repeated exposure to shortterm thermal fluctuations can hinder or alleviate metabolic costs of responding to cold temperatures. To achieve this, wild great tits (Parus major) were caught in late autumn and separated into three groups: control, heatwave, and cold spell. First, all birds were kept in a controlled ambient temperature (16°C). Birds in the heatwave and cold spell groups were then subjected to three short-term temperature fluctuations (for 48 hours, 7 days apart), with temperature increasing or decreasing by 10°C from the ambient temperature. Overnight whole-body metabolic rate (basal metabolic rate and metabolic rate below thermoneutrality) and mitochondrial function were assessed at the beginning and end of the experiment. Additionally, after the first wave, daytime metabolic rate was measured below thermoneutrality to study immediate changes. The results of this study could provide insights into how animals can cope with increased climate instability, by investigating the responses to temperature fluctuations and capacity for metabolic plasticity, at both the whole-body and cellular level.

A10.5 DIGESTIVE PHYSIOLOGY OF HIGHLAND DEER MICE ACCLIMATED TO COLD HYPOXIA

Tuesday 8th July 2025 10:15

Grant B McClelland (McMaster University, Canada), Vicky Chau (McMaster University, Canada), Zainab Saad (McMaster University, Canada)

grantm@mcmaster.ca

To maintain energy balance, animals must match energy costs with food intake and nutrient absorption. In chronic cold, rodents are known to increase food intake and induce hypertrophy of the gastrointestinal tract to support the increased cost of thermoregulation. However, in chronic hypoxia, appetite is reduced, intestinal food passage rates change, and there is a general antagonism of cold-induced responses. Mammals native to high altitude regions face chronic cold hypoxia and high daily energy needs, but how they maintain energy balance remains unclear. Using deer mice (Peromyscus maniculatus) native to 650m and 4300m, we test the hypothesis that highland (HA) mice match increases in energetic demand of cold hypoxia with equivalent energy intake, whereas lowland (LA) mice cannot. All mice were born and raised in common warm normoxic (WN) conditions and then a subset were acclimated for 6 weeks to cold hypoxia (CH) simulating HA conditions. We found that CH acclimation led to a hypertrophy of the small intestine, an increase in intestinal villi length, and higher activities of the enzyme aminopeptidase-N in HA but not LA deer

mice. Both LA and HA mice increased energy intake, fecal energy loss, and nutrient absorption in CH. However, these changes were not sufficient for LA mice to maintain lean mass, which decreased in CH. We conclude that HA deer mice maintain energy balance in CH, either by selective nutrient uptake or by reducing energy costs.

A10.6 CONTEXT-DEPENDENCE OF THERMAL PLASTICITY IN INSECTS

Tuesday 8th July 2025 14:00

Patrícia Beldade (University of Lisbon, Portugal)

pbeldade@ciencias.ulisboa.pt

Temperature shapes phenotypic variation through effects at different levels and time-scales; changes in phenotype frequencies due to natural selection and changes in phenotype expression due to phenotypic plasticity. In particular, the temperature experienced during development can determine the production of distinct adult phenotypes from the same genotype; a phenomenon called thermal developmental plasticity. This plasticity can match phenotype to ecological conditions and help organisms to cope with environmental heterogeneity, including differences between alternating seasons. I will use two insect models of seasonal plasticity to illustrate the importance of thermal plasticity in studies of variation in organismal phenotypes, and of the impact of climate change in natural populations. Temperature (T) during development affects a series of adult traits which impact their fitness. Some of these traits are fixed throughout adult life (e.g. body size and pigmentation) while others can still respond to adult environmental conditions (e.g. behaviour and immunity). I will present date documenting these effects and how thermal plasticity depends on genetic (G) and environmental (E) context. These GxT and ExT interactions will affect how thermally plastic populations might cope and adapt to temperature perturbation.

A10.7 EXPLORING THE GENOMIC AND PHYSIOLOGICAL BASIS OF ADAPTATION TO SEASONAL VARIATION IN THE COPEPOD EURYTEMORA AFFINIS

Tuesday 8th July 2025 14:30

Jennifer C Nascimento Schulze (GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany), Alexandra Hahn (GEOMAR Helmholtz Centre for Ocean Research Kiel, Gibraltar), Catriona Clemmesen (GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany), Meike Stumpp (Kiel University (CAU), Germany), Reid Brennan (GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany)

jnascimento@geomar.de

Species with short lifespans (e.g. weeks) experience environmental heterogeneity, both spatially and temporarily, including seasonal changes that occur across generations. Balancing selection, a process that maintains genetic diversity within populations by shifting allele frequencies as environmental conditions change, may facilitate rapid adaptation to fluctuating environments. Understanding the genomic and physiological mechanisms driving fast adaptive responses in

organisms can improve our ability to predict whether and how taxa may adapt to human-led climate change. In this study, we leverage a wild population of the copepod Eurytemora affinis from the Baltic Sea (Kiel, Germany) to identify the genomic and physiological responses to rapid environmental change. Copepods were collected at four timepoints from spring to summer of 2024 and commongardened over three generations to two experimental temperature regimes simulating the local seasonal sea surface conditions (7 o C and 16o C). We measured metabolic and feeding rates, and key fitness traits: growth and number of eggs per female. Additionally, whole-genome sequencing of 30 pooled individuals, collected in both spring and summer was used to identify rapid adaptation over a 13year time period (2009, 2011, 2015, 2022). We found nearly 1,000 loci consistently responding to seasonal variation across all years, indicating ongoing rapid evolution via balancing selection. Coldadapted populations from our common-garden experiments had lower energy requirements and outperformed warm-adapted populations in growth and fecundity in all but one collection, highlighting potential trade-offs in adaptation to fluctuating environments. These findings provide strong evidence of rapid evolutionary responses to seasonal change, affecting the physiological performance of Eurytemora affinis.

A10.8 IS THERMAL PLASTICITY IN AEDES AEGYPTI SENSITIVE TO PHOTOPERIOD?

Tuesday 8th July 2025 14:45

Ella H.M. De Nicola (Carleton University, Canada), Marshall W. Ritchie (Carleton University, Canada), Kyle K. Biggar (Carleton University, Canada), Heath A. MacMillan (Carleton University, Canada) elladenicola@cmail.carleton.ca

Thermal plasticity allows insects to adjust physiological traits in response to changing environmental temperatures. In temperate winter climates, low temperatures often coincide with shorter daylight periods. Photoperiod, the duration of darkness and daylight in a 24-hour cycle, affects many aspects of insect physiology, including seasonal plasticity and circadian rhythms. The yellow fever mosquito, Aedes aegypti, historically confined to tropical regions, is expanding its geographic range into poleward, temperate climates where it would experience varied temperature and photoperiod conditions. Ae. aegypt i is capable of cold acclimation under a standard tropical photoperiod (12h:12h). Cold acclimation reduces injury and enables survival at otherwise lethal low temperatures. To test whether the ability to acclimate is tied to photoperiod, and when during the lifecycle photoperiod is important to Ae. aegypti thermal tolerance, we used an extreme photoperiod outside of their typical range (20h:4h), introduced at three different life stages; during egg development, during adult acclimation, and at the parental generation. A chill coma onset (CCO) assay was used to confirm the capacity for cold acclimation. Here, we present the first evidence of a photosensitive acclimation phenotype in this species. Extreme photoperiod significantly influenced CCO temperature, however, the magnitude of plasticity depends on when during development a light-cycle was introduced. To investigate the possible molecular mechanisms underlying this photosensitive acclimation phenotype, we are using qPCR to measure expression of known clock genes. This approach will help us gain a deeper understanding of the complex relationship between photoperiod cues and cold acclimation in Ae. aegypti

A10.9 EFFECTS OF URBANISATION AND TEMPERATURE VARIATION ON DIAPAUSE IN A TEMPERATE BUTTERFLY

Tuesday 8th July 2025 15:00

Nadja Verspagen (University of Helsinki, Finland), Juho Kökkö (University of Helsinki, Finland), Philipp Lehmann (University of Greifswald, Germany), Kevin Roberts (University of Greifswald, Germany), Matthew Nielsen (University of Bremen, Germany)

nadja.verspagen@helsinki.fi

Urban areas provide novel environments with a variety of new selective pressures, which makes them excellent systems to study contemporary evolution in response to anthropogenic environmental change. They are generally warmer than their surroundings (urban heat island effect), which, at high latitudes, can lead to decreased snow cover in cities during winter. Snow acts as an insulator, and thus snow cover loss might lead to increased temperature variation in urban ground temperatures. Insects often escape harsh winter conditions by diapausing under the snow cover, and urban insects might thus be exposed to increased thermal variation compared to rural insects. However, information on the effects of variable temperature on organism physiology and survival is scarce, especially during the winter season. We performed a common garden laboratory study aiming to understand the effects of urbanisation and daily temperature variation on diapause energetics and termination timing inPieris napibutterflies. For this, we reared urban and rural populations at constant or variable temperature and measured diapause metabolic rate plasticity and diapause termination timing. We then combine these measurements with field microclimate temperature data to construct energy use models, which will help predict phenological patterns under field conditions. We expect that temperature variation will affect diapause metabolism and termination timing. However, if evolution in response to urbanisation has occurred, we expect urban butterflies to be less sensitive to temperature variation than urban ones. This study will provide valuable insights on the capacity of ectotherms to evolve in response to variable thermal conditions.

A10.10 INVESTIGATING THE EFFECTS OF DIFFERENT THERMAL REARING REGIMES ON THE STRESS AXIS OF THE EUROPEAN SEABASS

Tuesday 8th July 2025 15:15

Elisa Sniecinski (Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer), France), Marie-Odile Blanc (Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer), France), Damien Crestel (Institut national de recherche pour l’agriculture l’alimentation et l’environnement (INRAE), France), François Ruelle (Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer), France), Eva Blondeau-Bidet (Centre national de la recherche scientifique (CNRS), France), François Allal (Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer), France), Marc Vandeputte (Institut national de recherche pour l’agriculture l’alimentation et l’environnement (INRAE), France), Anthony Maire (EDF RD Laboratoire National d’Hydraulique et Environnement (LNHE), France), Marie-Laure Bégout (Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer), France), David J McKenzie (Centre national de la recherche scientifique (CNRS), France), Benjamin Geffroy (Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer), France)

elisa.sniecinski@ifremer.fr

Physiological stress responses to warm temperatures are not fully understood in fish. Activation of the Hypothalamus-Pituitary Interrenal (HPI) axis is essential to trigger adaptive stress responses, leading to cortisol synthesis, the primary stress hormone in fishes. While short-term temperature effects on the activation of this axis have been demonstrated in European seabass (Dicentrarchus labrax), the long-term impact of thermal challenges on the HPI axis has not been investigated in this species. Here, we studied the regulation of the HPI axis in European seabass from the Atlantic population, reared for two years in different thermal regimes reflecting natural environments: Atlantic as control (AT 10.2-18.4°C), and EastMediterranean as a warm regime (EM 16.7-28°C). Hypothalamus and pituitary samples were collected on individuals from each regime at 183, 400 and 764 days post-fertilization (dpf) and analyzed using RNA sequencing and RT-qPCR to assess gene expression. Our results show a significant down-regulation of most targeted genes in the warm EM regime compared to the AT control. We also investigated the role of epigenetic factors by studying miRNA production (using smallRNA sequencing and RT-qPCR) and DNA methylation (using WGEM sequencing). Finally, scales were used as a key matrix to compare cortisol levels accumulated over time in fish from the two regimes. ELISA assays revealed that there was more cortisol in scales in EM compared to AT regime. This study provides insights into physiological changes in fish due to global warming and improves our understanding of their long-term stress responses.

A10.11 METABOLIC ADAPTATION IN ICELANDIC THREESPINE STICKLEBACK

Tuesday 8th July 2025 16:00

Matthew K Brachmann (University of Glasgow, United Kingdom)

matthew.brachmann@glasgow.ac.uk

Climate change is predicted to cause rapid increases in temperature which will drive losses in freshwater biodiversity. Organisms will have to adapt to warming water conditions. Predicting the outcomes of climate change adaptation is important for species conservation but is challenging as most natural populations have yet to experience

these anticipated conditions. However, come contemporary natural populations can experience warming through geothermal activity and provide direct insights into adaptation to warmed environments. We leveraged Icelandic threespine stickleback (Gasterosteus aculeatus) from populations undergoing adaptive divergence along a geothermal-ambient habitat axis. We aim to uncover the genomic and developmental underpinnings of adaptation to natural geothermal habitats. This research will further our understanding of the evolutionary processes promoting adaptation to warming conditions.

A10.12 ARTIFICIAL SELECTION AND THE ADAPTIVE POTENTIAL OF THERMAL PERFORMANCE IN ZEBRAFISH

Tuesday 8th July 2025 16:30

Robine H. J. Leeuwis (Norwegian University of Science and Technology, Norway), Lorena Silva-Garay (Norwegian University of Science and Technology, Norway), Henning H. Kristiansen (Norwegian University of Science and Technology, Norway), Zara-Louise Cowan (University of Gothenburg, Sweden), Moa Metz (Norwegian University of Science and Technology, Norway), Christophe Pélabon (Norwegian University of Science and Technology, Norway), Fredrik Jutfelt (University of Gothenburg, Sweden)

rhjleeuwis@gmail.com

Rapid global warming poses a serious threat to aquatic ectotherms. Evolutionary adaptation is a key mechanism that may enable populations to maintain performance under rising temperatures, yet it is rarely experimentally examined in vertebrates. Previous research in our laboratory demonstrated that zebrafish (Danio rerio) can evolve higher acute thermal tolerance, but this process is slow. Here, we present a large artificial selection experiment on zebrafish assessing the potential for adaptation of thermal growth performance. We selected zebrafish for improved juvenile growth across six generations under chronic thermal stress (N>10,800). Using a genetically diverse ancestral population (offspring of wild-caught zebrafish), we established selected lines (2 replicates, 300 fish/replicate) at cold (20°C), control (28°C) and warm (34°C) temperatures, and selected the 33% fastest-growing individuals for breeding. The results reveal a sustained, positive response to selection in all lines. Notably, the log growth rate of the warm-adapted line gradually increased from 0.008 to 0.013 mm/day in the F0 to F4 generation (total increase of 65%), reaching growth rates close that of the control line prior to selection, which suggests high evolvability. Ongoing analysis of the F5 generation will provide further insights into the evolution of thermal performance, including overall rates of adaptation, heritability, and shifts in optima. These results contribute to our understanding of how vertebrates may adapt to climate change and underscore the role of selection in shaping thermal resilience in aquatic species.

A10.13 METABOLIC RESPONSE TO THERMAL CHANGE IN FOURTEEN POPULATIONS OF BROOK TROUT

8th July 2025 16:45

Erin MC Stewart (Trent University, Canada), Christian J Bihun (Trent University, Canada), Mark S Ridgway (Ontario Ministry of Natural Resources, Canada), Chris C Wilson (Ontario Ministry of Natural Resources, Canada), Graham D Raby (Trent University, Canada)

erinstewart@trentu.ca

The effects of climate change are expected to vary across aquatic habitats and geographic areas, so understanding how coldwater fish respond to warming below the species level will be essential for effective conservation and management. Brook trout, thermal generalists among salmonids, exhibit substantial phenotypic plasticity, giving rise to diverse ecotypes and life histories across their wide range, yet this diversity has not been captured in previous work on thermal performance. We investigated how brook trout from 14 populations with distinct ancestries, rearing environments, and life histories responded to thermal stress to elucidate the factors driving intraspecific variation in thermal performance. To do so, we quantified the metabolic plasticity of over 250 brook trout ranging from 46–448 mm (fork length) by briefly acclimating fish to either 15°C or 20°C in a laboratory setting. Standard and maximum metabolic rates were assessed both at their acclimated temperature and, without further acclimation, at the alternate temperature to evaluate aerobic scope under optimal and thermally challenging conditions. The differences detected in our study highlight the importance of examining thermal tolerance below the species level, as phenotypic plasticity, ontogeny, and heritable traits interact to shape resilience and the potential for adaptation in the face of environmental change.

A10.14 SEASCAPE TRANSCRIPTOMICS IN POLAR COD: PROFILING ALONG AN ENVIRONMENTAL CLINE

Tuesday 8th July 2025 17:00

Sarah Kempf (Alfred-Wegener-Institute Helmholtz-Center for Polar and Marine Research, Germany), Felix C Mark (AlfredWegener-Institute Helmholtz-Center for Polar and Marine Research, Germany), Magnus Lucassen (Alfred-WegenerInstitute Helmholtz-Center for Polar and Marine Research, Germany)

sarah.kempf@awi.de

Genetic studies on the Arctic key fish species Polar cod, Boreogadus saida, from the Svalbard archipelago have been limited by relatively sparse sampling, primarily focusing on open-water areas with few or no fjord locations included. These studies have not yet provided conclusive evidence of genetic differentiation between Svalbard and other populations. This study therefore sought to ascertain whether a more extensive sampling program, encompassing 10 fjord stations along the north and west coast of Svalbard, could reveal functional differences on the transcriptomic level and indicate potential local adaptations, thereby providing insights into the presence of differentiated ecotypes. Thus, we conducted a RNASeq experiment along an environmental cline. The sampled stations varied from open water locations with well mixed water columns to closed, silled fjords with a strong thermocline, huge temperature differences across the water column (e.g., Billefjorden ΔT = 7 °C), and oxygen depletion in the deep-water layer (O2 < 70 % air saturation). The analysis revealed significant transcriptomic variation in response to the environmental gradient. The gene expression was primarily influenced

by oceanic conditions (Atlantic or Arctic), local abiotic factors, and food availability, with primary production playing a key role in the different gene expression patterns observed between the clusters. These findings suggest local adaptation and the existence of four potential Polar cod ecotypes along the north-west coast of Svalbard and that a more detailed population-genomic analysis is essential to further explore the population structure of Polar cod in the high Arctic archipelago.

A10.15 IS THERMAL PERFORMANCE DURING HEATWAVES PREDICTED

Tuesday 8th July 2025 17:15

Lucy Cotgrove (Luonnonvarakeskus (Luke), Finland), Zara-Louise Cowan (University of Gothenberg, Sweden), Constance Oules (Luonnonvarakeskus, Finland), Evan Sala (Luonnonvarakeskus, Finland), Tutku Aykanat (University of Helsinki, Finland), Craig Primmer (University of Helsinki, Finland), Fredrik Jutfelt (University of Gothenberg, Sweden), Jenni Prokkola (Luonnonvarakeskus, Finland)

lucy.cotgrove@luke.fi

Understanding thermal physiology is critical for predicting population shifts due to climate change. During heatwaves, fish are particularly vulnerable due to increased energy demands and reduced oxygen levels in warmer waters. Current perceptions of heatwave risks often focus on short-term mortalities, neglecting fitness effects associated with sub-lethal physiological constraints. In Atlantic salmon (Salmo salar), age at maturity, a key lifehistory trait, is genetically linked to aerobic scope — an essential metabolic attribute for energy allocation. Energy allocation is highly responsive to environmental temperatures, but how do different life history genotypes respond to heatwave temperatures? First, we present a thermal performance curve for aerobic scope for juvenile salmon after acclimation. We also examine physiological differences between two vgll3 genotypes, which are linked to early or late maturation in adult salmon. We measured specific dynamic action, the metabolic cost of digestion and food assimilation, and aerobic scope of salmon juveniles at 15 and 20 °C to observe how fish manage energy expenditure as temperatures rise. This study has significant implications for understanding the fitness of Atlantic Salmon and linking the effects of heatwaves to their life history and physiological fitness. Variation in how different genotypes respond to non-optimal temperatures allows for more accurate predictions of how populations may change in terms of genotypic structure and behaviour. This research is crucial for understanding evolutionary responses to climate change and for developing conservation strategies, both globally and within Finnish waters.

A10.16

BIRDS:

Wednesday 9th July 2025

09:00

stef.darpa@gmail.com

In any environment, the temperature that individuals effectively experience depends on the availability and use of thermal refuges. Behavioural thermoregulation is routinely measured in ectotherms, but only rarely in endotherms, even though recent evidence suggest it may drastically affect species fate under rising temperature. Here, we present the first experimental assay to measure Voluntary Thermal Maximum (VTmax) in birds - the highest temperature an animal will voluntarily tolerate before seeking cooler conditions. We tested within-species variation in domestic Australian zebra finches (Taeniopygia guttata), a desert-adapted species, and interspecific variation in temperate European birds. Individuals were exposed to a progressively increasing temperature in a thermal chamber with an opening to let them escape. The individual’s behaviour and body temperature were continuously monitored. VTmax, as the maximum chamber temperature reached before exiting, varied between zebra finches from 34.6 to 49.5C and was moderately repeatable within individuals (n= 94 trials), indicating it is a quantifiable and meaningful individual trait. VTmax was also sensitive to acclimatisation, varying with the climate experienced in the days prior to testing. Additionally, VTmax differed across species (n= 49 trials in 7 species), supporting interspecific variation in heat avoidance behaviour. Preliminary results suggest that individual differences in VTmax were partly explained by variation in exploration tendency, highlighting the link between thermoregulatory and microhabitat use behaviours. These results demonstrate that VTmax is a quantifiable trait in birds, influenced by individual variation, species differences, and acclimatization, providing new tools and insights into behavioural thermoregulation and resilience to climate change.

A10.17 LIFE-HISTORY STRATEGY AND LOCAL ADAPTATION SHAPE RESILIENCE TO CLIMATE CHANGE IN BEES

Wednesday 9th July 2025 09:00

Lucas R Hearn (Tokyo Metropolitan University, Japan), Vanessa Kellermann (La Trobe University, Australia), Adam Cronin (Tokyo Metropolitan University, Japan)

Lucashearn7@gmail.com

Climate change is anticipated to drive both temperature and atmospheric water levels beyond the physiological tolerances of many species, with potentially cascading effects on animal populations that vary based on their life-history characteristics. Even closely related species may show divergent responses to climate change depending on their ecological strategies. We investigated how nesting behavior influences climate adaptation by comparing two bee genera: stemnesting Ceratina and ground-nesting Lasioglossum. Specimens were collected across a 3,000 km latitudinal gradient in Japan, spanning sub-arctic to sub-tropical climates. We experimentally tested thermal (critical thermal maximum/minimum) and hygric traits (desiccation resistance, water loss rate), comparing tolerances to local temperature and vapor pressure deficit (VPD). Our results revealed that stemnesting bees maintained broader physiological tolerances, while ground-nesting species showed significantly higher rates of water loss, especially in high-VPD regions (low latitude). Ground nesters also exhibited narrower thermal safety margins that decreased with latitude. These patterns likely reflect adaptation to different microclimate variability in nesting sites, with stable underground conditions potentially selecting against high thermal and desiccation

Stefania R D’Arpa (Estación Biológica de Doñana, Spain), Mylene M Mariette (Estación Biológica de Doñana, Spain)

stress tolerance. While ground-nesting bees can behaviorally thermoregulate within their burrows, their lower physiological plasticity—particularly their reduced desiccation resistance—may limit their ability to forage during extreme temperature events. Our findings emphasize that desiccation tolerance, during periods of high thermal stress, may be a critical determinant of pollinator vulnerability to climate change. Understanding how nesting strategies and other life-history traits mediate species’ responses to climate change will be essential for predicting and protecting pollinator populations.

A10.18 EVIDENCE THAT TOLERANCE OF ACUTE WARMING DECLINES WITH INCREASING BODY MASS IN FISHES

Wednesday 9th July 2025 09:30

Théo P Navarro (MARBEC Univ Montpellier CNRS Ifremer IRD INRAE Palavas-les-flots Sète Montpellier France, France), Davide Thambithurai (MARBEC Univ Montpellier CNRS Ifremer IRD INRAE Palavas-les-flots Sète Montpellier, France), Emma Duquenne Delobel (MARBEC Univ Montpellier CNRS Ifremer IRD INRAE Palavas-les-flots Sète Montpellier, France), Damien Crestel (MARBEC Univ Montpellier CNRS Ifremer IRD INRAE Palavas-les-flots Sète Montpellier, France), François Allal (MARBEC Univ Montpellier CNRS

Ifremer IRD INRAE Palavas-les-flots Sète Montpellier, France), Germain Salou (MARBEC Univ Montpellier CNRS

Ifremer IRD INRAE Palavas-les-flots Sète Montpellier, France), Gilbert Dutto (MARBEC Univ Montpellier CNRS Ifremer IRD INRAE Palavas-les-flots Sète Montpellier, France), Jérôme Bourjea (MARBEC Univ Montpellier CNRS

Ifremer IRD INRAE Palavas-les-flots Sète Montpellier, France), David J McKenzie (MARBEC Univ Montpellier CNRS

Ifremer IRD INRAE Palavas-les-flots Sète Montpellier, France) theo.navarro@cnrs.fr

It has been proposed that larger individuals within fish species may be more sensitive to global warming, as a result of limitations in their capacity to provide oxygen for aerobic metabolic activities. This could affect size distributions of populations in a warmer world but requires investigation. We studied four groups of individuals over a ~10-fold range in mass (20 – 800 g overall), two farmed species, Nile tilapia (Oreochromis niloticus) and European seabass (Dicentrarchus labrax), and two species captured in the wild, European seabass and gilthead seabream (Sparus aurata). In all groups, capacity to provide oxygen for aerobic activities (Absolute Aerobic Scope) was independent of mass at their acclimation temperature. Tolerance of acute warming, however, declined significantly with mass in all groups, when evaluated as the critical temperature for fatigue from aerobic swimming (CTSmax ). The CTSmax protocol challenges a fish to meet the oxygen demands of constant aerobic exercise while their metabolic demands are accelerated by incremental warming, until fatigue. The maximum rates achieved prior to fatigue declined very significantly with mass. Mass-related variation in CTSmax and maximum oxygen uptake rates were positively related in all groups, which may indicate a causal relationship. When fish populations are faced with acute thermal stress, larger individuals may become constrained in their ability to perform aerobic activities at lower temperatures than smaller conspecifics. This could affect survival and fitness of larger fish in a future world with more frequent and extreme heatwaves, with consequences for population productivity.

A10.19 THE BATTLE OF THE SEXES: MALE AND FEMALE AMPHIPODS DIFFERENCES IN THERMAL TOLERANCE AND METABOLOMIC PROFILES IN A WARMING OCEAN

Wednesday 9th July 2025 09:45

Joana Filipa Da Cunha Fernandes (University of AveiroCESAM, Portugal), Lauric Feugère (Université du Québec à Rimouski - UQAR, Canada), Luísa Marques (University of Aveiro - CESAM, Portugal), Mário Sousa Diniz (NOVA University of Lisbon - UCIBIO, Portugal), Piero Calosi (Université du Québec à Rimouski - UQAR, Canada), Diana Madeira (University of Aveiro - CESAM, Portugal)

joanafcf@ua.pt

Ocean warming is a major threat to shallow water marine communities, particularly their invertebrate species, whose biological rates are temperature dependent. Accurately predicting their fate in the face of ongoing warming will require to account for biological variation, particularly between males and females, of which we currently have little understanding. We experimentally evaluated the physiological and metabolomic responses, as well as reproductive output, of the marine amphipod Gammarus locusta exposed to a temperature gradient. Females and males were collected from a coastal lagoon subjected to four acclimation temperatures (16, 21, 26 and 31 ºC) for 21 days. Specimens were individually sampled for metabolomics profiling. Additionally, Critical Thermal Maximum (CTMax), thermal safety margins and acclimation response ratio were assessed in different specimens at day 21. Higher exposure temperatures led to higher CTMax, confirming thatG. locustais capable to adjust its CTMax via physiological plasticity. A positive thermal safety margin was found, and females displayed higher CTMax than males, suggesting that thermal tolerance is sex dependent. Additionally, offsprings number was significantly reduced at higher temperatures, suggesting negative impacts of OW on fecundity. Further metabolomics analysis will be performed to assess test the hypothesis that warming causes females to enhance energy production via TCA cycle and amino acid metabolism more than males to support heat stress and reproductive costs. We conclude that G. locusta is physiologically plastic, females being more plastic than males, but that population viability may still be at risk due to reduced reproductive output under OW.

A10.20 LIFE SIGNS BELOW ZERO: OVERWINTERING TRANSCRIPTOMIC RESPONSES OF THE MOUNTAIN PINE BEETLE RENAL SYSTEM

Wednesday 9th July 2025 10:00

Rebecca A Dean (Department of Biology Institute of Biochemistry Carleton University, Canada), Amanda D Roe (Natural Resources Canada Canadian Forest Service Great Lakes Forestry Centre, Canada), Leanne Petro (Department of Biological Sciences University of Alberta, Canada), Maya L Evenden (Department of Biological Sciences University of Alberta, Canada), Heath A MacMillan (Department of Biology Institute of Biochemistry Carleton University, Canada)

rebeccadean@cmail.carleton.ca

Insect geographical limits are tied to their ability to tolerate thermal extremes. Climate change is increasing both mean global temperatures and extreme weather event occurrences, which has implications for shifting habitats. This is not only making climates unsuitable for native species but also opening habitats for new species to invade.

Mountain Pine Beetles (Dendroctonus Ponderosae; MPB) are a species of bark beetle that have expanded past their native range in the westernmost part of north America, severely impacting the forests of British Colombia and Alberta, and continuing to expand eastward. As a freeze-avoidant insect, Pine Beetles have the capacity to lower their internal freezing temperature and survive extreme cold through maintenance of ion balance and cryoprotectant accumulation. Unlike less tolerant species, MPB can avoid a catastrophic loss of ion balance that drives tissue damage in the cold, possibly through changes to renal function in response to chilling. To broadly investigate how one component of the renal system responds to cold stress, we conducted tissue-specific mRNA sequencing of MPB Malpighian tubules before, during, and after a simulated cold snap in winter, the results of which suggest that this species may shut down renal ion transport and thereby maintain homeostasis during cold stress.

A10.21 ACCLIMATION DYNAMICS AND UPPER THERMAL TOLERANCE IN THREE SUNFISH POPULATIONS VARYING IN PARASITE PREVALENCE

Wednesday 9th July 2025 10:15

Jeremy De Bonville (University of Montreal, Canada), Andréa Serres (University of Montreal, Canada), Fredrik Jutfelt (University of Gothenburg, Sweden), Sandra A Binning (University of Montreal, Canada) jeremy.debonville@gmail.com

Climate change-induced increases in water temperature and heatwave frequency affect the thermal tolerance of aquatic ectotherms, including fishes. As fishes can increase their thermal tolerance through acclimation, the ability to rapidly adjust their thermal plasticity could improve survival during extreme weather events. However, few studies have investigated the exposure time required for individuals to acclimate to warmer temperatures or how acclimation dynamics vary among populations, limiting our understanding of species’ responses to acute heat stress. Additionally, several parasite species are expected to increase in prevalence and intensity as temperatures rise. While infection can negatively impact host thermal tolerance, its effect on fish acclimation dynamics remains unexplored and may contribute to population-level differences in thermal tolerance. We assessed thermal tolerance in pumpkinseed sunfish (Lepomis gibbosus ) from three lakes in Quebec, Canada, with varying parasite prevalence. Fish were acclimated to 22°C or 27°C for durations ranging from 3 hours to 60 days, after which their critical thermal maximum (CTmax ) was measured. CTmax increased with acclimation duration in all populations, with rapid plastic responses within 3 hours and full acclimation reached after 10 days. CTmax was highest in fish from a parasite-free lake and lowest in populations with greater infection intensity, though acclimation dynamics were largely similar across populations. Although pumpkinseed acclimate rapidly to warming, our results suggest parasites may constrain their upper thermal limits.

Understanding how biotic factors like parasitism influence thermal plasticity is essential for predicting how wild fish populations will respond to climate change.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A10.23 SEASONAL AND SEX DIFFERENCES IN THE THERMOREGULATORY RESPONSES OF EUROPEAN VESPERTILIONID BATS AT HIGH AIR TEMPERATURES

Matthew J Noakes (School of Animal Plant and Environmental Sciences University of the Witwatersrand, South Africa), Zenon Czenze (Centre for Behavioural and Physiological Ecology University of New England, Australia), Michal S Wojciehowski (Department of Vertebrate Zoology and Ecology Nicolaus Copernicus University, Poland)

matt.noakes@wits.ac.za

Deforestation has drastically reduced natural roost sites for European bats, with artificial roost boxes being a common conservation measure. However, concerns arise regarding the potential overheating of artificial roosts, particularly during summer heat waves. Female bats roosting in summer maternity colonies are especially vulnerable due to the hotter and more humid conditions compared to solitary males. This study investigated sex and seasonal differences in heat tolerance and evaporative cooling capacity in four species of vespertillinoid bats. Using indirect calorimetry and thermometry, we measured thermoregulation at air temperatures (Ta ) ranging from 28 to 48°C during spring (male bats only, females in reproductive phase) and summer (both males and females). Contrary to predictions, there were no sex differences in maximum Ta tolerated or evaporative cooling efficiencies. While there were also no seasonal differences in maximum Ta tolerated, male bats unexpectedly had lower maximum cooling efficiencies during summer compared to spring. Moreover, there were sex and seasonal differences in the patterns of increasing evaporative heat loss (EHL) with increasing Ta . Female bats started increasing EHL at higher Ta than males during summer, and male bats increased EHL more gradually with rising Ta in summer compared to spring. These differences in heat-dissipation strategies suggest potential adaptations for enhanced water conservation under hotter and more humid conditions, at both sex and seasonal levels. Using roost temperature and EHL data, we estimated daytime evaporative water costs of bats using artificial roosts, revealing that small bats are already at risk of lethal dehydration during present-day heat waves.

A10.24 CAN INDIVIDUAL FISH CELLS THERMALLY ACCLIMATE WITHOUT CENTRAL CONTROL?

Mafalda Tomás (University of Gothenburg, Sweden), Pierre Renaud (University of Caen Normandie, France), Joachim Sturve (University of Gothenburg, Sweden), Fredrik Jutfelt (University of Gothenburg, Sweden)

mafalda.tomas@bioenv.gu.se

Ectothermic organisms are particularly vulnerable to environmental temperature fluctuations, as their physiological processes are directly influenced by external thermal conditions. Shifts in temperature disrupt molecular stability, affecting biochemical reaction rates, protein conformation, and membrane dynamics, ultimately affecting overall performance. To cope with these challenges, ectotherms adjust through thermal acclimation—a suite of biochemical, physiological, and morphological modifications that enhance function across varying temperatures. While whole-organism acclimation is well established, the mechanisms underlying its initiation and regulation remain uncertain. It is unclear whether acclimation is centrally controlled by neuroendocrine signalling or arises from independent direct cellular responses to temperature changes. This study examines the hypothesis that individual cells possess an inherent ability to acclimate independently of systemic regulation. To explore this, an in vitro approach is used, subjecting rainbow trout gill RTgill-W1 cells to prolonged cold, control, or warm conditions, with proliferation assays conducted weekly to monitor growth. Following this chronic exposure, cells are subjected to an acute thermal challenge to assess if they have acclimated their acute upper thermal tolerance. Cellular responses are evaluated through viability assays, membrane fluidity, metabolic activity, mitochondrial density, heat shock protein concentration, and critical thermal tolerance (CTmax). By isolating cellular responses from systemic influences, this research investigates whether acclimation is centrally regulated or an emergent, decentralised phenomenon. Findings will elucidate the fundamental basis of thermal plasticity and enhance predictions of ectotherm resilience under climate change.

sophiafraser@cmail.carelton.ca

Temperature is a key environmental constraint on insect population size and distribution, and a crucial factor limiting establishment and spread of invasive species. For most insects, cold exposure results in progressive loss of ion balance dependent on both exposure duration and intensity. This ionoregulatory collapse, characterized by extracellular hyperkalemia, causes cell death, tissue damage and eventually death. However, unlike these chill-susceptible species, recent work shows that truly cold hardy insects (e.g. freeze-avoidant mountain pine beetle larvae) only partially lose ion balance during severe cold exposure and maintain extracellular [K+ ] just below lethal cellular limits. Whether this is a common capacity amongst cold-hardy species is unknown, as are the mechanisms behind this phenomenon. Asian longhorn beetle larvae (Anoplophora glabripennis; ALB) are a destructive invasive forest pest that accumulates cryoprotectants and becomes partially freeze-tolerant in winter. We tested whether cryoprotectants can increase cold tolerance by acting as osmoprotectants that mitigate cold-induced ionoregulatory collapse. Specifically, we explored the ability of this species to maintain ion balance in the cold by measuring hemolymph ion concentrations (e.g. Na+ /K+ ) and cryoprotectants during a prolonged cold stress. ALB larvae lab-reared on artificial diet were sampled at multiple time points during cold exposure at temperatures approaching and beyond their freezing point to measure hemolymph osmolality and ion and cryoprotectant concentrations. Results from this study suggest that ALB have an ability to prevent ionoregulatory collapse in the cold, and by extension that such an ability may be a pre-requisite to evolving freeze tolerance or freeze avoidance in insects.

A10.26 NETWORKING IN THE

COLD: CONNECTING RENAL TRANSCRIPTIONAL PLASTICITY TO CHILL INJURY PREVENTION THROUGH GENE NETWORK ANALYSIS.

Rebecca A. Dean (Department of Biology Institute of Biochemistry Carleton University, Canada), Ella H. M. De Nicola (Department of Biology Institute of Biochemistry Carleton University, Canada), Marshall W. Ritchie (Department of Biology Institute of Biochemistry Carleton University, Canada), Heath A. MacMillan (Department of Biology Institute of Biochemistry Carleton University, Canada)

rebeccadean@cmail.carleton.ca

Sophia M.S. Fraser (Department of Biology Carleton University, Canada), Amanda D. Roe (Natural Resources Canada Canadian Forest Service Great Lakes Forestry Centre, Canada), Michael L.A.E Easson (Michael Smith Laboratories University of British Columbia, Canada), Rebecca A. Dean (Department of Biology Carleton University, Canada), Marshall W. Ritchie (Department of Biology Carleton University, Canada), Mads K. Andersen (Department of Biology Carleton University, Canada), Joerg Bohlmann (Michael Smith Laboratories University of British Columbia, Canada), Catherine I. Cullingham (Department of Biology Carleton University, Canada), Heath A. MacMillan (Department of Biology Carleton University, Canada)

Most insects, including Drosophila melanogaster, suffer from a progressive loss of ion and water balance that causes cell, and ultimately organismal, death. This ionoregulatory collapse has been linked to temperature-induced reductions in membrane-bound transporter activity (e.g. Na+ /K+ -ATPase, H+ -ATPase) in the renal system. Cold acclimation can improve low temperature tolerance and is associated with an increase in water and ion transport rates in the Malpighian tubules (analogous to kidneys) of cold acclimated flies, but a paradoxical reduction in the activity of ATPases in the same tissues. This raises questions about whether the current models of ion transport apply to cold-acclimated insects, or if modulation by other mechanisms, such as membrane structural reorganization allow for improved renal function in the cold. Here, we report the results of transcriptomic sequencing of the anterior Malpighian tubules of warm and cold-acclimated flies before, during, and after a cold stress. We

used these results to construct gene networks, using a weighted gene correlation network analysis method. These results link networks of genes to specific traits and suggest that physiological state of tubules before a cold stress is more important to preventing downstream injury than a short-term response to chilling. They further suggest that cold acclimation elicits a tissue repair response in tubules during recovery, as opposed to an immune response seen in warm acclimated flies. Together, these findings allow us to generate hypotheses on how cold acclimation allows insects to adjust their cold tolerance.

A10.27 THERMAL PROFILING OF NOVEL AND KNOWN MIRNAS DURING COLD ACCLIMATION IN AEDES AEGYPTI.

Ella H.M. De Nicola (Carleton University, Canada), Kyle K. Biggar (Carleton University, Canada), Heath A. MacMillan (Carleton University, Canada)

edenicola@gmail.com

The disease vector, Aedes aegypt i, can better survive low temperature exposure following cold acclimation. This plasticity may be contributing to this species’ recent range expansion. However, the molecular mechanisms behind this ability remain unexplored. MicroRNAs (miRNAs) can drive rapid changes in gene expression and are known to regulate thermal plasticity in other animals. We used a bioinformatic approach to identify three novel miRNAs in Ae. aegypti After acclimating adult female Ae. aegypti to cold (15°C) and warm (25°C) conditions, we used RT-qPCR to perform differential expression analysis on these novel miRNAs and four other miRNAs downregulated during diapause in another mosquito species. Two novel miRNAs, aae-miR-novel2 and aae-miR-novel3, were upregulated in coldacclimated individuals. Two described miRNAs associated with lipid metabolism and reproduction, aae-miR-8-3p and aae-miR-13b-3p, were downregulated in the cold-acclimated group, suggesting these processes are affected during cold acclimation. Temperature alone can alter miRNA target genes, and the thermodynamic parameters used to predict miRNA targets are typically established assuming body temperatures relevant to endotherms, rather than those applying to poikilothermic ectotherms. Here, we instead tested for cold-influenced targets of miRNAs of interest, predicted to only become thermodynamically stable at 15°C. This approach provides insight into the putative roles that these novel miRNAs could play in cold acclimation. Many predicted targets were involved in processes associated with insect low temperature survival, like ion homeostasis and membrane stability, while others suggest roles for understudied processes. Our results suggest that miRNAs play a regulatory role in mosquito cold acclimation that deserves further attention.

A10.28 VARIATION IN UPPER THERMAL LIMITS OF ZEBRAFISH ACROSS FOUR WARMING RATES AND ACCLIMATION TEMPERATURES.

Rasmus Ern (Norwegian University of Science and Technology, Norway), Fredrik Jutfelt (University of Gothenburg, Sweden)

rasmus@ern.dk

This study investigates how warming rate (1, 5, 9, and 18°C per hour) and acclimation temperature (15, 21, 28, and 35°C) influence the critical thermal maximum (CTmax) of zebrafish (Danio rerio). Warming trials (n = 18 fish) were conducted using a novel automated and remotely controlled system for assessing the CTmax of fishes. Results show that the effect of warming rate on CTmax depends on acclimation temperature: at higher acclimation temperatures, CTmax increases as warming rate increases; at intermediate acclimation temperatures, CTmax remains unchanged across warming rates; and at lower acclimation temperatures, CTmax decreases as warming rate increases. These findings suggest that (1) the physiological mechanisms underlying CTmax exhibit dynamic thermal acclimation during warming trials and (2) the extent of this acclimation depends on acclimation temperature. Additionally, we propose a dynamic framework for predicting how CTmax responds to warming rates and acclimation temperatures, with potential applications in ecological forecasting and climate change resilience studies.

A10.29 PLASTICITY IN EPIDERMAL LIPIDS OF DESERT SNAKES REDUCES THEIR EVAPORATIVE WATER LOSS IN SUMMER

Shahar Dubiner (Tel Aviv University, Israel), Noa Kinar (Tel Aviv University, Israel), Taly Lapidot Cohen (Tel Aviv University, Israel), Yariv Brotman (Tel Aviv University, Israel), Noa Lavi (Tel Aviv University, Israel), Shai Meiri (Tel Aviv University, Israel), Eran Levin (Tel Aviv University, Israel) dubiner@mail.tau.ac.il

Extreme heat entails extreme evaporative water loss (EWL). Minimizing cutaneous EWL, the main component of water loss, is beneficial to the survival of species inhabiting arid regions. This is especially important in summer, when high temperatures lead to high vapour pressure deficits. We compared EWL of Mediterranean versus desert snake species, and their epidermal lipids which form their primary barrier against water loss. We obtained shed skins of Daboia palaestinae (Mediterranean) and Echis coloratus (desert) from a snake farm, and 17 local species (of both habitats) from a zoo , under identical conditions. Total EWL was measured using flow-through respirometry and cutaneous EWL was measured directly through the shed skin. Skin lipids were quantified after extraction in hexane and identified using UPLC-MS. Total EWL was 51% higher in Mediterranean compared to desert species and their cutaneous EWL was 178% higher in summer but only 67% higher in winter. Lipid content was negatively correlated with cutaneous EWL, and accordingly was twice higher in desert species, but only in the summer. The profile of hydrophobic compounds in the skin differed between habitats. Most differences were significant only among the zoo, perhaps since the farm-grown Echis and Daboia were kept in constant mild conditions, whereas zoo snakes were exposed to the seasonal fluctuations. Our results show that snake epidermal lipid content is higher in deserts (interspecifically) and in summer (intraspecifically). This can help them maintain water balance under the harsh conditions, by limiting water loss via a combination of adaptative and plastic mechanisms.

A10.30 TOO HOT TO HANDLE? THERMAL PERFORMANCE OF ROCK AND TREEDWELLING AGAMID LIZARDS IN A WARMING WORLD

Amanda Ben (IISc

Bangalore,

India), Marwa Abdul Rasak (IISER Tirupati, India), Maria Thaker (IISc Bangalore, India)

amandaben@iisc.ac.in

Global climate warming poses a mounting challenge to tropical ectotherms due to their narrow thermal safety margins and limited physiological plasticity. Understanding how temperature shapes performance traits is crucial for predicting species’ responses to climate change. We investigated how temperature influences the physiology and performance of two sympatric agamid lizards in Karnataka, India with distinct microhabitat preferences and varying geographical ranges: Psammophilus dorsalis (Peninsular rock agama), a rocky outcrop specialist with narrow distribution, and Calotes versicolor (common garden lizard), a vegetation-dwelling generalist with broader distribution. We measured physiological traits- preferred temperature range (Tpref) and critical thermal limits (CTmin and CTmax) followed by sprint speed, and bite force across six experimental temperatures (15, 20, 25, 30, 35, and 40°C) of adult lizards in controlled laboratory conditions. Using biophysical models in the natural habitats, we estimated thermal environments experienced by lizards in different microhabitats across the day and projected their performance under future warming scenarios. Results showed that the geographically widespread C. versicolor exhibited broader thermal tolerance and preferred temperature ranges compared to P. dorsalis Both species shared similar optimal temperatures (Topt) for sprint speed, while bite force remained consistent across temperatures in both species. Future climate projections suggest that moderate warming may initially enhance performance, but further temperature increases could significantly impair locomotor abilities. Our findings highlight the complex interplay between temperature, physiology, habitat choice, and performance traits that shape animal responses in a changing climate.

A10.31 MARINE HEAT WAVES IN THE SUBARCTIC: HOW TEMPERATURE AFFECTS GRAZING AND METABOLISM OF SEA URCHINS

Marie Koch (Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, Germany), Simon Jungblut (Universität Bremen, Germany), Christian Bock (AlfredWegener-Institute Helmholtz Centre for Polar and Marine Research, Germany), Reinhard Saborowski (Alfred-WegenerInstitute Helmholtz Centre for Polar and Marine Research, Germany)

marie.koch@awi.de

Continuous warming and the increasing frequency and intensity of marine heat waves (MHW) pose a new challenge to key species in Subarctic fjord ecosystems. The Porsangerfjord, Northern Norway, has warmed significantly in the last four decades and experiences water temperatures up to 16 °C during extreme MHW events. The green sea urchin, Strongylocentrotus droebachiensis, a dominant consumer of kelp, exhibits strong temperature-dependent grazing behaviour. In a laboratory experiment, sea urchins were fed with

the sugar kelp Saccharina latissima under acute temperature changes of 4 °C every three days within a thermal range of 2 to 22 °C. Grazing activity increased with temperature up to 10 °C, but declined at higher temperatures. Furthermore, metabolic profiling using 1 H-NMR spectroscopy revealed physiological changes with temperature. Glucose levels in the digestive organs reflected feeding rates, while at 22 °C, a shift from aerobic to anaerobic metabolism was indicated by rising levels of the anaerobiosis markers acetate, lactate, and succinate. We propose two potential future scenarios for the impact of sea urchins on their habitat. Elevated temperatures all year-around expect higher grazing pressure on the kelp community. However, extreme MHW events during summer may negatively affect the well-being of S. droebachiensis by pushing their metabolic limits. This may reduce grazing pressure and, in turn, help to preserve the rich kelp forest ecosystem. Understanding the metabolic responses of key grazers is fundamental to predict the future ecological dynamics of boreo-Arctic fjord ecosystems.

A10.32 SMALLER FISH SIZES ON THE WORLD’S HOTTEST CORAL REEFS: TESTING EXPLANATIONS FOR THE TEMPERATURE SIZE RULE

Matthew Mitchell (Yas SeaWorld Research and Rescue Center, United Arab Emirates), Jacob L Johansen (Hawaii Institute of Marine Biology (HIMB) University of Hawaii, United States), Jeroen Brijs (Institute of Zoology University of Innsbruck, Austria), Andrew Shantz (Cooperative Institute for Marine and Atmospheric Research University of Hawai’i at Mānoa, United States), John A Burt (5Mubadala Arabian Center for Climate and Environmental Sciences (Mubadala ACCESS) New York Universi, United Arab Emirates)

mmitchell@miral.ae

The Temperature Size Rule (TSR) states that as temperatures increase ectothermic species, such as fish, grow faster but attain smaller maximal size. While this phenomenon appears to be globally ubiquitous, the mechanisms that explain the TSR remain unresolved. Several competing hypotheses have been proposed to explain the TSR, with most focusing on oxygen-limitation either directly or indirectly e.g. due the need to maintain aerobic scope. These hypotheses have received much attention, however validation of any one is hampered by the need to examine performance over multiple generations. Here we used the world’s hottest (annual temperature range 18-36°C) coral reefs in the Arabian Gulf (AG), where fish have survived for over 6000 years and the cooler adjacent Gulf of Oman (GO) (21-32°C), as a model system to examine these competing hypotheses. We tested the metabolic performance of yellowfin hind (Cephalopholis hemistiktos) across three temperatures representing the annual median (27°C), and summer maxima of the GO (32°C) and AG (35.5°C). Our results show that for both populations basal metabolic demand increased with temperature, although at lower rates than expected, and that individuals were able to maintain their aerobic scope across all temperatures. Furthermore, we found that food intake was dependant on temperature; meal size was reduced at the highest temperature and the number of fish rejecting food entirely increased with temperature. These results provide new insights into the proposed mechanisms explaining TSR as well the adaptive capacity for fish to survive under future climate conditions.

A10.33 URBANISATION DRIVES CONTRASTING THERMAL AND DISPERSAL SELECTION ON BODY SIZE IN BURYING BEETLES

Syuan-Jyun Sun (National Taiwan University, Taiwan), Mu-Tzu Tsai (National Taiwan University, Taiwan), Mariana GC Reyes (National Taiwan University, Taiwan), Ming-Kuang Chung (National Taiwan University, Taiwan), Thomas Merckx (Vrije Universiteit Brussel, Belgium)

sjs243@ntu.edu.tw

Urbanisation reshapes natural habitats by introducing microclimatic changes and landscape modification, both of which can drive divergent selection on morphological traits. One key trait, body size, is fundamental to survival, reproduction, and dispersal, yet its response to urbanization remains inconsistent across taxa. While urban heat islands typically select for smaller body size due to increased metabolic demands, habitat fragmentation may favour larger individuals with greater dispersal ability. In this study, we examine how urbanisation influences body size in the burying beetle Nicrophorus nepalensisin northern Taiwan. Over the field breeding seasons in 2022-2024, we surveyed beetle abundance and morphology across 60 sites, spanning urban and rural gradients with varying build-up coverage. Our findings reveal that beetle abundance declines with increasing urbanization, yet body size responses vary across spatial scales. In urban landscapes, higher build-up coverage correlates with smaller body size, consistent with temperature-driven metabolic constraints. However, in rural landscapes, increased built-up coverage is associated with larger individuals, suggesting that habitat fragmentation imposes selective pressures favouring enhanced mobility. These results demonstrate that urbanization can simultaneously impose opposing selective forces on body size, with its impact contingent upon landscape context. Our study highlights the importance of integrating thermal and dispersal constraints to understand how species persist in humanmodified environments, offering key insights into the evolutionary consequences of urbanisation.

A10.34 FLEXIBILITY OF METABOLIC RATE TO TEMPERATURE COINCIDES WITH DIAPAUSE MODE

Kevin T Roberts (University of Greifswald, Germany), Henrika J Bosua (Stockholm University, Sweden), Philipp Lehmann (University of Greifswald, Germany)

kevin.roberts@uni-greifswald.de

In seasonal environments, insects often enter dormancy to survive challenging conditions. During dormancy, insects operate on a fixed energetic budget and suppress metabolic rate to extend the duration that their energy reserves can last. Extending energy stores to last an entire winter can pose quite a challenge, as some habitats can have winters that last a majority of the year. There are some cases where insects enter dormancy in the middle of summer and remain dormant until the following spring. This multi-season dormancy should pose quite the energetic challenge, since these insects must conserve energy during an already long winter, as well as the warmest period of summer. To investigate energy conservation from a metabolic standpoint, we compared metabolic rate-temperature curves of two closely related species of Pierid butterflies: Pieris napi, which is

dormant through winter, and Anthocharis cardamines, which exhibits a multi-season dormancy. This comparison was conducted at several time points in dormancy and under several acclimation conditions. We found that A. cardamines is able to maintain considerable metabolic suppression when acclimated to warm conditions, which is only maintained until they are exposed to cold. Overall P. napi exhibits much lower levels of plasticity in metabolic rate. Metabolic suppression exhibited in A. cardamines is enough to prevent higher rates of mass loss at warm temperatures. Together, this provides evidence that both environment and life history timing of dormancy can shape metabolic plasticity.

A10.35 EXPLORING FISH AEROBIC SCOPE IN A CHANGING CLIMATE

Emily R Lechner (University of Gothenburg, Sweden), Mafalda Tomáz (University of Gothenburg, Sweden), Leon Pfeufer (University of Gothenburg, Sweden), Fredrik Jutfelt (University of Gothenburg, Sweden)

Emily Lechner1* , Mafalda Tomas1 , Leon Pfeufer1 , and Fredrik Jutfelt1

1 Department of Biological and Environmental Sciences, Faculty of Science, University of Gothenburg, 41390, Gothenburg, Sweden

emilylechner@trentu.ca

A warming climate can have consequences on the performance of ectotherms through increases in metabolic demand. Understanding how variation in water oxygen saturation and supra-optimal temperatures affect the vulnerability of fishes to heatwaves and hypoxic zones is imperative to predicting anthropogenic impacts on wild organisms. However, we do not yet have a full understanding of how water oxygen saturation influences aerobic capacity, and how this may be temperature dependent. This study investigates the constraints imposed by warming and hypoxia on aerobic performance in two model species with distinct thermal niches: the cold-adapted rainbow trout (Oncorhynchus mykiss) and the warm-adapted zebrafish (Danio rerio). Here, we present swim performance and aerobic scope profiles of these two species in response to variable oxygen saturation and temperature regimes. We used racetrack swim-tunnel respirometry to measure swim performance and maximum metabolic rates along a gradient of air saturation (from 25% to 200%). Fish will be acclimated to three temperatures that are ecologically relevant to their species (sub-optimal, optimal, supra-optimal). The results will be discussed in relation to the mechanisms limiting aerobic performance in fish and will address gaps in knowledge that relate to oxygen dynamics and thermal resilience of aquatic ectotherms. This work is essential for improving projections of aquatic biodiversity under future climatic scenarios.

A10.36 WARM AND COOL TEMPERATURES DECREASE EARLY-LIFE TELOMERE LENGTH IN WILD PIED FLYCATCHERS

Clémence Furic (Department of Biology University of Turku, Finland), Coline Marciau (Institute for Marine and Antarctic Studies University of Tasmania, Australia), Bin-Yan Hsu (Department of Life Science Tunghai University, Taiwan), Nina Cossin-Sevrin (Department of Biology University of Turku, Finland), Julie Fleitz (Department of Biology University of Turku, Finland), Sophie Reichert (Department of Biology University of Turku, Finland), Suvi Ruuskanen (Department of Biological and Environmental Science University of Jyväskylä, Finland), Antoine Stier (Université de Strasbourg CNRS IPHC UMR 7178, France)

cmfuri@utu.fi

Climate change represents one major challenge for avian species. It is characterized by an increase in average ambient temperature, but also in occurrence of extreme weather events, such as heat weaves and cold snaps. These abrupt temperature changes can modify the immediate and long-term survival prospects of nestling birds when their thermoregulatory capacities are still not fully developed. While immediate nestling survival can easily be measured, long-term survival is more challenging to evaluate. Yet, early-life telomere length has been suggested as a potential biomarker of fitness prospects. To evaluate the potential impact of changes in early-life temperature, we thus experimentally increased (ca.+2°C) and decreased (ca.-1.5°C) nestbox temperatures in wild pied flycatchers (Ficedula hypoleuca) during nestling postnatal growth, and measured nestling telomere length before fledging. Shorter telomeres were observed in individuals exposed both to an experimental heating or cooling during growth. Our results suggests that long-term survival prospects or long-term performance of individuals exposed to abrupt changes in early-life temperature may be decreased.

A10.38 WHEN THE HEAT RISES: SEX-SPECIFIC EFFECTS OF MARINE HEATWAVES ON REPRODUCTIVE SUCCESS AND ENERGY METABOLISM IN THE AMPHIPOD GAMMARUS LOCUSTA

Joana Filipa Da Cunha Fernandes (University of Aveiro - CESAM, Portugal), João Ferreira (University of AveiroCESAM, Portugal), Mário Sousa Diniz (NOVA University of Lisbon - UCIBIO, Portugal), Ricardo Calado (University of Aveiro - CESAM, Portugal), Diana Madeira (University of Aveiro - CESAM, Portugal)

joanafcf@ua.pt

Marine heatwaves (MHWs) are becoming more frequent, intense, and prolonged with ongoing global changes. This study aimed to evaluate the impacts of sex-specific exposure to MHWs on the reproduction and energy metabolism of the amphipod Gammarus locusta. Females (F) and males (M) were sampled at a coastal lagoon and kept individually during a 7-day period under a control (20 °C) or a MHW (25 °C) scenario. After 7 days, females and males were sampled for mitochondrial and digestive enzymes activities, while the remaining specimens were used to form breeding pairs in different

combinations (FControl /MControl , FControl /MMHW , FMHW /MControl , and FMHW /MMHW ). These breeding pairs were kept at control temperature (20 °C) until either reproducing or dying. Survival, reproductive success, fecundity and offspring body-sizes were subsequently determined. Reproductive success and fecundity were extremely reduced when both adults were exposed to MHWs, when compared to breeding pairs with both adults coming from the control treatment. Significant differences were also observed in the sizes of neonates, with offspring from control couples displaying smaller sizes, when compared to those from breeding pairs in which one of the adults was exposed to MHWs. We predict that MHWs will induce sex-specific enzymatic responses, such as differential energy allocation via changes in mitochondrial enzyme activity and the disruption of the endocrine system-related enzymes. MHWs imposed significant metabolic challenges on G. locusta, leading to sex-specific responses. Our findings highlight the need to consider sex as a biological variable in global change research to better predict species resilience and population stability.

A10.39 EFFECTS OF HIGH TEMPERATURE AND WATER STRESS ON BEHAVIORAL PERFORMANCE OF A SUBTROPICAL FOREST LIZARD: IMPLICATIONS FOR VULNERABILITY TO CLIMATE CHANGE

Shu-Ping Huang (National Sun Yat-sen University, Taiwan), Ting-Wei Liu (National Sun Yat-sen University, Taiwan), Yue-Lin Cai (National Sun Yat-sen University, Taiwan) sphuang0711@mail.nsysu.edu.tw

Temperature and precipitation changes due to global climate change are adversely affecting many reptile species. Various physiological traits have been incorporated in models to assess changes in reptiles’ ecological performance under climate change. However, these models often overlook reptiles’ water conservation behavior under water stress, potentially underestimating the impact of climatic changes, especially as droughts become more frequent. This study quantified reptile behavioral changes induced by temperature and dehydration using a controlled laboratory experiment. Using the forest skink, Scincella formosensis, as a model species, we found that massspecific evaporative water loss rates were greater in juveniles than in adults, with a greater difference observed at 30°C compared to 25°C. In adults, exploration time decreased with increasing dehydration, with a more pronounced reduction at 30°C, likely as a strategy to minimize water loss. Combined with field temperature and humidity recordings, these results suggest that this species’ habitat is restricted to the wet, cool forest floor, which is consistent with its current habitat distribution. Our findings suggest that S. formosensis may be more vulnerable to climate change than previously predicted, as prior models only incorporated adult thermal traits. The pronounced behavioural response of individuals to dehydration underscores the necessity to integrate water balance constraints into ecological models to improve predictions of species responses to climate change.

A10.40 ENERGY DYNAMICS IN MOUNTAIN PINE BEETLE AND EMERALD ASH BORER DURING OVERWINTERING

Fouzia Haider (Carleton University, Canada), Mads K Andersen (Aarhus University, Denmark), Maya Evenden (University of Alberta, Canada), Amanda Roe (Natural Resources Canada, Canada), Joerg Bohlmann (University of British Columbia, Canada), Heath A MacMillan (Carleton University, Canada) fouzia.haider@outlook.com

Two notorious species of bark beetles that have caused major economic and ecological damage to Canadian forests are the Mountain Pine Beetle (MPB, Dendroctonus ponderosae) and Emerald Ash Borer (EAB, Agrilus planipennis). MPB is native to northwestern North America and has invaded eastward, whereas EAB invaded North America from Asia. Both species rely on physiological plasticity to withstand the harsh winters in Canada, including cryoprotectant accumulation, cessation of feeding, and dormancy. Most physiological processes are suppressed during overwintering, but basal maintenance, post-dormancy recovery, and repair rely on stored energy reserves. As feeding ceases over winter, prudent use of stored macromolecules, such as protein, carbohydrate, and lipid as well as lowering the basal maintenance cost might help beetles survive through winter and by extension disperse successfully in summer. To better understand how energy dynamics change in these two forest pests during overwintering, we measured whole-animal concentrations of each macromolecule during overwintering, and during stepwise temperature decreases (0, -5, -10°C), sampling subsets of animals throughout. We hypothesized that both species shift fuel use during winter, accumulating sugar polyols for cryoprotection and that overwintering will be energetically demanding, with an increased need for energy to fuel repair following exposures to colder temperatures. Our results show that overwintering capacity is species- and life-stage specific. EAB relies on lipids in winter. In contrast, MPB relies on the production of cryoprotectants. Understanding the underlying mechanisms that allow species to cope with winter can be used to mitigate the population expansion of these invasive species.

A10.41 EFFECT OF TEMPERATURE ON POPULATION DYNAMICS: TESTING THE ROLE OF ASYMMETRY IN CONSUMER AND RESOURCE ENERGETICS

Romain Richard (National Sun Yat Sen University, Taiwan)

romain.richard@mail.nsysu.edu.tw

Observations on population responses to temperature show diverse patterns, with some populations increasing and others decreasing with warming. The factors driving this variability remain unclear. Theoretical models suggest that asymmetry in the thermal sensitivity of interacting species may explain much of this diversity, but experimental support is lacking. We tested this hypothesis using modelling and laboratory experiments on aDaphnia-algae system, in which the algal food supply was experimentally manipulated to create two contrasting scenarios of thermal asymmetry. We characterized the temperature dependence ofDaphniaperformance and embedded it in a population model. As predicted,Daphniaequilibrium biomass increased when their

performance was less sensitive to temperature than algal supply and decreased in the opposite case. A carefully parameterized energy budget captured these changes quantitatively. Additionally, temperature strongly increased sexual reproduction, with up to 90% of reproductive energy allocated to male and resting egg production at the highest temperature. This constitutes an energy sink because, as resting eggs remain dormant for months, they do not immediately contribute to population growth. However, integrating sexual reproduction into the population model’s predicted equilibrium biomass due to compensatory effects: reduced competition allowed individuals to grow faster and reproduce more. These results confirm that thermal asymmetry in species energetics is a key factor shaping population responses to temperature. Moreover, carefully parameterized models of individual energetics can effectively predict these patterns. Further refinements should incorporate mechanisms regulating sexual reproduction to improve predictions of population dynamics inDaphnia-algae systems.

A10.42 STAYING CHILL: THE ROBUST RESPONSE OF THE GOLDFISH TO ANOXIA & RE-OXYGENATION AT COLD TEMPERATURES.

Michael P Wilkie (Department of Biology Wilfrid Lauier University, Canada), Matthew Trzcinski (Department of Biology Wilfrid Laurier University, Canada)

mwilkie@wlu.ca

Snow- and ice-covered lakes and ponds are notoriously sensitive to drops in O2 leading to hypoxic or anoxic conditions that can lead to mass mortality of fishes or winterkill. The goldfish (Carassius auratus) and crucian carp (Carassius Carassius) however, can live many weeks under such conditions. A challenge they may face following anoxia is the risk of oxidative damage to tissues including brain and liver, caused by reactive oxygen species (ROS) generation during the period of re-oxygenation. To simulate how goldish responded to anoxia and re-oxygenation in nature, they were acclimated to 4°C for 3 months to simulate an overwintering period and then subjected to acute anoxia for 4 days (4°C) or 1 day (14°C comparison group). We predicted that oxidative damage would be lower in the cold vs warmer water goldfish during the post-anoxia recovery period (12h). Anoxia resulted in marked ethanol accumulation in the plasma and muscle at both temperatures, which was eliminated more slowly during reoxygenation at 4°C compared to 14°C. Greater lipid peroxidation was observed in the liver of cold-water goldfish under normoxic conditions, possibly a homeoviscous response. Neither lipid peroxides or protein carbonyls changed in any tissues during anoxia or during the 12h re-oxygenation period. Nor did antioxidant enzyme activities, including catalase, superoxide dismutase or glutathione peroxidase, change during the re-oxygenation period. We conclude that goldfish exhibit a robust response to acute anoxia, and that they are resistant to oxidative tissue injury during re-oxygenation at both cold and moderate temperatures.

A10.43 DOES PREDICTABILITY MATTER?

EFFECT OF STOCHASTIC AND CYCLIC THERMAL VARIATIONS ON ENERGETIC BUDGET IN A FRESHWATER FISH

Chloé Souques (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Julia Watson (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Juliette Fernandes (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Ludovic Guillard (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Laetitia Averty (Animalerie Conventionnelle Sauvage d’Expérimentation de la Doua (ACSED), France), Candice Bastianini (Animalerie Conventionnelle Sauvage d’Expérimentation de la Doua (ACSED), France), Angeline Clair (Animalerie Conventionnelle Sauvage d’Expérimentation de la Doua (ACSED), France), Hervé Capra (INRAE RiverLy, France), Damien Roussel (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Anne Morales-Montaron (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), François-Xavier Dechaume-Moncharmont(*) (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Yann Voituron(*) (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Loïc Teulier(*) (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France)

chloe.souques@univ-lyon1.fr

In a changing climate, organisms are experiencing increasing thermal stochasticity. However, the role of the unpredictability of conditions on the biological consequences of thermal variability remains poorly explored. In particular, the sensitivity of metabolic performance to temperature could have large consequences from individual fitness to ecological communities via its influence of resource intake. In this context, we investigated the effect of ecologically relevant patterns of stochastic and cyclic thermal variations on the energetic budget of a pelagic freshwater fish, the European chub (Squalius cephalus). Fish (n=131) were exposed to constant temperatures regimes (13°C, 19°C or 25°C) or experienced profiles with variable temperatures sharing the same mean (19°C) and variance. Variable groups underwent either stochastic variations randomly oscillating between 13°C and 25°C, or cyclic variations following a circadian pattern. Both energy expenditure through whole-organism oxygen consumption and energy intake with predation rate were assessed on the same fish after one and six weeks of exposure to thermal treatments. After one week of exposure, preliminary results show that metabolic responses are driven by the mean temperature experienced, conversely to predation rates that are even sensitive to the pattern of variations. These results point out the necessity of accounting for thermal variability in experimental contexts and shed the light on our upcoming results investigating the plasticity of responses after a prolonged exposure. Additionally, such findings raise questions about a potential shift of thermal optima across biological traits and therefore highlight the relevance of assessing multiscale effects of environmental variability in studying climate change.

A10.44 CAPACITY FOR RAPID THERMAL ACCLIMATION DIFFERS ACROSS EELGRASS-ASSOCIATED FISHES

Elena Tamarit (University of Gothenburg, Sweden), Felix Steinbrecher (University of Gothenburg, Sweden), Leon Pfeufer (University of Gothenburg, Sweden), Emily R. Lechner (University of Gothenburg, Sweden), Hannah Sauer (University of Gothenburg, Sweden), Hans W. Linderholm (University of Gothenburg, Sweden), Martin Gullström (Södertörn University, Sweden), Fredrik Jutfelt (University of Gothenburg, Sweden)

elena.tamarit@gu.se

Coastal habitats are among the most productive ecosystems on Earth, acting as biodiversity hotspots and essential nursery grounds for marine life. In Scandinavia, seagrass Zostera marina habitats provide food and shelter for many fishes. However, these meadows are typically confined to shallow areas due to water turbidity and eutrophication. As global warming intensifies the severity, frequency, and duration of heat waves, eelgrass-associated fishes are increasingly at risk of thermal stress. Yet, the extent of species-specific thermal limits and their plasticity for acclimation remains poorly understood. To address this gap, we investigated the effects of warming on wild eelgrass-associated fish during summer, when their thermal history is highest and temperature extremes are most impactful. We exposed twelve species from six families to a control temperature (19°C) or a simulated heatwave (23°C) for five days. We then studied their thermal tolerance using the Critical Thermal Maximum (CTmax) test and measured the temperature at loss of equilibrium. Our results showed differences in upper thermal limits across species, partly influenced by phylogenetic history. Most species exhibited an acclimation response to warming, reflected by an increase in CTmax, though some species acclimated faster than others. Our findings emphasize the importance of considering species-specific thermal responses when assessing the ecological impacts of heatwaves on coastal fish communities.

A11: OPEN WATER: THE BIOLOGY OF PELAGIC FISH

ORGANISED BY: DAPHNE CORTESE (MARBEC, IFREMER), DAVIDE THAMBITHURAI (UNIVERSITY OF GLASGOW)

A11.1 WHY SARDINES SHRINK IN THE NW MEDITERRANEAN SEA?

Wednesday 9th July 2025 11:00

Quentin Queiros (Swedish University of Agricultural Sciences) quentin.queiros@slu.se

Small pelagic fish used to be a major component of commercial fisheries in NW Mediterranean Sea, but landings have drastically fallen over the last decade due to a severe decline in fish size and body condition. This situation seems to result from bottom-up control linked to changes in plankton size and composition. However, mechanisms behind these effects remain to be investigated. Through experiments on a captive population of sardines, we first showed that sardine growth and condition were significantly impacted by food size and quantity. We hypothesized that sardines expended more energy filtering small prey than capturing larger ones. To test whether foraging on smaller prey increases energy expenditure - especially under warming conditions - we conducted a second experiment. We examined the synergic effects of temperature as a direct consequence of climate change and an indirect effect through food modulation (size and quantity) on the energy expenditures of sardines. Interestingly, the energy costs of filtering mode on small particles were twice as high as those of directly capturing large particles. Despite lower digestion energy costs, the daily energy expenditures of sardines fed on small particles were greater than those fed on large items, and the gap widened as temperature increased. These findings highlighted how changes in prey size modified sardines’ feeding behaviour, affecting their metabolism, likely altering energy allocation towards life-history traits (e.g., growth

A11.2 COLOR DYNAMICS: NOVEL STRUCTURAL COLOR MECHANISMS MAY MEDIATE CAMOUFLAGE STRATEGIES OF BLUE SHARKS

Wednesday 9th July 2025 11:30

Viktoriia Kamska (City University of Hong Kong, Hong Kong), Chiara Micheletti (Max Planck Institute of Colloids and Interfaces, Germany), Emeline Raguin (Max Planck Institute of Colloids and Interfaces, Germany), Luca Bertinetti (B CUBE - Center for Molecular Bioengineering, Germany), Shahrouz Amini (Max Planck Institute of Colloids and Interfaces, Germany), Michael Blumer (Institute of Clinical and Functional Anatomy Medical University Innsbruck, Austria)

vkamska@cityu.edu.hk

Numerous animals exhibit remarkable adaptations for dynamically altering skin coloration. For instance, chameleons modify guanine crystal spacing in their cells, flounders regulate skin pigment visibility, and cephalopods utilize complex light-diffusing structures to achieve effective camouflage. While shark skin is often perceived as grey, some species demonstrate diverse coloration and camouflage strategies, including countershading and bioluminescence. Recent reports suggest that great white sharks possess dynamic camouflage, as evidenced by the great white shark’s skin color changes to a lighter hue when exposed to adrenaline, while melanocyte-stimulating hormone (MSH) causes a darker hue. Our study on blue sharks (Prionace glauca) reveals a potential nanostructural mechanism for this via a direct association between shark coloration and their skin’s tooth-like dermal denticles, which are well known for their hydrodynamic properties. We show that each denticle produces highly saturated, non-iridescent color through nanoscale structural interactions within its pulp cavity. Inside denticles, varying spatial interactions between pigment cells and cells packed with complex crystal stacks (likely guanine) mediate the perceived color in different body regions. These cellular associations, however, also offer a palette whereby small changes in tissue architecture can manifest as local color changes. Our optical observations of excised blue shark skin reveal it can transition from blue to green, gold to slate gray in response to external stimuli, such as changes in humidity. This suggests that our identified structural color mechanisms provide a pathway for dynamic camouflage, opening an unexplored window into shark ecological adaptations and novel structural mechanisms for producing mutable colors.

A11.3 HOW AWESOME IS THE CARDIORESPIRATORY SYSTEM OF THE ROCKSTARS OF PELAGIC TELEOSTS, THE BLUEFIN TUNAS?

Wednesday 9th July 2025 11:45

Timothy D Clark (Deakin University, Australia)

t.clark@deakin.edu.au

Pelagic fishes have many adaptations to enable their active lifestyles. Arguably, the rockstars of the pelagic teleosts are the bluefin tunas, as they can attain extremely large body sizes (up to ~700 kg), they can swim at very high speeds, they have large areas of the body served by countercurrent heat exchangers, and they can roam into deep and high-latitude waters that are too cold for other tunas. As such, the cardiovascular and respiratory physiology of bluefin tunas has been assumed to be exceptional compared with other teleosts, although testing this assumption has proved difficult due to the substantial challenges of working with highly pelagic species that spend their lives in open water. This presentation will discuss what is known about the cardiorespiratory physiology of bluefin tunas, with an aim to understand just how awesome these species are in comparison with all the other loser teleosts.

A11.4 SURVIVAL AND POST-RELEASE BEHAVIOUR OF PELAGIC SHARKS CAUGHT IN RECREATIONAL

CATCH-ANDRELEASE FISHERIES – INSIGHTS FROM ELECTRONIC TAGGING

Wednesday 9th July 2025 12:00

Francesco Garzon (University of Exeter, United Kingdom), Thomas W. Horton (University of Exeter, United Kingdom), Owen M. Exeter (University of Exeter, United Kingdom), Cat Gordon (Shark Trust, United Kingdom), Lucy A. Hawkes (University of Exeter, United Kingdom), Ali Hood (The Shark Trust, United Kingdom), Alex Plaster (Government of Jersey Marine Resources, Jersey), David Righton (Centre for Environment Fisheries and Aquaculture Science, United Kingdom), Hannah Rudd (Angling Trust, United Kingdom), Joana F. Silva (Centre for Environment Fisheries and Aquaculture Science, United Kingdom), Bryce Stewart (University of Plymouth, United Kingdom), Simon Thomas (University of Plymouth, United Kingdom), James Thorburn (Edinburgh Napier University, United Kingdom), Matthew J. Witt (University of Exeter, United Kingdom)

fg350@exeter.ac.uk

Understanding how sharks respond to catch and release (C&R) recreational fisheries is a key challenge for both management and biologging research. Survival rates and recovery periods are highly species- and setting-dependent, yet no study has been conducted in European recreational fisheries, despite their popularity. We present the first example of electronic tagging to assess C&R effects on blue ( Prionace glauca ), porbeagle ( Lamna nasus ) and tope (Galeorhinus galeus) sharks in the UK, for which data are lacking.

Electronic tags (n=69) revealed high (94.7 – 96.2%) survival rates in all three species, with one case of mortality in each. Mortalities could not be definitively attributed to one aspect of the capture event, as animals appeared in good health upon release. However, two individuals (a porbeagle and a tope shark) were deeply hooked and released with hooks in place, which may have caused injuries invisible to observers. Depth time-series (10-minute resolution; n=16) were used to infer when sharks had recovered from angling through changepoint analysis of 4 movement metrics. Recovery time varied among species, but in most cases lasted less than a day. Pre-recovery, abnormal behaviour varied between- and within-species, though typically involved depth-holding either mid-water or near the sea floor and lower vertical velocities. The results suggest that when C&R fisheries are conducted within current best-practice guidelines, post release survival can be high. The recovery analysis further offers important insight into the shortterm behaviour of electronically tagged animals, which needs to be better accounted for in telemetry studies of marine species.

A11.5 ON-LINE ARTERIAL OXYGEN TENSIONS PROVIDE INSIGHT INTO GILL OXYGEN UPTAKE DYNAMICS IN RAINBOW TROUT

Wednesday 9th July 2025 12:15

Luis L Kuchenmüller (Deakin University, Australia), Timothy D Clark (Deakin University, Australia), Erik Sandblom (Gothenburg University, Sweden), Andreas Ekström (Gothenburg University, Sweden)

.kuchenmueller@deakin.edu.au

Oxygen uptake across the gills has been proposed as a bottleneck in the oxygen transport cascade of pelagic fish with high aerobic requirements. However, most investigations of this topic have relied on intermittent blood sampling, which only provides a snapshot in time of blood oxygenation, so large knowledge gaps remain. We present a novel method with exciting potential for the study of oxygen uptake limitation in fish. By implanting oxygen sensors into the dorsal aorta of the highly athletic rainbow trout (Oncorhynchus mykiss , n =25), arterial oxygen tension (PaO 2 ) immediately downstream of the gills could be monitored continuously. We combined this with whole animal respirometry at two distinct water flow regimes within the respirometers (10 and 20 l min -1) and hypothesised that increased flow rates would enhance arterial oxygenation and maximum metabolic rate (MMR) following exhaustive exercise at 20°C. The Pao2 recordings were validated by assessments of dorsal aortic PaO 2 and O 2 content from intermittent blood samples collected from a separate group of fish. Intriguingly, PaO2 closely tracked the minor water oxygen deviations associated with flush and seal cycles during respirometry. Pilot tests exposing the fish to <20% water oxygen saturation confirmed that fish only loosely defend their PaO2 via hyperventilation and other measures. High water flow did not significantly affect MMR or PaO2 recovery times, suggesting gill oxygen uptake was not limited following exercise. We highlight research avenues that our new approach has uncovered and discuss how remaining knowledge gaps surrounding gill oxygen uptake dynamics of fish can be addressed.

A11.6 OTOLITH RESPIROMETRY IN PELAGIC FISHES: CALIBRATION AND ECOPHYSIOLOGICAL INSIGHTS

Wednesday 9th July 2025 15:00

Clive Trueman (University of Southampton)

trueman@soton.ac.uk

Marine pelagic fishes present challenges for metabolic study. Many pelagic fish species are difficult to maintain in aquarium and respirometry conditions due to their requirements for large water volumes, sensitivity to handling and often schooling social behaviour. Consequently, basic physiological data on marine pelagic fishes is relatively sparse, and such data that does exist may reflect unrealistic and/or stressful conditions. Recently the development of stable isotope-based proxies for total oxygen consumption rate offers a possibility of obtaining metabolic rate estimates retrospectively from free swimming pelagic fishes at relatively low cost. In this presentation I will: (a) outline the physiological mechanism underpinning the otolith isotope metabolic rate proxy, (b) compare metabolic rate data obtained from otolith, oxygen uptake rate and electron transfer system respirometry approaches as applied to pelagic fishes ranging from deep pelagic bristlemouths to bluefin tuna. Finally, I will demonstrate the use of otolith-derived metabolic data to identify optimal thermal habitat and thermal sensitivity of large pelagic fishes, and to quantify the contribution of deep pelagic fishes to global carbon export flux.

A11.7 LIDOCAINE USE IN LARGE PELAGIC FISH RESEARCH

Wednesday 9th July 2025 15:30

Ghalia Abel (University of Exeter, United Kingdom), Alex Allison (Red Kite Veterinary Consultants Ltd, United Kingdom), Francesco Garzon (University of Exeter, United Kingdom), Lucy A Hawkes (University of Exeter, United Kingdom), Thomas W Horton (University of Exeter, United Kingdom), Gregory C Paull (University of Exeter, United Kingdom), Alexander Plaster (Government of Jersey, Jersey), David Righton (Centre for Environment Fisheries and Aquaculture Science, United Kingdom), Jessica L Rudd (University of Exeter, United Kingdom), Lynne U Sneddon (University of Gothenburg, Sweden), Matthew J Witt (University of Exeter, United Kingdom)

gma208@exeter.ac.uk

Biologging tags are used to understand wild animal movements for research, conservation and management. However, interpreting biologging data can be challenging owing to potential responses to capture and tagging (e.g. discomfort from invasive tag attachment), which may bias results. Fish possess sensory receptors that respond to painful stimuli, and local anaesthetics such as lidocaine have been shown to block nociception in fish, improving welfare and potentially reducing behavioural bias. Here, we explore the practicalities and effects of lidocaine use in wild Atlantic bluefin tuna (ABT), tagged with acoustic and/or pop-up satellite archival tags using intramuscular darts. Lidocaine was used on twenty-six ABT, a further fifty ABT did not receive lidocaine and were used as control individuals. Doses were administered at 0.1 ml/kg (2% lidocaine). ABT were either single

(lidocaine n=11, control n=42) or double tagged (lidocaine n=15, control=8). Administration of lidocaine did not increase handling time on deck for single tagged ABT, but for double tagged fish, requiring two doses of lidocaine (one for each tag), handling time increased by 35% (mean = 3 minutes 47 seconds ± 34 seconds) compared to controls (mean = 2 minutes 39 seconds ± 28 seconds). Time required to conduct drug delivery also reduced with increasing researcher experience. The behaviour of fish receiving lidocaine remains under investigation, but preliminary results suggest by 30 days post-release, there are no differences in movement between groups. This cautiously suggests that lidocaine delivery can be used to improve welfare, without impacting tagging operations.

A11.8 PHYSIOLOGICAL CONDITION OF YELLOWFIN TUNA CHARACTERIZED THROUGH A FASTING EXPERIMENT

Wednesday 9th July 2025 15:45

Ignatius T Hargiyatno (MARBEC (IRD Ifremer Université de Montpellier CNRS), France), Fabien Forget (MARBEC (IRD Ifremer Université de Montpellier CNRS), France), Jhon H Hutapea (Research Center for Fishery-National Research and Innovation Agency (BRIN)- Indonesia, Indonesia), Quentin Schull (MARBEC (IRD Ifremer Université de Montpellier CNRS), France), Ananto Setiadi (Research Center for FisheryNational Research and Innovation Agency (BRIN)- Indonesia, Indonesia), Gunawan Gunawan (Research Center for FisheryNational Research and Innovation Agency (BRIN)- Indonesia, Indonesia), Laurent Dagorn (MARBEC (IRD Ifremer Université de Montpellier CNRS), France), Wudianto Wudianto (Research Center for Fishery-National Research and Innovation Agency (BRIN)- Indonesia, Indonesia), Manuela Capello (MARBEC (IRD Ifremer Université de Montpellier CNRS), France)

ignatius.hargiyatno@ird.fr

Tuna associated with Fish Aggregating Devices (FADs) often exhibit higher proportions of empty stomachs and lower condition factors. However, it remains unclear whether this lower condition is a cause or a consequence of FAD association and whether the FAD-associated tuna condition is good or bad, due to the lack of fundamental knowledge on tuna physiology. This study aimed to quantify the physiological condition of tuna during food deprivation. 25 captive tuna individuals (FL: 31-71 cm) were initially fed ad libitum for 2 weeks and then subject to a controlled fasting period of 36 days. During fasting, 3 to 7 individuals were sampled at regular intervals (every 3-6 days) to assess various condition factors, including biometric parameters (e.g., Le Cren condition factor (Kn), hepatosomatic index (HSI), and girth length index (GL)), bioelectrical impedance analysis (BIA), body composition, and blood parameters. The results indicate that tuna initially mobilized the energy stored in the liver and then in the muscles. Three distinct phases of fasting were identified: Phase 1 (high HSI and Kn during ad libitum feeding and the early fasting days), Phase 2 (low HSI and high Kn, from days 4 to 14), and Phase 3 (low HSI and low Kn after 14 days of fasting). When comparing these results with condition factors measured on wild tuna associated with drifting FADs, it appears that all FAD-associated tuna fall within Phases 1 and 2. These results suggest that FAD-associated tuna do not attain the low Kn values observed during extended periods of fasting.

A11.9 USE OF ACCELEROMETRY TO MEASURE THE DYNAMICS OF ACTIVITY PATTERNS OF ATLANTIC BLUEFIN TUNA AFTER TAGGING AND RELEASE

Wednesday 9th July 2025 16:00

Jessica L Rudd (University of Exeter, United Kingdom), Kim Aarestrup (Technical University of Denmark, Denmark), Ghalia Abel (University of Exeter, United Kingdom), Francisco Alemany (International Commission for the Conservation of Atlantic Tunas, Spain), Henrik Baktoft (Technical University of Denmark, Denmark), Francis Binney (Government of Jersey Marine Resources, Jersey), Samantha Birch (Centre for Environment Fisheries and Aquaculture Science, United Kingdom), Kim Birnie-Gauvin (Technical University of Denmark, Denmark), Barbara A Block (Stanford University, United States), Martin A Collins (British Antarctic Survey, United Kingdom), Owen M Exeter (University of Exeter, United Kingdom), Francesco Garzon (University of Exeter, United Kingdom), Thomas W Horton (University of Exeter, United Kingdom), Alex Plaster (Government of Jersey Marine Resources, Jersey), David Righton (Centre for Environment Fisheries and Aquaculture Science, United Kingdom), Jeroen Van der Kooij (Centre for Environment Fisheries and Aquaculture Science, United Kingdom), Matthew J Witt (University of Exeter, United Kingdom), Serena Wright (Centre for Environment Fisheries and Aquaculture Science, United Kingdom), Lucy A Hawkes (University of Exeter, United Kingdom)

jr646@exeter.ac.uk

Research on the direct effects of capture and tagging on postrelease behaviour is typically limited to short-term deployments. To investigate both immediate and longer-term behavioural responses, we deployed eight Cefas G7 tags (1Hz depth and temperature, and 20 Hz triaxial acceleration) for 21 - 94 hours and MiniPATs (depth, temperature, light and triaxial acceleration, each at 0.2 Hz) for 110 - 366 days on Atlantic bluefin tuna (ABT) in the English Channel. Post-release, ABT exhibited a highly active initial swimming response, aligning with previous pelagic fish tracking studies. Accelerometry tags revealed that activity (VeDBA), tailbeat amplitude and dominant strokefrequency were 2.4, 3.2 and 1.4 times greater respectively in the first hour post-release than the subsequent 24 hours, stabilising at lower levels within 5 - 9 hours. Long-term MiniPATs data revealed reduced activity for 11 ± 7.9 days (range: 2-26 days), with disrupted diel patterns of activity and fewer burst energy events (5 min/day vs. 14 min/day during “recovery” periods). Subsequently, activity levels stabilised, with increased high-magnitude acceleration events (potential feeding) and became more active during the day than at night. Year-long deployments revealed that consistent diel vertical migration, diurnal patterns of activity, and increased time allocation to fast starts are typical for ABT off the British Isles in summer months, and their absence at the start of data collection may be related to the effect of capture and tagging, which may be longer lasting, and more complex than previously appreciated.

A11.10 THE SCALED SARDINE’S UNIQUE METABOLIC PHENOTYPE AND ITS IMPLICATIONS FOR THE SUSCEPTIBILITY OF SMALL TROPICAL PELAGIC FISHES TO CLIMATE CHANGE

Wednesday 9th July 2025 16:15

Anthony K Gamperl (Memorial University of Newfoundland and Labrador, Canada), Emma S. Porter (Memorial University of Newfoundland and Labrador, Canada), Amy B Brooks (Island School, Bahamas)

kgamperl@mun.ca

Small pelagic fishes (sardines, anchovies and their relatives) are preyed upon by many fishes, birds and mammals, and thus, are key species in marine food webs and with respect to ecosystem health and productivity. However, nearly everything we know about the physiology and environmental tolerances of these ‘forage’ fishes is limited to temperate sardines and anchovies that live at < 20o C, and data suggest that tropical fishes may already be living close to their upper temperature limits. Such information is critical to predicting how these fishes may be impacted by climate change and in implementing effective conservation strategies. As a first step, we determined the maximum swimming speed, aerobic capacity [maximum metabolic rate (MMR) and aerobic scope (AS)] and cost of transport (COT; energy required to swim a given distance) of scaled sardines (Harengula jaguana) collected in Eleuthera (The Bahamas) at 27o C. The scaled sardine’s critical swimming speed (Ucrit ) was ~ 5-6 body length’s per second, and this agrees with data collected on free-swimming schools of similar fishes in the wild. However, they had unexpectedly high values for MMR (4570 mg O2 kg-1 hr-1 ) and AS (3446 mg O2 kg1 hr-1 ) (~ 25 and 70% greater than tuna, respectively, when mass and temperature corrected), and for minimum COT (2246 mg O2 kg1 km-1 ). These findings have important implications with regard to how these ecologically important fishes will potentially respond to climate change-related challenges such as increased temperature and decreases in the biomass and size of plankton upon which they feed.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A11.11 ATLANTIC BLUEFIN TUNA BEHAVIOURAL PLASTICITY FOLLOWING MARINE HEAT WAVE

Daphne Cortese (MARBEC, France), Davide Thambithurai (MARBEC, France), John F Steffensen (University of Copenhagen, Denmark), Simeon Deguara (AquaBioTech, Malta), Justin Galea (AquaBioTech, Malta), Vincent Kerzerho (LIRMM, France), Asgeir Bjarnason (Star-Oddi LTD, Iceland), Olivier Derridj (MARBEC, France), David J McKenzie (MARBEC, France), Tristan Rouyer (MARBEC, France) daphne.cortese@ifremer.fr

The Atlantic bluefin tuna (ABFT), Thunnus thynnus, is an emblematic large and highly migratory pelagic fish of significant economical importance with physiological specializations for its lifestyle, including partial endothermy and obligate ram ventilation. Its ability to regulate the temperature of specific body parts (brain, viscera, and red muscle) enables long-distance migrations and access to relatively deep and cold waters. However, its capacity to cope with increased temperatures is an important aspect to consider in the current climate change and, to our knowledge, has yet to be demonstrated in experimental settings and in semi-wild environments. We used high-resolution acoustic telemetry and heart rate biologgers to follow movements and cardiac activity of twenty individuals (mass range: 25 to 200 kg) over the course of a year in a sea-pen (50m diameter and 30m depth) off the coast of Malta, Mediterranean Sea. During this period, in the summer 2023, a heat wave occurred with surface sea temperature reaching 31˚C. Preliminary results suggest behavioural plasticity, with the fish limiting their time in areas where temperature reached or exceeded 26°C. These findings may have major implications for ABFT migratory behaviours under both current and future climate conditions, with important consequences for the management and conservation of this highly exploited and socioeconomically important species.

A11.12 SPONTANEOUS SWIMMING ACTIVITY OF ATLANTIC BLUEFIN TUNA (ABFT) IN CAPTIVITY ACROSS FOUR SIZE CLASSES

Davide Thambithurai (IRD, France), Daphne Cortese (IFREMER, France), John F Steffensen (University of Copenhagen, Denmark), Patricia R Barón (Instituto Español de Oceanografía, Spain), Aurelio Ortega (Instituto Español de Oceanografía, Spain), Fernando De la Gándara (Instituto Español de Oceanografía, Spain), Tristan Rouyer (IFREMER, France), David J McKenzie (CNRS, France)

davide.thambithurai@glasgow.ac.uk

The Atlantic bluefin tuna (Thunnus thynnus, ABFT) is a large pelagic fish with a complex life history. Despite its ecological and commercial

significance, its physiology remains poorly understood, partly due to the challenges of studying it in the wild. Migration is central to ABFT ecology, making it crucial to quantify spontaneous swimming capacity and its response to environmental factors like oxygen availability. This study examines spontaneous swimming behavior in captive ABFT across four size classes (20–15 cm, 25–35 cm, 40–100 cm, and ~150–200 cm). Using a custom-built stereo-camera system with two GoPro 9 Black cameras, we recorded fish movements in tanks of varying depths (4 m, 6 m, and 10 m) under normoxic and hyperoxic conditions. Video analysis with VidSync extracted data on acceleration, speed, and body size. We hypothesize that spontaneous swimming speed decreases under hyperoxia due to reduced ram ventilation demand. Understanding these behavioral responses across size classes provides insight into ABFT locomotion and the effects of oxygen fluctuations on movement ecology. These findings help bridge key knowledge gaps regarding how environmental changes may impact ABFT activity and migration.

A11.13 MAPPING BLUEFIN TUNA AND KILLER WHALE SPATIAL OVERLAP FOR CONSERVATION INSIGHTS: AN ECOLOGICAL NICHE MODEL APPROACH

Katie Anna Dunmore (University of Exeter, United Kingdom), Francis C T Binney (Government of Jersey Marine Resources, Jersey), Samantha Birch (Centre for Environment Fisheries and Aquaculture, United Kingdom), Barbara A Block (Department of Oceans, United States), Bruno Diaz-Lopez (Bottlenose Dolphin Research Institute, Spain), Owen M Exeter (Centre for Ecology and Conservation, United Kingdom), Francesco Garzon (Environment and Sustainability Institute, United Kingdom), Lucy A Hawkes (Environment and Sustainability Institute, United Kingdom), Thomas W Horton (Environment and Sustainability Institute and Centre for Ecology and Conservation, United Kingdom), Jeroen Van der Kooij (Centre for Environment Fisheries and Aquaculture, United Kingdom), Severine Methion (Bottlenose Dolphin Research Institute, Spain), Alex Plaster (Government of Jersey Marine Resources, Jersey), David Righton (Centre for Environment Fisheries and Aquaculture and School of Environmental Sciences, United Kingdom)

kd490@exeter.ac.uk

In the Strait of Gibraltar, a population of killer whales (Orcinus orca) is critically endangered due to limited food resources but is thought to specialise on bluefin tuna. The fishing of bluefin tuna (Thunnus thynnus) has occurred for centuries, but recent decades of overfishing led to a population crash. Although management efforts have helped the stock recover, actions prioritised tuna stock recovery alone, overlooking ripple effects on the ecosystem such as effects to predators who suffered from limited food. This study aims to inform recovery of this killer whale population by identifying areas of killer whale interaction with bluefin tuna or potential hunting grounds. Seasonal ensemble ecological niche models were developed for both tuna and killer whales, predicting habitat suitability using presence data and correlating environmental factors. Habitat suitability overlap differed throughout seasons. Winter had the lowest overlap index (0.41) and smallest area of overlap, whereas summer had the highest overlap index (0.76) and largest area of overlap. Overlap areas in the summer were largely focused in the Bay of Biscay and along the Portuguese coast. Further, fishing data were overlaid with these areas to explore how commercial fishing may compete with killer whales for

tuna. Understanding the relationship between tuna and killer whales allows for better-informed decisions that consider ecosystem health.

A11.14 OCEAN MIGRATION BEHAVIOUR OF CHUM SALMON IN THE SUMMER BERING SEA USING POP-UP SATELLITE ARCHIVAL TAG

Takaaki K. Abe (Nihon University, Japan), Kentaro Honda (Fisheries Resources Institute Japan Fisheries Research and Education Agency, Japan), Satoki Oba (Atmosphere and Ocean Research Institute the University of Tokyo, Japan), Tomoki Sato (Fisheries Resources Institute Japan Fisheries Research and Education Agency, Japan), Yuki Iino (Fisheries Resources Institute Japan Fisheries Research and Education Agency, Japan), Yuya Makiguchi (College of Bioresource Science Nihon University, Japan), Takashi Kitagawa (Graduate School of Frontier Sciences the University of Tokyo, Japan)

t.abe.hpa@gmail.com

Pacific salmonids are anadromous and generally migrate to the Bering Sea in summer to forage. Chum salmon (Oncorhynchus keta), one of the most abundant Pacific salmonids in the summer Bering Sea, spends a significant portion of its life at sea. However, due to its migratory nature, little is known about its foraging migration ecology. This study investigated the open-ocean migratory behavior of chum salmon using satellite pop-up archival tags (PSATs). A chum salmon, captured in the central Bering Sea (56.0°N, 175.0°W) on 30th July 2024, was tagged with a PSAT (miniPAT-348) and released. The PSAT surfaced as scheduled 75 days later in the North Pacific Ocean near the waters off Amchitka Island, Aleutians (50.8°N, 179.3°E). Over the next seven days, the PSAT transmitted depth, water temperature, and activity data, with 50.4% of the recorded data successfully retrieved. From 60 days after release until three days before surfacing, the PSAT recorded sea surface temperatures above 20 °C, suggesting predation by an endothermic fish. The estimated migration path, excluding the predation period, indicated a generally southward movement from the release site but remained in the Bering Sea. The salmon primarily used the surface (above 20 m) but occasionally dived below the thermocline (below 40 m). The fish did not exhibit diel vertical movement; however, it tended to increased activity around sunrise and sunset. This study provides insights for the open-ocean migratory behaviour of chum salmon but further study is required to explore this in more detail.

A12: BIOTIC INTERACTIONS IN FRESHWATER ECOSYSTEMS UNDER ANTHROPOGENIC ENVIRONMENTAL CHANGE

ORGANISED BY: NEDIM TÜZÜN (LEIBNIZ INSTITUTE OF FRESHWATER ECOLOGY AND INLAND FISHERIES (IGB)), SARAH HASNAIN (HACETTEPE UNIVERSITY)

A12.6 EVOLUTION, BIOTIC INTERACTIONS AND THE MAGNITUDE OF ENVIRONMENTAL CHANGE: DOES IT MATTER FOR COMMUNITY DYNAMICS?

Friday 11th July 2025 09:30

Lynn Govaert (IGB Berlin, Germany)

lynn.govaert@igb-berlin.de

Humans are drastically altering environments and changing selection pressure on many species’ populations. A large amount of literature shows rapid trait responses of species’ populations and shifts in community composition to these altered environments. However, how trait responses to environmental change affect biotic interactions, which in turn can alter the trait response to the environmental change remains unclear. While a recent study suggests that stressful environments can decouple the interaction between density and trait dynamics of two competing freshwater species, it is unclear how such interactions play out within a community of multiple species. Here, we address this question by using a pool of 6 distinct protozoan species and creating random single-, two-and four-species combinations. These combinations were then subjected to three environmental change scenarios: no, slow and fast salinity increase. By recording the trait and density dynamics of each species, we can track how the magnitude and speed of environmental change induces trait responses in all species and how this affects the density dynamics of each species.

A12.7 INDIRECT EFFECTS OF WARMINGINDUCED BODY SIZE REDUCTIONS VERSUS DIRECT KINETIC EFFECTS OF WARMING: IMPLICATIONS FOR POPULATION AND COMMUNITY RESPONSES TO CHANGING CLIMATE

Friday 11th July 2025 10:00

David Boukal (Faculty of Science University of South Bohemia, Czech Republic), Samuel Dijoux (Ifremer UMR MARBEC Montpellier University, France), Arnaud Sentis (INRAE Aix Marseille University, France), Robby Stoks (KU Leuven, Belgium)

dboukal@prf.jcu.cz

Warming affects a range of individual traits in aquatic ectotherms, with cascading effects on species interactions and community structure and dynamics. In addition to the direct kinetic effects of temperature, warming often leads to a smaller body size, which indirectly affects individual life history, population dynamics and species interactions. We provide a framework to study the effects of warming-induced changes in body size at multiple levels of biological organisation and use a tri-trophic food chain model with size-and temperature-dependent vital rates and species interaction strengths to explore the role of direct kinetic effects of temperature and warming-induced smaller body sizes on community structure along resource productivity and temperature gradients. We find that community structure, including the propensity for sudden collapse along environmental gradients, is primarily driven by the direct kinetic effects of temperature on vital rates and thermal mismatches between the consumer and predator species, overshadowing the effects mediated by shrinking body sizes. Overall, our study shows that warming-induced reductions in body size modulate population- and community-level responses to warming and emphasises the need for robust data on the temperature dependence of basic processes, such as body growth, to make more accurate predictions about the future impact of global change on communities and ecosystems.

A12.8 VARIATION IN BEHAVIOUR OF NATIVE PREY MEDIATES THE IMPACT OF AN INVASIVE SPECIES ON PLANKTON COMMUNITIES

Friday 11th July 2025 10:15

Sarah S Hasnain (Institut de la Mer de Villefranche, France), Shelley E Arnott (Queen’s University, Canada)

sarah.s.hasnain@gmail.com

Trait variation in predator populations can influence the outcome of predator-prey dynamics, with consequences for trophic dynamics and ecosystem functioning. However, the influence of prey trait variation on the impacts of predators is not well understood, especially for introduced predators where variation in prey can shape invasion outcomes. In this study, we investigated if intra-specific differences in vertical position of Daphnia influenced the impacts of the invasive zooplankton predator, Bythotrephes cederströmii, on plankton communities. Our results show that vertical position of Daphnia influenced Bythotrephes predation on smaller cladoceran species and impacts on primary production. Larger reductions in small cladoceran density and greater algal biomass were observed in mesocosms with less spatial overlap between Daphnia and Bythotrephes. These results suggest that differences in vertical position of Daphnia can alter the type and magnitude of Bythotrephes impacts in invaded systems.

A12.9 WHO GETS HOOKED? PHENOTYPIC DIVERGENCE OF TASMANIA’S MOST POPULAR RECREATIONAL FISH

Friday 11th July 2025 10:30

Harriet R Goodrich (Institute for Marine and Antarctic Studies, Australia), Finlay Rossiter-Hill (Institute for Marine and Antarctic Studies, Australia), Rachel Breslin (Institute for Marine and Antarctic Studies, Australia), Asta Audjizontje (Institute for Marine and Antarctic Studies, Australia), Barrett Wolfe (Institute for Marine and Antarctic Studies, Australia), Sean Tracey (Institute for Marine and Antarctic Studies, Australia)

harriet.goodrich@utas.edu.au

The sand flathead (Platycephalus bassensis) is the most popular recreational species in lutruwita’s (Tasmania’s) recreational fishery, targeted by 70% of the state’s 106,000 recreational fishers each year. Interestingly, some populations of sand flathead are now classified as depleted, with notable regional differences in growth rates, size-atage, and maturation between lightly fished northern, and more heavily fished southern regions. This disparity raises concerns about the longterm sustainability of sand flathead populations and the potential for fishing-induced changes to life history and physiological traits. To investigate potential phenotypic divergence between regions, we assessed boldness, metabolic rate, thermal tolerance, plasticity, and size-at-age in fish from remote northern locations like Flinders Island, and more densely populated, heavily fished southern locations such as the D’Entrecasteaux Channel. Our findings reveal divergent energy allocation strategies between regions and differing responses to acute and chronic temperature exposure. In high-pressure environments, fish exhibit energetically costly traits, such as a 62% higher standard metabolic rate (SMR) and increased metabolic plasticity, which may enhance survival in dynamic or disturbed conditions or align with the evolution of a fast-paced life history. Conversely, in low-pressure areas, fish display energy-efficient strategies, including a reduced SMR which may prioritise growth and reproduction at larger sizes. These results have important implications for fisheries management and conservation and emphasise the need to assess phenotypes in exploited wild populations, where trait expression will be influenced by the interactive effects of fishing pressure and the regional environment.

A12.10 DISENTANGLING EVOLUTIONARY AND PLASTIC RESPONSES TO OVERFISHING OF MALAWI CICHLID FISH IN A COMMON GARDEN EXPERIMENT

Friday 11th July 2025 10:45

Alex Hooft van Huysduynen (University of Antwerpen, Belgium), Wilson Sawasawa (University of Antwerpen, Belgium), Hannes Svardal (University of Antwerpen, Belgium), Gudrun De Boeck (University of Antwerpen, Belgium)

alex.hooftvanhuysduynen@uantwerpen.be

Over-fishing is a consequential anthropogenic driver of demographic and phenotypic changes in aquatic fish populations. In Lake Malombe, Malawi, over the past 40 years, intense fishing pressure has led to local extinctions, dramatic population declines, and rapid life history shifts in several commercially important benthic cichlid species. In some of these species, size at maturation has decreased by approximately 50% within only 20 generations, suggesting a strong effect of either fisheries-induced evolution or phenotypic plasticity in response to human induced harvest pressure. To disentangle the genetic and plastic components of this life history shift, we conducted a common garden experiment using offspring from populations experiencing contrasting fishing pressures. Juveniles from heavily fished and weakly fished populations were reared under standardised laboratory conditions to control for environmental effects and isolate genetic differences. We observed an accelerated growth, earlier maturation, but reduced reproductive investment in offspring from heavily fished populations, consistent with a rapid evolutionary responses to fisheries pressure. Importantly, because of the non-size selective fisheries in Lake Malombe these shifts in life history traits are driven by biotic interactions such as competition for mates and reproductive opportunities, with smaller, faster-maturing individuals potentially gaining an advantage in heavily fished populations. This work and evolutionary genomic investigations we have carried out highlight how human-induced pressures reshape the genetic determination of life history strategies, with cascading consequences for intra- and interspecific interactions, population stability, and the long-term resilience of biodiversity hotspots like Lake Malawi.

A12.11 THE BRIGHT SIDE OF CHYTRID

FUNGAL PARASITES ON STABILISING BIODIVERSITY AND ECOSYSTEM

FUNCTIONING AT THE PHYTOPLANKTONZOOPLANKTON INTERFACE UNDER HUMAN-INDUCED PRESSURE

Friday 11th July 2025 11:30

Andras Abonyi (HUN-REN Centre for Ecological Research, Hungary)

abonyiand@gmail.com

Classical pelagic food web ecology has traditionally viewed the phytoplankton-zooplankton interface as a two-way interaction: phytoplankton provide energy and essential molecules for zooplankton, while zooplankton regulate phytoplankton through

grazing. Diverse phytoplankton communities enhance ecosystem functioning by improving resource use efficiency, primary production, and dietary quality through key molecules like polyunsaturated fatty acids (PUFAs). However, human-induced pressures such as global warming and eutrophication often promote filamentous or gelatinous cyanobacteria that are less edible and low in PUFA content, thereby constraining the trophic interface. Parasitic chytrids, an intermediate functional group, occupy this interface by channeling energy to zooplankton through small, nutritious zoospores—a process known as the “mycoloop”—and by fragmenting inedible cyanobacteria into more ingestible particles. In my talk, I will highlight three ways chytrids mitigate the negative impacts of eutrophication and warming.

First, chytrid infection upgrades cyanobacterial carbon quality and enhances PUFA availability, thereby boosting Daphnia fitness. Second, under experimental warming (+6°C), chytridinfected cyanobacteria alleviate detrimental effects on Daphnia’s survival, growth, and reproduction compared to uninfected diets. Third, chytrids may enforce “kill-the-winner” dynamics by selectively infecting dominant, inedible cyanobacteria, promoting a more diverse, edible phytoplankton community that ensures the flow of essential molecules to higher trophic levels. Although human-induced pressures often constrain pelagic food webs, chytrids may be crucial in buffering essential dietary molecules at the phytoplankton-zooplankton interface, particularly during cyanobacteria blooms. Providing multiple ways for “insurance” against the negative impacts of eutrophication and climate change, chytrids may act as potential stabilisers for pelagic ecosystem functioning.

A12.12 LIGHT POLLUTION SHAPES INTERACTION BETWEEN A PARASITIC FLATWORM AND THE WATER FLEA DAPHNIA MAGNA

Friday 11th July 2025 12:00

Nedim Tüzün (IGB Berlin, Germany), Franz Hölker (IGB Berlin, Germany), Luc De Meester (IGB Berlin KU Leuven, Belgium)

nedim.tuezuen@igb-berlin.de

Artificial light at night (ALAN) can strongly alter organismal traits, but its role in shaping species interactions remains poorly understood, especially so in aquatic ecosystems. By capitalizing on a recently discovered antagonistic interaction between a brood-parasitic flatworm and Daphnia magna water fleas, we tested whether this interaction depends on exposure to ALAN. During a 19-day laboratory population growth experiment, we manipulated flatworm presence and nighttime light conditions in a full-factorial design. We confirmed the negative effects of flatworm predation on Daphnia abundance at the population level. Importantly, we showed that the flatwormcaused decrease in Daphnia abundance under ALAN (81%) was twice as strong compared to dark-night conditions (39%). Our findings are relevant for assessing the impact of ALAN on the development of Daphnia populations and thus top-down control of phytoplankton. Freshwater ecosystems in urbanized areas, where this parasitic interaction was first encountered, may be especially at risk, as these are typically exposed to high levels of stress factors, including light pollution.

A12.13 ECO-EVOLUTIONARY DYNAMICS IN THE COMMUNITY ASSEMBLY OF DAPHNIA GUT MICROBIOME

Friday 11th July 2025 12:15

Aditi Gurung (KU Leuven, Belgium), Caroline Souffreau (KU Leuven, Belgium), Shinjini Mukherjee (KU Leuven, Belgium), Ellen Decaestecker (KU Leuven, Belgium), Luc De Meester (KU Leuven, Belgium)

aditi.gurung@kuleuven.be

Ecology and evolutionary processes can occur at the same time scale and mutually influence each other. The interaction of these processes, termed eco-evolutionary dynamics has gained significant momentum in the past years integrating theoretical models, conceptual frameworks, proof of principle experiments and genomic insights. In this study, we focus on integrating the microbiome into the framework of eco-evolutionary dynamics to examine the extent to which such feedbacks impact the gut microbiome and in turn influence individual host fitness, using the freshwater cladoceran, Daphnia as our model system. More specifically, we focus on one of these processes, namely, priority effects, i.e., the influence of species arrival order and timing on community assembly and their role in structuring the gut microbiome. Furthermore, we extend our study to investigate these processes scaled up to the zooplankton community level and test whether such priority effects impact the assembly of these communities and to what extent they are microbiome mediated. Overall, our results highlight the relative importance of these simple yet significant processes such as the arrival order and timing of colonization in the achievement of the final gut community composition and broader zooplankton community assembly dynamics.

A12.14

THE GUT MICROBIOME SHAPES LATITUDINAL DIFFERENCES

IN HOST IMMUNITY AND PATHOGEN

LOAD, AND BUFFERS AGAINST IMMUNOSUPPRESSION UNDER FUTURE WARMING

Friday 11th July 2025

12:30

Charlottte Theys (KU Leuven, Belgium), Sarah Jorissen (KU Leuven, Belgium), Lizanne Janssens (KU Leuven, Belgium), Nedim Tüzün (IGB, Germany), Ellen Decaestecker (KU Leuven, Belgium), Julie Verheyen (KU Leuven, Belgium), Robby Stoks (KU Leuven, Belgium)

theys.charlotte@kuleuven.be

Latitudinal patterns in fitness-related traits within species are getting increased attention as these inform how high-latitude populations may evolve in response to global warming. The underlying mechanisms for these latitudinal trait patterns remain poorly understood, and recently the gut microbiome has been suggested to be a potentially important proximate driver of these patterns. We investigated the novel idea whether the gut microbiome drives differences in immune function and pathogen load between slow-paced, Southern Swedish, highlatitude and fast-paced, Southern French, low-latitude populations of Ischnura elegans damselflies. A reciprocal gut microbiome transplant

was performed between high- and low-latitude larvae, at both a colder and warmer thermal regime, whereafter larvae were exposed to Escherichia coli , a pathogen naturally found in aquatic ecosystems. During the experiment, larval mortality, growth rate, phenoloxidase level (a measure of immune function), E. coli burden (a measure of pathogen load), and the gut microbiome diversity (β-diversity) and community compositions (β-diversity) were analysed. Exposure to the pathogen increased mortality, especially under warming. Our results confirmed latitude-associated thermal adaptation and a faster paceof-life of the low-latitude larvae, and revealed this to be associated with a lower immune function and higher pathogen load. Moreover, our results provided the first experimental evidence that the gut microbiome causally contributed to latitudinal differences in the host’s immune function and pathogen load. Taking into account how the gut microbiome shapes latitudinal patterns in fitness-related traits will deepen our understanding of the evolution of host populations under warming.

A12.15 ADAPTATION-MEDIATED IMPACTS OF A PESTICIDE SWITCH ON A NON-TARGET SPECIES, DAPHNIA MAGNA

Friday 11th July 2025 12:45

Rafaela A. Almeida (KU Leuven, Belgium), Maxime Fajgenblat (KU Leuven, Belgium), Pieter Lemmens (KU Leuven, Belgium), Kiani Cuypers (KU Leuven, Belgium), Jade Maes (KU Leuven, Belgium), Kristien I Brans (Vrije Universiteit Brussel, Belgium), Luc De Meester (KU Leuven, Belgium)

rafaela.almeida@kuleuven.be

Exposure to pesticides can drive adaptation of non-target populations in the vicinity of farms, but may leave resistant individuals more susceptible to new stressors due to fitness costs. Pesticide switches are a common practice in pest management, which results in populations, including non-target ones, being sequentially exposed to different pesticides. Here, we assessed how pre-exposure to one pesticide affected genetic composition and densities of aDaphnia magnapopulation upon exposure to a second pesticide. We used a selection experiment, in which the populations were exposed to a pesticide, and subsequently exposed to a switch in pesticide, either to a different pesticide with an identical mode of action or one with a different mode of action compared to the initial one. Our results show that pre-exposure imposed strong genetic differentiation between pre-exposed and non-exposed populations. Pre-exposure also determined the demographic response of the populations, and the direction of the impact was linked to the mode of action of the pesticides, with pre-exposed population performing better when subsequently exposed to pesticides with a similar mode of action, but reaching lower densities when exposed to pesticides with differing modes of action. These results highlight that frequent switches in pesticides impose negative evolutionary and ecological effects on non-target populations, leaving them more vulnerable to scenarios of global change.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A12.1 A SIGNIFICANT FUNCTIONAL ANALYSIS REVEALED THE HAZARD CAUSED BY THE APPARENTLY LOW LEVEL OF SEPM CONTAMINATION

Cleo A C Leite (UFSCar, Brazil), Carolina F De Angelis (UFSCar, Brazil), Michelly P Soares (UFSCar, Brazil), Israel L Cardoso (UFSCar, Brazil), Marisa N Fernandes (UFSCar, Brazil)

cleo.leite@ufscar.br

This study investigated the impact of settleable atmospheric particulate matter (SePM) from metallurgic activities on Nile tilapia (Oreochromis niloticus), focusing on gill morphofunctional changes and aerobic capacities. SePM, a source of air-to-water cross-contamination, has been shown to cause sublethal effects on aquatic biota, with traditional ecotoxicological biomarkers potentially underestimating its impact. Fish were exposed to SePM (96h) and submitted to swimming trials and hypoxia to analyze their capacity to overcome common ecological challenges. SePM significantly reduced resting metabolic rate (-28%) and aerobic scope (-29%), Ucrit (-40%), and maximum swimming efficiency (-40%). Furthermore, it reduced gill ventilatory volume (-21%) and increased oxygen extraction (+32%). The alterations limited the response to hypoxia increasing critical oxygen tension (+23.5%). Moreover, SePM increased epithelial filament thickness (+11%) and reduced distance between lamellae (-30%). After swimming, exposed fish had a 40% reduction in epithelial filament thickness, a 37% increase in distance between lamellae, a 20% increase in lamellar height, and other morphofunctional alterations. Additionally, there was substantial plasmatic Na+ and Cl- reduction (-9% and -18%) and an increase in plasmatic K+. These structural and ionoregulatory alterations compromised whole-body maintenance, leading to 30% lethality after swimming. The findings highlight SePM severe ecological impact, impairing fish performance, gill plasticity, and ion balance, potentially reducing the fitness of natural fish populations. This study underscores the silent threat of SePM contamination and its role in sudden fish mortality events, emphasizing the need for physiological assessments to evaluate ecological risks.

A12.2 THERMAL STRESS AND SPIDER PREDATION: CASCADING EFFECTS ON ARTHROPOD COMMUNITIES

Assya Lamaizi (Faculty of sciences Ben M’sik Casablanca, Morocco), Zineb AGOURRAM (Faculty of sciences Ben M’sik Casablanca, Morocco), Nouhaila EL FENNI (Faculty of sciences Ben M’sik Casablanca, Morocco), Anass KETTANI (Faculty of sciences Ben M’sik Casablanca, Morocco), Mouad MKAMEL (Faculty of sciences Ben M’sik Casablanca, Morocco) contact@mkamelmouad.com

Rising global temperatures, driven by climate change, are predicted to significantly impact ecosystems. This study investigates the effects of increased thermal stress on Hogna maroccana, an endemic Moroccan wolf spider, focusing on predatory behavior and venom characteristics. Adult spiders were collected from a natural population and maintained under controlled conditions, subjected to either 25°C (control) or 38°C (high-temperature, simulating regional climate change). Venom was extracted and tested on crickets using time-to-paralysis assays and LD50 determination. The time-to-paralysis was significantly shorter, and the LD50 significantly lower, for venom from 38°C-exposed spiders, indicating a faster-acting and more potent venom. SDSPAGE electrophoresis revealed distinct venom protein banding patterns, implying temperature-driven shifts in venom composition. Predation experiments showed spiders exposed to 38°C consumed significantly more crickets within 24 hours compared to controls. These findings indicate that anthropogenic warming enhances H. maroccana’s predatory efficiency, potentially disrupting arthropod community structure. The increased predation pressure could lead to reduced prey populations, altering competitive dynamics among arthropods and impacting ecosystem-level processes like nutrient cycling. Future research should examine the longterm eco-evolutionary consequences of these changes, including multigenerational experiments to assess adaptation potential and investigate the genetic mechanisms underlying altered venom and behavior.

Keywords: Hogna maroccana, climate change, thermal stress, predatory behavior, arthropod communities, biotic interactions, ecosystem functioning, Moroccan spiders, adaptation.

A12.3 HIGHER PREDATION PRESSURE IN AQUATIC INSECT LARVAE UNDER ARTIFICIAL LIGHT AT NIGHT

Joana M. S. Carmo (CESAM Department of Biology University of Aveiro, Portugal), Robby Stoks (Laboratory of Evolutionary Stress Ecology and Ecotoxicology University of Leuven, Belgium), João L. T. Pestana (CESAM Department of Biology University of Aveiro, Portugal)

joana.m.s.carmo@ua.pt

Artificial light at night (ALAN) is an emerging stressor affecting the physiology, behaviour and ecology of aquatic organisms and ecosystems. Although biological effects of ALAN in many species have been documented, there are still few studies that test for its consequences on predator-prey interactions. Here, laboratory settings were used to evaluate effects of ALAN exposure (10 lux during nighttime) on Chironomus riparius larvae mortality and growth when in the presence of a fish predator. One male adult zebrafish (Danio rerio) was added to each aquarium containing 100 4th stage C. riparius larvae (in 3.5 L of ASTM water and 3 cm layer of sediment). Fish were added to aquaria during nighttime for 4 consecutive nights. For each treatment, eight aquaria were used (three control aquaria without fish and five with fish). After 5 days remaining larvae were collected and measured. Results show that predation increased under ALAN (58% vs 38% larvae mortality due to predation in ALAN vs. control dark night treatment). C. riparius larvae grew slightly less in aquaria with fish with no significant effects induced by ALAN suggesting increased prey mortality due to predator feeding behaviour or prey increased activity during nighttime. Current work is investigating if ALAN alters C. riparius life-history responses under fish predation risk (tested using zebrafish kairomones). These preliminary results provide evidence that ALAN can increase the mortality of aquatic insect larvae

due to predation with possible consequences for population dynamics calling for more research on the effects of light pollution on species interactions.

A12.4 DOES LIGHT POLLUTION CHANGE DAPHNIA MAGNA RESPONSES TO PERCEIVED PREDATION RISK?

Bruna S. Silva (CESAM Department of Biology University of Aveiro, Portugal), Marta Vasconcelos (Department of Biology University of Aveiro, Portugal), Amadeu M.V.M Soares (CESAM Department of Biology University of Aveiro, Portugal), João L.T. Pestana (CESAM Department of Biology University of Aveiro, Portugal)

bruna.ssilva@ua.pt

Artificial light at night (ALAN) is a widespread anthropogenic pollutant that can negatively affect biodiversity organisms’ physiology and lifehistory responses but also behavioural patterns, promoting changes on migration, feeding, and potentially changing the outcome of predator-prey interactions. Since trait-mediated effects are wellknown to play a key role in population dynamics it is important to assess if ALAN exposure can increase the costs or impair inducible antipredator defences leading to maladaptive responses in prey populations. Here, we tested if exposure to ALAN (10 lux during night-time, simulated using white LED lamps) altered the life-history responses of Daphnia magna to perceived predation risk (simulated using kairomones from zebrafish). Our results showed that ALAN did not change daphnia’s life-history responses and inducible defences to fish predation pressure (earlier reproduction, increased brood size, smaller neonates, and reduced size at maturity) and thus we found no clear suggestion that light pollution could induce maladaptive responses under fish predation pressure. Ongoing work is assessing daphnia’s feeding behaviour to complement these results. Effects of ALAN on both prey and predators’ behaviour should also be asssessed to better predict viability of Daphnia natural populations in urban ecosystems commonly affected by light pollution.

A12.5 ARTIFICIAL LIGHT AT NIGHT (ALAN) AND COLLECTIVE GROOMING IN AQUATIC ARTHROPODS: AN ECOPHYSIOLOGICAL PERSPECTIVE

Farhan Jamil (Ethophilia Research Foundation, India), Chayan Munshi (Ethophilia Research Foundation, India)

chayanbio@gmail.com

Artificial Light at Night (ALAN) is an emerging anthropogenic issue showing significant impact on the ecosystem and residing biodiversity. Despite being a passive biohazard, ALAN actively disrupts critical ecological and physiological processes, including alteration in robust behavioural patterns. With the notion of grooming behaviour as the index of neurological stress, we have designed our study to focus on the collective grooming pattern in a prawn, Macrobrachium lamarrei, to understand the adverse effect of ALAN on the said organism. Our experimentations aimed to assess the how prolonged intense night light (LED light) modulate the collective or population-based grooming patterns, in a time kinetic manner. Findings elucidated that

ALAN insult can induce notable upliftment in the collective grooming activity after 4th day prolonged light exposure, in comparison to the normal light-dark cycle. The analysis of the adaptive process in these organisms in response to different intensities (low to high) of ALAN exposure. We are trying to establish the change in the collective grooming bouts is a comparatively new concept of population-based neuroethological or ecophysiological stress in animals, where we have emphasized the broader impacts of anthropogenic environmental impact on freshwater inhabitants. We believe that Macrobrachium lamarrei can be indicator species to evaluate the light pollution in aquatic ecosystem, where artificial illumination continues to increase in natural and seminatural areas, compromising ecological stability.

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A13: THE ENVIRONMENTAL CAUSES AND CONSEQUENCES FOR OFFSPRING OF PARENTAL EFFECTS

ORGANISED BY: JOSE C. NOGUERA (UNIVERSITY OF VIGO), TIM BURTON (NORWEGIAN INSTITUTE FOR NATURE RESEARCH), NEIL B. METCALFE (UNIVERSITY OF GLASGOW)

A13.2 THE CONSEQUENCES OF LATELIFE REPRODUCTION: OFFSPRING FROM OLD-AGED PARENTS MAY SHIFT TO A FAST PACE-OF-LIFE

Tuesday 8th July 2025 09:00

Lisa NS Shama (Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research Wadden Sea Station, Germany)

Lisa.Shama@awi.de

Parental exposure to environmental stressors can lead to transgenerational plasticity (TGP), whereby offspring phenotypes are shaped by non-genetic factors inherited from stressed parents. Identifying mechanisms underlying TGP is important for predicting potential consequences for populations facing rapid climate change. Using common garden experiments, we investigated the influence of parental exposure to ocean warming (+1.5°C and +4°C), increased temperature variation and marine heatwaves (MHWs) on stickleback (Gasterosteus aculeatus) offspring phenotypic variation. We consistently found that exposure to +4°C had negative effects on offspring growth (smaller fish) compared to ambient conditions. Yet, offspring of mothers acclimated to +4°C reached larger sizes at +4°C via TGP, with optimised mitochondrial metabolism and gene expression inherited from mothers underlying transgenerational benefits. Comparing transcriptomes of parents (eggs/sperm) and embryos across development showed that massive changes to the epigenetic landscape occurred at +1.5°C in the blastula stage, potentially reflecting a key “window of opportunity” for adaptive epigenetic responses to ocean warming. Exposing parents to fluctuating environments, however, led to maternal bet hedging (changes to offspring phenotypic variance) and smaller offspring size. When confronted with MHWs, exposure to single, extreme MHWs lowered fecundity, offspring growth and survival, but fish exposed to recurring MHWs grew better (e.g. via thermal hardening) and had higher fecundity, especially if their parents also experienced recurring MHWs, indicating that stress memory to MHWs may also act transgenerationally. Our studies show that stickleback employ multiple strategies to cope with rapidly changing ocean conditions, and that transgenerational benefits may mitigate some of the negative effects.

Tuesday 8th July 2025 09:30

Mark D Pitt (University of Glasgow, United Kingdom), Brendan O’Connor (University of Glasgow, United Kingdom), Timothy Sheen (University of Glasgow, United Kingdom), Davide Dominoni (University of Glasgow, United Kingdom), Jelle Boonekamp (University of Glasgow, United Kingdom) markdavidpitt@gmail.com

Across invertebrates, the offspring of older parents exhibit a tendency for reduced longevity compared to those of younger parents (parental effect senescence). Such a reduction in total lifespan may not impact fitness if shorter-lived individuals can compensate by accelerating development and maximising early-life fecundity. However, whether the offspring can compensate for reduced longevity depends on how parental age affects offspring mortality. If parental effect senescence manifests through increased baseline mortality, then offspring fitness will be constrained from birth. Meanwhile, if parental effect senescence only accelerates the offspring’s age-specific mortality in late life, this could then facilitate the switch to a fast pace-oflife. Here, using individually-housed two-spotted crickets (Gryllus bimaculatus) in a within-individual longitudinal study, we observed that as parental age at reproduction increased, offspring post-natal developmental rates and adult body mass decreased, while adult lifespan increased. Surprisingly, we observed no effect of parental age on offspring total lifespan, with the baseline and age-specific mortality rates being comparable among offspring from young-and old-aged parents. The benign laboratory conditions in which our study population was maintained could have masked any negative effects of parental age on offspring longevity, which may only manifest under certain environments (e.g. with increased competition, pathogens, predation). However, our initial results tentatively suggest that the offspring from old-aged parents’ are shifting towards a fast paceof-life strategy, as evidenced by their accelerated development and reduced body size. Future work will focus on establishing if any parental age effects persist trans-generationally to similarly influence the grand offspring’s life-histories.

A13.3 CRYPTIC INTERGENERATIONAL INBREEDING EFFECTS ON NESTLING

Tuesday 8th July 2025 09:45

Anne Peters (Monash University, Australia), Jennifer Evans (Australian National University, Australia), Justin Eastwood (Monash University, Australia), Niki Teunissen (Monash University, Australia)

anne.peters@monash.edu

Telomere length is an integrated biomarker of lifespan and lifetime reproductive success in purple-crowned fairy-wrens (Malurus coronatus coronatus), including in early life. Telomere length is also known to be sensitive to adverse, hot and dry, climatic conditions during the nestling period. Here, we assess effects of direct (individual) and intergenerational (parental) inbreeding on nestling telomere length. Using high quality telomere measurements in a large long-term dataset from a wild population, we find no direct effect of individual inbreeding on nestling telomere length. This did not change when including hot and dry climatic conditions, alone or in interaction with inbreeding. Contrary to most studies in similar bird species, offspring telomere length was not associated with paternal inbreeding or age, but it was negatively associated with maternal age and maternal inbreeding. This could be due to maternal accumulation of inbreeding and ageing costs within a mother’s lifetime, affecting preand post-natal reproductive investment. The inheritance of shorter telomeres from older and more inbred mothers could be exacerbated by shorter nestling telomere length, delayed breeding, and reduced natal dispersal associated with adverse climatic conditions. Across generations, this could lead to population-level changes in performance and demography. As adverse conditions are predicted to become more common with climate change, understanding the pathways of indirect inbreeding costs and telomere inheritance are particularly important in this Endangered species under threat from habitat decline and climate change.

A13.4 HEAT STRESS SHAPES PARENTAL CARE AND REPRODUCTIVE SUCCESS IN BURYING BEETLES ACROSS CRITICAL LIFE STAGES

Tuesday 8th July 2025 10:00

Tanzil G. Malik (International Degree Program in Climate Change Sustainable Development National Taiwan University, Taiwan), Benjamin J. M. Jarrett (School of Environmental Natural Sciences Bangor University Bangor, United Kingdom), Mu-Tzu Tsai (International Degree Program in Climate Change Sustainable Development National Taiwan University, Taiwan), Syuan-Jyun Sun (International Degree Program in Climate Change Sustainable Development National Taiwan University, Taiwan)

tanzilasi89@gmail.com

Climate change-induced heat waves significantly threaten biodiversity by disrupting critical behaviours, such as parental care, essential for

offspring development and survival. While parental care can buffer offspring against environmental stressors, its components may respond differently to heat stress. In this study, we investigated how elevated temperatures affect parental care and its buffering role in reproductive performance in the burying beetle Nicrophorus nepalensis across critical life stages. Using experimental warming, we tested the effects of mild (20°C) and severe (22°C) heat stress, compared to ambient temperatures (18°C), on pre-hatching care (carcass preparation) and post-hatching care (offspring provisioning). Severe heat stress completely inhibited egg hatching, whereas mild heat stress reduced brood size and offspring weight. Reciprocal experiments, where carcasses prepared under ambient and heatstressed conditions were exchanged between breeding females, revealed that heatwaves affecting only one care period did not significantly alter reproduction. However, when both pre- and posthatching periods were exposed to heat stress, reproductive success declined sharply. Females breeding under heat stress exhibited higher energy expenditure, shown by greater body mass loss during provisioning. Notably, heat stress had long-lasting effects on offspring through carcass preparation, resulting in smaller adult sizes and higher mortality rates. These findings demonstrate that different parental care components respond variably to heat stress, with cascading effects on offspring development. This study highlights the importance of assessing parental care behaviours and their interactions across life stages to better understand species’ vulnerability to rising temperatures.

A13.5 A HEAT WAVE INDUCES COMPENSATORY ACCLIMATION OF PERFORMANCE BUT REDUCES REPRODUCTIVE FITNESS

Tuesday 8th July 2025 10:15

Chandler Tsz To Tsang (The University of Sydney, Australia), Frank Seebacher (The University of Sydney, Australia)

chandlertsang@gmail.com

Understanding how heat stress affects performance and reproductive fitness is essential for predicting the fate of species and populations. Our aim was to test phenotypic and reproductive responses to a heat wave in zebrafish (Danio rerio), and the potential role of DNA methylation in mediating these responses. We exposed wild-type and DNA methyltransferase 3a (DNMT3a) knock-out fish to a control temperature (25°C) and a +5°C heatwave for 28 days. Zebrafish acclimated to compensate swimming performance for warming. After re-acclimation at 25°C, the swimming performance of the heatwave-treated fish returned to pre-warming levels, indicating that thermal acclimation in adults is reversible. DNMT3a knock-out altered responses to heating, identifying DNA methylation as a mechanism underlying acclimation. Heatwave and genotype interacted to reduce the number of fertilised eggs produced (at one-tailed significance). Heating reduced offspring survival in wild-type fish, and survival was further reduced in DNMT3A knock-out fish. Our data show that despite acclimation compensating for heating, there was a reduction in reproductive success. Warming and disruption of DNA methylation by anthropogenic factors therefore can reduce fitness and potentially impact population size.

A13.6 MATERNAL THYROID HORMONES AND TRANSGENERATIONAL PLASTICITY

Tuesday 8th July 2025 14:00

Bin-Yan Hsu (Department of Life Science Tunghai University, Taiwan)

binyanhsu@gmail.com

Given the rapidly changing environment, parental effects are increasingly recognized as influencing offspring phenotype according to environmental conditions. Among the various potential mediators, thyroid hormones (THs) are particularly promising to convey environmental information to the offspring and induce adaptive phenotypic changes, due to their roles in thermoregulation and metabolism. Using the great tit (Parus major), a widely distributed passerine species, as our model system, we combined experimental and modelling approaches to explore the key links necessary for maternal THs to induce transgenerational plasticity. Our results provided statistical evidence for the flexible transfer of maternal THs within females, a prerequisite of environment-dependent allocation. Moreover, across twelve European populations, we observed higher concentrations of THs in egg yolks when the ambient temperature during egg formation was lower, after controlling for latitude. This finding underscores the environmental responsiveness of maternal TH transfer. Experimentally elevation of yolk TH levels, intended to simulate a higher maternal transfer, resulted in enhanced nestling growth but also accelerated telomere shortening. Furthermore, when nest-box temperature was experimentally increased by approximately 2 °C, we observed a quadratic effect of temperature on nestling body mass, as well as a delayed acceleration in telomere shortening. Collectively, these findings suggested that in anticipation of a colder environment, higher maternal TH transfer may prioritize early nestling growth at the cost of faster aging.

A13.7 LIGHTS OUT: TRANSGENERATIONAL EFFECTS OF ARTIFICIAL LIGHT AT NIGHT ON ZEBRAFISH

Tuesday 8th July 2025 14:30

Maria S. Costa (CESAM - Centre for Environmental and Marine Studies University of Aveiro, Portugal), Carla Quintaneiro (CESAM - Centre for Environmental and Marine Studies University of Aveiro, Portugal), Amadeu M.V.M Soares (CESAM - Centre for Environmental and Marine Studies University of Aveiro, Portugal), João L.T. Pestana (CESAM - Centre for Environmental and Marine Studies University of Aveiro, Portugal), Marta S. Monteiro (CESAM - Centre for Environmental and Marine Studies University of Aveiro, Portugal)

mssousacosta@ua.pt

Artificial light at night (ALAN) is an emerging environmental stressor in urban aquatic ecosystems, increasingly co-occurring with chemical pollutants. Light pollution disrupts circadian rhythms in

various organisms, affecting essential biological processes such as reproduction, hormone regulation, and stress responses. However, its long-term and transgenerational effects remain understudied. This study assessed ALAN’s impact on zebrafish (Danio rerio) reproduction and offspring development. Adult zebrafish were exposed to either 0 or 10 lux during the night for 10 weeks, with reproductive output assessed biweekly. Egg viability at 0 and 24 hours was recorded, and F1 embryos were exposed to the same light conditions. Embryo development was monitored for 120 hours post-fertilization (hpf), evaluating mortality, hatching success, malformations, and heart rate at 48 hpf. To assess transgenerational effects, offspring from both exposure groups underwent acute exposure to 3,4-dichloroaniline (3,4-DCA) (0.375–6 mg/L) under control light conditions (0 lux). Results indicate that ALAN-exposed adults laid fewer and lowerquality eggs than controls. Additionally, parental ALAN exposure significantly increased offspring heart rate, regardless of their own light exposure. Offspring from ALAN-exposed parents also exhibited heightened sensitivity to 3,4-DCA, with increased mortality at 1.5 and 3 mg/L. These findings highlight ALAN as a key environmental stressor affecting zebrafish reproduction, development, and transgenerational responses to pollutants. This study underscores the need to integrate light pollution into ecotoxicological risk assessments and consider its ecological implications for aquatic ecosystems.

A13.8 GROWING

UP IN A CROWD - THE EARLY LIFE OF LESSER BLACK-BACKED GULL CHICKS

Tuesday 8th July 2025 14:45

Wendt Müller (University of Antwerp, Belgium), Reyes Salas (University of Antwerp, Belgium), Mélibée Morel (University of Antwerp, Belgium), Frederick Verbruggen (Ghent University, Belgium), Eric Stienen (Research Institute Nature and Forest, Belgium), Luc Lens (Ghent University, Belgium)

wendt.mueller@uantwerpen.be

The social environment during early life can play a pivotal role in the development of the behavioural phenotype. As colonial breeding species experience significant variation in their social environment, with central parts typically showing higher concentrations of territories then peripheral parts, the parental territory choice could have consequences for the their offspring’s behavioural phenotype. To accommodate these effects parents might pre-adjust their offspring via maternal effects to match the post-hatching conditions. We tested in lesser black-backed gulls whether the fact that chicks in dense breeding areas are exposed to more aggression impinges on their movement activity and exploratory behaviour. We crossfostered full clutches between and within high- and low-density parts of the colony, used ultra-wideband tags to track free-ranging chicks, and collected data on the chicks’ exploratory phenotype in an open field test. Post-fledging exploratory movements of juveniles were studied over a 20-day period using GPS tracking. We found that movement activity and exploratory behaviour measured different aspect of the chicks phenotype, but both were affected by the social environment. Chicks reared in denser areas had a lower movement activity, and chicks in high breeding densities were less explorative, which was reinforced by pre-natal maternal effects. When studying exploratory aspects of foraging post-fledging, only habitat preferences were weakly linked to the chicks’ exploratory phenotype pre-fledging. We conclude that offspring adjust their behaviour to their early social environment, facilitated by maternal effects, but the (as yet limited) juvenile data suggest that these effects are not lasting.

A13.9 CAN MITOCHONDRIA FROM OOCYTES SHAPE THE EARLY DEVELOPMENT OF FISH IN A HYPOXIC WORLD?

Tuesday 8th July 2025 15:00

Amélie Crespel (University of Turku, Finland), Alycia Valvandrin (University of Turku, Finland), Mélanie Bouqueau (University of Turku, Finland), Tom Grassin (University of Turku, Finland), Luisa Bermejo Albacete (University of Turku, Finland), Katja Anttila (University of Turku, Finland)

amelie.crespel@utu.fi

Inter-generational effects are effects inherited from the parents to the offspring without modifications of the genome. These effects may either limit or prepare the offspring to survive in its environment. Although not completely understood, many mechanisms may play a role, including maternal provisioning, microbiome transfer, or inheritance of epigenetic markers. While mitochondria, mainly inherited via the oocytes, are also passed down to the next generation, their role in providing a good start in life to the offspring remains overlooked. As the mitochondrial metabolism is essential to sustain aerobic functions, a modification in its capacity is likely to alter how the offspring are able to cope in their early life with environmental changes, especially in hypoxic (i.e. low oxygen) environments. Using wild three-spined sticklebacks (Gasterosteus aculeatus) that have been previously exposed or not to strong hypoxic events, we investigate the mitochondrial functions of oocytes and its impact on the embryo and larvae early development (hatching success, survival) and metabolism (oxygen consumption) under both normoxic and hypoxic conditions. Overall, this research provides new insights on the potential role of mitochondrial function from oocytes in shaping the resilience of early stages offspring to environmental changes, ultimately deepening our understanding of how inter-generational effects may occur to affect the survival and development of future generations in changing environments.

A14 - VULNERABILITY AND ADAPTATIONS OF EARLY LIFE STAGES TO ENVIRONMENTAL STRESSORS

ORGANISED BY: PAT MONAGHAN (UNIVERSITY OF GLASGOW), VALERIA MARASCO (UNIVERSITY OF VETERINARY MEDICINE, VIENNA), ZARA-LOUISE COWAN (UNIVERSITY OF GOTHENBURG), JEREMY DE BONVILLE (UNIVERSITY OF MONTREAL), PATRICE POTTIER (UNIVERSITY OF NEW SOUTH WALES), TIANA KOHLSDORF (UNIVERSITY OF SÃO PAULO)

A14.1 PREGNANCY AS A CRITICAL WINDOW FOR UNDERSTANDING VULNERABILITY AND ADAPTATION TO STRESS: FROM MODELS TO MAGGOTS

Tuesday 8th July 2025 16:00

Sinead English (University of Bristol)

It is widely appreciated that early developmental stages are highly sensitive to environmental stressors, resulting both in immediate impacts (including death) and more pervasive, long-term effects through to adulthood. The extent to which such heightened plasticity reflects adaptive responses or unavoidable vulnerability due to the nature of developmental processes is highly debated and depends on several aspects, including the organism’s life history, type of stressor and patterns of environmental change. Here, I give an overview of our work on maternal responses to stressors in pregnancy (heat, nutrition and infection) from an evolutionary perspective, including developing theoretical models; comparative studies across taxa, and experiments on insect models of viviparity, the tsetse fly (Glossina species) and Pacific beetle mimic cockroach (Diploptera punctata). Our work highlights the insights to be gained from considering stressors across different stages of gestation, whether maternal responses are always in the best interest of current offspring, and the challenges in establishing vulnerability versus adaptation.

A14.2 BORN TO AGGRESSIVE MOTHERS – ARE CERTAIN CHICKS MORE SUSCEPTIBLE TO EARLY LIFE EXPOSURE TO AGGRESSION

Tuesday 8th July 2025 16:30

claragco@gmail.com

Mothers sometimes exhibit aggression towards their dependent offspring, a behaviour often linked to the weaning conflict, where such maternal behaviour could promote offspring independence. However, maternal aggression may also arise from genetic abnormalities or be induced by certain environmental factors. Yet, the biological mechanisms underlying maternal aggression and the interplay between genetic and environmental components remain poorly understood. Despite evidence suggesting that exposure to aggression may have stronger effects on genetically predisposed individuals. To investigate possible biological mechanisms, we conducted an experiment in domestic canaries (Serinus canaria), a species in which mothers may exhibit maternal aggression (MA) towards their chicks. Full clutches were cross-fostered within and between MA mothers and no-MA mothers, creating four experimental groups to identify genetic and environmental influences. Juveniles were exposed to a series of behavioural tests, and we hypothesised that early MA exposure would increase impulsivity, reduce neophobia in a feeding context, and enhance aggression, potentially leading to higher dominance ranks. These effects should be amplified in individuals genetically predisposed to aggression. We found that the relative importance of genes and environment varied across behavioural traits. Aggression-related traits and response inhibition were primarily driven by genetic factors, possibly reflecting a genetic component of MA. Dominance rank or food motivation were predominantly shaped by the early life environment influences, with poorer conditions in broods of MA mothers. In contrast to our expectations a gene-by-environment interactions was only found for neophobia, but it remains speculative how and why the results differ from the other behavioural traits.

Clara Garcia-Co (University of Antwerp, Belgium), Judith Morales (Museo Nacional de Ciencias Naturales-Consejo Superior de Investigaciones Científicas (MNCN-CSIC), Spain), Frederick Verbruggen (University of Ghent, Belgium), Wendt Müller (University of Antwerp, Belgium)

A14.3 DETERMINANTS OF EARLY-LIFE TELOMERES LENGTH IN TREE SWALLOWS

Tuesday 8th July 2025 16:45

Claudie-Anne Langlois (Université de Sherbrooke, Canada), Fanie Pelletier (Université de Sherbrooke, Canada), Dany Garant (Université de Sherbrooke, Canada)

clauclaudie@gmail.com

Early life environmental conditions are key fitness determinants that can modulate the expression of morphological, behavioral, and lifehistory traits. The impact of early life conditions is hypothesized to be reflected at the cellular level in the length of telomeres, the protective DNA structures at the ends of chromosomes. In many animal species, telomeres shorten with age and are related to individual life expectancy. Previous studies have also showed that telomere length is partly heritable, and that this trait is also potentially influenced by parental effects and environmental conditions. The aim of this project is to assess the genetic and environmental (e.g., temperature, brood size, and breeding habitat) determinants of telomere length in Tree Swallow (Tachycineta bicolor) nestlings. Our preliminary results suggest the presence of a genetic and/or a maternal effect influencing early-life telomere length. We also found significant differences in telomere length of nestlings among broods from different females , highlighting the need for further investigation into the determinants of this variability. This project will contribute to a better understanding of aging dynamics and life-history strategies across contrasting environmental conditions.

A14.4 DOES THE GUT MICROBIOME MEDIATE LONG-LASTING EFFECTS OF EARLY-LIFE ENVIRONMENTAL CONDITIONS ON ADULT THERMAL PHYSIOLOGY ?

Tuesday 8th July 2025 17:00

Suvi Ruuskanen (University of Jyväskylä, Finland), Charli Davies (University of Jyväskylä, Finland), Clemence Furic (University of Turku, Finland), Julie Fleitz (University of Turku, Finland), Jenna Palttala (University of Jyväskylä, Finland), Sophie Reichert (University of Turku, Finland)

suvi.k.ruuskanen@jyu.fi

Temperature variation is an environmental challenge all organisms need to cope with. Recently it has been suggested that a novel mechanism, the gut microbiome, contributes to host thermoregulation. For example, we recently showed in birds how short-term variation in environmental temperature affects the adult gut microbiome, this change having causal effects on tolerance of cold temperatures. Microbiome therefore adds a whole new layer of complexity in understanding phenotypic variation. The gut microbiome has further been suggested to help mediate long-lasting effects of early-life conditions experienced by the host, but data from wild populations is scarce. To this end, we studied the long-lasting effects of earlylife environmental conditions on adult thermal physiology and the possible role of gut microbiome in mediating these effects, using wild great tits (Parus major) as the study system. Developing individuals were experimentally exposed to either altered temperatures or

administered antibiotics (to directly modify gut microbiome) during the nestling period in the wild. These individuals were then reared in outdoor aviaries until late winter, and various metabolic and thermal traits (including whole animal metabolism metabolic rate and mitochondria function) were measured. This unique dataset contributes to our understanding of long-lasting effects of early-life conditions, but also opens a new avenue for studying host-microbe interactions, and their role in developmental plasticity.

A14.5 EVOLUTION OF SNAKELIKE PHENOTYPES IN THE HERPETOFAUNA: ECOLOGICAL ASSOCIATIONS AND DEVELOPMENTAL MECHANISMS

Tuesday 8th July 2025 17:15

Tiana Kohlsdorf (University of São Paulo, Brazil), Anieli G Pereira (University of São Paulo, Brazil), Vinicius Aneli (University of São Paulo, Brazil)

tiana@usp.br

Snakelike morphologies evolved several times in amphibians and reptiles, and are characterized by elongated trunks and reduced or absent limbs. A classical example of snakelike animals is observed in the clade Serpentes, but this phenotype also evolved in other tetrapod lineages, including Amphisbaenia (Lepidosauria) and Gymnophiona (Lissamphibia). Evolution of snakelike phenotypes often occurred in association with the use of specific ecological settings. Here we present results using large datasets composed by all major Squamata lineages to report ecomorphological relationships in snakelike bodies that are exclusive to specific lineages as well as phenotypic evolutionary patterns that seem recurrent even among phylogenetically distant clades. Evolution of snakelike phenotypes in the herpetofauna involved changes in developmental pathways, especially those related to limb and trunk development. The axial morphology of snakes, amphisbaenians and caecilians is characterized by an increased number of vertebrae that are all associated with ribs, andremarkable changes in developmental pathways related to HoxH1Myf5 seem to challenge definitions of molecular convergence and parallel evolution. Molecular signatures in genes involved in limb development also suggest that limblessness evolved in different lineages through distinct changes in molecular pathways. Finally, comparisons of mitochondrial genomes enable integration between ecology and development, and we report results from analyses of selection regimes related to fossoriality and limblessness during the recurrent evolution of snakelike phenotypes in the herpetofauna.

A14.6 PREDICTING THE VULNERABILITY OF REPTILES TO CLIMATE WARMING: THE IMPORTANCE OF EMBRYO PHYSIOLOGY

Wednesday 9th July 2025 09:00

Weiguo Du (School of Life Sciences Fudan University, China)

duweiguo@fudan.edu.cn

Traditional studies evaluating the impact of climate warming mainly focus on post-embryonic stages, with much less attention on embryos. I would like to use two case studies to explain how we can predict the vulnerability of animals to climate warming based on behavioral and physiological traits of embryos. First, behavioral thermoregulation may play an important role in buffering the impact of climate warming. By manipulating behavioral thermoregulation of turtle embryos in nests, we found that behavioral thermoregulation by embryos influenced offspring sex ratio, expanding the range of ambient conditions under which nests produce equal numbers of male and female offspring. To predict offspring sex ratios under climate change, we developed models incorporated embryonic behavioral thermoregulation. Our models predict that the sex-ratio shift induced by global warming will be buffered by the ability of embryos to influence their sexual destiny via behavioral thermoregulation. Second, We experimentally determined the mean and developmental plasticity of embryonic upper thermal tolerance (EUTT) for three latitudinally-distributed populations of an oviparous lacertid lizard. Based on the means and plasticity of EUTT and weather data across China, we project that the heat stress frequency would increase from present to the future and increase towards low latitudes. Furthermore, heat stress becomes more extensive with the incorporation of developmental plasticity. Overall, these studies highlight the importance of embryonic behavior and physiology for predicting species vulnerability and range shifts in response to climate change.

A14.7

HOT TEMPERATURES ELEVATE THE PREVALENCE OF NEGATIVELY SELECTED TURTLE SHELL PHENOTYPES

Wednesday 9th July 2025 09:30

Gerardo Antonio Cordero (University of Valencia, Spain), José Vicente Bataller (Centro Acuícola de El Palmar, Spain), Matthieu Lassalle (Centro Acuícola de El Palmar, Spain), Fredric Janzen (Michigan State University, United States), John Tucker (Illinois Natural History Survey, United States)

gecorgue@uv.es

Climate warming predictions point to an increase in the occurrence of heat wave events that may complicate reproductive efforts in animals that lay eggs and render no parental care to developing offspring, such as non-avian reptiles. To address this issue, I present research on the thermal responsiveness and heritability of a suite of intricately interrelated traits: The turtle’s shell. Via a series of eco-evodevo and quantitative genetic experiments, we established that: I) Laboratory-simulated heat waves increase the likelihood of abnormal shell development; II) Abnormal shell phenotypes are selected against in wild populations; III) Over 50% of variability in malformations may be explained by heritable genetic factors. These findings clarify population-level responses to extreme weather events that might not be entirely mitigated by adjustments in maternal nest-construction behaviors. I discuss ongoing research on whether the frequency of potentially maladaptive shell phenotypes is magnified by modified gene-by-environment interactions.

A14.8 ONTOGENETIC VULNERABILITY OF ATLANTIC SALMON, SALMO SALAR, TO CLIMATE WARMING

Wednesday 9th July 2025 09:45

Zara-Louise Cowan (University of Gothenburg, Sweden), Lucy Cotgrove (Natural Resources Institute Finland (Luke), Finland), Lilian Redon (Natural Resources Institute Finland (Luke), Finland), Fredrik Jutfelt (University of Gothenburg, Sweden), Jenni Prokkola (Natural Resources Institute Finland (Luke), Finland)

zaralouisecowan@gmail.com

As climate change increases mean temperatures and the frequency, intensity and duration of heatwaves, there is a growing need to identify species and populations that are vulnerable to warming. Ectothermic animals, such as fish, may be particularly vulnerable as their basic physiological functions are strongly influenced by environmental temperature. In addition, some life stages of fish are predicted to be more vulnerable than others due to ontogenetic differences that affect thermal tolerance and differences in thermal exposure throughout the life cycle. To (i) investigate how thermal tolerance varies across the life cycle of Atlantic salmon (Salmon salar) and (ii) identify life stages that may be particularly vulnerable to climate warming, notably acute warming events, we measured the acute upper thermal tolerance limits (CTmax ), from embryo to spawning stage. Salmon from each life stage were sexed, providing a comprehensive insight into the effect of sex on thermal tolerance across the entire life cycle. We also measured the difference between water temperature and internal body temperature at three heating rates in juvenile and adult salmon. In line with recent literature predictions, the upper thermal tolerance limit of embryos was significantly lower than for post-hatch life stages, however, the spawning life stage showed a remarkable resilience, and the variation in thermal tolerance across all life stages was much smaller than predicted.

A14.9

BORN INTO A CHANGING OCEAN: PHYSIOLOGICAL VULNERABILITY AND

RESILIENCE

OF NEONATAL REEF SHARKS TO CLIMATE STRESSORS

Wednesday 9th July 2025 10:00

Jodie L Rummer (James Cook University, Australia)

jodie.rummer@jcu.edu.au

Neonatal sharks are born into an increasingly challenging world, as climate change is driving shifts in temperature, oxygen availability, and ocean chemistry during their most vulnerable life stage. Since 2013, our long-term Physioshark research program in Mo’orea, French Polynesia – home to the world’s largest shark sanctuary – has been investigating how climate-driven stressors impact the physiology and survival of newborn reef sharks. Across 10 nursery habitats, we have conducted >3,000 hours of field-based sampling and tagged more than 2,500 neonatal blacktip reef (Carcharhinus melanopterus) and sicklefin lemon (Negaprion acutidens) sharks, integrating this with controlled physiological experiments. Our findings indicate that, while elevated temperatures improve hypoxia tolerance, we also see a 35% increase in stress recovery times, 11% decrease in thermal safety

margins, 20% reduction in growth efficiency, and 15% decline in body condition in warmer habitats, suggesting potential developmental and metabolic trade-offs, impacting fitness at the individual and population levels. Through our Apex Mothers initiative, we use birth alert tags, telemetry, and blood biomarkers to track maternal movements, physiology, and environmental exposure, linking maternal health to offspring resilience and survival. These insights reveal the developmental plasticity of early life stages and their potential for local adaptation. By integrating field ecology, whole-organism performance, and molecular physiology, our research provides a predictive framework for understanding how neonatal sharks navigate environmental stressors. As climate change intensifies, identifying physiological tipping points and adaptive capacity in early life stages is essential for informing conservation strategies and maintaining healthy shark populations in rapidly shifting ecosystems.

A14.10 HOW SENSITIVE ARE DEVELOPING EMBRYOS TO CHANGING TEMPERATURES?

Wednesday 9th July 2025 10:15

Patrice Pottier (University of New South Wales, Australia) patrice.pottier37@gmail.com

Early environmental conditions can exert profound and lasting effects on ectotherm phenotypes. However, we still lack a broad understanding of how developmental temperatures shape life history traits across different taxa. In this study, we synthesised data from >800 papers published over the last 110 years to quantify how embryonic temperatures influence development time, body size, growth, and survival in oviparous ectothermic vertebrates (i.e., fishes, reptiles, amphibians). I will discuss how deviations from optimal temperatures affect these life history traits, how these effects vary among taxa, habitats, and egg-laying strategies, and whether they have lasting consequences for ectotherm phenotypes. Finally, I will discuss how these findings can refine our understanding of the evolution of developmental plasticity and help predict the impacts of climate change on ectotherms.

A14.11 EVERY STAGE MATTERS: EXPLORING THE IMPACT OF EARLY LIFE STRESS ON DEVELOPMENT AND PERFORMANCE IN AMPHIBIANS

Wednesday 9th July 2025 11:00

Katharina Ruthsatz (CSIC Doñana Biological Station, Spain)

katharinaruthsatz@gmail.com

Global evironmental change presents significant challenges to wildlife, particularly for ectotherms with complex life cycles, where the most vulnerable life stage ultimately determines population sensitivity and persistence. Amphibians exemplify this challenge, undergoing one of the most dramatic metamorphic transitions in the animal kingdom, marked by profound morphological, physiological, and ecological shifts as they emerge from a pre-metamorphic aquatic into a post-metamorphic terrestrial habitat. Their dependence on both

habitat types makes them especially vulnerable to climate-induced stressors. As the most threatened vertebrate taxon, with over 41% of species at risk of extinction, gaining a mechanistic understanding of how environmental stressors affect amphibians is therefore essential for predicting their persistence under global change. I will summarize our current knowledge on how environmental stressors such as temperature fluctuations and pollution affect amphibian development and performance in later life stages. I will present experimental and meta-analytical results on both the “cold side of climate change,” focusing on increasing winter variability, and the “warm side of climate change,” examining the effects of elevated developmental temperatures. Additionally, I will highlight how early-life stress carries over to later stages, shaping important performance traits such as thermal tolerance, responsiveness to acute stressors, and growth. Lastly, I will discuss methodological challenges in studying early-life stress in amphibians. Overall, our findings demonstrate that early-life conditions may shape both individual performance and population resilience in response to environmental change. Recognizing these effects is essential for predicting amphibian vulnerability and informing conservation strategies in a rapidly changing world.

A14.12 GLOBAL CHANGE AND PREMATURE HATCHING OF AQUATIC EMBRYOS

Wednesday 9th July 2025 11:30

Leon Green (University of Gothenburg, Sweden), Zara-Louise Cowan (University of Gothenburg, Sweden), Timothy D. Clark (Deakin University, Australia), Tamzin A. Blewett (University of Alberta, Canada), Jeremy De Bonville (Université de Montréal, Canada), Thomas Gagnon (Université de Montréal, Canada), Elisabeth Hoots (Deakin University, Australia), Luis Kuchenmüller (Deakin University, Australia), Robine H. J. Leeuwis (Norwegian University of Science and Technology, Norway), Joaquín Navajas Acedo (University of Basel, Switzerland), Lauren E. Rowsey (University of New Brunswick, Canada), Hanna Scheuffele (Deakin University, Australia), Michael R. Skeeles (Deakin University, Australia), Lorena Silva-Garay (Norwegian University of Science and Technology, Norway), Fredrik Jutfelt (University of Gothenburg, Sweden), Sandra A. Binning (Université de Montréal, Canada)

leon.green@bioenv.gu.se

Human-induced environmental changes are increasingly subjecting organisms to stimuli and stressors beyond their evolutionary adaptations. In aquatic ecosystems, certain life stages are expected to be particularly vulnerable, with embryos identified as highly sensitive to environmental stress. Notably, research across diverse taxa indicates that embryos can hatch prematurely, potentially as an adaptive mechanism in response to external stressors, despite potential drawbacks such as underdeveloped behavioral or physiological traits. Surprisingly, in aquatic environments, little research has explored the frequency, causes, and consequences of premature hatching. In this presentation, we give an overview of the current knowledge on premature hatching in aquatic embryos and examine how this process may be exacerbated by human-driven global change. Specifically, we (1) review hatching mechanisms and factors that trigger premature hatching in both experimental and natural settings; (2) assess the biological and ecological consequences of premature hatching across different levels of organization, from individuals to ecosystems; and (3) identify knowledge gaps and propose directions for future

research on the causes and implications of this phenomenon. Our review highlights that aquatic embryos exhibit premature hatching in response to a broad range of abiotic (e.g., temperature, oxygen levels, pollutants, light, pH, salinity) and biotic (e.g., predators, pathogens) stressors. Additionally, we provide evidence that rapid thermal ramping can induce premature hatching in fish. Premature hatching is an intriguing yet underexplored area of research and knowledge of the phenomena may play a role in enhancing the resilience of aquatic communities amid ongoing global environmental change.

A14.13 COMBINED EFFECTS OF BIOTIC AND ABIOTIC FACTORS ON LARVAL LIFE-HISTORY TRAITS: INSIGHTS FROM MESOCOSM EXPERIMENTS

Wednesday 9th July 2025 11:45

Lumír Gvoždík (Institute of Vertebrate Biology AS CR, Czech Republic)

gvozdik@ivb.cz

Environmental change impacts early developmental stages through complex interactions between biotic and abiotic factors. However, most studies have examined these factors in isolation. Here, I present findings from two mesocosm experiments that manipulated both biotic (intra- and interspecific competition) and abiotic (temperature and drying) conditions during amphibian larval development. Both experiments revealed a striking pattern: abiotic factors affected larval developmental time, while body mass at emergence was influenced by competition. These experiments highlight (1) the intricate interplay between biotic and abiotic factors in shaping larval life-history traits and (2) the importance of multistressor studies under seminatural conditions in understanding how environmental change affects amphibian population dynamics.

A14.14

INTERACTIVE

EFFECTS OF TEMPERATURE AND OXYGEN AVAILABILITY ON ZEBRAFISH EARLY DEVELOPMENT AND UPPER THERMAL TOLERANCE

Wednesday 9th July 2025 12:00

Lorena Silva Garay (Norwegian University of Science and Technology, Norway), Moa Metz (Norwegian University of Science and Technology, Norway), Henning H Kristiansen (Norwegian University of Science and Technology, Norway), Leon Pfeufer (University of Gothenburg, Sweden), Emily Lechner (University of Gothenburg, Sweden), Rasmus Ern (Norwegian University of Science and Technology, Norway), Anna H Andreassen (Technical University of Denmark, Denmark), Fredrik Jutfelt (University of Gothenburg, Sweden) lorena.silvagaray@gmail.com

Understanding how multiple environmental stressors interact to influence early life development and thermal tolerance is crucial for predicting climate change impacts. Early life stages of fishes have been suggested to be highly susceptible to warming due to their

undeveloped physiological systems, reduced access to oxygen, and limited ability to move away from environmental stressors. While the effects of temperature on development and hatching success have been studied, the interactions between temperature and oxygen remain underexplored. Here, we investigated how temperature (14–39°C) and oxygen availability (12.5–200% air saturation) influence key traits in zebrafish (Danio rerio). Using a temperature gradient table, we exposed embryos and early-stage larvae to 50 different temperature-oxygen combinations and measured embryonic development, heart rate, hatching success, survival, and juvenile upper thermal tolerance (CTmax ). In general, the impact of hypoxia was stronger at higher temperatures than at cooler temperatures. Severe hypoxia (12.5% and 25%) reduced hatching success, delayed heart development, lowered heart rates, and reduced larvae length at hatching. At high temperatures heart rate fluctuations suggested cardiac stress. Interestingly, hyperoxia did not alleviate the impacts of high temperatures, indicating that these effects are not related to an oxygen limitation. Finally, the exposure to the various temperature and oxygen treatments during development did not appear to affect the upper thermal tolerance of subsequent life stages, suggesting a lack of developmental plasticity in this trait. Our findings highlight that hypoxia can exacerbate thermal stress, emphasizing the importance of considering stressor interactions in climate resilience studies.

A14.15

FROM EGGS TO ADULTHOOD: SUSTAINED EFFECTS OF EARLY DEVELOPMENTAL TEMPERATURE AND CORTICOSTERONE EXPOSURE ON PHYSIOLOGY AND BODY SIZE IN AN AUSTRALIAN LIZARD

Wednesday 9th July 2025 12:15

Daniel Noble (Australian National University, Australia), Ondi Crino (Flinder’s University, Australia), Kris Wild (University of Melbourne, Australia), Chris Friesen (University of Wollongong, Australia), Dalton Leibold (Australian National University, Australia), Naomi Laven (Australian National University, Australia), Amelia Peardon (Australian National University, Australia), Pablo Recio (Australian National University, Australia), Karine Saline (Ifremer, France)

daniel.noble@anu.edu.au

Developing animals are increasingly exposed to elevated temperatures as global temperatures rise as a result of climate change. Vertebrates can be affected by elevated temperatures during development directly, and indirectly through maternal effects (e.g. exposure to prenatal glucocorticoid hormones). Past studies have examined how elevated temperatures and glucocorticoid exposure during development independently affect vertebrates. However, exposure to elevated temperatures and prenatal corticosterone could have interactive effects on developing animals that affect physiology and life-history traits across life. We tested interactions between incubation temperature and prenatal corticosterone using a widespread Australian lizard species. We treated eggs with high or low doses of corticosterone and incubated eggs at 23°C (cool) or 28°C (warm). We measured the effects of these treatments on development time, body size and survival from hatching to adulthood and on adult hormone levels and mitochondrial respiration. We found no evidence for interactive effects of incubation temperature and prenatal corticosterone exposure on phenotype. However, incubation temperature and corticosterone treatment each independently

decreased body size at hatching and these effects were sustained into the juvenile period and adulthood. Lizards exposed to low doses of corticosterone during development had elevated levels of baseline corticosterone as adults. Additionally, lizards incubated at cool temperatures had higher levels of baseline corticosterone and more efficient mitochondria as adults compared with lizards incubated at warm temperatures. Our results show that developmental conditions can have sustained effects on morphological and physiological traits in oviparous lizards but suggest that incubation temperature and prenatal corticosterone do not have interactive effects.

A14.16 SENSING STRESS: CHEMICAL COMMUNICATION IN THERMALLY STRESSED ZEBRAFISH EMBRYOS

Wednesday 9th July 2025 15:00

Sofia Vámos (University College Dublin, Ireland), Katharina Wollenberg Valero (University College Dublin, Ireland)

sofia.duartevamos@ucdconnect.ie

Extreme heat events are predicted to be more frequent and intense over the next few decades. Ectotherm early stages are particularly sensitive to such events due to their reliance on the external environment to perform their daily activities and maintain body temperature. Exposure to higher temperatures during fish development can increase mortality, growth rates, and may impact adult phenotypes. Yet very little is known about the early-life responses, interactions and developmental plasticity to thermal stress in aquatic species. In this study, we measured the photomotor response (PMR) of 1 day post fertilization zebrafish embryos at different rearing densities (10, 20, and 40 eggs), with and without regular social and heat-induced chemical cues. We found that embryos exposed to stress metabolites showed significant changes in PMR magnitude and recovery time, indicating they may detect and respond to stress-related chemical cues. Higher rearing densities were associated with lower activity, and the combined effects of thermal stress and stress metabolites resulted in a unique behavioral phenotype, suggesting interactions that may amplify the stress responses. Thus, we showed that zebrafish embryo activity is significantly affected by early life exposure to higher temperatures and that social cues may create a buffer when not directly exposed to thermal stress. Since the photomotor response can be a proxy for how well sensory information and motor actions are coordinated, rearing density and social cues emerge as important factors for understanding the response of developing fish to environmental stressors.

A14.17 PHYSIOLOGICAL DRIVERS OF SCOTOTAXIS DEVELOPMENT IN LARVAL SHEEPSHEAD MINNOWS ACROSS TWO TEMPERATURES

Wednesday 9th July 2025 15:00

Madison Schumm (University of Texas at Austin Marine Science Institute, United States), Andrew Esbaugh (University of Texas at Austin Marine Science Institute, United States)

mschumm7@utexas.edu

Marine fish must overcome challenges associated with environmental stress by altering their physiology and behavior. This is of particular concern for larval fishes, which face exorbitant rates of predation and whose antipredation tactics may be reduced with available energy under warming. Increases in energy demand must be facilitated through simultaneously enhanced uptake of resources, which may result in increased risk-taking (e.g., boldness). In the adult sheepshead minnow, we have previously shown that warming reduces preference for dark substrate (scototaxis)—a behavior strongly present in the adult phenotype that aids in crypsis. With this background, our objective was to assess changes in scototaxis behavior (light/dark preference) in larval sheepshead minnows reared at 25°C and 32°C at weekly intervals throughout development. Our larval data conforms with patterns seen in zebrafish where larvae across temperatures prefer the white substrate until 17 dph in opposition to the highly scototaxis adult phenotype, and these patterns may reflect changes in melanophores across development. Interestingly, larvae reared at 32°C at 10 dph demonstrated significantly greater white preference compared to larvae at 25°C and all other time points. We next sought to explore physiological drivers of individual variation at 10 dph using routine metabolic rate as a proxy for energetic demand, and cortisol as a measure of stress reactivity. Our data highlight that temperature impacts how highly vulnerable larval fish interact with their environment which may impact populations under intense predation.

A14.18 GENETIC COMPATIBILITY AND LARVAL DIETARY REGIME SHAPE MITOCHONDRIAL FUNCTION AND AGEING PATTERNS IN FRUITFLY POPULATIONS

Wednesday 9th July 2025

15:30

Stefano Bettinazzi (University College London, United Kingdom), Avishikta Chakraborty (University College London, United Kingdom), Finley Grover Thomas (University College London, United Kingdom), Florencia Camus (University College London, United Kingdom)

s.bettinazzi@ucl.ac.uk

Our climate is changing drastically, with consequences for species persistence and distribution. Mitochondria will have a major role in providing the metabolic flexibility needed by populations to adapt to novel environments. Nutritional stress - caused by fluctuations in food availability and composition - is predicted to place a significant burden on mitochondrial and organismal physiology, particularly when experienced at key stages of development. Another layer of complexity resides in mitochondrial function depending on precise interactions between coadapted mitochondrial and nuclear genes. As climate change drives shifts in population distributions, admixture events between once-isolated populations are expected to increase. This raises the chance that incompatibilities between mito-nuclear gene sets will be exposed, which has been shown to severely impact phenotypes in many species. Here, we explored how genetic compatibility and larval dietary regime shape mitochondrial function and ageing patterns in Drosophila melanogaster. Using a fly panel consisting of mito-nuclear matched populations and their reciprocal cybrid lines, we manipulated larval development by inducing accelerated growth through a diet shift from low- to highprotein. Adult lifespan was assessed alongside mitochondrial function in young and old flies. Under standard conditions, cybrids exhibited

age-related decline in mitochondrial performance, as well as reduced mean lifespan compared to matched lines. In contrast, fluctuating food availability mitigated the main phenotypic impact of genetic incompatibility, promoting mitochondrial homeostasis and survival across all lines. Our findings highlight the interplay between genetic and environmental stressors in shaping phenotypes, and underscore the importance of mitochondrial flexibility in adaptation to shifting environments.

A14.19 DOES WARMING AMPLIFY OR ATTENUATE THE IMPACTS OF POLLUTANTS AND LOW PH ON ZEBRAFISH SKELETAL DEVELOPMENT? EVIDENCE FROM GENE EXPRESSION, BONE FORMATION AND SWIMMING PERFORMANCE.

Wednesday 9th July 2025 09:00

Quinte F. Geessinck (Radboud University, Netherlands), Wilco C.E.P Verberk (Radboud University, Netherlands), Peter H.M. Klaren (Radboud University, Netherlands), Marianne J.W. Obers (Radboud University, Netherlands), Roxane I. Dimitriadis (Radboud University, Netherlands), Lianne J.C.M Kuper (Radboud University, Netherlands), Juriaan R. Metz (Radboud University, Netherlands)

quinte.geessinck@ru.nl

Any skeletal abnormalities arising in early life can have lifelong consequences for fish performance. Skeletogenesis is a tightly regulated process, highly sensitive to abiotic factors and environmental change. Fish must cope with increased temperatures and declining pH, as well as with pollutants released into the environment by human activities. Our study aims to determine how warming modulates stressor impacts on zebrafish skeletal development. Zebrafish larvae were exposed to warming (31.5°C), acidification (pH 4.5) and cadmium (0.3µM) from 0 till 7 days post fertilisation. Multiple lines of evidence show clear disruption of skeletogenesis following exposure to stressors (gene expression, staining, whole-body mineral content and swimming essays). Warming accelerates all physiological processes, including calcification, and was shown to partly attenuate the disruption due to acidification. This attenuating effect of warming was found even after accounting for thermal effects on development by comparing fish at the same developmental stage. In contrast, cadmium induced disruption was not attenuated by warming. Cadmium and acidification were found to affect the swimming behaviour of larvae during the night, dependent on environmental temperature. In summary, we found that multiple stressors impact calcium metabolism, bone development and swimming behaviour of zebrafish larvae. However, we did not observe strong amplification of stressor effects in a multi-stressor context.

A14.20 DEVELOPMENTAL EFFECTS AND ENDOCRINE DISRUPTING POTENTIAL OF IN OVO EXPOSURE TO PER- AND POLYFLUOROALKYL SUBSTANCES

(PFAS) IN MALLARD DUCKLINGS (ANAS PLATYRHYNCHOS)

Wednesday 9th July 2025 16:00

Veerle L.B. Jaspers (Norwegian University of Science and Technology (NTNU), Norway), Silje Peterson (Norwegian University of Science and Technology (NTNU), Norway), Anne-Fleur Brand (Norwegian University of Science and Technology (NTNU), Norway), Kang Nian Yap (Norwegian University of Science and Technology (NTNU), Norway), Tomasz M. Ciesielski (Norwegian University of Science and Technology (NTNU), Norway), Céline Arzel (Turku University, Finland)

veerle.jaspers@ntnu.no

Waterbird populations are declining globally. Additionally, concerning observations of male-skewed sex ratios and increased hatching failures are being reported in the Baltic. Environmental contaminants and endocrine disrupting chemicals, such as per- and polyfluoroalkyl substances (PFAS), are potential contributors to these declines. PFAS have been linked to multiple adverse health effects in wildlife species, yet the specific modes of toxicity in avian models remain uncertain and establishing clear links between exposure and toxicity is complicated by factors such as co-contaminants, environmental conditions and biological variables. Thus, controlled exposure studies are valuable when addressing these challenges.

This study experimentally investigated the developmental toxicity and endocrine disrupting potential of two unregulated PFAS, Perfluoro-4-ethylcyclohexanesulfonic acid (PFECHS) and Perfluorododecanesulfonic acid (PFDoDS), alongside the regulated Perfluorooctanesulfonic acid (PFOS), using the mallard duck (Anas platyrhynchos) as a model organism. Farmed mallard eggs were exposed to PFAS via in ovo injections at environmentally relevant doses.

A lower hatching success was observed in eggs exposed to PFECHS and PFDoDS compared to controls and PFOS exposed eggs. Additionally, a potential shift in sex ratio was observed in the exposed groups. Changes in plasma levels of corticosterone, 11-deoxycorticosterone and progesterone levels were found, with significant differences in corticosterone levels between the PFAS-exposed groups. These findings highlight the potential of PFAS for developmental effects and endocrine disruption, particularly among unregulated PFAS, emphasizing the need for further research on their effects on avian health and population dynamics.

A14.21 THE INFLUENCE

Wednesday 9th July 2025 16:15

Valeria Marasco (University of Veterinary Medicine Vienna, Austria), Tim Boswell (Newcastle University, United Kingdom), Bin-Yan Hsu (Tunghai University, Taiwan), Steve Smith (University of Veterinary Medicine Vienna, Austria), Leonida Fusani (University of Vienna University of Veterinary Medicine Vienna, Austria)

valeria.marasco@vetmeduni.ac.at

Exposure to environmentally generated stressors during early development can profoundly shape physiology and behaviour. To which extent such organisational effects might be contingent on subsequent environmental circumstances, maximise physiological resilience and fitness outcomes remain unclear. Using a highly seasonal study system, the migratory Common quail (Coturnix coturnix), we tested the prediction that exposure to food uncertainty potentiate the expression of seasonal migratory fattening and that such a response is stronger in those birds previously exposed to the same environmental stressor during early post-natal growth. To this end, we combined known proxies of physiological energetics signalling the emergence of the migratory phenotype (including fat stores and nocturnal energy expenditure) with circulatory measurements of metabolic hormones (plasma corticosterone and plasma thyroid hormones), and gene expression measurements of candidate genes in the brain. Our results suggest that the impact of stress exposure on the migratory phenotype is dependent on early-life priming effects, and potential functional mechanisms will be discussed.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

DESERT VIPERS OF THE GENUSCERASTESAS A MODEL FOR TEMPERATURE-DEPENDENT CRANIOFACIAL DEVELOPMENT: A MORPHO-MOLECULAR ANALYSIS

Nouhaila El Fenni (Faculty of sciences Ben M’sik Casablanca, Morocco), Zineb Agourram (Faculty of sciences Ben M’sik Casablanca, Morocco), Assya Lamaizi (Faculty of sciences Ben M’sik Casablanca, Morocco), Anass Kettani (Faculty of sciences Ben M’sik Casablanca, Morocco), Mouad Mkamel (Faculty of sciences Ben M’sik Casablanca, Morocco)

contact@mkamelmouad.com

Early development is highly sensitive to environmental stressors, with temperature shaping phenotypic trajectories in ectotherms. This study examines thermal plasticity in craniofacial development of two desert vipers,Cerastes cerastes(horned viper) and Cerastes vipera(non-horned viper). Adapted to arid extremes, they offer a model to explore how temperature-driven disruptions may cause phenotype-environment mismatches under climate change. Eggs were incubated at 22°C, 28°C, and 34°C (15 per species/ treatment) to simulate desert temperatures. Growth was tracked via photogrammetry and linear morphometrics, including snout-vent and horn length. Skeletal development was assessed using Alizarin Red staining, while qPCR quantified osteogenic markers BMP2 and RUNX2.

C. cerastesshowed strong thermal plasticity: at 34°C, horn length increased 42% vs. 28°C, with accelerated ossification and 31% higher bone density. BMP2 and RUNX2 were upregulated 3.2- and 2.8-fold, linking thermal stress to osteogenesis.C. viperashowed no significant morphological or molecular changes, highlighting species-specific vulnerability.

These results show that thermal stress during embryogenesis shapes craniofacial traits via conserved osteogenic pathways. However, exaggerated horns at high temperatures may hinder burrowing or predator avoidance inC. cerastes, illustrating potential maladaptation in warming deserts. This study integrates experimental and evolutionary approaches to predict phenotype-environment mismatches and identify molecular targets, like BMP signalling, for resilience in thermally sensitive ectotherms.

Keywords: Experimental Developmental Biology, Thermal Plasticity, Osteogenic Pathways, Climate Resilience,Thermo-morphogenesis.

A14.23 EXPLORING DEVELOPMENTAL EFFECTS OF ACUTE THERMAL STRESS ON REPRODUCTIVE AND PARENTAL CARE ABILITIES IN BURYING BEETLES

Jakob Wiil (St Andrews University, United Kingdom) jw414@st-andrews.ac.uk

Environmental temperature is a key determinant of fitness in insects, influencing survival, reproduction, and behaviour. With climate change increasing the frequency and intensity of extreme thermal events, it is crucial to understand the adaptational capacity of insects to this new thermal reality. While the impacts of acute thermal stress on physiological traits are well-documented, less is known about the developmental effects of such extreme events, particularly regarding environmental buffering mechanisms like parental care behaviours. In this study, we investigated how exposure to a heatwave during the larval stage ofNicrophorus vespilloidesinfluenced reproductive success and parental care in adulthood. Larvae were exposed to either a heatwave (26°C for 72 hours) or kept at control conditions (20°C) and assessed for reproductive and behavioural outcomes in the adult focal individuals and their offspring. We found that heatwave exposure significantly reduced survival to eclosion in the focal larvae. However, there was no significant impact of the heatwave on either the parental behaviour or the duration of care exhibited. Similarly, no developmental effects of thermal stress were observed on adult reproductive traits or for offspring fitness. These results suggest that extreme thermal events early in life do not necessarily have longterm detrimental effects, contrary to recent findings on ontogenetic sensitivity in insects. This highlights the complex interactions between temperature and insects’ life history and underscores the need for further research to more accurately assess resilience in a rapidly changing world.

A14.24 HOW EXPOSURE TO ARTIFICIAL LIGHT AT NIGHT AFFECTS THE METABOLIC RATE OF CRESTED NEWTS DURING EARLY LIFE STAGES

Marko D Prokic (Department of Physiology Institute for Biological Research Siniša Stanković, Serbia), Marija Drobnjaković (Department of Evolutionary Biology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Maja Ajduković (Department of Evolutionary Biology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Jelena Gavrić-Čampar (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Svetlana Despotović (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Branka Gavrilović (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Tijana Radovanović (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Tijana Vučić (Institute of Biology Leiden University Leiden, Netherlands), Tamara Petrović (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia)

marko.prokic@ibiss.bg.ac.rs

Light pollution is the most common and fastest-growing form of urban pollution worldwide. While urbanization is recognized as one of the primary drivers of the global decline of amphibians, little attention has been paid to the impact of artificial light at night (ALAN) on this particularly threatened group of vertebrates. In this study, we investigate the direct effects of two types of LED lights (5 lux warm-2700K and 5 lux cold-6000K) on the metabolic rate of larvae of the crested newt species,Triturus ivanburschi. We also examined the delayed effects of ALAN. Metabolic activity was investigated in juvenile individuals three weeks after their development under ALAN. The oxygen uptake of individuals at rest was measured as a proxy for the standard metabolic rate at both life stages. Our findings showed that larvae developed under both cold and warm LED lights had higher metabolic rates compared to the control group. However, in juveniles, alterations were observed only in individuals that have been exposed to cold LED lights; these individuals exhibited lower metabolic activity than both the control and warm LED groups. Overall, the results suggest that ALAN affects the metabolic activity of crested newt larvae, with possible delayed effects in subsequent life stages. These changes may have long-term negative impacts on the fitness of newt populations, which is crucial for biodiversity conservation in a world plagued by light pollution.

A14.25 EFFECTS OF TWO TYPES OF LED LIGHTS AT NIGHT ON THE DEVELOPMENT, BODY GROWTH, AND BEHAVIOR OF LARVAE OF TWO CRESTED NEWTS SPECIES AND THEIR HYBRIDS

Tamara G Petrovic (Department of Physiology Institute for Biological Research Siniša Stanković, Serbia), Marija Drobnjaković (Department of Evolutionary Biology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Maja Ajduković (Department of Evolutionary Biology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Jelena Gavrić-Čampar (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Svetlana Despotović (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Branka Gavrilović (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Tijana Radovanović (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia), Tijana Vučić (Institute of Biology Leiden University Leiden, Netherlands), Marko Prokić (Department of Physiology Institute for Biological Research “Siniša Stanković” Serbia, Serbia)

tamara.petrovic@ibiss.bg.ac.rs

Artificial light at night (ALAN) is a widespread pollutant that impacts wildlife at various levels. However, our understanding of the effects of ALAN on amphibians, particularly tailed amphibians, is limited. In this study, we examined how ALAN affects the development, growth rate, and activity of larvae from two species of crested newts:Triturus macedonicusandT. ivanbureschi, as well as their hybrids. Given that responses to ALAN can vary based on light intensity, spectral composition, and duration of exposure, we compared the effects of warm (2700K) LED light and cold (6000K) LED light. Larvae were exposed to two light intensities (5 lux and 30 lux) from hatching until they reached developmental stage 62. Our results indicated that while both types of light can alter development, body size, and movement activity, cold LED light at higher intensity resulted in more significant effects. Comparing the species, we found thatT. ivanbureschiand theT. macedonicus-mothered hybrids showed a greater response to ALAN. Specifically, these larvae experienced prolonged development, lower growth rates, and reduced activity when exposed to 30 lux of cold light. This type of light is generally considered to be more harmful to organisms. Our research highlights the complex effects of ALAN on amphibians and emphasizes the difficulty in generalizing its impact across different species.

A14.26 A CALL FOR DISTRIBUTED EXPERIMENTS ON FISH EMBRYONIC THERMAL TOLERANCE

Patrice Pottier (University of New South Wales, Australia) patrice.pottier37@gmail.com

As ectothermic animals, fish are particularly vulnerable to the impacts of rising temperatures, with many populations approaching their thermal limits. A holistic understanding of the vulnerability of fish populations is thus vital to mitigate environmental and societal

impacts under climate warming. While early life stages have been suggested to be more vulnerable to thermal stress than juveniles and adults, existing methods for measuring heat tolerance are inconsistent between fish life stages. These methodological inconsistencies have fuelled debates about the increased sensitivity of embryos to thermal stress and have limited our ability to predict the impacts of climate change on fish populations. Fortunately, alternative approaches to measuring thermal tolerance now allows us to standardise assessments across life stages. I propose to conduct a distributed experiment—uniting researchers across the world to collect data on embryonic thermal tolerance using standardised methods. These experiments will be simple, replicated across various species and regions, and all contributors will be co-authors on the resulting publication. By identifying the developmental stage most sensitive to heat stress, this project will yield crucial knowledge to predict the impacts of climate change on fish populations.

A14.27 REPRODUCTIVE DYSFUNCTION IN SEAWATER MAY LIMIT THE SPREAD OF THE INVASIVE ROUND GOBY NEOGOBIUS MELANOSTOMUS

Leon Green (University of Gothenburg, Sweden), Martina Griful-Dones (EURECAT Technology Centre, Spain), Charlotta Kvarnemo (University of Gothenburg, Sweden)

leon.green@bioenv.gu.se

Salinity plays a crucial role in shaping species distributions by imposing physiological constraints. Understanding when and how these constraints arise can help predict colonization patterns, such as those occurring during species invasions. To assess the effects of

high salinity environments on the ongoing spread of the invasive round goby (Neogobius melanostomus) toward the North Sea, fish from the invasion front were bred in a common-garden experiment across two different salinities. Reproductive adults were acclimated to a control salinity (20 PSU), reflecting current invasion front conditions, and a higher salinity (30 PSU), representative of North Sea coastal waters. Within these salinities, fish were assigned to spawning groups, and spawning activity and egg development were monitored over 1.5 months. The findings revealed a significant impact of the 30 PSU treatment, with complete developmental failure of all clutches spawned at this salinity. This failure led to a notable increase in egg consumption by nest-guarding males. Furthermore, sperm velocity declined with increasing salinity when tested in both experimental salinities and an intermediate level. Despite these reproductive challenges, few physiological differences were observed in adults exposed to different salinity treatments. These results indicate that, although adult N. melanostomus can acclimate to North Sea coastal conditions, their gametes currently lack the capacity to tolerate salinities at the predicted limits of their expansion. While adaptation or transgenerational acclimation may eventually enable reproduction at higher salinities, we recommend that current models incorporate a reproductive threshold for N. melanostomus at 30 PSU.

A16: INSIGHTS AND TOOLS FROM BIOLOGGING FOR CONSERVATION PHYSIOLOGY

ORGANISED BY: ANDREA FULLER (UNIVERSITY OF THE WITWATERSRAND), EMILY BENNITT (UNIVERSITY OF BOTSWANA)

A16.9 FROM SLEEP TO CONSERVATION: CYBERINFRASTRUCTURE,

Thursday 10th July 2025 09:00

Jessica Kendall-Bar (University of California San Diego, United States)

jkendallbar@ucsd.edu

Sleep, a critical physiological process for almost all animals, both encodes and impacts health across multiple timescales. However, months-long sleep studies are challenging in the wild, especially for animals that display extreme shifts in behavior across seasons. We examined short-term EEG records and long-term time-depth records in northern elephant seals (Mirounga angustirostris) that seasonally shift from sleeping 10 hours a day on land to less than 2 hours a day for up to 8 months at sea. Our open-source database and processing workflow, including a sleep identification algorithm for time-depth records based on EEG records, accelerated comparison of shorter, high resolution multi-sensor data with longer, lower resolution diving records. We analyzed 323 dive records from adult females during shorter post-breeding trips (74.6 ± 9.5 days) and longer post-molt trips (217.7 ± 24.7 days). Seals slept less during the short trip (1.1 ± 1.1 h) and seldom exhibited extended surface intervals, which we classified as “surface sleep” (<8% of total sleep time). Seals slept twice as much during the long trip (2.2 ± 1.6 h) and, as they gained body fat, surface sleep decreased from 12% to 8%. This suggests that, due to a reduced dive capacity, skinnier seals sleep less overall and spend a higher proportion of time sleeping at the surface, where they do not perform REM sleep and face higher risks of predation. These findings highlight the potential of combining short- and long-term datasets to better understand the ties between sleep physiology and foraging success across animal systems.

A16.10 HEARTS UNDER STRESS: CHRONIC STRESS ALTERS CARDIAC WORKLOAD, IMPAIRS SWIMMING PERFORMANCE AND DEPLETES ENERGY RESERVES IN ATLANTIC SALMON

Thursday 10th July 2025 09:30

April Grace R Opinion (University of Antwerp, Belgium), Debora Maria Alvéstegui Montalvo (Ghent University, Belgium), Holly Shiels (Manchester University, United Kingdom), Johan Aerts (Ghent University, Belgium), Gudrun De Boeck (University of Antwerp, Belgium) aprilgrace.opinion@uantwerpen.be

Salmonids have experienced significant mortality in both aquaculture and natural environments, with cardiac abnormalities identified as a major contributing factor. Chronic stress has been linked to cardiac dysfunction, largely due to the ability of exogenous cortisol to induce maladaptive cardiac remodeling. However, because exogenous cortisol does not fully replicate the physiological effects of prolonged stress, the relationship between cardiac abnormalities and endogenous cortisol remains unclear and unconfirmed experimentally. In this study, we examined the effects of chronic stress on heart rate, cardiac morphology, and swimming performance in Atlantic salmon. Fish implanted with heart rate loggers to monitor cardiac workload were either left undisturbed (control) or exposed to unpredictable chronic stress for 30 days. Stressed fish developed larger, rounder, and less symmetrical hearts, which corresponded with reduced cardiac performance, as indicated by lower critical swimming speed (Ucrit). This cardiac remodeling appeared to be linked to a sustained increase in cardiac workload, evidenced by chronically elevated routine heart rate. Although basal glucose and lactate levels were unaffected by stress, the reduced post-Ucrit elevation of these parameters and a lower hepatosomatic index suggested depleted energy reserves, further contributing to Ucrit impairment. Surprisingly, plasma cortisol levels were similar between treatments and did not explain the observed cardiac remodeling. Overall, our findings demonstrate that long-term handling stress increases cardiac workload, leading to structural and functional cardiac impairment and energy depletion through mechanisms independent of plasma cortisol.

A16.11 HOT DOGS: PHYSIOLOGICAL VULNERABILITY OF AFRICAN WILD DOGS TO RISING TEMPERATURES

Thursday 10th July 2025 09:45

Jennifer F Linden (University of OxfordZoological Society of London, United Kingdom)

jennifer.linden@biology.ox.ac.uk

Direct climate change impacts on species arise from weather affecting individual physiology, which in turn influences behaviour and survival. Understanding these physiological impacts is therefore crucial for predicting climate change impacts on species, populations, and ecosystems. The African wild dog (Lycaon pictus, ‘wild dog’) is an endangered carnivore known to persist in only 8% of its historic range. Recent research suggests climate change as an emerging threat that could compound existing pressures and heighten extinction risk. It has been hypothesised that high temperatures limit wild dog hunting behaviour, yet the underlying mechanism remains unclear. Here, I present a study on wild dog thermoregulation, in which core body temperature (Tb ) was recorded in 14 individuals across four sites in southern Africa, alongside energy expenditure data from biologging collars on 9 individuals. Results reveal exceptional thermal lability in wild dogs, surpassing that observed in similar-sized mammals. Tb is positively correlated with energy expenditure, a relationship further intensified by environmental temperature, at times pushing individuals toward Tb extremes nearing the risk of organ failure. With rising temperatures and increasing aridity predicted for this region, these findings suggest potential physiological vulnerability in wild dogs. Future work will explore how wild dogs manage such Tb extremes and the resulting effects on hunting behaviour.

A16.12 INFERRING ENERGY INTAKE OF YELLOWFIN TUNA (THUNNUS ALBACARES) BASED ON THE HEAT INCREMENT OF FEEDING

Thursday 10th July 2025 10:00

Takaaki Hasegawa (Fisheries Resources Institute Japan Fisheries Research and Education Agency, Japan), Kei Okamoto (Fisheries Resources Institute Japan Fisheries Research and Education Agency, Japan), Kazunori Kumon (Amami Field Station Fisheries Technology Institute Japan Fisheries Research and Education Agency, Japan), Takeshi Eba (Amami Field Station Fisheries Technology Institute Japan Fisheries Research and Education Agency, Japan), Daniel W Fuller (Inter-American Tropical Tuna Commission, United States), Takaaki Abe (Department of Marine Science College of Bioresource Science Nihon University, Japan), Takashi Kitagawa (Graduate School of Frontier Sciences The University of Tokyo, Japan)

hasegawa_takaaki53@fra.go.jp

Quantifying energy intake in free-ranging fish is crucial for understanding the mechanisms that drive foraging, growth, and reproduction. However, because direct observations of feeding are difficult in highly mobile species living in the open ocean,

estimating their energy intake in the wild is extremely challenging. In homeotherms, digestion-induced heat production leads to an increase in body temperature, which is known as the Heat Increment of Feeding (HIF). In tunas, which are regionally endothermic, HIF has been observed using internal temperature sensors in electronic tags. Previous studies demonstrated that energy intake can be estimated based on HIF in species such as Pacific bluefin (Thunnus orientalis) and skipjack tuna (Katsuwonus pelamis). However, no studies have explored the applicability of this method in yellowfin tuna (T. albacares). This study aimed to quantify the relationship between food consumption and HIF in yellowfin tuna. We conducted feeding experiments in an offshore sea cage in Japan in February and November 2024 using a total of 40 archival tagged fish. We found that the extent of HIF of yellowfin tuna significantly increased with the amount of food provided. Using a mixed-effects model with accounting for individual variation, we established the equation to estimate energy intake based on HIF. We applied this method to archival tagging data from yellowfin tuna collected in the Eastern Pacific Ocean to demonstrate its application for estimating energy intake in the wild.

A16.13 ANIMAL RESPONSES TO ECOLOGICAL CHALLENGES: INSIGHTS FROM ELEPHANTS IN THE DAY AND LIZARDS AT NIGHT

Thursday 10th July 2025 10:15

Maria Thaker (Indian Institute of Science, India)

mthaker@iisc.ac.in

Biologging is a powerful tool to track the behavioural and physiological responses of animals. In this talk, I will share insights of how animals respond to challenges, using two examples that differ dramatically in spatial and temporal scales. At the largest spatial scale, I will show how movement strategies of African elephants during the day are influenced by temperature. Thermal stress is a major concern for large mammals including savanna elephants, which have amongst the greatest challenge for heat dissipation in arid environments. We tracked 14 herds of elephant in South Africa for 2 years using GPS collars with inbuilt temperature sensors. We show how ambient temperature (calibrated from the collars) is an important predictor of movement and water use across the landscape, with elephants responding facultatively to a “landscape of thermal stress.” At a much smaller spatial scale, I will share how nocturnal sleep in lizards can be influenced by ecologically-relevant challenges. Animals show substantial flexibility in sleep duration and distribution, but robustly quantifying such variation at ecologically relevant scales is challenging. Using recently developed miniature loggers, we recorded sleep in wild-caught Peninsular rock agama lizards. I will share how EOG-derived sleep parameters and behaviourally-measured sleep intensity is influenced by anthropogenic disturbance and stress induced by predation risk. Overall, I will draw parallels from these studies to show how biologging can provide unexpected insights on how animals manage their days and nights in response to challenges.

A16.14 HEART RATE AS A PROXY OF METABOLIC RATE IN BLACK-LEGGED KITTIWAKES (RISSA TRIDACTYLA)AT MIDDLETON ISLAND, ALASKA

Thursday 10th July 2025 11:00

Emily Choy (McMaster University, Canada)

choye1@mcmaster.ca

Seabirds are considered sentinels of marine ecosystem health. Black-legged kittiwakes (Rissa tridactyla) have experienced population declines as a result of prey shortages due to changing oceanographic conditions. Since 2019, a collaborative study on heart rate in black legged kittiwakes has been conducted by scientists at McGill University, University of Liverpool, University of Roehampton, and McMaster University at the Institute of Seabird Research and Conservation on Middleton Island, Alaska. To examine the indirect physiological effects of prey shortages, we used heart rate as a proxy of oxygen consumption and fine scale energetics. The recent development of a new prototype logger for birds has significantly improved data quality, with a 99% accuracy rate between manual and automatic heart rate measurements. In 2024, 45 kittiwakes were implanted with heart rate loggers and gps-accelerometers to identify which behaviours (flight, resting, etc.) required the most energy during different stages of the breeding season. Flapping flight was identified as the most energy-costly behaviour in kittiwakes, which is performed mainly during the chick-rearing stage. To examine the affect of supplemental feeding, 30 kittiwakes that were implanted with heart rate loggers were fed capelin three times a day for 10 days. Heart rate and body temperature differed significantly between fed and unfed birds after a feeding event. Our work will provide novel insights into the use of heart rate as a novel proxy of energetics and help to identify tipping points in which declines in prey availability could result in an energy deficit in kittiwakes and other seabirds.

A16.15 IMPLANTATION OF A MICROACOUSTIC TAG SEVERELY ALTERS

FEEDING BEHAVIOUR IN THE INVASIVE SEA

LAMPREY

Thursday 10th July 2025 11:30

Hugo Flávio (Dalhousie University, Canada), Evan Bellhouse (Wilfrid Laurier University, Canada), Scott Miehls (USGS, United States), Julia Xeni (Wilfrid Laurier University, Canada), Michael Wilkie (Wilfrid Laurier University, Canada) hflavio@dal.ca

The invasion of the Laurentian Great Lakes by sea lamprey (Petromyzon marinus) had catastrophic effects on fisheries. These animals start as filter-feeding larvae, but after metamorphosis, juvenile sea lamprey migrate downstream and become parasitic. While this juvenile life-stage is desirable for the application of targeted management options, very little is known about the movements and early behaviour of the juveniles as they enter the lakes. The eel/ lamprey acoustic tag (ELAT) is a micro-acoustic tag that could expand our knowledge of the juvenile life-stage, providing key information for the sea lamprey control program. However, prior to using this tag

to determine variables such as distribution, attack rates, survival, and damage to fisheries, we must validate that the ELAT does not impose significant sub-lethal effects that could compromise the natural behaviour of juvenile sea lamprey. Here, we explored the behaviour of tagged and control animals in the presence of host fish, to determine any tag-induced changes in feeding behaviour and growth. By performing replicated video trials, we determined that the ELAT severely limited the tagged animals’ capacity to attach to a host compared to the control groups. Furthermore, even when the tagged animals did attach, they did not grow at the same rate as controls and animals which had only undergone surgery. This study highlights the importance of going beyond classic metrics such as post-surgery survival and wound healing when determining the efficacy of new tagging technology. Sub-lethal physiological effects caused by tag implantation could compromise behaviour, leading to erroneous data interpretation.

A16.16 HEAT DOME DANGER: INVESTIGATING DIFFERENCES IN METABOLIC AND THERMOREGULATORY RESPONSE TO A EXTREME HEAT EVENT

Thursday 10th July 2025 11:45

Lauren Schreck (Oregon State University, United States), Paige Prentice (Oregon State University, United States), Nicholas Shirkey (California Department of Fish and Wildlife, United States), Emma Lantz (California Department of Fish and Wildlife, United States), Leigh Combrink (The University of Arizona, United States), Clinton W. Epps (Oregon State University, United States), Holly Arnold (Oregon State University, United States), Brianna Beechler (Oregon State University, United States), Anna Jolles (Oregon State University, United States)

lauren.e.schreck@gmail.com

Understanding the physiological mechanisms of metabolic regulation of body temperature during heat stress is an increasingly urgent challenge as climate change intensifies the frequency and severity of extreme heat events (EHEs). Biologging technology enables exploration of physiological tradeoffs between thermoregulation and energy expenditure in extreme environments. We assessed physiological and behavioral responses of desert bighorn sheep by capturing, collaring, deploying rumen implant transmitters (RITs), and re-releasing 49 free-living wild individuals from multiple ecologically and genetically distinct populations. RITs recorded heart rate and body temperature, the collar recorded external temperature of the individual, the accelerometers collected activity data, and nearby weather stations tracked ambient temperature. Both collar temperature and ambient temperature captured an unprecedented natural EHE widely documented in summer 2021 in the Pacific Northwest of the United States and Canada. I will showcase thermal and energetic responses before, during, and after the heat event by first describing trends in individual strategies (thermoregulating, thermoconforming, behaviorally regulating, and altering activity), and defining significant drivers of individual variation (demographical, nutritional, genetic, and immunological traits) using generalized additive mixed models. I will outline my intended approach to validate my findings using an unsupervised clustering algorithm adapted for longitudinal data for creating functional profiles of animals who respond similarly to the EHE; common explanatory traits will be identified for each time step. Leveraging biologger technology and a natural case study, we

will elucidate the effects of physiological stress and the energetic strategies for coping with EHEs in a wild population for effective conservation and management.

A16.17 NO STRINGS ATTACHED: WIRELESS TEMPERATURE BIOLOGGERS TO IMPROVE REMOTE PHYSIOLOGICAL DATA COLLECTION

Thursday 10th July 2025 12:00

Ashleigh C Donaldson (University of the Witwatersrand, South Africa), Shane Maloney (University of Western Australia, Australia), Bryn Morgan (Loggermate, Australia), Luoyang Ding (University of Western Australia, Australia), Andrea Fuller (University of the Witwatersrand, South Africa)

ashleigh.donaldson@wits.ac.za

Biologging physiological variables in free-living animals is crucial for conservation but presents practical and technological challenges. Implanted biologgers enable long-term data collection but require surgical or post-mortem retrieval. Wireless data transmission enables periodic data collection without explantation. In this study we tested a wireless temperature biologger. Wireless biologgers (mass 10g) were inserted into the rumens of three sheep, where they remained for two weeks. Attempts to download data were made every five days at 1m intervals, from 0 to 5m from the sheep. To compare performance with a validated non-wireless model (mass 2g), a wireless and nonwireless biologger combined in one unit was inserted into the rumen of two sheep and implanted retroperitoneally in two African buffalo. Biologgers were recovered post-slaughter (sheep) or after predation (buffalo). The wireless biologgers in the rumen of sheep downloaded successfully, with 1440 data points downloaded within 10s from up to 2m away. The wireless biologgers were accurate and precise (bias -0.004°C to -0.002°C; SD 0.048°C to 0.090°C), with 99% of paired recordings differing by ≤0.05°C. The limits of agreement between temperature measurement methods ranged from -0.18°C to 0.17°C and were influenced by sudden decreases in temperature associated with drinking, with the larger wireless biologger exhibiting greater thermal inertia and responding more slowly. Both biologgers from predated buffalo were found in the field (using received signal strength indication) despite no carcass recovery, with wireless signals detected up to 45m away. Our study demonstrates the reliability and applicability of wireless biologgers for remote body temperature monitoring.

A16.18 QUANTIFYING AEROBIC AND ANAEROBIC SWIMMING IN SOCKEYE SALMON DURING THEIR 1200KM FRESHWATER MIGRATION USING ACCELEROMETER TAGS

Thursday 10th July 2025 12:15

Kim Birnie-Gauvin (Technical University of Denmark, Denmark)

kbir@aqua.dtu.dk

Energy is the currency for life, and how animals partition this energy into different functions poses an important trade-off that must be balanced. In fishes, the cost of swimming likely represents a large component of their energy budget. In particular, energy is an important, and limited commodity for upstream migrating adult Pacific salmon that have ceased feeding. Thus, quantifying how these fish partition their energy during their migration to ensure they successfully spawn is of conservation interest. In the Fraser River (British Columbia, Canada), some sockeye salmon populations migrate upwards of 1200 km to reach their spawning grounds, and encounter severe hydraulic challenges along the way. Understanding how sockeye partition their finite energy budget into aerobic (sustained) and anaerobic (burst) swimming could help us understand why some fish successfully make it to the spawning grounds while others do not. We tagged sockeye salmon upon their entry in freshwater with archival accelerometer radio tags and recovered 23 tags from both successful and unsuccessful individuals. We quantified how much time these fish spent swimming aerobically and anaerobically throughout their migration. We further estimated how fast sockeye can recover from these anaerobic bursts to determine whether ‘physiological thresholds’ underlie performance and migration success. Our study furthers our understanding of how swimming performance is affected by both internal and external factors, which is fundamental to predicting how fish are likely to cope with environmental change, and for focusing conservation efforts aimed at mitigating anthropogenic impacts.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A16.1 MONITORING THE ‘MUNDANE’:

WHAT DO KOALAS DO WHEN THEY’RE NOT SLEEPING?

Gabriella R Sparkes (The University of Queensland, Australia), William Ellis (The University of Queensland, Australia), Sean FitzGibbon (The University of Queensland, Australia), Benjamin Barth (The University of Queensland, Australia), Oakleigh Wilson (University of the Sunshine Coast, Australia), Ami Fadhillah Amir Abdul Nasir (The University of Queensland, Australia), Robbie S Wilson (The University of Queensland, Australia)

g.sparkes@uq.edu.au

Koala populations in Australia have declined by 54% in the last three decades. Millions of dollars are spent annually on protecting koalas, focussing on safeguarding habitat and treating disease. Yet, two thirds of all koala deaths occur when they are moving along the ground, due to vehicle strikes and dog attacks. Despite decades of research, little is known about how koalas move on the ground. Traditional GPS tracking provides limited insight into these movements, as they generally record locations only once or twice a day. To address this gap, we use accelerometers—bio-loggers that record three-dimensional movement at hundreds of points per second—to determine the orientation and movement of koalas during specific behaviours. We collared 10 koalas in the wild with accelerometers and high-resolution

GPS devices for an average of 8 days. From these data, we quantified (1) the frequency and duration of ground visits, (2) the speed and distance moved, and (3) the locomotion style used on the ground (e.g., walking, bounding). We found that koalas visited the ground three times per day on average, totalling only 45 minutes. Koalas travelled on average 260 metres per ground visit, mainly walking at 1.7 km/h with occasional bounding at 10.4 km/h. Combining accelerometer and GPS data, we identified the specific trees koalas moved between. This is the first comprehensive analysis of koala movement in the wild, revealing new insights into their ground behaviour. Understanding these movement patterns is crucial for protecting koalas where they are most vulnerable.

A16.2 EXPLORING NEW DEPTHS: KING PENGUINS BREAK DIVE RECORDS DURING THE AUSTRAL WINTER

Maëlle Oberlin (The Hubert Curien pluridisciplinary Institute – IPHC - CNRS (UMR7178), France), Manfred R Enstipp (The Hubert Curien pluridisciplinary Institute – IPHC - CNRS (UMR7178), France), Céline Le Bohec (Monaco Scientific Center - Polar Biology Department, France), Robin Dardel (The Hubert Curien pluridisciplinary Institute – IPHCCNRS (UMR7178), France), Charles-André Bost (Centre for Biological Studies of Chizé - CEBC - CNRS (UMR 7372), France), Yves Handrich (The Hubert Curien pluridisciplinary Institute – IPHC - CNRS (UMR7178), France)

maelle.oberlin@iphc.cnrs.fr

The king penguin is one of the champion avian divers, surpassed only by its larger relative, the emperor penguin. The foraging ecology of king penguins is typically studied during the austral summer, when foraging trips are relatively short (weeks). Consequently, little is known about the fall/winter period, when birds undertake long foraging trips (months) and the descent of their preferred prey to greater depth might challenge their dive capacity. Investigating the dive behaviour of 7 king penguins from the Crozet Islands during fall/ winter, we found that birds conducted deeper and longer dives during this period. Most birds exceeded the previous depth and duration records but the deepest (424.5 m) and longest (10 min) dives were conducted by the same individual. These dives are the deepest and longest yet reported for king penguins and illustrate their ability to respond to seasonal changes by enhancing their dive capacity, likely through gradual acclimatization.

A16.3 ASSESSING METABOLIC RATE AND POST-TAGGING RECOVERY IN JUVENILE FISH

Hugo Flávio (Dalhousie University, Canada), Oscar Notman-Grobler (Dalhousie University, Canada), Paris Mastrodimitropoulos (Dalhousie University, Canada), Alessandro Bevilacqua (Dalhousie University, Canada), Robert Lennox (Dalhousie University, Canada)

hflavio@dal.ca

Juvenile fish play a crucial role in the health of aquatic ecosystems, serving both as the lifeline for future generations, but also as a

valuable food source for a thriving ecological community. However, these juvenile animals are particularly vulnerable to both biotic and abiotic changes in the ecosystem. Understanding the juvenile lifestage of fish is challenging, because juveniles tend to be small and hard to track, making it hard to gather information about them. As new acoustic tags become smaller and smaller, we are finally being able to shed light into understudied life-stages, including juvenile fish, forage fishes, and even baitfishes. But tagging such small animals can introduce sub-lethal effects that alter their physiology and behaviour, ultimately biasing the collected data and any subsequent analyses and conclusions. Here, we tested if tagging juvenile brook trout (Salvelinus fontinalis) of two size classes (10-12 cm and 13-16 cm fork length) with a 417 kHz LOTEK PinTag induced changes in their oxygen consumption rates (MO2 ) immediately after tagging and over a period of two days. Findings will help to guide new research on small fish and open telemetry towards previously intractable species and size classes.

A16.4 PRACTICAL GUIDELINES FOR SUPERVISED MACHINE LEARNING MODEL VALIDATION IN ACCELEROMETER-BASED ANIMAL BEHAVIOUR CLASSIFICATION

N Oakleigh Wilson (University of the Sunshine Coast, Australia), David Schoeman (University of the Sunshine Coast, Australia), Andrew Bradley (Whipbird Signals Pty Ltd, Australia), Christofer Clemente (University of the Sunshine Coast, Australia)

oaw001@student.usc.edu.au

Supervised machine learning is widely used to detect fine-scale animal behaviour from accelerometer data. However, there is currently no standardised protocol for verifying the accuracy of this technique, and the risks associated with common machine learning verification pitfalls have yet to be widely recognised. One such pitfall is model overfitting, which occurs when a model becomes too closely aligned with the training data, memorising noise rather than capturing generalisable patterns. As a result, while the model may show high performance on the training set, its ability to generalise to new, unseen data is compromised. This limitation can be detected with the application of robust time-series specific validation techniques. We conducted a systematic review of 119 accelerometer-based behaviour classification supervised machine learning papers to see what proportion of existing literature conducted appropriate timeseries validation. We found that 79% (94 papers) did not validate their models sufficiently well to identify potential overfitting. Although this does not inherently imply that these models are overfit, the absence of independent test sets limits the interpretability of their results. To address these challenges, we provide a theoretical overview of overfitting in the context of time-series accelerometer data and propose succinct, ecologist-accessible guidelines for optimal timeseries validation techniques. Our aim is to equip ecologists with the tools necessary to adapt general machine learning theory to the specific requirements of time-series biologging, facilitating reliable overfitting detection and continuing to advance the field.

A16.6 IDENTIFYING A THERMAL PHENOTYPE FROM FIELD MEASUREMENT OF THE CORE TEMPERATURE OF EWES

Peter M Panizza (The University of Western Australia, Australia), Luoyang Ding (The University of Western Australia, Australia), Dominique Blache (The University of Western Australia, Australia), Shane K Maloney (The University of Western Australia, Australia) ppanizza98@gmail.com

Background: There is individual variability in the response of core body temperature (CBT) during exposure to heat load. Ewes classified as having high rectal temperatures on hot days before breeding had smaller lambs, with those lambs having lower survival rate than the lambs from ewes that had a lower rectal temperature on hot days before breeding. The ability to classify animals as having either a high or low body temperature suggests the possibility that a thermal phenotype may exist in CBT.

Aims: Rumen temperature (Trumen ) was recorded as a proxy for CBT in ewes during summer to determine whether a repeatable thermal phenotype could be identified within individuals.

Methods: Trumen was recorded every five minutes over 34 days during the hottest period of summer in 43 ewes kept in a paddock with no access to shade, while data from a weather station were used to calculate the average daily temperature-humidity index. On each day, each ewe was ranked based on its 95th percentile Trumen for that day. The consistency of the ranking was assessed across days by correlating each ewe’s ranking on a given day with its ranking on every other day during summer.

Results: The individual ranking of Trumen was stable over time, with the correlation coefficient between days ranging between 0.25 and 0.75. Conclusion and Implications: Ewes have a thermal phenotype in CBT during summer. This thermal phenotype may impact animal performance and welfare.

A16.7 MEASURING STRESS IN A HEARTBEAT: LINKING HEART RATE TO CONVENTIONAL STRESS BIOMARKERS IN TELEOST AND ELASMOBRANCH FISHES

Shamil Debaere (University of Antwerp, Belgium), April Grace R Opinion (University of Antwerp, Belgium), Jodie L Rummer (James Cook University, Australia), Gudrun De Boeck (University of Antwerp, Belgium)

shamil.debaere@uantwerpen.be

Stress biomarkers are of utmost importance to underpin conservation strategies and management decisions in both wild and aquaculture populations of fishes. Here, we explore the use of heart rate loggers to validate haematological indicators of acute and chronic stress in Atlantic salmon (Salmo salar) and spiny dogfish (Squalus suckleyi). Small heart rate loggers (Star-Oddi DST milli-HRT) were surgically implanted in the abdominal cavity of the fishes, between the pectoral fins, and programmed to make ECGs at hourly intervals for the duration of the experiments. Following a recovery period, we applied a stress paradigm based on commonly encountered and easily reproducible stressors to experimentally induce the acute or chronic phase of the stress response over 20-30 day experiments.

Blood samples were collected at periodic intervals throughout the experiments to capture changes in several haematological metrics (metabolites of the primary or secondary stress response), either following an acute stressor or basal circulating levels during sustained stress. We subsequently correlate the measured heart rates with these haematological responses. Additionally, in a subset of the animals, we recorded respiration rates via intermittent-flow respirometry to investigate cardiorespiratory effects of stress. Through this approach, we aim to test the applicability of heart rate loggers to biologically and physiologically validate stress biomarkers across fishes, providing insights that could have profound implications for their conservation and management.

A16.8 RESPONSES OF AFRICAN BUFFALO TO DISEASE AND ENVIRONMENTAL CHANGE IN THE KRUGER NATIONAL PARK, SOUTH AFRICA

Tshepiso L Majelantle (University of the Witwatersrand, South Africa)

tshepiso.majelantle@wits.ac.za

Climate change in southern Africa is associated with warming, including a higher frequency of heatwaves, and changes in precipitation, including intense drought. The direct effects of these changes, together with indirect effects on the resources available to wildlife, may impact an animal’s health, susceptibility to disease, and ability to cope with infection. We investigated the link between infection, disease and climate-related variables, and body temperature patterns of free-ranging large herbivores, using African buffalo (Sycerus caffer) as a model species. African buffalo are economically and ecologically important species as they are wildlife maintenance hosts for bovine tuberculosis (bTB) and foot-and-mouth disease viruses (FMDVs). In late 2024, 24 juvenile African buffalo (age range 1 – 2.5 years) were darted and surgically implanted with wireless temperature-sensitive data loggers in the Kruger National Park, South Africa. Thereafter, data was retrieved from the animals, using the wireless connection, when they were darted for disease monitoring ~6 months later. We report how body temperature varied with changing environmental conditions and disease status. The results of this study will assist us in understanding how climate change impacts will alter disease progression and health of free-living large herbivores.

A17: OPEN ANIMAL

ORGANISED BY: JACK THOMSON (UNIVERSITY OF LIVERPOOL)

A17.1 (FINALLY) TESTING

THE HYPOTHESIS: DOES OCEAN ACIDIFICATION AFFECT CEREBROSPINAL FLUID CHEMISTRY?

Tuesday 8th July 2025 16:00

Garfield T Kwan (University of Exeter, United Kingdom), Jennifer Finlay (University of Exeter, United Kingdom), Andrea J Johnson (MacEwan University, Canada), Aidan Donnelly (University of Exeter, United Kingdom), Jack Jarvis (University of Exeter, United Kingdom), Trystan Sanders (University of Exeter, United Kingdom), Oleg Savin (MacEwan University, Canada), Trevor J Hamilton (MacEwan University, Canada), Martin Tresguerres (Scripps Institution of Oceanography, United States), Rod W Wilson (University of Exeter, United Kingdom)

gkwan09@gmail.com

Research on ocean acidification (OA) and its alteration of fish behavior has provoked controversy, yet the hypothesis seeking to explain its mechanism remains untested. Nilsson et al. (2012) posits the physiological response to high CO2 (increased cerebrospinal fluid (CSF) [HCO3 - ], decreased [Cl- ]) reverses the GABAA receptor’s neuronal electrochemical potential. While blood [Cl- ] has been observed to decrease at nearly a 1:1 ratio as HCO3 - accumulates, no study to date has measured CSF acid-base and ionic responses to elevated CO2 . Here, we measured lumpfish (C. lumpus) blood and CSF after 1-hour, 5-day, and 5-week of elevated CO2 (3,000 – 6,000 μatm), as well as after 15 min to 4 hours of 10,000 μatm of CO2 . Lumpfish blood and CSF pH recovered and [HCO3 - ] accumulated within hours of exposure. Interestingly and unlike its blood response, lumpfish CSF [HCO3 - ] at 5 weeks of exposure was significantly lower than at 5 days of exposure. CSF [Cl- ] was not affected by 3,000 – 6,000 μatm CO2 exposure. Instead, CSF [Cl- ] significantly increased over the 4-hour exposure to 10,000 μatm of CO2 . The 5-week CO2 exposure significantly decreased distance moved, but did not affect thigmotaxis. Brain pHi and TCO2 measurements are ongoing, and together with our CSF data will determine whether chronic CO2 exposure induces a reversal in GABAA receptor electrochemical potential. This research advances our understanding of CSF regulation and neurobiology in non-model fishes, and highlights the need to directly measure (and not assume blood responses are similar across) physiologically-regulated fluids.

A17.2 MWILL YOU MISS ME WHEN I AM GONE? GASTRIC PROTON PUMP KNOCK OUT AND THE IMPORTANCE OF GASTRIC ACID IN DIGESTION, METABOLISM AND GROWTH IN FISH.

Tuesday 8th July 2025 16:00

Patrícia G. Ferreira (University of Ottawa, Canada), Jonathan M. Wilson (Wilfrid Laurier University, Canada) patricia.ferreira@uottawa.ca

The defining innovation of the vertebrate stomach is acid-peptic digestion. The acidic stomach pH is produced by the gastric proton pump (H+ /K+ -ATPase) and proteolysis by the aspartic peptidase, pepsin. This provides advantages in protein digestibility and other key functions. Although highly conserved, secondary loss or regression has paradoxically occurred independently in multiple lineages primarily in the fishes. To better understand the role of gastric acidification and the consequences of loss, we developed the first non-mammalian knockout (KO) of the gastric proton pump by targeting the catalytic a-subunit (Atp4a) using CRISPR-Cas9 gene editing in the model teleost fish Astyanax mexicanus. We have set out to elucidate the impact of acid in digestion and nutrient assimilation, and on the molecular mechanisms involved in the gastric chloride and potassium movement. In the KO animals, gastric acidification was abolished with no adverse effects on specific growth rates and appetite although body protein, Ca, Mg and P were lower, and lipid was higher compared to wild-type. We also found a striking new role for the stomach in lipid uptake. RNAseq analysis was also performed and identified 2064 differentially expressed genes (DEGs) in stomach and 160 DEGs in anterior intestine of atp4a-/- fish. The differentially regulated gastric and intestinal pathways in atp4a-/- animals elucidate the impact of stomach acid in oxidative stress, and lipid and iron metabolism. Taken together, our results shed light on the role of the stomach in the processes of nutrient assimilation, opening the door to further analyses using this novel genetic line.

A17.3 STRESS-INDUCED ELEMENTAL RETENTION IN AN ECTOTHERMIC VERTEBRATE.

Tuesday 8th July 2025 16:30

Avik Banerjee (Indian Institute of Science, India), Maria Thaker (Indian Institute of Science, India)

avikb365@gmail.com

Stress responses require increased energy utilization to combat the

challenging period. When energy reserves deplete, animals can meet their energetic demands either by actively foraging for carbonrich food resources or by selective retention of ingested nutrients. In our manipulative study, we test the effects of elevated stress on elemental retention in an ectothermic vertebrate, Psammophilus dorsalis. Adult lizards of both sexes were allotted to either a stressed group, where they underwent daily constraint in a cloth bag for 10 days, or a control group where they were undisturbed. All lizards were provided with mealworms to eat and the elemental (carbon and nitrogen) compositions of both ingested and egested content were measured to determine overall elemental retentions. Baseline corticosterone, glucose, and triglyceride levels were also measured at the beginning and end of the experiment. We found that lizards from both control and stressed groups had higher corticosterone levels at the end of the experiment compared to the beginning, indicating that captivity itself induced a stress response. Glucose and triglyceride levels did not correlate with baseline corticosterone but showed sexspecific differences when compared between the beginning and the end of experiment. Lizards from both treatments also retained approx. 1.3 times more carbon than nitrogen, which is consistent with the prediction that carbohydrates and lipids are essential macronutrients during stressful periods. Our study provides new insights on how elemental retention can be an adaptive compensatory post-ingestive strategy to meet stress-induced energetic demands when foraging opportunities are limited.

A17.4 PLASTIC BIODEGRADATION BY INSECTS

Tuesday 8th July 2025 16:45

Bryan J Cassone (Brandon University, Canada)

cassoneb@brandonu.ca

Plastic polymers are ubiquitous in our lives, and while their resilience makes them ideal for a variety of uses, finding means to effectively dispose of them represents a major challenge. Recently, a variety of “plastivore” insects have been discovered that possess the remarkable ability to consume and rapidly degrade petro plastics. Focusing on the caterpillar larvae of the greater wax moth (Galleria mellonella) and low-density polyethylene, we will explore how much plastic is consumed, the relative contributions from the insect and its microbiome to the biodegradation process, and the impacts of plastic ingestion on larval fitness. Further, the possibility of using the larvae in large-scale plastic bioremediation and as part of a circular economy will be discussed.

A17.5 THE EFFECT OF TEMPERATURE ON THE IMMUNE RESPONSE IN ZEBRAFISH BY IN VIVO IMAGING

Tuesday 8th July 2025 17:00

Moa Metz (Norwegian University of Science and Technology, Norway), Louise Von Gersdorff Jørgensen (University of Copenhagen, Denmark), Fredrik Jutfelt (University of Gothenburg, Sweden)

moa.metz@ntnu.no

Climate warming is directly affecting aquatic ectotherms. In addition, aquatic animals are constantly threatened by potential infections from various pathogens. Heatwaves and warming of habitats have been associated with increases in disease outbreaks and mortality in several ectotherms, suggesting the immune system can be an important component determining climate impacts. Fish rely heavily on the innate immune system with its generalist leukocytes in fighting pathogens, cell signalling, repairing wounds and regenerating tissue. The aim was therefore to investigate how temperature affects the immune response and regeneration. We did this byin vivoimaging of transgenic zebrafish (Danio rerio) larvae, with fluorescent neutrophils and macrophages, that were incubated at either 20°C, 28°C, 31°C, 33°C or 35°C. We performed tail amputations and observed the immune cell recruitment for 12 hours and tail regeneration over three days, while maintaining the thermal treatments. Both immune cell recruitment and regeneration were strongly affected by temperature. Recruitment of neutrophils was faster and higher in recruited cell numbers with increasing temperature. Macrophages, however, showed impaired recruitment at the highest temperature. Tissue regeneration displayed a typical thermal performance curve, where 20°C showed the slowest regeneration, increasing regeneration with temperature up to 35°C, over where it declined. These results suggest that fishes might be more vulnerable to infections at warm temperatures, and it is possible that the climate change driven disease outbreaks we observe in natural populations can be partly explained by a decreased function of the innate immune response.

A17.6 TELOMERE DYNAMICS OF THE EUROPEAN GREEN TOAD (BUFOTES VIRIDIS) IN THE CONTEXT OF URBANIZATION AND POLLUTION

Tuesday 8th July 2025 17:15

Magdalena Spießberger (BOKU University, Austria), Steve Smith (University of Veterinary Medicine, Austria), Gopi Munimanda (University of Veterinary Medicine, Austria), Stephan Burgstaller (BOKU University, Austria), Lukas Landler (BOKU University, Austria) magdalena.spiessberger@boku.ac.at

Environmental stressors such as chemical and light pollution can have detrimental effects on the fitness of animals. One proposed link between these stressors and survival are telomeres, which play an important role in genome protection, ageing and somatic maintenance and are known to be shortened due to harsh environmental conditions. Amphibians are especially susceptible to environmental stressors because of their permeable skin and complex life cycle, characterized by metamorphosis from larvae to adults, making them an ideal model species to investigate possible effects of anthropogenic disturbance on telomere length. Therefore, we test the effects of chemical and light pollution on the telomere dynamics of the European green toad (Bufotes viridis) from larval stage until adulthood, in controlled lab experiments as well as in field studies in and around Vienna. We are developing a real-time quantitative polymerase chain reaction (qPCR) assay to analyze the relative telomere length (RTL) from DNA swabs from the larval, juvenile and adult stages. This longitudinal approach to understanding telomere dynamics of amphibians is the first one of this kind and the results will broaden our understanding about how anthropogenic disturbance acts on wildlife on a molecular basis and will therefore help to further improve animal conservation.

A17.7 INSIGHTS INTO DAPHNIA MATING BEHAVIOUR THROUGH 3D LONG-TERM TRACKING

Wednesday 9th July 2025 09:00

Martin Horstmann (Ruhr University Bochum, Germany), Linda Brinkmann (Ruhr University Bochum, Germany), Luxi Chen (Ruhr University Bochum, Germany), Ralph Tollrian (Ruhr University Bochum, Germany), Linda C. Weiss (Ruhr University Bochum, Germany)

martin.horstmann@rub.de

Freshwater crustaceans of the genus Daphnia usually reproduce parthenogenetically but can switch to sexual reproduction when environmental conditions deteriorate. This allows genetic recombination to broaden the genetic pool of the offspring, increasing their success in coping with changing environments. While females should select males that increase the success of their offspring, males must also identify the correct fertility stage, as females in different reproductive modes and fertility stages can occur simultaneously, and mating with an asexually reproducing female incurs costs. However, it is unknown how daphnids locate and identify potential mating partners. Using a 3D tracking system, we analysed up to 24-hour long video sequences for characteristic behavioural patterns (e.g., velocity, position selection) of Daphnia magna males encountering females. Conducting these experiments in both light and dark conditions allowed the main mating period to be identified. We detected altered male velocities and depth selection when encountering females in different fertility stages, suggesting male Daphnia magna can distinguish between them. We also found a continuous search for females in all males studied, suggesting mating time depends on the females. Circadian rhythms and female moulting also seemed to play an important role, and even hour-long guarding of the fertilised females was observed. These results complete the limited knowledge of mating behaviour in Daphnia

A17.8 DETECTION OF PERIVITELLINEBOUND SPERM DONOR IDENTITY USING DNA MICROSATELLITES ANALYSIS: A TOOL FOR EXTRAPAIR AND CRYPTIC MATE CHOICE EVALUATION

Wednesday 9th July 2025 09:00

Justine M Simms (Hobart and William Smith Colleges, United States), Kathryn Crandall (Hobart and William Smith Colleges, United States), Thomas Jensen (Hobart and William Smith Colleges, United States)

simms@hws.edu

DNA microsatellites are small tandem repeats within the genome, which are ideal for individual identification and paternity. While this technique was developed for use in crime-scene investigations, it is now regularly used to aid in animal breeding, conservation efforts, and field research. For example, microsatellites are often used to determine chick paternity, which helps determine which chicks resulted from extrapair copulations (EPCs).

We generated DNA microsatellites profiles for all male and female

quail (Coturnix coturnix) within our breeding colony. To evaluate sperm donor identity only, we removed the blastodisc from the PVM prior to gDNA isolation. Sperm donor identity was determined by generating MS profiles from PVMs to exclude females and non-contributing males. We were able to successfully exclude all but one male in 50% of the eggs analyzed using four MS primer sets. We expect that adding more MS primer sets will allow us to successfully identify the male donor in all eggs.

Because studbooks are mostly based on pairings and not genetic testing, paternity in colony managed populations may not be accurate depending on EPC rates, making studbooks paternity inaccurate. Using this method, EPC rates for specific colonies or species can be analyzed allowing facilities to determine whether the costs of chick paternity testing is justified.

Unlike chick paternity, this method shows all sperm donors present at the oocyte membrane which could significantly impact captive management and our understanding of basic avian reproductive physiology, including cryptic female choice and sperm storage tubule function, and behaviors such as EPCs.

A17.9 LINKING ACTIVITY PATTERNS AND REPRODUCTIVE OUTCOME IN AN INCOME BREEDER

Wednesday 9th July 2025 09:30

Liv Monica Trondrud (INRAE National Research Institute for Agriculture Food and Environment, France), A. J. Mark Hewison (INRAE National Research Institute for Agriculture Food and Environment, France), Nadège Bonnot (INRAE National Research Institute for Agriculture Food and Environment, France), Nicolas Morellet (INRAE National Research Institute for Agriculture Food and Environment, France), Jean-Michel Gaillard (CNRS, France) liv-monica.trondrud@inrae.fr

Reproduction, particularly lactation, is one of the costliest energetic processes for mammals. During this period, females must allocate energy to offspring growth and development while also sustaining their own metabolic requirements. In an income breeder like roe deer (Capreolus capreolus), particularly during the early hider phase, energy requirements of the mother, and hence foraging and ranging behaviour, increase substantially to support fawn growth. Using biologging data from 90 GPS-collared reproductive female roe deer over a 17-year period, we investigated activity patterns linked to foraging during three key phases of reproduction (late gestation, early lactation, late lactation until weaning) to determine how the energy- and time- budgets were related to reproductive outcomes (number of fawns at weaning). We found that activity peaked during the first month post-parturition with a predicted increase in daily time spent active from 48% pre-parturition to 56% during peak lactation. The number of fawns at weaning explained some of the variation in both timing and intensity of activity: females with one or two fawns were more active overall, particularly during mid-day, compared to those with no fawns at weaning. Females with two fawns had higher activity levels, although not doubled, than those with just one. Our preliminary results therefore suggest that females with two fawns either acquire energy more efficiently, or face a trade-off between maintenance and allocation to fawn growth. Further investigations will elucidate these potential trade-offs, allowing us to better map the relationship between energetic constraints and reproductive outcome in this income breeder.

A17.10 THE EFFECT OF RELOCATION AND DIETARY CHANGE ON THE FOUNDER GENERATION OF WILD HOUSE MICE

Wednesday 9th July 2025 09:45

Ekaterina Gorshkova (Kiel University and Max Planck Institute Plön, Germany), Daniela E. Winkler (Kiel University, Germany), Anja Guenther (Universität Hildesheim and Max Planck Institute Plön, Germany), Christine Böhmer (Kiel University, Germany)

gorshkova@evolbio.mpg.de

The concept of the “island syndrome” phenomenon has been recognised since the era of Darwin, and it is characterised by the presence of distinct behavioural and morphological traits within island populations that differ from those of the mainland. While most studies have investigated changes that have already occurred, questions regarding the mechanisms and causes of these changes remain unanswered. In this study, we have focused on the founding generation of wild house mice relocated to “islands,” a situation analogous to being introduced to novel environments by human transportation. The “islands” utilised in this study are seminatural and comprise distinct dietary regimens. These diets differed in consistency but were comparable in caloric content and mimicked the natural diet of the mice. We then compared mice’s behaviour and morphological traits from these “islands” with those of a control population maintained on an artificial pellet diet after seven months. The behavioural stress-coping strategies and foraging behaviours of the subjects were examined, as these are critical for survival during and after environmental change. The analysis revealed no statistically significant differences in stress-coping, however, there were some differences in foraging behaviour. The examination of morphological traits, including body length, tail length, and masticatory muscle strength, revealed a trend suggesting that these traits were beginning to diverge from those of the control population. This outcome is particularly noteworthy given that these were the founder generations that underwent relocations during their early life stages.

A17.11 FISHING FOR ANSWERS:

USING LAB AND FIELD

STUDIES

TO UNDERSTAND THE IMPACTS OF SELECTIVELY HARVESTING ORNAMENTAL FISH

Wednesday 9th July 2025 10:00

Mar Pineda (University of Glasgow, United Kingdom), Daiani Kochhann (Universidade Estadual Vale do Acaraú, Brazil), Jan Lindstrom (University of Glasgow, United Kingdom), Kathryn Elmer (University of Glasgow, United Kingdom), Shaun Killen (University of Glasgow, United Kingdom)

m.pineda.1@research.gla.ac.uk

The harvest of animals from the wild can be intensive and selective on traits related to size, age at maturation, behaviour, and physiology. While the impacts of selectively removing animals are beginning to be understood for terrestrial animals and commercial food fisheries,

removal has been overlooked in smaller-scale artisanal fisheries. This is surprising given that harvesting for ornamental fisheries is selective for traits such as size and colouration, and the methods used to capture individuals may work in a manner analogous to commercial food fisheries. Here, we use combinations of lab and field experiments to understand what traits influence vulnerability to capture, what traits may be targeted by different gears, and finally what are the behavioural decisions involved when encountering gears in the wild. In the lab, we found that individuals with a higher vulnerability to capture were smaller, fatigued faster, and had lower metabolic rates. In the wild, we found that gear type influenced behavioural traits such as boldness and sociability. The findings from this research offer a rare look at selective pressures in the ornamental fishing industry and contribute to our broader understanding of how we can use lab and field work to understand how selective harvesting may drive evolutionary changes in wild fish populations.

A17.12 BEHAVIOURAL TRAITS OF BROOK TROUT PARR (SALVELINUS FONTINALIS): INVESTIGATING ECOTYPES

Wednesday 9th July 2025 10:15

Sofia Sabbagh (Université du Québec à Rimouski, Canada), Eva Enders (Institut National de la Recherche Scientifique, Canada), Emmanuelle Chrétien (Université du Québec à Rimouski, Canada)

sofia.sabbagh@uqar.ca

Brook trout (Salvelinus fontinalis) populations have experienced marked declines throughout their native range in North America, with anadromous individuals being particularly affected. The anadromous ecotype of brook trout migrates to saltwater habitats, whereas the resident ecotype remains in freshwater. Both ecotypes can coexist within the same population and interbreed, but they are morphologically indistinguishable before parr migration. Since behavioural traits likely co-evolved with life-history traits, studying behavioural biology can help better understand the mechanisms that underlie ecotype determination, which is essential for optimizing conservation efforts. To explore the links between parr behaviour and the adopted ecotype, we quantified boldness, exploration, and aggressiveness in brook trout parr from the Sainte-Marguerite River (QC, Canada), comparing individuals captured downstream during their spring migration (anadromous) and in upstream tributaries (residents). All individuals were subjected to a shelter test, an openfield test, and a mirror test. Results showed that latency to emerge from shelter as well as explored surface area did not differ between ecotypes. However, resident individuals stayed mostly along the arena’s periphery during the open-field test, whereas anadromous fish ventured more often into the center, indicating greater boldness in the latter. During the mirror test, resident individuals exhibited significantly higher frequencies of striking their reflection than anadromous individuals. This suggests residents are more aggressive, which may reduce their need to migrate for resources. Overall activity increased with sampling date, suggesting seasonal variations in behavioural expression. These findings improve our understanding of ecotype-associated traits and provide insights for brook trout conservation.

A17.13 UNRAVELING THE ENERGY

PHYSIOLOGY

OF SEA URCHIN LARVAE IN RESPONSE TO ENVIRONMENTAL CHANGE

Wednesday 9th July 2025 11:00

Min-Chen Wang (Christian-Albrechts-University Kiel, Germany), Meike Stumpp (Christian-Albrechts-University Kiel, Germany)

mcwinlab@gmail.com

Larval fitness strongly determines a marine species’ performance and population recruitment, influencing its role in ecosystem dynamics. As part of the planktonic food web, sea urchin larvae contribute to nutrient cycling and overall ecosystem stability. However, how environmental stressors like ocean acidification (OA) impact energy allocation and metabolic regulation during their development remains unclear. This study investigated how sea urchin larvae regulate their energy fuel to maintain homeostasis under normal conditions and how they respond to stress. Our results indicated that sea urchin larvae experienced a high-energy-demand phase before feeding. Our results indicated that sea urchin larvae experienced a high-energy-demand phase before feeding. However, under OA stress, mortality increased after feeding began, when energy consumption had already declined. Whether this is due to an imbalance between food supply and energy demand requires further investigation.

A17.14 A PROTON CHANNEL REGULATES VESICULAR PH RELEVANT FOR CALCIFICATION IN THE SEA URCHIN LARVA

Wednesday 9th July 2025 11:00

Marian Y Hu (Institute of Physiology Kiel University, Germany)

m.hu@physiologie.uni-kiel.de

Many marine calcifiers produce their shells and skeletons by the intracellular formation of an amorphous mineral precursor. Here calcification and pH regulation are intrinsically linked due to the pHdependency of the carbonate system. However, the pH conditions within CaCO3 forming vesicles and how they are affected by changes in environmental pH remain little understood. Here we study the function of a proton channel Otop2l in mediating proton permeability between the marine environment and the calcification vesicles inside of calcifying primary mesenchyme cells (PMCs) of the sea urchin larva. Intracellular and intra-vesicular pH recordings using pH sensitive dyes demonstrated a high proton permeability of PMCs that also affects pH in endocytotic vesicles in with the mineral precursor is formed. Functional characterizations of the proton channel Otop2l in heterologous expression systems demonstrate an activation by Ca2+ and Mg2+, two ions that are highly enriched in the calcification vesicle. Life-cell recordings using simultaneous tacking of pH and calcium ions in endocytosed vesicles demonstrate a trafficking of Ca2+ and alkaline CO3 2- rich vesicles that exocytose their contents to the mineralization front. Based on these findings we propose that calcifying cells of the sea urchin larva use an “open” calcification system to promote

high carbonate saturation states in sub-cellular compartments to promote CaCO3 production which can be considered energetically advantageous. Our results also suggest a partly separate trafficking of Ca2+ and CO3 2- -rich vesicles to the site of mineralization which leads us to rethink the concept of vesicular mineralization.

A17.15 THE COLD STRESS SYNDROME OF INSECTS ACROSS TIME, TEMPERATURE, AND THERMAL NICHE

Wednesday 9th July 2025 11:30

Mads K Andersen (Aarhus University, Denmark), Sebastian F Jakobsen (Aarhus University, Denmark), Clara G Byrge (Aarhus University, Denmark), Johannes Overgaard (Aarhus University, Denmark)

mads.andersen@bio.au.dk

Thermal tolerance is a key factor limiting insect biogeography, with cold tolerance strongly predicting species distribution. Cold-hardy species can either survive freezing, or survive extreme cold by avoiding freezing, but most insects are chill susceptible and succumb to direct effects of low temperature. However, different chill susceptible species vary enormously in their ability to tolerate cold. Research over the last two decades has outlined a number of commonalities in these insects that seem to suffer from the same homeostatic disruption when exposed to stressful cold. This cold stress syndrome stems from insufficient ionoregulatory capacity at low temperature and manifests as a gradual increase in hemolymph K+ concentration (hyperkalemia). The loss of ion balance depolarizes excitable tissues, resulting in cell death and ultimately also mortality. In the present study, we used a comparative model system of closely and distantly related Drosophila species to examine the temporal progression of hemolymph hyperkalemia during cold stress, in order to explore how the onset of injury and mortality relates to the cold-induced hyperkalemia. These experiments included exposure of different species to varying intensities of cold stress, and our preliminary findings support a strong and explanatory association between the degree of hyperkalemia and the onset of cold-induced injury, regardless of species tolerance. Together, our data suggests that all chill susceptible Drosophila species are limited in their cold tolerance by a shared physiological sensitivity to hemolymph K+ and, by extension, that differences in tolerance are directly linked to interspecific variation in their ability to mitigate this disruption.

A17.16 HIGH CO2 AND ALKALINITY IN AQUACULTURE SEVERELY IMPACT HAEMOLYMPH IONIC COMPOSITION AND PROTEIN HOMEOSTASIS IN KING PRAWNS (PENAEUS VANNAMEI)

Wednesday 9th July 2025 11:45

Trystan B Sanders (University of Exeter, United Kingdom), Joseph L. Costello (University of Exeter, United Kingdom), Nicholas Smirnoff (University of Exeter, United Kingdom), Robert P. Ellis (University of Exeter, United Kingdom), Rod W. Wilson (University of Exeter, United Kingdom)

t.sanders3@exeter.ac.uk

The global expansion of intensive aquaculture is exposing aquatic animals to increasing environmental pCO2 , but also alkalinity which is artificially elevated to at least partially restore seawater pH. While CO2 -driven ocean acidification research has revealed negative effects on marine invertebrate physiology and growth, the combined effects of high pCO2 and alkalinity are poorly understood. To address this, we exposed economically important king prawns to five aquaculture relevant pCO2 levels for 6 weeks (1,100-20,000 µatm) all pH adjusted to 7.5 by adding NaHCO3 to reflect common aquaculture practices. We fully characterised haemolymph acid-base parameters and ionic composition (inorganic cation/anions, protein and organic osmolytes) in combination with measures of protein homeostasis. These included hemocyanin oxygen affinity (P50 ) as a measure of protein function, and protein ubiquitination and 20S proteasomal activity, both indicators of protein degradation. Initial results show that rising CO2 /alkalinity causes up to 20 % reductions in haemolymph [Na+ ], [K+ ] and [Cl- ] which were associated with a slight linear decrease in hemocyanin P50. Ongoing work also suggests that protein degradational activity, which is important for body growth and in maintaining a functional proteome, is impaired by high CO2 /alkalinity. Overall, we show that high CO2 and alkalinity in aquaculture severely alters extracellular ionic composition and modifies the function of a key respiratory protein and the regulation of whole-body protein turnover. These findings give insight into how high CO2 impacts protein homeostasis in marine organisms, highlighting a potential mechanism by which adverse environmental conditions impact physiological function and performance in marine organisms.

A17.17 MECHANISMS OF NITROGENOUS WASTE AND ACID-BASE REGULATION DURING PARASITISM BY THE JUVENILE SEA LAMPREY, PETROMYZON MARINUS

Wednesday 9th July 2025 12:00

Alex R Quijada-Rodriguez (Wilfrid Laurier University, Canada), Kyle Sarabia (Wilfrid Laurier University, Canada), Bhavik Mistry (Wilfrid Laurier University, Canada), Patrícia Ferreira (University of Ottawa, Canada), Jonathan M Wilson (Wilfrid Laurier University, Canada), Michael P Wilkie (Wilfrid Laurier University, Canada)

aquijadarodriguez@wlu.ca

Sea lamprey are anadromous fishes native to the Atlantic coast of North America and Europe. They are considered invasive in the Laurentian Great Lakes, where landlocked populations have contributed to native fisheries’ decline. Sea lamprey spend most of their life cycle as filter-feeding larvae before undergoing a complex metamorphosis into a parasitic blood-feeding juvenile, which migrates to sea or in landlocked populations to lakes where they feed on fish hosts (e.g. salmonids). As parasitic juveniles, sea lamprey can consume as much as 30% of their body mass per day in blood, requiring efficient mechanisms to deal with metabolic wastes (ammonia, urea, and acids) from the host blood and those produced through their catabolism of ingested protein. This study investigated the nitrogenous waste and acid-base regulatory capacity of juvenile sea lamprey after three weeks of parasitizing rainbow trout. Further, we focused on the cellular and molecular mechanisms of post-prandial nitrogenous waste handling and acid-base regulation at the gills and throughout the digestive tract. Our results revealed a partially

uncompensated respiratory acidosis, increased nitrogenous waste, and base excretion in feeding lamprey. In the intestine, feeding led to acidification of the anterior and mid-intestinal regions and coincided with more pronounced apical/sub-apical H+ -ATPase staining in the enterocytes. These findings reveal key insights into the regulatory capacity that has allowed sea lamprey to contribute to declines in fish populations in the Great Lakes and provide insights into mechanisms utilized by sanguivores to deal with the challenges of blood-feeding.

A17.18

THE

FISH PSEUDOBRANCH:

NA+/H+ EXCHANGER 5’S ROLE IN BLOOD ACIDIFICATION FOR EYE OXYGENATION. NOW YOU SEE IT, NOW YOU DON’T?

Wednesday 9th July 2025 12:15

Jonathan Wilson (Wilfrid Laurier University, Canada), |Patrícia Ferreira (University of Ottawa, Canada), Tali Laszlo (Wilfrid Laurier University, Canada), Raunaq Khan (Wilfrid Laurier University, Canada), Filipe Castro (CIIMAR, Portugal)

The pseudobranch is an enigmatic organ in fishes with a still elusive function .[PF1] It has its origin as gill tissue and has retained similarities in structure; however, in a number of species it has evolved as an embedded structure within the wall of the buccalopercular cavity without a free surface exposed to the water, and thus lacking typical branchial roles in gas, ion and acid-base exchange with the environment. Since it represents a portal system with oxygenated blood continuing to the retina of the eye, it has thus been proposed to have a role in acidifying blood to aid oxygen unloading at the eye. We have evidence in other fishes that the sodium-proton exchanger-5 (nhe5/slc9a5) may be important in this blood acidification mechanism. To test this hypothesis, our objective was to compare the pseudobranch and Nhe5 expression in the eyedsurface and eyeless Chica cavemorphs of the Mexican tetra (Astyanax mexicanus). We predicted a reduced pseudobranch and reduction/ absence of Nhe5 expression in the cavemorph. We found blood facing Nhe5 expression in the pseudobranch of the surface morph, and noted the apparent absence of this organ in the adult cavemorph. However, the organ could be detected histologically and although much reduced in size still expressed Nhe5. This was also reflected during larval development where the pseudobranch could be more easily detected than in the cavemorph. Taken together, our results indicate that the pseudobranch’s function is likely linked to the eye although not completely lost in A. mexicanus Chicacavemorphs.

A17.52 CONSTRAINTS ON CARDIAC PUMPING CAPACITY AND TISSUE

EXTRACTION, NOT HEART RATE, LIMIT HYPOXIA TOLERANCE

Thursday 10th July 2025 09:00

Fiona P.H. Durnford (Memorial University, Canada), Emma S Porter (Memorial University, Canada), Kurt A Gamperl (Memorial University, Canada)

fvandenbogae@mun.ca

Understanding the mechanisms that mediate fish responses to the climate change stressors of high temperature and hypoxia is crucial for identifying environmental thresholds and implementing effective conservation and management strategies. Studies have examined the effects of hypoxia on fish upper thermal tolerance and cardiorespiratory physiology. In contrast, in this study, we fitted 10o C-acclimated Atlantic salmon (Salmo salar) with blood flow probes, placed them into respirometers, and measured their cardiorespiratory response to decreasing water oxygen levels (5% air sat. every 15 minutes) at 10o C and after temperature was first increased to 14 and 18o C overnight. No clear critical oxygen threshold (Pcrit ) was identified at 10o C, and the % air sat. at which the salmon went bradycardic was 42.4. Whereas values for Pcrit and the oxygen level at which bradycardia were initiated in 14 and 18o C fish were 52.1 vs. 57.2 and 61.0 vs. 77.1, respectively. Fish at 10o C lost equilibrium (LOE) at 21.0 % air sat. vs. 27.5 at 14o C and 41.9 at 18o C. Interestingly, their LOE was inversely related to heart rate (fH , 29.1, 36.6 and 42.8 beats min-1 at 10, 14 and 18o C, respectively), and it was the inability of salmon at 18o C to increase stroke volume when fH fell, and to increase blood oxygen extraction (MO2 /Q; which was much higher in normoxia at 18o C), that limited hypoxia tolerance. These data are consistent with recent studies which show that higher fHs are detrimental to hypoxia tolerance, whereas the heart’s pumping capacity and increases in MO2 /Q are critical.

A17.53 THE ROLE OF PLASMA ACCESSIBLE CARBONIC ANHYDRASE IN INCREASING HYPOXIA TOLERANCE IN ATLANTIC SALMON (SALMO SALAR)

Thursday 10th July 2025 09:00

Colin J Brauner (The University of British Columbia, Canada) brauner@zoology.ubc.ca

During stress, adrenergically stimulated sodium-proton-exchangers (β-NHE) create H+ gradients across the red blood cell membrane that are short-circuited in the presence of plasma-accessible carbonic anhydrase (paCA) at the tissues in some teleosts, enhancing O 2 unloading from their pH-sensitive haemoglobins (Hb). This has been shown to be important during exercise but has not been investigated during exposure to environmental hypoxia. We hypothesized that the presence of paCA would increase hypoxia tolerance. To test this, Atlantic salmon were subjected to a progressive reduction in environmental O2 levels (at a rate of 1.79 ± 0.21% O2 min-1 ) until loss of equilibrium (LOE) with and without injection of C18, a membrane impermeable CA inhibitor. In fish injected with C18, LOE occurred at 19.50 ± 1.74% O2 while those receiving only a saline injection exhibited LOE at 13.17 ± 1.90%. Thus, the presence of paCA clearly plays an important role in increasing hypoxia tolerance in Atlantic salmon, providing further support for the functional significance of RBC β-NHE short-circuiting in cardiovascular O2 transport in vivo

A17.54 GETTING TO THE HEART OF THINGS: DOES HEART RATE DETERMINE THE THERMAL TOLERANCE OF NILE TILAPIA (OREOCHROMIS NILOTICUS)?

Thursday 10th July 2025 09:30

Emma S Porter (Memorial University of Newfoundland, Canada), Frank M Smith (Dalhousie University, Canada), Kurt Gamperl (Memorial University of Newfoundland and Labrador, Canada)

esporter@mun.ca

This research examined the cardiac thermal tolerance of Nile tilapia across different levels of biological organization to better understand the heart’s role in determining fish thermal tolerance. First, we performed critical thermal minimum and maximum tests (at 2°C h-1) on 25°C-acclimated adult tilapia (~350 g) fitted with Transonic® flow probes [to measure cardiac output (Q) and heart rate (fH )] until the loss of equilibrium (LOE), which occured at ~9.5 and 40.5°C, respectfully. Given that these fish relied predominantly on fH to modulate Q, and that LOE occurs due to the loss of homeostasis at the tissue/cellular level, we then measured cardiac electrocardiograms and electrical conduction in isolated hearts from fingerlings (<10 g) to acute changes in temperature (±0.5°C min-1 ) until they experienced AV block. Cardiac failure in vitro occurred at ~ 14 and 38°C, respectively, suggesting that isolated hearts had a constrained thermal window (by ~22%). Futher, tilapia studied in vitro had: 1) higher values for both minimum and maximum fH (by 61 and 17%, respectively); 2) a similar absolute scope for fH (i.e., 115.5 beats min-1 in vitro vs. 110.7 beats min-1 in vivo); and 3) a temperature at maximum fH that was 5°C lower than in vivo. Collectively, these data suggest that while fH (pacemaker function and electical conductance across the AV junction) largely determine the survival of tilapiain vivowhen exposed to acute changes in temperature, other important cardioprotective mechanisms (e.g., hormonal modulation and cholinergic tone) are crucial to preserving cardiac function.

A17.55 THERMAL TOLERANCE OF NATIVE AND HYBRID AUSTRALIAN MUSSELS: IMPLICATIONS UNDER A WARMING CLIMATE

Thursday 10th July 2025 09:45

Alex A Berry (Deakin University, Australia), Louisa Williams (University of Exeter, United Kingdom), Samantha Howitt (University of Queensland, Australia), Timothy Clark (Deakin University, Australia), Robert Ellis (University of Exeter, United Kingdom), Brent Lockwood (University of Vermont, Australia), Cynthia Riginos (University of Queensland, Australia), Craig Sherman (Deakin University, Australia) jmwilson@wlu.ca

Understanding the upper thermal tolerance thresholds of animals is an important component in predicting their responses to anthropogenic climate change. Methodology for testing this in fish is well established, with the temperature at which loss of equilibrium (LOE) occurs defined as the critical thermal maximum (CTmax). The effect of

rapidly increasing temperature on heart rate has been investigated in Mytilus mussels, with Arrhenius break point temperature and flatline temperature identified as key indicators of thermal tolerance. While valuable, these are extreme end point measurements that do not allow assessment of the behavioural mechanisms mussels use to cope with increased thermal stress. Currently, there are no widely used behavioural indicators of thermal tolerance limits in mussels. Here, we investigated the effects of rapidly warming temperature on valve gape behaviour and heart rate in two lineages of Mytilus currently inhabiting the Australian coastline: native M. planulatus and hybrids of M. planulatus with invasive M. galloprovincialis. By concurrently measuring heart rate and valve behaviour under rapid warming, we assess if these parameters are important behavioural mechanisms for bivalves under thermal stress and if variation exists between mussel lineages. Our results provide insight into how Australian Mytilus populations will be affected by climate change in an ocean warming hotspot.

Email Address for correspondence: a.berry@deakin.edu.au

09:45 Thursday 10th July 2025

A17.77 REGULATION OF CARDIAC REMODELING IN FISH DURING THERMAL ACCLIMATION

Thursday 10th July 2025 10:00

Todd E Gillis (University of Guelph, Canada), Elizabeth Manchester (University of Guelph, Canada), Jared Shaftoe (University of Guelph, Canada)

tgillis@uoguelph.ca

Thermal acclimation can lead to significant changes to the form and function of the heart of some fish species. This includes increases to the rate and level of force generation by the trout heart with cold acclimation as well as modifications to the structure and composition of trout and zebrafish myocardium. We have recently demonstrated that modifications to the zebrafish heart, caused by cold acclimation, are reversable with rewarming but that this response decreases body condition. To gain insight into the cellular processes that initiate the remodelling response during cold exposure and cold acclimation we recently characterized the cardiac phosphoproteome and proteome of zebrafish following 24 ...h or 1 week exposure to 20°C from 27°C; or at multiple points during 6 weeks of acclimation to 20°C from 27°C. Our results indicate that cold exposure causes an increase in mitogenactivated protein kinase signalling, the activation of stretch-sensitive pathways, cellular remodelling via ubiquitin-dependent pathways and changes to the phosphorylation state of proteins that regulate myofilament structure and function. This work also suggests that the change to the zebrafish heart with cold acclimation is a stepwise process starting with changes to the phosphorylation of critical proteins then transitioning to changes in protein expression as the duration of acclimation increases. Finally, coupled with our previous work these results suggest that the remodeling response is initiated by an increase in biomechanical forces activating cell signalling pathways that lead to changes to the composition and structure of the heart.

A17.57 GILL ARCH SPECIFIC TISSUE REGENERATION IN RELATION TO FISH IMMUNE STATUS IN RAINBOW TROUT

Thursday 10th July 2025 10:15

Ensiyeh Ghanizadeh-Kazerouni (The University of British Columbia, Canada), Negar Norouziesfahani (The University of British Columbia, Canada), David Metzger (The University of British Columbia, Canada), Mark D. Fast (University of Prince Edward Island, Canada), Colin J. Brauner (The University of British Columbia, Canada)

ghanizad@zoology.ubc.ca

Fish gills are susceptible to damage from various stressors, which can impact gill physiology and compromise fish health and survival. We have previously shown that gills can regenerate in Atlantic salmon with significant inter- and intra-individual variation. Using rainbow trout as a model, this study investigated whether fish immune system status can predict gill tissue regeneration and how that is affected by level of tissue loss. Additionally, we examined whether gill regeneration differs across the four gill arches given their speculated functional differences.

Juvenile rainbow trout (average mass: 424.1g ± 62) underwent 30% and 50% resection on all four arches. The resected filament tips were collected (baseline) and analyzed for immune- and metabolismrelated gene expression (il-4,il-15,cox,mif,pdk,mcsf2, andil-8). Filament regeneration was quantified at week-12 post-resection. Our findings showed that rainbow trout gill tissue regenerates following resection, with 50% resected filaments exhibiting a higher regeneration ratio than 30% resected filaments. Regeneration also varied among arches and while the fourth arch showed the highest regeneration ratio, the second arch had the lowest. The expression of immune- and metabolism-related genes did not differ across arches. However, there was a negative correlation betweencoxandmifand the regeneration ratio in 50% resection, and betweenmcsf2andcoxand the regeneration ratio in 30% resection.

These findings highlight arch-specific differences in gill regeneration and suggest that fish immune and metabolic status may contribute to inter-individual variation in tissue regeneration, with their role depending on the level of tissue loss.

A17.58 SUCCINATE – AN ANAEROBIC END-PRODUCT ALLOWING ANOXIC SURVIVAL IN CRUCIAN CARP (CARASSIUS CARASSIUS)

Thursday 10th July 2025 11:00

Göran E Nilsson (University of Oslo, Norway), Lucie Gerber (University of Oslo, Norway), Jenny Lundeberg (University of Oslo, Norway), Sjannie Lefevre (University of Oslo, Norway)

g.e.nilsson@ibv.uio.no

The members of the cyprinid genus Carassius , crucian carp ( C. carassius ) and goldfish ( C. auratus ), are well known for their unique ability to produce ethanol as an end-product of anaerobic metabolism, an ability that is thought to be a major explanation for their anoxia tolerance. Here we show that they also run Complex II

(succinate dehydrogenase) of the mitochondrial electron transport system (ETS) backwards, producing succinate from fumarate. This will allow Complex I of the ETS to maintain proton pumping and keep the mitochondria charged in the absence of oxygen as electron acceptor. The maintained mitochondrial membrane potential is essential for anoxic survival as depolarized mitochondria is a death signal. While the strategy leads to a build-up of succinate, our data suggest that this happens primarily in the liver. In addition, a significant amount of succinate is released into the water, probably over the gills just like ethanol. Upon reoxygenation the extensive succinate load needs to be handled in a way that does not lead to hyper-charged mitochondria with free electrons causing a detrimental production of oxygen radicals. The liver is likely to take on this task by both having ADP available so that ATP synthase can harvest the proton gradient for ATP production, and by a massive up-regulation of uncoupler protein 2 (UCP2) which can allow protons to flow back into the mitochondrial matrix. Like ethanol production, we suggest that succinate production is fundamental for allowing crucian carp to be one of the most anoxiatolerant vertebrates.

A17.59 EXPOSURE TO ENVIRONMENTALLY REALISTIC FLUCTUATIONS IN TEMPERATURE AND SALINITY REDUCES THE HYPOXIA TOLERANCE OF TOADFISH

Thursday 10th July 2025 11:00

M. Danielle McDonald (Rosenstiel School of Marine Atmospheric and Earth Science University of Miami, United States), Isabelle Nelson (Rosenstiel School of Marine Atmospheric and Earth Science University of Miami, United States), Meghan Roberts (Rosenstiel School of Marine Atmospheric and Earth Science University of Miami, United States), Zofia Kaleta (Rosenstiel School of Marine Atmospheric and Earth Science University of Miami, United States), Catherine Toole (Rosenstiel School of Marine Atmospheric and Earth Science University of Miami, United States)

dmcdonald@miami.edu

The Gulf toadfish, Opsanus beta, is a benthic marine teleost fish found in seagrass beds within the Gulf of Mexico and along the Southern coast of Florida. Even in healthy seagrass beds, toadfish in the summer months are exposed to diurnal fluctuations in oxygen and temperature as well as periodic bouts of reduced salinity due to intense rain. But, anthropogenic nutrient inputs to seagrass beds have fueled algal blooms, which over time has killed off the seagrass, and has made the natural environmental fluctuations even more extreme, resulting in seasonal fish kills. Toadfish are amongst the most susceptible. While toadfish are considered tolerant to most environmental stressors, regulation index and Pcrit data do not necessarily support a high tolerance to hypoxia. Therefore, the objectives of this study were to directly quantify the hypoxia tolerance of toadfish and then to ascertain whether high temperatures and acute reductions in salinity reduce hypoxia tolerance. To do this, toadfish were exposed to low oxygen (PO2 = 0.4 kPa) and the time for toadfish to lose equilibrium (tLOE) was measured under normal conditions and when exposed to a combination of high temperatures and low salinity, mimicking summer environmental conditions in Biscayne Bay. We found that toadfish are very hypoxia tolerant and high temperatures and reduced salinities reduced their hypoxia tolerance. This finding could account for why toadfish are found in high numbers during summer fish kills in

Biscayne Bay and speaks to the importance of improving regulations on nutrient inputs to coastal watersheds.

A17.61 INDIVIDUALS OF THE INVASIVE ROUND GOBY FACE PHYSIOLOGICAL AND BEHAVIOURAL TRADE-OFFS IN THEIR SENSITIVITY TO SALINITY

Thursday 10th July 2025 11:45

Tommy Norin (DTU Aqua - Technical University of Denmark, Denmark), Mikael Van Deurs (DTU Aqua - Technical University of Denmark, Denmark), Jane W. Behrens (DTU AquaTechnical University of Denmark, Denmark)

tnor@aqua.dtu.dk

=Invasive species are organisms that spread, often humanmediated, from their native range into novel environments where they become established and often cause ecological (and economic) damage, including competition with native species for space, food, and survival. One of these species is the round goby (Neogobius melanostomus), a fish introduced into both fresh and brackish waters around the world. To understand how round goby will perform in the ocean, if they continue to spread into this higher-salinity environment, we investigated how individuals differ in their physiological and behavioural (co)sensitivity to changes in salinity. We measured the physiology (metabolic rates, growth) and behaviour (activity, dispersal, exploration) of 77 individual round goby after acclimation to each of five salinities (0, 10, 19, 24, 28 ppt) in the laboratory and quantified trait variation and sensitivity to salinity as their reaction norm intercepts (at 10 ppt) and slopes. We find that the fastestgrowing individuals at 10 ppt—the salinity the fish were caught at—are also the most behaviourally active and explorative at this salinity, and thus more likely to spread to new locations and dominate. However, at salinities higher than 15 ppt, these individuals lose their growth advantage and are faced with the most severe reductions in aerobic metabolic scope relative to conspecifics. This cross-over at 15 ppt for which phenotypes have the performance advantage is likely to determine the trait composition of round goby populations, the selective pressures acting on these (combinations of) traits, and thus the continued invasion success of the species.

A17.62 CAN SEX-DIFFERENCES IN FIELD METABOLIC RATE HELP EXPLAIN SEXUAL SIZE DIMORPHISM IN WALLEYE?

Thursday 10th July 2025 12:00

Christian J Bihun (Trent University, Canada), Graham D Raby (Trent University, Canada), Matthew D Faust (Ohio Department of Natural Resources, United States), Jake W Brownscombe (Department of Fisheries and Oceans, Canada), Erin M.C Stewart (Trent University, Canada), Erin B Ritchie (Trent University, Canada)

Christianj.bihun@gmail.com

Bioenergetic models provide a useful approach to predicting climatedriven changes to fish populations, and can be used to address

fundamental questions in animal ecology. The bioenergetic model for walleye has been used extensively for decades yet is not parameterized with robust estimates of metabolism, potentially limiting its accuracy. Walleye are also sexually dimorphic, with females growing to much larger sizes than do males, a phenomenon whose proximate cause is not fully understood. To improve walleye bioenergetic models and help unravel the mystery of sexual size dimorphism, we have engaged in a multi-year field and lab project to estimate metabolism (including standard metablolic rate, specific dynamic action, and field metabolic rate) in male and female walleye across a range of water temperatures and body sizes. Here, we will review our progress in updating the walleye bioenergetic model via field and lab experiments. Accelerometer sensor transmitters implanted in walleye across four Great Lakes are giving us unprecedented insights into spatial and temporal patterns of energy expenditure in wild fish, and are helping us tease apart sex-differences in fish bioenergetics

A17.63 LIFE HISTORY ATTRIBUTES INFLUENCING METABOLIC VARIATION IN AN ESTUARINE FISH

Thursday 10th July 2025 12:15

Elizabeth C Hoots (Deakin University, Australia), Luis L Kuchenmueller (Deakin University, Australia), Michael R Skeeles (Deakin University, Australia), Timothy D Clark (Deakin University, Australia) beth.hoots@research.deakin.edu.au

Maintenance metabolism, or standard metabolic rate (SMR), is an important metric for understanding the baseline metabolic requirements of animals and is measured on fasted, resting individuals. Ongoing debate surrounds some of the practicalities and interpretations of measuring SMR in juvenile animals, especially fish, as it can be argued that even fasted juvenile animals will maintain some level of metabolic activity associated with “background” growth. Equally, there is little consensus around the role of reproductive maturation in influencing the measurement and interpretation of SMR.

Here, we take three large datasets on Galaxias maculatus , a diadromous fish species with a pelagic oceanic larval phase, to assess differences in SMR in differentially growing individuals as they transition from juveniles to reproductive adults across four acclimation temperature treatments (15, 18, 20, and 23 °C). We predict that if growth and/or the level of reproductive maturation are significant drivers of variability in SMR, there will be positive relationships between mass-standardised SMR and individual growth phenotypes and/or gonadal volume.

Linear regression analyses showed that individual growth phenotypes had negligible influence on the magnitude or variability in SMR, suggesting that SMR measurements of fasted juvenile fish are not detectably impacted by growth. We also found no clear evidence of a positive relationship between SMR and level of reproductive maturation, raising questions around the energetic burden of reproduction on fish. It has been suggested that metabolism, growth and reproductive investment are co-evolved to maximize lifetime fitness, and we encourage further research into the complicated nature of this relationship.

A17.65 GETTING A BURN-OUT: HOW HEATWAVES IMPACT EUTROPHIC FRESHWATER ECOSYSTEMS

Friday 11th July 2025 09:30

Sabiha Akter (ECOSPHERE University of Antwerp, Belgium), Jeroen Van Wichelen (Research Institute for Nature and forest, Belgium), Jonas Schoelynck (ECOSPHERE University of Antwerp, Belgium), Gudrun De Boeck (ECOSPHERE University of Antwerp, Belgium)

sabiha031@gmail.com

Aquatic ecosystems are increasingly disrupted by anthropogenic stressors such as nutrient-driven eutrophication and global warming. Understanding these multi-stressor effects is crucial yet challenging due to the complexity of ecosystem interactions. Here, we investigated the impacts of nitrate enrichment (5, 50, or 200 mg/L) and heatwaves on semi-realistic mesocosm aquatic ecosystems, assessing primary producers (algae, submerged and floating macrophytes) and consumers (Daphnia, fish). The findings revealed that heatwaves and nutrient loading influence ecosystems in complex ways. At the ecosystem level, we did not observe a synergistic positive effect of heatwaves and nitrate on algal growth, as is often reported in studies focusing on single organisms. Moreover, results revealed that nitrate enrichment alone reduced submerged macrophyte growth while promoting floating macrophyte dominance. Combined nitrate and heatwave stressors led to a decline in both macrophyte types, though the reduction was not statistically significant for floating macrophytes. We can conclude that neither stressor alone shifted the ecosystem to a phytoplankton-dominated turbid state; however, nitrate enrichment alone resulted in a floating macrophyte-dominated turbid state. Additionally, nitrate and heatwave interactions negatively affected both primary (Daphnia) and secondary (fish) consumers, potentially allowing the ecosystem to shift to a phytoplankton-dominated turbid under extreme conditions. In conclusion, these findings underscore the species-specific and time-dependent nature of stressors impacts. Moreover, our finding emphasizes the importance of conducting additional mesocosm experiments with longer durations and more diverse species compositions to elucidate ecosystem-level responses and adaptive capacities under multi-stressor scenarios.

A17.66 DOUBLE TROUBLE: THE COMBINED IMPACT OF HEATWAVES AND OCEAN ACIDIFICATION ON MARINE LARVAE

Friday 11th July 2025 10:00

Christine Blurton (Institute of Zoology Christian-AlbrechtsUniversität zu Kiel, Germany), Rose Chanfreau (Department of Biological and Environmental Sciences University of Gothenburg, Sweden), Sam Dupont (Department of Biological and Environmental Sciences University of Gothenburg, Sweden), Meike Stumpp (Institute of Zoology ChristianAlbrechts-Universität zu Kiel, Germany)

cblurton@zoologie.uni-kiel.de

Climate change is increasing the frequency and intensity of marine heatwaves, which, alongside ocean acidification, represent significant

challenges for marine organisms. Heatwaves, which involve prolonged periods of unusually high temperatures, can disrupt physiological processes, reduce nutrient availability by limiting deep-water mixing, and compound the effects of decreasing ocean pH. While the effects of chronic ocean acidification are well studied, the impacts of shortterm temperature spikes combined with acidification on larval development remain unclear. We aim to assess how acute heatwave events and decreasing pH influence larval resilience, metabolism, and stress in green sea urchin (Strongylocentrotus droebachiensis) larvae. Larvae will be reared under controlled pH conditions (ambient and lower pH) and exposed to simulated marine heatwaves to examine the combined effects of elevated temperature and decreasing pH. This setup allows us to determine how rising temperatures and acidification interact, affecting larval physiology. To assess these effects, we will evaluate a range of physiological and developmental responses. We will measure larval resilience and development, focusing on density, growth, and calcification. Additionally, we will assess energy metabolism and physiological stress, with a focus on metabolic rates. Lastly, we will examine nutritional dynamics, focusing on feeding behavior, gut alkalinity, digestive enzyme activity, and energy storage.

By studying how heatwaves and acidification interact, this research will provide critical insights into the physiological and developmental responses of marine calcifiers to future climate conditions.

A17.67 1.IMPACTS OF INCREASING TEMPERATURES ON KEY PHYSIOLOGICAL FUNCTIONS OF THE MEDITERRANEAN SPIDER CRAB MAJA SQUINADO (HERBST, 1788)

Friday 11th July 2025 10:15

Jehan-Hervé Lignot (UMR MARBEC, France), Marie-Catherine Raffalli (University of Corte, France), Eric Durieux (University of Corte, France), Montserrat Solé (CSIC Barcelona, Spain), Ouafa El-Idrissi (University of Corte, France), Radia Lourkisti (University of Corte, France), Jeremy Bracconi (University of Corte, France), Ambre Crescioni (University of Corte, France), Nicolas Gattacceca (University of Corte, France), Jean-Baptiste Ronchi-Perfetti (University of Corte, France), Jean-José Filippi (University of Corte, France)

jehan-herve.lignot@umontpellier.fr

Since the 1950s, atmospheric and oceanic warming has intensified, significantly increasing the frequency of marine heatwaves (MHWs) and impacting marine ecosystems. Poikilotherms, such as the Mediterranean spider crab Maja squinado, are particularly vulnerable due to their inability to regulate body temperature. This ecologically and economically valuable species is declining and even disappearing in some Mediterranean regions, making it a key candidate for ecological restoration. Females lay eggs at sub-surface waters, above the thermocline, and juveniles remain at 5–20 m depth for about two years before reaching maturity and migrating deeper. Therefore, during growth and reproduction,Maja squinadois exposed to rising surface temperatures and MHWs. Understanding the physiological impact of warming on juveniles and adults is essential for conservation. This study investigates temperature effects on key physiological functions: energy, hydromineral and oxidative stress balance along with detoxification mechanisms, in order to describe the integrated heat stress response, and to provide a better understanding of M. squinado’s interactions with its ecosystem.

This study revealed that juvenile and adult metabolic rates increase with temperature, adults reacting at lower temperatures likely due to environmental acclimation. Juvenile hemolymph osmotic pressure rises quickly before stabilizing, indicating significant but manageable stress. Oxidative stress also increases with temperature, but juveniles activate antioxidant enzymes and detoxification mechanisms to counteract it. While rising temperatures strongly impact this species, it demonstrates resilience through defense mechanisms. However, it is crucial to consider potential physiological trade-offs, such as the impacts of feeding or predator defense, resulting on increased energy investment in these physiological responses.

A17.68 ASSESSING BIOPHYSICAL MODEL PERFORMANCE FOR PREDICTING THERMOREGULATORY RESPONSES IN FYNBOS BIRDS

Friday 11th July 2025 10:30

Martine Van den Berg (University of Cape Town, South Africa), Shannon R Conradie (University of Witwatersrand, South Africa), Susan J Cunningham (University of Cape Town, South Africa) vbrmar025@myuct.ac.za

A hotter and drier future with more frequent fire is predicted for the Fynbos biome. This will result in higher operative temperatures in the landscape, which may challenge birds’ ability to maintain body temperature (T b ) through evaporative water loss (EWL), while avoiding dehydration. Accurately modelling the physiological mechanisms underlying Fynbos birds’ thermoregulation will aid their conservation, however, it demands extensive species-specific data, which may be difficult to obtain. Therefore, we (1) used a model species, the White-browed Sparrow-weaver (Plocepasser mahali), to assess the sensitivity of a biophysical model to variation in speciesspecific morphological input parameters. We did this by evaluating the model’s performance in predicting EWL and Tb under standard respirometry conditions, using morphometric measurements from (a) live Sparrow-weavers from a specific study population and b) museum skins collected across the species range. The biophysical model accurately captured thermoregulatory responses of Sparrowweavers regardless of morphological parameterisation. We then (2) parameterised the biophysical model for 11 Fynbos bird species using species-specific museum data, and compared model predictions to published respirometry data for these species. Our model accurately captured EWL and Tb for each species modelled, except Orangebreasted sunbirds (Anthobapes violacea), where EWL predictions could not be validated. Biophysical models are a promising noninvasive tool to predict animals’ thermoregulation, and can be successfully parameterized with morphometric data from museum specimens. By using easily-obtained museum data, biologists can model impacts of climate change on thermal physiology for a large number of species across space and time.

A17.69 USING METABOLIC TRAITS TO EVALUATE SOUTHERN FLOUNDER HABITAT SUITABILITY IN THE GULF OF MEXICO

Friday 11th July 2025 10:45

Julie JH Nati (University of Texas Marine Science Institute, United States), Lu Lin (University of Texas Marine Science Institute, United States), Jeb Armstrong (University of Texas Marine Science Institute, United States), Andrew J Esbaugh (University of Texas Marine Science Institute, United States)

julienati3@gmail.com

Southern flounder (Paralichthys lethostigma) are a commercially and recreationally important species with a relatively narrow distribution in the western Atlantic ocean, extending from Virginia (USA) to the midpoint of the Gulf of Mexico. Despite consistent efforts on the part of fisheries managers, the southern flounder population has been in precipitous decline over the past 40 years. Here, we sought to inform on this dire situation by modelling theoretical habitat availability of southern flounder on the basis of the thermal and oxygen sensitivity of metabolic traits, while also comparing outputs to those of overlapping species with more robust populations (e.g. red drum and sheepshead minnow). To parameterize habitat availability models, we measured the thermal sensitivity of standard metabolic rate (SMR), maximum metabolic rate (MMR) and the critical oxygen threshold (Pcrit ) at four different temperatures (18,22,26 and 30°C). All metabolic traits were collected using standard intermittent flow respirometry protocols. The available data suggest that southern flounder exhibit a hypoxia vulnerability (i.e. Pcrit ) that is particularly thermally sensitive as compared to sheepshead minnow and red drum. More specifically, the thermal sensitivity of southern flounder is double that of red drum, while sheepshead minnow Pcrit is remarkably thermally insensitive. All species show relatively similar thermal sensitivities on SMR. These data will be discussed in the context of metabolic habitat availability along the Texas coast on the basis of seasonal water temperature and oxygen level data of relevant coastal and offshore habitats.

A17.70 ZONOCERUS VARIEGATUS AND ITS SURVIVAL STRATEGIES: DECADES OF STUDIES ON THE STRUCTURE, SECRETION, AND FUNCTION OF THE REPELLENT GLAND

Friday 11th July 2025 11:30

Adewumi B Idowu (Federal University of Agriculture Abeokuta, Nigeria), Oluwaseun S Odubote (Federal University of Agriculture Abeokuta, Nigeria), David Audu (Indiana University, United States)

idowuab@funaab.edu.ng

The repellent gland of the African grasshopper, Zonocerus variegatus, plays a central role in its defense mechanism. My decades of research into its anatomy and functionality have found this cuticle-lined lumen in the first and second abdominal segments, with activity from the third instar, and the size and secretory cells increasing with each moult. Preliminary characterisation of Z. Variegatus gland

secretions revealed the presence of alkaloids, proteins, free amino acids, trypsin-like proteinase, carbohydrases, lipases, Ca2+ , Mg2+ , and K+ ions, but not Na+ and (PO4)2− . Alkaloids were synthesised by the insect itself rather than being sequestered from food plants. The glycosides found in the secretions of wild grasshoppers revealed their potential to sequester secondary plant chemicals from their diets. Recent GC/MS analysis showed that the chemical composition of the repellent secretions of reared Z. variegatus secreted esters, alkanes, and alkenes, whereas wild insects exhibited a more diverse chemical profile, including heterocyclic aromatic hydrocarbons, amines, ethers, esters, and alcohols. Pyrazine, known for its role in chemical aposematism, was consistently detected in secretions from both reared and wild Zonocerus. The hydrocarbon constituents enhanced the repellent’s spreading ability by reducing viscosity. Food plants significantly influenced the secretion volume collected from adults, whereas seasonal changes had no significant effect. Later instars and adults could spray secretions up to 42 cm with a very pungent odour. This repellent gland secretion together with the species’ aposematic colouration serves as a potent defense against predators, contributing to its survival.

A17.71 THE SCENT OF DANGER: ELECTROPHYSIOLOGICAL AND BEHAVIOURAL RESPONSES OF THE CLAM (RUDITAPES DECUSSATUS) TO POTENTIAL ALARM CUES

Friday 11th July 2025 11:30

Ana Rato (Centro de Ciências do Mar do Algarve (CCMAR), Portugal), Joana Costa (Universidade do Algarve, Portugal), Diana Gonçalves (Centro de Ciências do Mar do Algarve (CCMAR), Portugal), Domitília Matias (Instituto Português do Mar e da Atmosfera (IPMA I.P), Portugal), Sandra Joaquim (Instituto Português do Mar e da Atmosfera (IPMA I.P), Portugal), Peter C. Hubbard (Centro de Ciências do Mar do Algarve (CCMAR), Portugal)

ana.rato@ipma.pt

Although aquatic organisms are strongly dependent on chemosensory systems for food detection and predator avoidance, little is known about these systems in bivalves. An electrophysiological technique – the electro-osphradiogram – was used to understand how the carpet shell clam (Ruditapes decussatus) senses the environment by assessing the response of the osphradium to different odorants (amino acids) and odours (predator-released cues and signals from conspecifics). The osphradium proved to be sensitive to mostproteinogenic amino acids, eliciting negative, tonic and concentrationdependent responses. However, acidic amino acids (L-glutamic and L-aspartic acid) and L-arginine failed to evoke any response. While cues from injured conspecifics evoked strong responses, predatorreleased cues (green crab,Carcinus maenas) failed to do so. That predator-released cues failed to evoke an electrophysiological response may indicate that clams use signals released by injured prey – alarm cues – to avoid predation. Considering this, a set of behaviours were analysed to evaluate how clams make use of such sensory input; an ‘activity index’. Clams were exposed to different stimuli: microalgae mix diet (positive control) or ‘putative alarm cue’ (water conditioned with injured conspecifics). After exposure, the activity index increased in the presence of the diet while decreased in the presence of the alarm cue, suggesting that clams, as other bivalves, respond to chemicals released by injured conspecifics. We

believe that the electro-osphradiogram will be useful in the isolation and eventual identification of such cues.

A17.72 PREDICTING THE BEHAVIOUR OF WILD FISH USING METABOLISM, GROWTH, AND DIET

Friday 11th July 2025 12:00

Bradley E Howell (Trent University, Canada), Mitchell B Shorgan (Trent University, Canada), Christian J Bihun (Trent University, Canada), Leah C Howitt (Trent University, Canada), Luc LaRochelle (Carleton University, Canada), Aaron T Fisk (University of Windsor, Canada), Steven J Cooke (Carleton University, Canada), Graham D Raby (Trent University, Canada)

bradleyehowell1@gmail.com

The pace-of-life hypothesis predicts that intrinsic traits such as rates of metabolism and growth influence behaviour, with highmetabolism individuals expected to be bolder, more aggressive, and more exploratory. These behavioural tendencies may increase predation risk by driving individuals to forage in riskier habitats. We tested this hypothesis in a freshwater fish community by integrating metabolic assays, growth analysis, stable isotope analysis, and acoustic telemetry. Using lakeside intermittent flow respirometry, we measured routine metabolic rate (RMR) as a proxy for baseline energy expenditure. Using biopsy, we back-calculated individual rates of growth and quantified stable isotope ratios ( 13 C and 15 N) to infer diet composition and trophic position. Fish were then implanted with predation-sensing acoustic transmitters to track movement, habitat use, and predation events in a whole-lake acoustic positioning system (Ontario, Canada). The lake was divided into habitat zones (e.g., open water, vegetated shallows, nearshore areas) to assess how individuals used risky versus safe habitats. We studied prey species (bluegill Lepomis macrochirus, pumpkinseed Lepomis gibbosus) and a predator (largemouth bass Micropterus salmoides) to characterize metabolicbehavioural syndromes and their links to diet, growth, movement, and survival. This research rigorously tests the pace-of-life hypothesis and may inform conservation efforts by identifying traits that increase vulnerability to predation and environmental change.

A17.73 DOES ANTIPREDATOR PERFORMANCE DECLINE WITH AGEING IN A SHORT-LIVING

Friday 11th July 2025 12:15

Luca Pettinau (Department of Animal Health and Welfare Wageningen University Research, Netherlands), Stefano Marras (IAS-CNR Istituto per lo studio degli impatti Antropicie Sostenibilità in ambiente marino CNR, Italy), Christel Lefrançois (LIENSs LIttoral ENvironnement et Sociétés Université de La Rochelle, France), Alessandro Cellerino (Classe di Biologia Scuola Normale Superiore di Pisa, Italy), Fabio Antognarelli (IAS-CNR Istituto per lo studio degli impatti Antropicie Sostenibilità in ambiente marino CNR, Italy), Andrea Satta (IAS-CNR Istituto per lo studio degli impatti Antropicie Sostenibilità in ambiente marino CNR, Italy), Paolo Domenici (IAS-CNR Istituto per lo studio degli impatti Antropicie Sostenibilità in ambiente marino CNR, Italy)

luca.pettinau@wur.nl

The physiological performance of individuals decline with aging negatively affecting their survival and Darwinian fitness. In this context, the capacity to escape from predators is a fundamental trait directly linked to survival and fitness. In fishes, one of the main antipredator strategies is the fast-start escape response, characterized by fast bursts and quick maneuvers that thrust the fish away from the predator. While the biomechanics of the fast-stars response is well known, very little is known about how it changes during life history and how it is affected by ageing.

This aspect is especially relevant in fishes as they express the biggest variety of lifespan in the animal world, with species living over 100 years and others only a few weeks, e.g. Turquoise killifish. Given its short lifespan and rapid aging, the Turquoise killifish provides an excellent model to examine age-related changes in escape performance.

In this study, we investigated how ageing impacts the escape response of this short-living killifish at different time points through their lifespan and whether different thermal conditions (i.e. 22°C and 26°C) and diets (daily and alternate days feeding) modulate this swimming behaviour. The results of this study will contribute to our understanding of the antipredator response during aging, at different temperatures and diet regimes. Additionally, this research will provide important insights into the evolutionary trade-offs among ageing, lifespan and physiological performance in this short-lived fish, particularly regarding predator avoidance.

A17.74 PREY–PREDATOR INTERACTIONS IN

THE

DEEP

SEA BETWEEN KING PENGUIN AND ITS PREY FISH OBSERVED BY ANIMAL-BORNE VIDEO CAMERA

Friday 11th July 2025 12:30

Leo Uesaka (Atmosphere and Ocean Research Institute the Unversity of Tokyo, Japan), Charles André Bost (Centre d’Etudes Biologiques de Chizé Centre National de la Recherche Scientifique, France), Katsufumi Sato (Atmosphere and Ocean Research Institute the Unversity of Tokyo, Japan), Kentaro Q. Sakamoto (Atmosphere and Ocean Research Institute the Unversity of Tokyo, Japan)

leo-u@g.ecc.u-tokyo.ac.jp

Certain animal groups are able to capture prey in the deep ocean, where sunlight is severely limited, and each has its own strategy

along with their sensory and locomotive capacities. King penguins (Aptenodytes patagonicus) have the remarkable ability to dive to depths exceeding 100 meters and capture fish in near-total darkness. However, no study has successfully recorded visual evidence of how this penguin captures its prey in deep sea, and its foraging strategies and the predator-prey interactions are largely unknown. Here, we present a successful record of king penguin’s foraging behavior and prey response in the dark ocean depths using a video logger with an LED light source (N = 1). The king penguin targeted its prey fish 0.5 to 1.5 seconds before predation by directing its head, and exhibited a high feeding success rate of 86.8% (118/136). The penguin repeatedly ascend and descend below 100 m during dives, while most feeding events (81.6%) occurred during ascent, suggesting advantages for king penguins in capturing prey from below. The prey fish remained stationary or did not attempt evasive maneuvers until 0.0 to 0.1 seconds before capture, which highlights king penguins’ ability to stealthily approach their prey. In the same oceanic region, king penguins share their habitat with elephant seals and fur seals, competing for the same fish species. Understanding how penguins develop foraging strategies and how fish respond is crucial for contributing to comparative studies of foraging strategies among marine predators.

A17.75 BEHAVIOURAL PROGRAMS IN MINI-BRAINS: OPTOMOTOR RESPONSE IN THE MINIATURE FLOWER THRIPS

Friday 11th July 2025 12:45

Tomer Urca (University of Rostock, Germany)

tomerurca@gmail.com

Miniaturization requires a reduction and simplification of physiological systems. An extreme example is the visual system of the one-millimeter western flower thrip Frankliniella occidentalis. With only 60 ommatidia in each eye and reduced brain size, it is unknown whether thrips have lost vision-mediated locomotion control, particularly stabilizing behaviors such as the optomotor response (OR). We, therefore, performed an in-depth investigation of the thrips’ visual system and visually mediated behavior. We began by directly measuring the interommatidial angles and acceptance angles of the photoreceptors from high-fidelity μCT scans (both ~18°). We then walked thrips in an arena surrounded by rotating black bar patterns, which elicited circular walking paths following the angular direction of the visual stimulus. The response magnitude was calculated as the thrips’ turning velocity in response to pattern temporal frequency. We then fit a correlation-based Elementary Motion Detection (EMD) model to the data, extrapolating the value of the time delay of the temporal filter between two ommatidia ( , ~0.045s) and the optimal temporal frequency which elicits maximal response (~3.5Hz). We then characterized the thrips’ wavelength sensitivity, which fit the output of a correlation-based EMD model with the optical characteristics we measured for the thrips’ visual system. Altogether, changes in optic flow illicit a behavioral response in thrips, which fits the criteria for OR revealing that the miniature brain of F. occidentalis supports basic vision-controlled locomotor behaviors.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

A17.20 METABOLIC RESPONSES TO CLIMATE CHANGE IN INVERTEBRATES

Milad Shokri (University of Salento, Italy), Alberto Basset (University of Salento, Italy), Anton Potapov (Senckenberg Museum of Natural History Gorlitz, Germany), Francesco De Leo (National Research Council, Italy), Félix P. Leiva (Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Germany), Alexei V. Uvarov (Russian Academy of Sciences, Russia)

milad.shokri@unisalento.it

Climate change is causing significant alterations at levels ranging from individual organisms to entire ecosystems, posing a threat to biodiversity. The response of organisms to climate change is primarily mediated by its impact on their metabolic rates, which, in turn, drive various biological and ecological processes. Understanding and predicting the impact of climate change is urgently needed for conservation efforts and policy decisions. The aim of this study is to spatially predict changes in metabolic rates in invertebrates by 2100 under the conservative emission scenario, RCP2.6. We estimate substantial increases of up to 44% in the metabolic rate, even under the modest climate change scenario of RCP2.6.

A17.21 COST OF GROWTH IS THE MAJOR CONTRIBUTOR TO THE SDA RESPONSE IN DIGESTING SNAKES

Katja Last (Aarhus University - zoophysiology, Denmark), Maria Skovbjerg Slot (Aarhus University - zoophysiology, Denmark), Emil Rindom (Aarhus University - zoophysiology, Denmark), Hans Malte (Aarhus University - zoophysiology, Denmark), Kasper Hansen (Aarhus University - Department of Forensic Medicine, Denmark), Tobias Wang (Aarhus University - zoophysiology, Denmark)

kbl@bio.au.dk

The SDA response – the characteristic and ubiquitous rise in metabolism during digestion – has been extensively studied across a variety of taxa, but the underlying processes remain debated. Here, we determine how much the cost of growth contribute to the overall SDA response in Burmese pythons. Using automated intermittent closed respirometry, we continuously measured oxygen consumption in 16 pythons subjected to different feeding- regimes over 60 days, while assessing changes in body mass and body composition. Costs of growth could then be estimated as the slope of the linear relationship between total growth and metabolism, and we estimate that growth account for more than 70% of the SDA response. CT scans revealed a linear relationship between food intake and both adipose tissue and muscle growth. In addition, fecal nitrogen analysis demonstrated

a high protein retention efficiency across feeding regimes, with approximately 75% being utilized specifically for protein synthesis, lending additional support to the conclusion that protein synthesis and growth are major contributors to the SDA response. We conclude that the SDA response is primarily driven by postprandial growth and thus challenge the common misperception of the SDA as a measure of the “cost of digestion”.

A17.22 THE GREAT DIVIDE: INVESTIGATION OF HOW WILD- AND LAB-REARED POPULATIONS OF DAPHNIA RESPOND TO AN EMERGING CONTAMINANT

Ivan G Cadonic (University of Alberta, Canada), Aaron Boyd (University of Alberta, Canada), R. Glen Uhrig (University of Alberta, Canada), Tamzin A Blewett (University of Alberta, Canada)

cadonic@ualberta.ca

Laboratory studies often use populations of organisms that have been reared under constant conditions for the entirety of their life history. These lineages make it easier to standardize and compare contaminant toxicity across different studies; however, wild organisms experience daily variations and may have altered responses to toxicants due to both genotypic differences between populations and variable physicochemical conditions associated with natural environments. Therefore, the objective of this study was to assess the proteomic response of lab and field-caught Daphnia pulex to a new and emerging contaminant -ultraviolet filters (UVFs; avobenzone, oxybenzone, or octocrylene). Additionally, we wanted to investigate how Daphnia protein expression responded to rearing under nonancestral water conditions (i.e. field caught in lab water and vice versa). Field and lab populations of Daphnia were exposed to high concentrations of UVFs (100 µg/L) for 21 days in their ancestral water (i.e., lake or lab). Concurrently, the impact of altered water conditions on both populations was assessed in the absence of UVFs by rearing Daphnia in both water sources. Protein abundance associated with chronic toxicant exposure or altered rearing conditions was assessed using system level quantitative proteomic analysis. Wild and lab reared populations had altered responses to UVF exposure, indicating that Daphnia strain has an impact on the chronic response to toxicants. Overall, the results of this study outline the importance of environmental relevance in toxicological assessment. Designing studies that mimic natural conditions will generate more realistic data that government agencies can utilize when defining water quality guidelines.

A17.23

ROLE OF ECTODERM IN THE PROTECTION OF THE LARVAL SKELETON IN SEA URCHINS. AN IN VIVO APPROACH.

Ornina Merza (Physiological Institute Christian-Albrecht University Kiel, Germany)

o.merza@physiologie.uni-kiel.de

The larval skeleton in sea urchins is formed by the primary mesenchyme cells (PMCs) that fuse and form a syncytium in which the mineral is formed. PMCs are embedded in a proteoglycan matrix surrounded by an ectoderm. To date it remains unknown how well the skeleton is protected from changes in seawater pH which is essential for estimating the sensitivity of the calcification process to rapid changes in environmental pH.

Here, we used in vivo pH imaging using BCECF-free acid to characterize pH changes in matrix and spicule in relation to the surrounding sea water. Further, we use Calcein, a Ca+2 binding fluorescent-dye, to measure changes in spicule size and integrity in response to external pH.

These measurements demonstrated different spicule dissolution rates in respect to the integrity of the ectoderm. The spicules in larvae with an intact ectoderm resist external acidification (pH 6) for up to 6h. Whereas complete disintegration of the spicule occurs in about 1525 min. when the ectoderm was removed. Interestingly, not only the absence of ectoderm, but also the integrity of the ectodermal tissue e.g., compromised cellular junctions, seems to effect total spicule dissolution time of about 1-2h.

These results demonstrate that the larval skeleton in sea urchins is partly shielded against environmental pH fluctuations with the ectoderm and extracellular matrix playing a central role in this protective mechanism.

A17.24 THE PUTATIVE ROLE OF HCN CHANNELS IN ACID-BASE COMPENSATORY MECHANISMS OF LOBSTER

Garett JP Allen (Biology Department Acadia University, Canada), Alex Quijada-Rodriguez (Biology Department Wilfrid Laurier University, Canada), Maria Sachs (Biological Sciences Department University of Manitoba, Canada), Dirk Weihrauch (Biological Sciences Department University of Manitoba, Canada)

garett.allen@acadiau.ca

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are highly conserved proteins that have gained recent attention as ammonium transporters involved in acid-base regulation of mammalian kidneys. The specific inhibition of these channels by ZD7288 in perfused gills of the European green shore crab, Carcinus maenas, supports a similar acid-secretory function in crustaceans by enhancing ammonium excretion rates and alleviating hypercapnic stress. The present work investigated whether HCN channels present within the trichobranchiate gills and epipodites of the American lobster, Homarus americanus, hold a similar functional role. Investigation of mRNA transcript abundances of an identified HCN channel across the pluero-, arthro-, and podobranch gills as well as epipodites of the lobster revealed no statistical differences. The capacity of isolated and perfused lobster gills to alkalize an artificial hemolymph-like saline was significantly reduced when HCN channel activity was inhibited by adding ZD7288 to the basolateral perfusion saline. This impairment coincided with a significant 0.3fold impairment of transbranchial ammonium excretion rates as well as significant 0.28-fold reductions in the transbranchial transport of inorganic carbon as assessed by CO2 excretion rates and HCO3accumulation rates. Hemi-epipodites mounted in an Ussing chamber yielded similar results, except that ZD7288 evokes a 17.8-fold increase in transepithelial HCO3 - excretion rates. Functional expression of the lobster HCN channel reduced the rate that the ammonium ion

proxy methylamine accumulated within Xenopus laevis oocytes. Methylamine uptake was confirmed to be blocked upon exposing the oocytes to ZD7288 as well as low pH environments, suggesting that the HCN channel function is acid sensitive.

A17.25 RESILIENCE IN A HYPOXIC WORLD: BEHAVIORAL AND METABOLIC RESPONSES OF STICKLEBACK POPULATIONS

EXPOSED TO MULTIGENERATIONAL

FLUCTUATING HYPOXIA

Ludovic Toisoul (University of Turku, Finland), Alycia Valvandrin (University of Turku, Finland), Luisa Bermejo Albacete (University of Turku, Finland), Katja Anttila (University of Turku, Finland), Amelie Crespel (University of Turku, Finland)

ludovic.toisoul@utu.fi

The frequency of climate change-induced hypoxic events defined as a decrease in dissolved oxygen levels in water is increasing at an unprecedented rate. Enclosed ecosystems are particularly vulnerable, as organisms in these environments cannot escape hypoxia and must develop ways to cope with its chronic effects to avoid extinction. When exposed to short-term hypoxia, fish can rapidly adjust their phenotype through direct plasticity. If environmental conditions remain similar across generations, intergenerational plasticity can also occur. When the stressor becomes persistent, adaptation may take place. Therefore, more research is needed to understand how fish respond to multigenerational hypoxia. To investigate this, we studied two populations of Gasterosteus aculeatus collected from separate streams, one that has been exposed to hypoxia for a decade and one that has not. Within each population, we bred two generations, exposing offspring to either normoxia (100% dissolved oxygen, DO) or fluctuating hypoxia (30% DO at night and 100% DO during the day). This experimental setup resulted in eight groups, allowing us to examine direct plasticity, intergenerational plasticity (when offspring matched parental environmental conditions), and adaptation between the populations. We measured various fitness-related traits, including social and risk-taking behavior, metabolic rate (standard metabolic rate, SMR), and hypoxia tolerance. When directly exposed to hypoxia, fish reduced their social and risk-taking behaviors but showed no change in metabolic rate. However, after multiple generations of exposure, fish maintained active social and risk-taking behaviors while decreasing their SMR. This study disentangles the responses to hypoxia within and across generations used by fish.

is a medical procedure involves removing a small sample of tissue or cell from the breast examine for cancer cells[2]. There are many different types of biopsies (Incisional biopsy, Core needle biopsy, U/S guided biopsy and Fine needle aspiration cytology)[3].FNAC is a diagnostic procedure used to investigate lumps or masses under the skin including breast lumps and thyroid nodules. FNAC location issues refer to the challenges and limitation of performing FNAC biopsy on lesions or masses located in difficult to access areas of the breast. In FNAC procedure a thin sterile needle usually 22-25 gauge is inserted into the skin and guided to the target lesion[4]. The needle is attached to a syringe and gentle suction is applied to aspirate cells from lesion. Needle location issues in FNAC refer to challenges and limitation of accurately placing the needle in target lesion during procedure in order to place accurate needle the external measurement of breast by vernier caliper can be used [5].

A17.28 BLOOD PRESSURE CONTROL: QUERCETIN POTENTIATE

IN EXPERIMENTAL HYPERTENSIVE RATS

Abiola Adeosun (Lead City University, Nigeria), Oluseyi A Akinloye (Federal University of Agriculture Abeokuta, Nigeria), Dorcas Akinloye (Federal University of Agriculture Abeokuta, Nigeria), Adenike Jokotola (Federal University of Agriculture Abeokuta, Nigeria), Aniekan Okon (Federal University of Agriculture Abeokuta, Nigeria), Esther Osho (Federal University of Agriculture Abeokuta, Nigeria)

adeosun.amuhammad@lcu.edu.ng

Umair Masood awan (Royal college of surgeon of England, Pakistan)

umairawan0505@gmail.com

Approximately 2.3 million women worldwide were diagnosed with breast cancer. Breast cancer is a type of cancer that form in the cells of the breast[1]. Breast cancer diagnosis typically involves a combination of clinical evaluation, Imaging tests and biopsy. Breast cancer biopsy

Combining quercetin with a prototype angiotensin-converting enzyme may produce a better outcome in blood pressure control. The current study evaluated the efficacy of the combination of quercetin with lisinopril blood pressure control in hypertensive rat models. Twenty-five male rats were randomized into five groups (n = 5) of normotensive control, hypertensive untreated and hypertensive treated with quercetin only, lisinopril only and the combination of quercetin and lisinopril, respectively. High BP (BP ≥ 140/90) was induced by a single subcutaneous dose of 2 mg/kg dexamethasone and the water was replaced with 4% NaCl for two weeks. After 7 days of treatment, the average reduction in systolic BP of the treated rats was in the order quercetin with lisinopril (75 mm Hg) > quercetin only (59 mm Hg) > lisinopril only (45 mm Hg) while reduction in diastolic BP were in the order quercetin (57) > quercetin with lisinopril (46 mm Hg) > lisinopril only (13 mm Hg). Rats treated with combined quercetin and lisinopril and those treated with individual drugs have marked decreases in ACE, CK, CK isozyme and LDH1 activities, decreased endothelin expression while increasing circulatory nitric oxide compared to untreated hypertensive rats. Rats treated with quercetin, lisinopril and the combination have decreased serum cholesterol with increased HDL-cholesterol concentration, however, triglyceride levels decreased in quercetin-lisinopril-treated hypertensive rats. Conclusively, quercetin potentiates lisinopril’s effect on blood pressure control through its ability to mediate energy demand, enhance nitric oxide production, maintain lipid homeostasis and diminish the production of free radicals in hypertensive rats.

A17.29 INCREASED OXYGEN EXTRACTION IS KEY TO THE ABILITY OF SCHOOLMASTER SNAPPER (LUTJANUS APODUS) TO SWIM MAXIMALLY AT HIGH TEMPERATURES

Fiona P H Durnford (Memorial University, Canada), Kurt A. Gamperl (Memorial University, Canada), Emma S Porter (Memorial University, Canada)

fvandenbogae@mun.ca

In a previous study, it was: shown that this species had a maximum metabolic rate (MMR) during a critical thermal maximum while swimming (CTSMax ) test that was 60% higher than measured during a critical thermal maximum (CTMax ) test (i.e., on resting fish); and suggested that this higher MMR allowed these swimming fish to tolerate only slightly lower maximum temperatures (37.5 vs. 38.9o C, respectively). However, the mechanism(s) mediating this difference in MMR was/were not known. Thus, we performed CTMax and CTSMax tests in a swim-tunnel respirometer on snapper that had been implanted with Transonic® blood flow probes so that heart rate (fH ), stroke volume (SV ), cardiac output (Q) and oxygen extraction (ṀO2 / Q) could be measured. The ~ 1.75 fold higher MMR in schoolmaster snapper given a CTS Max vs.CTMax test was not due to a greater contribution of SV to Q in swimming fish exposed to acute warming as was previously hypothesized. Instead the increase in fH was ~ 40 beat min-1 (25% higher) in fish given the CTSMax test, and ṀO2 / Q was ~ 1.55-fold greater. This increase in ṀO2 / Q may be related to improved oxygen uptake at the gills (and thus oxygen content of the arterial blood) and/or increased extraction efficiency in swimming fish at warm temperatures. Nonetheless, these data are another example of the importance of ṀO2 / Q in determining the tolerance of fish exposed to combined stressors, and how estimating thermal tolerance based on measures of fH alone may be misleading.

A17.30 CHARACTERISTICS AND DRUG SUSCEPTIBILITY ANALYSIS OF BURKHOLDERIA CEPACIA ISOLATES

Chun-Yu Huang (Department of Laboratory Medicine and Biotechnology Tzu Chi University, Taiwan), Wen-Jui Wu (Department of Laboratory Medicine and Biotechnology Tzu Chi University, Taiwan), Kai-Chih Chang (Department of Laboratory Medicine and Biotechnology Tzu Chi University, Taiwan)

111312103@gms.tcu.edu.tw

Burkholderia cepacia is a bacterium commonly found in humid environments and water sources, which can cause severe respiratory infections in immunocompromised patients or those with specific chronic diseases. Due to its unique survival and proliferation abilities, this bacterium can thrive in natural water bodies, specific sterile or non-sterile preparations, and in environments where antibiotics and disinfectants are present and in nutrient-deficient conditions. This makes it a significant threat to the water supply systems in medical facilities. Many broad-spectrum antibiotics, such as penicillins and polymyxins, are ineffective against B. cepacia, complicating the treatment process, and its transmission characteristics increase the likelihood of healthcare-associated infections. Therefore,

conducting in-depth analyses of this bacterium is crucial to propose more precise and effective prevention and treatment strategies. This study collected approximately 80 strains isolates of B. cepacia. First, random amplified polymorphic DNA (RAPD) typing was performed, and then their potential to cause nosocomial infections was analyzed. Subsequently, drug susceptibility testing was conducted using the disk diffusion method to identify effective antibiotics, aiming to prevent the potential spread of this bacterium.

A17.31 AI-DRIVEN AUTOMATION IN ANIMAL BIOLOGICAL RESEARCH: ENHANCING DATA PROCESSING AND RESOURCE EFFICIENCY

Chih-Yuan Yang (Department of Laboratory Medicine Mackay Memorial Hospital, Taiwan), Chuan-Chuan Liu (Department of Physiology Mackay Memorial Hospital Taipei, Taiwan), Wern-Cherng Cheng (Department of Laboratory Medicine Mackay Memorial Hospital, Taiwan), Po-Jui Hsu (Department of Laboratory Medicine Mackay Memorial Hospital, Taiwan)

simon132321@gmail.com

With advanced information technology geared toward biochemical assays, molecular diagnostics, and physiological measurements across the animal kingdom, animal biological research nevertheless suffers from a more archaic laboratory workflow, involving fragmented data acquisition, manual sample handling, and spurious quality control, leading to high variability and turnaround time. Complementary to the challenges, we developed intelligent AI-based automation in life sciences for improved data acquisition, processing, and analysis, unlike anything, thus far increasing efficiency and resource management. The system allows optimizing the workflow with machine learning algorithms that continuously tune the processing parameters based on the samples’ performances to improve accuracy while minimizing error. A high-throughput data management framework allows realtime synchronization of biochemical, molecular, and physiological data sets. Intelligent quality control ensures anomaly detection and thus also increases the reliability of data and reproducibility across experiments. When applied to animal physiological and biochemical research, a reduction in turnaround time of the order of 18% to manual labor of 30% was described. Energy consumption was minimized by 30% with the use of automated processes and 180 kg of laboratory waste was greatly reduced, therefore providing such green benefits for high-throughput studies. Further work will expand the biomonitoring driven by AI on wildlife physiology and the predictive modeling of metabolic and ecological research, giving a more scalable framework to integrate AI-driven automation into animal biology and research to improve production efficiency, reproducibility, and sustainability moving forward.

A17.32 ISOLATION AND CHARACTERIZATION OF BACTERIOPHAGES TARGETING BURKHOLDERIA CEPACIA COMPLEX

Chun-Cheng Hsu (Department of Laboratory Medicine and Biotechnology Tzu Chi University, Taiwan), Wen-Jui Wu (Department of Laboratory Medicine and Biotechnology Tzu Chi University, Taiwan), Kai-Chih Chang (Department of Laboratory Medicine and Biotechnology Tzu Chi University, Taiwan)

111312119@gms.tcu.edu.tw

Burkholderia cepacia complex is a Gram-negative, non-fermentative bacterium in humid environments like soil, water, and plants. Initially isolated from onion bulbs, it is now detected in freshwater, agricultural runoff, and various ecological niches. Its adaptability allows it to thrive in natural and artificial aquatic systems, posing potential risks to animals and ecosystems. Amid growing concerns about antibiotic resistance, bacteriophages present a promising alternative for bacterial control. This study aims to isolate phages infecting Burkholderia cepacia complex from various freshwater sources and describe their characteristics. Seventy-eight strains were collected and genotyped using random amplified polymorphic DNA (RAPD) analysis. Phage screening on these isolates identified several effective lytic phages for potential bacterial control applications. By exploring phagebacterium interactions in natural settings, this research proposes novel biocontrol strategies to inhibit the proliferation of Burkholderia cepacia complex in water sources, potentially offering eco-friendly solutions for mitigating bacterial contamination in animal habitats, agriculture, and aquaculture.

A17.33 CARNIVOROUS SHOREBIRDS ADJUSTING TO HERBIVORY: A DIETCHANGE EXPERIMENT IN RED KNOTS

Marie De Wilde (Royal Netherlands Institute for Sea Research (NIOZ), Netherlands), Theunis Piersma (University of Groningen (RUG), Netherlands)

marie.de.wilde@nioz.nl

The red knot (Calidris canutus) is a migratory shorebird experiencing a climate-driven trophic mismatch during breeding, resulting in smaller chicks that develop into juveniles with shorter bills. These birds are unable to reach their preferred prey and have adapted by shifting from a deeper bivalve- to shallower seagrass-dominated diet. The nutritional adequacy of diets that lack animal protein, however, remains unclear. We conducted a controlled diet-change experiment in the laboratory with two groups of five captive red knots fed a standard diet, rich in animal protein for 13 weeks, followed by 42 days on a strictly vegetarian diet. Body mass and faecal matter were monitored as the main indicators of overall health. Body mass initially declined after the diet change but then gradually increased and stabilized to levels normal for the season and stage. Faecal matter transitioned from green to dry brown, and then to a colour and consistency similar to that of wild red knots, but notably in a higher amount. Upon returning to the standard, high-protein diet, the body mass of birds rapidly increased, was abnormally high for two days, and then stabilized to normal levels. This study is one of the first controlled laboratory experiments to examine a herbivorous diet in carnivorous

shorebirds and demonstrated that red knots can adapt to and survive on a strictly plant-based diet. Future measurements will characterize potential changes in the gut microbiome of red knots in captivity in relation to these diet shifts.

A17.34 MICROBIAL COMMUNITY DYNAMICS IN AQUACULTURE UNDER CLIMATE CHANGE: IMPACTS ON WATER QUALITY

Po-Jui Hsu (Department of Laboratory Medicine Mackay Memorial Hospital, Taiwan), Chien-Yuan Pan (Department of Life Science National Taiwan University, Taiwan), YungChe Tseng (Marine Research Station Institute of Cellular and Organismic Biology Academia Sinica, Taiwan)

ray60115@gmail.com

Climate change disrupts aquaculture systems increasingly in terms of water temperature, pH, and microbial community structure, thereby deteriorating water quality and increasing disease risk. While subtropical islands in East Asia undergo drastic seasonal temperature variation and extreme weather events, they also further influence the aquaculture environment. To that end, it is essential to recognize these shifts in microbes in formulationally sustainable fish culture. The research has conducted investigations on the microbial community structure in the aquaculture ponds on a subtropical island, emphasising the relationship between climate-induced changes in water quality. We shall identify critical environmental circumstances affecting microbial population dynamics, including their roles in aquaculture sustainability. Water samples were collected from aquaculture ponds across central and southern regions, targeting economically important species such as milkfish and shrimp. Microbial communities were analysed through 16S rRNA sequencing, and physicochemical parameters, including temperature, dissolved oxygen, pH, and nitrogen compounds, were monitored. The microbial shifts were shown to be highly seasonal, with disruptions of the nitrogen-cycler bacteria with a strong effect on water quality. This advance underscores the importance of monitoring microbial communities as a means of acclimatizing to climate hazards within the aquaculture sector, and thus should be in place to formulate an effective water quality regulation strategy and promote a microbial regime that grants fish health and production efficiency: a prerequisite for the resilience and sustainability of aquaculture industries in East Asia against environmental change.

A17.35 IMPACTS OF ENDOGENOUS FACTORS AND ONTOGENETIC STAGES ON THE METABOLIC RATE OF THE MEDITERRANEAN SPIDER CRAB MAJA SQUINADO (HERBST, 1788)

Jehan-Hervé Lignot (UMR MARBEC, France), Marie-Catherine Raffalli (University of Corte, France), Jean-José Filippi (University of Corte, France), Jeremy Bracconi (University of Corte, France), Nicolas Gattacceca (University of Corte, France), Jean-Baptiste Ronchi-Perfetti (University of Corte, France), Ambre Crescioni (University of Corte, France), Eric Durieux (University of Corte, France)

jehan-herve.lignot@umontpellier.fr

In the Mediterranean, populations of the spider crab, Maja squinado, are drastically declining. As a necessary step for successful restoration programs, this study focuses on ontogenetic changes in M. squinado (from larvae to adults), and takes into account intrinsic factors such as energy balance, size, molt and gender. For this purpose, individual routine metabolic rates were collected from reared larvae and juveniles and wild-caught adults. Results revealed distinct metabolic variations throughout development.

Zoea 1, the first planktonic larval stage, has higher metabolic rates than zoea 2, likely due to an increase in inactive material and reliance on egg reserves, while zoea 2 depends on external food. As development progresses to megalopa and benthic juvenile stages, metabolic rates rise exponentially, reflecting increased activity and organ development, making essential self-maintenance processes more energy dependent. From 7-month-old juveniles to adults, metabolic rates decline, likely due to extended intermolt periods and reduced growth, along with different survival strategies and behaviors. In reproductive adults, males have twice the metabolic rate of females, possibly due to territorial competition and reproductive efforts. Metabolic rate inversely correlates with size: individuals under 20 g consume oxygen at twice the rate of those over 80 g. Molting significantly impacts metabolism, with lower rates in post-molt individuals compared to pre-molt stages.

The successful rearing of M. squinado and the significant physiological insights gained into the different developmental stages enhance our understanding of the species’ ecosystem interactions, and pave the way for further analyses before the implementation of restoration trials.

A17.36 SEVERE ENVIRONMENTAL CONSTRAINTS CAN ALTERED MITOCHONDRIAL COUPLING

EFFICIENCY: IS IT TRULY BENEFICIAL OR JUST THE LAST CHANCE TO SURVIVE?

Damien Roussel (Université Claude Bernard Lyon1, France)

damien.roussel@univ-lyon1.fr

Converting food to cellular energy (ATP) is a fundamental requirement to sustain life. In aerobic organisms, mitochondria are the major source of ATP, becoming a strong physiological link between environmental resources and organism’s performances. Environmental fluctuations in abiotic (temperature and oxygen) and biotic (food resources) parameters have the potential to alter mitochondrial oxidative ATP production and efficiency at different temporal levels. For instance, it is well described that thermal acclimation induces compensatory adjustments triggering mitochondrial fluxes resilience across large shifts in temperature. Poor food quality or quantity is also known to triggers a shift of mitochondrial metabolism toward a more economical phenotype. Using several experimental studies, we will try to answer the following question: is change in energy coupling efficiency is truly beneficial or the ultimate mitochondrial adjustment to sustain life on “the razor blade”.

A17.37 CONTROL OF OTOLITH GROWTH AND BIOMINERALIZATION UNDER EXPERIMENTAL CONDITIONS

Iki Murase (University of Southampton, United Kingdom), Takahiro Irie (National Institute of Advanced Industrial Science and Technology, Japan), Clive N Trueman (University of Southampton, United Kingdom)

iki.murase@gmail.com

Fish otoliths grow periodically with increasing body size, resulting in the formation of daily increments. Following the discovery of this microstructural pattern, otoliths have been widely used as a tool for determining daily age and providing chemical proxy records for location, environment and physiology. However, disruptions to otolith biomineralization in terms of daily growth deposition and mineral polymorph complicate determination of daily age and chemical proxy use. Mechanisms leading to disruptions in otolith growth are poorly understood, with potential physiological and mechanical underpinnings. Here we present results from a series of experiments investigating the expression, location and mechanisms underpinning irregular otolith growth. We propose a new mechanism contributing to carbonate polymorph switching and quantify the impact of disruptions in daily increment formation on estimates of daily age.

A17.38 SUBSTRATE VISCOELASTICITY MODULATES FIBROBLAST ADHESION, CYTOSKELETAL ORGANIZATION, AND YAP SIGNALING

Namrata Gundiah (Indian Institute of Science, India), Neha Paddillaya (Indian Institute of Science, India), Akshar Rao (Indian Institute of Science, India), Anshul Shrivastava (Indian Institute of Science, India), Imnatoshi Jamir (Indian Institute of Science, India), Kundan Sengupta (Indian Institute of Science Education and Research Pune, India)

namrata@iisc.ac.in

Mechanical properties of the extracellular matrix (ECM) regulate cellular adhesion, migration, proliferation, and mechanotransduction. Although substrate stiffness has been widely studied in mechanobiology, the role of ECM viscoelasticity in fibroblast function remains poorly understood. To examine how viscoelasticity affects the biophysical properties and biochemical signaling of human mammary fibroblasts, we developed elastic (E) and viscoelastic (VE) polyacrylamide hydrogels with similar storage moduli (~14.52 ± 1.03 kPa) but 36.9% higher loss modulus for the VE gels. We hypothesized that fibroblasts on viscoelastic substrates have altered adhesion dynamics, cytoskeletal organization, and mechanotransduction. We assessed cell adhesion strength, migration, traction forces, stress fiber formation, YAP nuclear translocation, and proliferation to determine how viscoelasticity modulates fibroblast mechanobiology. Cells on E hydrogels exhibited greater spreading (2428.93 ± 864.71 μm²), enhanced stress fiber formation, higher zyxin intensity indicating robust focal adhesions, and higher traction stresses (2931.57 ± 1732.61 Pa). In contrast, VE substrates had 54.2% smaller focal adhesion areas, 51.8% lower critical adhesion strengths, and 21% reduced traction stresses (p < 0.001), indicating significantly weaker adhesions as compared to E hydrogels. Fibroblasts on VE substrates

also showed enhanced migration speeds and higher proliferation, whereas E substrates promoted YAP nuclear translocation, aligning with increased contractility. Reduced YAP activity on VE substrates suggests a mechanotransduction shift, likely involving alternative pathways such as PI3K-AKT or Rho/ROCK signaling, to promote proliferation and migrations. These findings highlight the role of viscoelasticity in determining fibroblast function and suggest that tuning ECM viscoelasticity can be a powerful strategy to regulate cell behavior.

A17.39 ERYTHROCITE: A SYSTEMATIC MAP AND OPEN-SOURCE DATABASE ON RED BLOOD CELL SIZE OF FISHES

Félix P. Leiva (Radboud University, Netherlands), Rafael Molina-Venegas (Universidad Autónoma de Madrid, Spain), Katharina Alter (Royal Netherlands Institute for Sea Research, Netherlands), Carolina A. Freire (Universidade Federal do Paraná, Brazil), A. Jan Hendriks (Radboud University, Netherlands), Adam Hermaniuk (Jagiellonian University, Poland), Léon Serre-Fredj (Royal Netherlands Institute for Sea Research, Netherlands), Milad Shokri (University of Salento, Italy), Marcin Czarnoleski (Jagiellonian University, Poland), Felix C. Mark (Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Germany)

felixpleiva@gmail.com

Cell size is a key trait for understanding cellular functions, physiological adaptations, and evolutionary processes in living organisms. For decades, scientists have been intrigued by the considerable variation in cell sizes amongst animals, yet systematic efforts to compile such data have been limited. To address this gap, we employed a systematic map approach, focusing on the most diverse vertebrate group, to create ErythroCite, an open-source database of fish erythrocyte sizes. This comprehensive resource encompasses 1,764 records from 660 species across four major lineages: Actinopterygii (bony fishes), Chondrichthyes (cartilaginous fishes), Dipnoi (lung fishes), and Cyclostomata (jawless fishes). Our findings reveal a remarkable 414fold range in cell volume, with most studies concentrating on bony fishes and limited data on juveniles and earlier life stages. Notably, life stage and sex were infrequently reported, although adult females and males were equally represented when data were available. ErythroCite offers valuable insights for studies in macroecology, macrophysiology, comparative physiology, evolutionary biology, and cell biology. We anticipate this resource will facilitate comparative approaches and meta-analyses, globally driving further exploration of erythrocyte diversity and function in fish. In addition to mapping existing information and identifying current gaps, we highlight the need for further research, particularly into the causes and consequences of the variation in cell size among fishes.

A17.41 BENEATH THE SAND: EXPLORING FLATFISH BURIAL STRATEGIES

Hendrik D Du Toit (Wageningen University Research, Netherlands), Johan L Van Leeuwen (Wageningen University Research, Netherlands), Martin J Lankheet (Wageningen University Research, Netherlands), Sander W S Gussekloo (Wageningen University Research, Netherlands)

hendrik.dutoit@wur.nl

Burial is a key concealment strategy in benthic flatfish. The common sole (Solea solea) and European plaice (Pleuronectes platessa), are particularly adapted for rapid burial, utilizing undulatory body motions to manipulate sediment and achieve effective burial beneath the sandy. However, how sediment properties influence burial kinematics and achievable depth remains poorly studied for these two species. This study investigates the biomechanics of burial in sole across different sediment grain sizes. Using high-speed video recordings in controlled experimental setups, we quantified burial rates, undulatory frequency, and burial depth across a range of sediment grain sizes. Preliminary results indicate that burial rate remains unaffected by grain size, while average burial depth is significantly greater in intermediate grain-sized sediment compared to both the finest and coarsest sediments tested.

Additionally, this study employed a novel technique utilizing transparent sand and high-speed videography to film burial events of plaice across a range of size classes. This approach allows for the quantification of burial rate, depth, and undulation frequency, as well as the use of Fourier analysis to characterise undulation amplitude during the transition from water to a sand medium. Furthermore, we are currently exploring the effect of stress-induced burial responses by implementing non-physical stressors such as handling stress, light and vibration.

Our findings provide novel insights into the locomotor biomechanics of burial in flatfish and the influence of substrate properties on burial efficiency. To our knowledge, this is the first study to quantitatively assess burial depth responses of flatfish species such as sole and plaice.

A17.42 STUDY OF EXPERIMENTAL MODELS OF LACTOSE INTOLERANCE IN RATS: SEXUAL DIMORPHISM AND RELATIONSHIP WITH PSYCHIATRIC DISORDERS

Thiago B Kirsten (Environmental and Experimental Pathology Paulista University, Brazil), Marcella C Galvão (Environmental and Experimental Pathology Paulista University, Brazil), Nathalia A Galvão (Environmental and Experimental Pathology Paulista University, Brazil)

thik@outlook.com

Lactose intolerance presents high incidence, although the mechanisms have not yet been fully elucidated and there are few/limited experimental models for their study. Some studies suggest a sexually dimorphic effect and a greater predisposition to psychiatric disorders. The objectives of this study were to propose experimental models of lactose intolerance, evaluating the manifestation of behaviours related to psychiatric disorders and the incidence in each sex. Moreover, it was objective to elucidate the neurobiological processes involved. Male and female adult Wistar rats were exposed for 14 consecutive days to two types of diets rich in lactose: a solution containing 14% lactose and a commercial formula of milk. Clinical signs were monitored: body weight and stool consistency. Behaviours related to psychiatric disorders were evaluated: light-dark box (anxiety) and social preference tests, as well as brain dopamine levels. Both diets impaired the stool consistency, with a peak effect on the 12th day of exposure. From there, the results were sexually dimorphic. Males presented anxiolytic behaviour after the lactose diet. The socialization

of males was impaired by both diets, especially after the commercial formula. The behavioural impairments found in males were attributed to the modulating role of lactose on the dopaminergic system. In females, the lactose-rich diets reduced cortical dopamine levels, which resulted in an anxiogenic effect. In conclusion, both lactose-rich diets (14% lactose and commercial formula) induced clinical signs of lactose intolerance in male and female rats, accompanied by sexually dimorphic behavioural impairments associated with psychiatric disorders that were explained by dopaminergic modulation.

A17.43 DEVELOPMENT OF RETINAL OXYGEN SECRETION IN ZEBRAFISH

Anne Sofie S Rasmussen (Aarhus University, Denmark), Rikke Nielsen (Aarhus University, Denmark), Kasper Kjær-Sørensen (Aarhus University, Denmark), Claus Oxvig (Aarhus University, Denmark), Christian Damsgaard (Aarhus University, Denmark)

asr@bio.au.dk

Retinas have an extremely high oxygen demand due to the large number of metabolically active neurons; however, the teleost retina lacks the internal blood vessels that typically supply the tissue with the necessary oxygen. In many fish species, retinal oxygenation is instead secured by generating a high pO2 behind the retina (a process called oxygen secretion), resulting in a steep transretinal oxygen diffusion gradient. The oxygen secretion mechanism is based on the combined presence of the choroid rete mirabile, a structure that increases pO2 and pCO2 within the eye cup, and the Root effect hemoglobins, where reduced blood pH causes lowered oxygen affinity. Furthermore, the process is dependent on beta-NHE pumps (in the red blood cell membrane) and fast-acting CA2 (within the red blood cells). Multispecies studies show that the presence of a choroid rete mirabile is correlated with a larger Root effect and with an increased retinal thickness for improved visual processing. While several studies have examined the development of the fish retina, no studies have examined the development of the choroid rete and the Root effect. In this project, I traced the development of the choroid rete mirabile and key red blood cell proteins in zebrafish to examine how the development of oxygen secretion affects retinal development and visual function. This was done by integrating histological data of choroid rete mirabile development with single-cell RNA-seq data from developing red blood cells, to uncover the temporal development of the oxygen secretion mechanisms in the teleost retina.

A17.44 FIRST CHARACTERIZATION OF 7 INVERTEBRATE SEPTATE JUNCTION PROTEINS EXPRESSED IN DECAPOD CRUSTACEANS

Dirk Weihrauch (University of Manitoba, Canada), Mina Amiri Farahani (University of Manitoba, Canada)

Dirk.weihrauch@umanitoba.ca

Our knowledge on Septate Junction proteins (SJPs) is very limited with only a few functional studies being published examining their roles and localization in insects. Similar to Tight Junction proteins in vertebrates, invertebrate SJPs appear in clusters and regulate the permeability of the paracellular pathway in epithelia for small

molecules. In the invasive green crab Caricinus maenas we identified in an ongoing project so far 7 SJPs: Megatrachea(Mega), KuneKune(Kune), Würmchen1(Wrm1), Contactin(Cont), NeurexinIV(NrxIV), Gliotactin(Gli), and Mesh. All show high similarities in their predicted secondary protein structure and 58-91% similarities in the amino acid sequence to their respective insect counterparts. A tissue expression analysis in osmoregulating green crabs revealed for all SJPs highest abundance in gills and the antennal gland, followed by the hindgut. The lowest expression was observed in claw muscle. Relative to each other, branchial transcript levels of mega and kune were highest followed by wrm1. Low expression levels were observed for cont, nrxIV, gli, and mesh. Further, mRNA expression levels of mega, kune, wrm1, gli and mesh were higher in the gills of hyperregulating crabs when compared to the gills of osmoconforming animals. Of all 7 investigated SJPs only mRNA expression levels of wrm1 and mesh were higher in water-secreting antennal glands of hyperregulating crabs. Interestingly, when osmoconforming crabs were exposed for 1 week to 1 mM of NH4 Cl, branchial mRNA expression of wrm1 slightly decreased, while expression of mesh almost tripled, indicating a protective role for mesh in high environmental ammonia.

A17.45 BANK VOLES DO NOT REDUCE

THEIR RESTING METABOLIC RATE TO COMPENSATE FOR LOW FORAGING ACTIVITY IN AN UNKNOWN HABITAT

Julia Nowack (Liverpool John Moores University, United Kingdom), Jana Eccard (Universität Potsdam, Germany), Rika Hunecke (Universität Potsdam, Germany), Melanie Dammhahn (Universität Münster, Germany)

J.Nowack@ljmu.ac.uk

Balancing the need for food with the risk of predation during foraging is one of the main challenges animals have to face on a daily basis. We aimed to investigate whether homeothermic bank voles, Myodes glareolus, are able to compensate reduced foraging activity in response to high perceived predation risk by lowering their metabolic rate during rest. Bank voles were transferred into a new habitat and exposed to two contrasting predation risk scenarios by altering the illumination of their enclosure. We found that giving up density was higher during the light phase, indicating that animals perceived foraging in the unknown habitat in daylight as riskier. Bank voles further adjusted food intake to the perceived risk. While average resting metabolic rate was significantly lower during the light phase than the dark phase during the first two days after transfer into the new environment, this was caused by an increase in resting metabolic rate during the first two nights after transfer. Neither energy intake, nor resting metabolic rate were correlated to consistent differences in risk-taking behaviour of individuals. Our data suggest that bank voles prioritised vigilance behaviours over energy saving in a new unknown habitat.

A17.46 THE ROLE OF SKIN IN THE CONVERGENT EVOLUTION OF GLIDING IN MAMMALS

Claudia J Baldry (University of Southampton, United Kingdom), Isabella T M Stenhouse (Royal Veterinary College, United Kingdom), Neil J Gostling (University of Southampton, United Kingdom), Bharath Ganapathisubramani (University of Southampton, United Kingdom), Jorn A Cheney (University of Southampton, United Kingdom)

cjb1g19@soton.ac.uk

Mammalian gliders are remarkably diverse in evolutionary history and vary in body mass by over two orders of magnitude. They support their weight during gliding using membranes of skin, which have independently evolved at least six times in extant gliding mammal lineages: three times in marsupials, twice in rodents and once in a sister group to primates. In each instance, the membrane wing is formed of thin, compliant, elastic skin that billows in response to the aerodynamic forces it generates, which in turn influences the aerodynamics, forming an aeroelastic coupling. The ratio of aerodynamic force produced by the membrane to the membrane tension resisting that force (Weber Number (We)) determines the magnitude of billowing/camber. Increasing camber generally enhances lift, increasing glide duration, and can increase glide efficiency. We explore whether the scaling relationship of We with body mass is consistent across lineages, using measurements from museum skins and published mass values to generate general linear models. We tested three hypotheses: 1) We does not scale, which would indicate consistent camber across body mass; 2) We scales with body mass to the 0.33 power as predicted by isometry; and 3) all lineages share a common relationship between We and body mass. We found that We scales above 0.33, rejecting our first two hypotheses, and that marsupials have lower We but similar scaling to eutherians. Our results excitingly indicate that despite gliding mammals sharing similarities in form, they glide distinctly due to both their mass and evolutionary history.

A17.47 METABOLIC AND CONTRACTILE SHIFTS IN BROOK TROUT MYOTOMAL MUSCLE ACCLIMATED TO WARM WATER

David J Coughlin (Widener University, United States), Xavier Ernest (Widener University, United States), Evelyn Peyton (Widener University, United States), Mya Abers (Widener University, United States), Mia Rosati (Widener University, United States)

djcoughlin@widener.edu

Cold-water fishes, such as salmonids, face environmental stresses resulting from climate change. We examined the thermal acclimation response of the hatchery-reared brook trout (Salvelinus fontinalis) to explore how the metabolic function and contractile properties of their myotomal muscle might shift to mitigate the impact of a warming environment. When tested at a common temperature (10o C), metabolic rate in fish acclimated to 20o C was significantly lower than those acclimated to 10o C. Contractile properties such maximum muscle shortening velocity and isometric relaxation showed corresponding changes, with warm acclimated fish showing slower contraction kinetics. These fish also showed changes in the

expression of a wide variety of muscle and metabolic genes with elevated temperature, thus providing a mechanistic foundation for their thermal acclimation. We carried out a parallel study on wild brook trout collected in summer, fall and winter to explore if a native population of these fish undergoes the same thermal acclimation response observed with our hatchery fish. These fish showed similar but not identical shifts in muscle function and gene expression with a warming environment, suggesting that wild populations of brook trout may vary in their thermal acclimation response across the range of this cold-water salmonid.

A17.48 THE CALCIFICATION PROCESS IN SEA URCHIN LARVAE: INSIGHTS INTO PH REGULATION MECHANISMS IN INTRACELLULAR VESICLES OF PRIMARY MESENCHYME CELLS (PMCS)

Lucas Crovetto (Institute of Physiology University of Kiel, Germany), Sima Jonusaite (University of Tulsa, United States), Marian Hu (CAU Kiel, Germany)

l.crovetto@physiologie.uni-kiel.de

Calcification is a widespread process in marine organisms and depends on tight control of pH and carbonate chemistry. Sea urchin larvae have been extensively used to study the transport mechanisms underlying the formation of an elaborate calcitic endoskeleton. The generation of this complex mineral structure is initiated in primary mesenchyme cells (PMCs), where amorphous calcium carbonate (ACC) is formed in intracellular vesicles. The intracellular precipitation of ACC requires a specific chemical environment in which pH plays a critical role. However, the pH dynamics within these vesicles and their role in carbon transport are still poorly understood. We developed in vivo methods to characterize vesicular pH in PMCs of Stongylocentrotus purpuratuslarvae to unravel the underlying mechanisms of proton and carbon transport. Inverted confocal microscopy in combination with the ratiometric fluorescent dye SNARF-1 allowed us to accurately measure the pH of intracellular vesicles in PMCs. Simultaneous tracking of endocytosed calcein accompanied by pH recordings allowed a high spatial and temporal resolution of pH dynamics in Ca2+ rich vesicles. This system provides a unique model for live- tissue imaging and sheds light on pH regulatory mechanisms in intracellular calcifying vesicles. Preliminary results showed the presence of acidic and alkaline vesicle populations in PMCs, which can regulate their luminal pH to maintain a favorable chemical environment forCaCO3 formation. Future studies are planned to understand how the larvae can cope with environmental stressors such as ocean acidification, where the decrease in seawater pH is accompanied by a decrease in carbonate ion concentration.

A17.49 DIFFERENT VASCULAR RESPONSES TO CATECHOLAMINES IN FASTING AND DIGESTING SNAKES

Caroline Fernanda S. Dal Pozzo (State University of Campinas (UNICAMP), Brazil), Gilberto De Nucci (State University of Campinas (UNICAMP), Brazil), Tobias Wang (Aarhus University, Denmark)

caroline.sdalpozzo@gmail.com

During digestion, snakes experience large cardiovascular changes to accommodate increased metabolic demands, including tachycardia driven by vagal tone withdrawal and non-adrenergic, non-cholinergic factors. Stroke volume doubles without cardiac growth, while blood pressure remains stable, likely due to reduced peripheral resistance. However, specific modifications transitions in arterial resistance from fasting to digestion remain unclear. Endothelialderived catecholamines, 6-cyanodopamine and 6-nitrodopamine, are potent endogenous positive chronotropic factors in isolated rat heart. Additionally, 6-nitrodopamine is released by the corn snake’s aorta and promotes vasodilation in aortic rings, but the effects of 6-cyanodopamine in snakes are unknown. This study aimed to analyze the adrenergic regulation of the mesenteric arteries of fasting (2–3 weeks) and digesting (24–48 hours) pythons. Second order arteries were mounted in a wire myograph, and concentrationresponse curves for adrenaline and noradrenaline were performed, with or without pre-incubation with 100 nM 6-cyanodopamine. We observed a significant reduction in Emax only for adrenaline in digesting snakes compared to fasting ones. This finding suggests that different mechanisms regulate the vascular response to adrenaline and noradrenaline in fasting and digesting snakes. Additionally, 6-cyanodopamine enhanced the maximum response to noradrenaline exclusively in fasting snakes. The absence of this effect in digesting snakes is likely related to the same mechanism underlying the altered response to adrenaline. These findings indicate that arterial responses to catecholamines differ between fasting and digestion, suggesting metabolic state-dependent vascular regulation.

DMBA-INDUCED BREAST CANCER IN FEMALE WISTAR RATS.

Ceaser A Moses (Federal University of Agriculture Abeokuta, Nigeria), Oluseyi A Akinloye (Federal University of Agriculture Abeokuta, Nigeria), Adio J Akamo (Federal University of Agriculture Abeokuta, Nigeria), Adesina S Sodiya (Federal University of Agriculture Abeokuta, Nigeria)

mosesca@funaab.edu.ng

Breast cancer remains a leading cause of cancer-related mortality among women globally, with chronic inflammation and dysregulated farnesyltransferase (FTase) activity implicated in its pathogenesis. This study investigated the anticancer potential of ellagic acid (EA) and α-tocopherol (TP) in a DMBA-induced breast cancer model in female Wistar rats. Breast cancer was induced via intraperitoneal administration of DMBA (35 mg/kg) thrice in 12 weeks. Fifty-four rats were randomly assigned to nine groups (n=6): control, DMBAonly, DMBA+EA (50 mg/kg), DMBA+TP (100 mg/kg), DMBA+EA+TP, DMBA+Letrozole (2.5 mg/kg), EA-only, TP-only, and EA+TP groups, with treatments administered for 28 days. Molecular docking was used to analyse the binding affinities of EA and TP to the human FTase catalytic site. Oxidative stress markers (superoxide dismutase and catalase activities, and malondialdehyde level), IL-6 expression, and tumour suppressor genes (p53 and p27) were evaluated in the mammary tissue and serum. Molecular docking revealed superior binding affinity of EA (-7.8 kcal/mol) to FTase when compared to TP

(-6.5 kcal/mol) and standard ligand ED50 (-6.3 kcal/mol). DMBA significantly (p<0.05) decreased antioxidant enzymes activities and elevated malondialdehyde levels in mammary tissue and serum. Additionally, DMBA upregulated IL-6 expression while downregulating p53 and p27 genes. Treatment with EA and TP, particularly in combination, significantly (p<0.05) ameliorated DMBA-induced oxidative stress, downregulated IL-6 expression, and upregulated p53 and p27 expressions. The combined intervention demonstrated superior efficacy compared to monotherapy and was comparable to letrozole. These findings suggest EA and TP exert synergistic anticancer effects through multiple mechanisms, warranting further investigation as adjunctive therapeutic agents.

A17.76 MOLECULAR EVOLUTIONARY RECONSTRUCTION OF PRIMATE DIVING CAPACITY REVEALS POTENTIALLY SEMI-AQUATIC ANCESTORS

Michael Berenbrink (University of Liverpool, United Kingdom), Meghan L Hill (University of Liverpool, United Kingdom)

michaelb@liverpool.ac.uk

The suggestions of past semi-aquatic lifestyles in extinct giant lemurs, ancestors of New World monkeys (NWM’s), and ancestors of modern humans, based on partial fossils or comparative soft and hard tissue anatomy, have been amongst the most controversial claims in primate palaeobiology. We have earlier shown that the maximum concentration of Mb in locomotor muscles of several groups of living mammals is a strong indicator of their diving capacity and linked to the net surface charge of the protein, that can be modelled from its sequence. Here we use a molecular evolutionary approach to reconstruct the evolution of diving capacity in ancestral primates based on maximum-likelihood ancestral sequence reconstruction and homology modelling of the O2 -storing muscle protein myoglobin (Mb). Our results suggest a temporal increase in maximum Mb concentrations of ancestral NWM’s during their initial divergence in South America ~24 - 17.5 million years ago (Mya) after which values started to decline in several descendant lineages. Intriguingly, this period overlaps with the mega-wetland Pebas system that originated ~23 Mya due to Andean uplift and covered large parts of a greatly expanded ‘Pan-Amazonia’ whose break-up ~10 Mya is held responsible for increased speciation/extinction dynamics. By contrast, available Mb sequences from ancient DNA fragments of a subfossil giant lemur and Neanderthal and Denisovan genomes do not support aquatic adaptations in these groups. In conclusion, our molecular evolutionary results raise the possibility of a semi-aquatic phase in ancestral NWM’s whose palaeobiology remains largely unknown due to their notoriously poor fossil record.

A17.78 INVESTIGATING THE PHENOTYPIC DRIVERS OF THE INVASION DYNAMIC IN ROUND GOBY

Chloé Souques (Université Claude Bernard Lyon 1 –CNRS ENTPE UMR 5023 LEHNA, France), Jeremy Dykstra (Department of Psychology Neuroscience and Behaviour McMaster University, Canada), Anna Farley (Department of Psychology Neuroscience and Behaviour McMaster University, Canada), Sina Zarini (Department of Psychology Neuroscience and Behaviour McMaster University, Canada), Sana Abdullah (Department of Psychology Neuroscience and Behaviour McMaster University, Canada), Graham Raby (Department of Biology Trent University, Canada), Yann Voituron (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Loïc Teulier (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), François-Xavier Dechaume-Moncharmont (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Grant McClelland (Department of Biology McMaster University, Canada), Sigal Balshine (Department of Psychology Neuroscience and Behaviour McMaster University, Canada)

chloe.souques@univ-lyon1.fr

Biological invasions can cause deleterious impacts for biodiversity, ecosystem health and the economy, yet how individual traits impact invasive population spread and range expansion remain unclear. In this study we investigated the morphological, behavioural and physiological phenotypes of round goby (Neogobius melanostomus), a highly invasive fish, from populations at the edge and the core of an invasion gradient along the Trent Severn River Waterway, in Canada. Our edge (invasion front) population was significantly male biased, with larger and more reproductive fish compared to the fish at the core, an area established over 20 years ago. Using 68 size-matched males from each population we conducted repeated behavioural assays to assess boldness, and activity. In addition, thermal tolerance (CTmax) tests were conducted initially at 19°C, and then again after a 4-week acclimation to either 15°C or 27°C. While boldness and activity were similar between populations, core fish exhibited higher CTmax at 19°C but had similar thermal tolerance after acclimation, suggesting a comparable thermal plasticity. Our findings suggest larger and reproductive individuals are involved in the range expansion of round goby and appear to be in boom or population expansion phase. The results also suggest a more limited role of individual behaviour in shaping the invasion dynamic and raise questions about potential trade-offs between physiological tolerance and dispersal. By offering insights into the mechanisms underlying the invasion process, this study highlights invasion gradients as promising frameworks for invasion research and for developing mitigation strategies.

A17.79 VERIFICATION OF THE ENHANCED PHYSIOLOGICAL PERFORMANCE OF LABORATORY HEATHARDENED MEDITERRANEAN MUSSELS WHEN ACCLIMATIZED IN THE COMPLEX FIELD CONDITIONS

Ioannis Georgoulis (Laboratory of Animal Physiology Department of Zoology School of Biology Aristotle University of, Greece), Ioannis A. Giantsis (Aristotle University of Thessaloniki, Greece), Basile Michaelidis (Aristotle University of Thessaloniki, Greece), Konstantinos Feidantsis (University of Patras (financed by the funding programme “MEDICUS” of the University of Patras), Greece)

georgoim1707@gmail.com

Due to the ongoing global warming, extreme marine heat wave events have increased in severity, frequency and duration, setting marine ecosystems at high risk. In this context, the application of methods that can alleviate global warming devastating impacts on marine organisms constitutes a necessity. Repeated time-limited exposure of an organism to an environmental stimulus modifies its response mode, enhancing its resilience and adaptation to environmental stress. This “stress memory” effect is referred to as “hardening”. From this perspective, in the present study, we have applied the heat hardening process onMytilus galloprovincialis mussels. Our aim was to investigate the heat hardening effect on mussels’ cellular pathways and identify the underlying biochemical mechanisms, in terms of apoptosis, that enhance these organisms’ thermal tolerance in the laboratory. Thereafter, heat-hardened mussels were transferred to the field where they were left to acclimatize under increasing ambient sea water temperatures, to evaluate their resilience to constantly changing environmental conditions. Heat hardening resulted in decreased apoptosis at all elevated temperatures (24 °C, 26 °C, and 28 °C) in the heat-hardened mussels compared to the nonhardened individuals. In the field, increased ambient temperature resulted to increasing levels of apoptosis in the nonhardened mussels, with the hardened individuals exhibiting a significant decrease in apoptotic indicators compared to their counterparts. In conclusion, the exposure of mussels to heat hardening in the laboratory seems to provide a “stress memory” response that enhances heat tolerance and increases cell survival through reduced cell death when mussels were exposed to complex natural conditions.

CELL BIOLOGY ABSTRACTS

C1 - CROSS KINGDOM PROTEOSTASIS: UNDERSTANDING THE RULES OF PROTEIN HOMEOSTASIS

ORGANISED BY: ARI SADANANDOM (UNIVERSITY OF DURHAM), DELLA DAVID (BABRAHAM INSTITUTE), BERNADETTE CARROLL (BRISTOL UNIVERSITY)

C1.1 TOWARDS HEALTHY AGEING: INVESTIGATING THE REGULATION OF PROTEIN AGGREGATION

Tuesday 8th July 2025 09:00

Della David (Babraham Institute, United Kingdom) della.david@babraham.ac.uk

Accumulation of protein aggregates is an inherent part of normal ageing in numerous organisms. Protein aggregation with age affects the proteome of different tissues, cellular compartments as well as in the extracellular space. Age-dependent protein aggregates contribute to functional decline and thus are prime targets in the search of strategies to promote healthy ageing (Huang et al.,eLife,2019). We discovered mechanisms to prevent age-dependent protein aggregation outside cells inC. elegans. Specifically, we identified over 50 components of the extracellular proteostasis network inC. elegansthat protect against extracellular protein aggregation. Promoting extracellular proteostasis can prolong lifespan and, during a pathogenic attack, can enhance survival (Gallotta et al.,Nature,2020). Switching on a longevity program in mid-life helps to clear extracellular aggregates, concomitant with the rejuvenation of acute stress responses (Molière et al.,Geroscience,2024). Follow-up work reveals conserved anti-aggregation activity in a secreted human protein with homologies toC. elegansextracellular proteostasis components. Notably, its overexpression promotes healthy ageing inC. elegans. Together our work exposes proteostasis mechanisms used by the organism to protect its extracellular proteome against aggregation during ageing, with potentially conserved activities in corresponding human proteins.

C1.2 HIGH TEMPERATURE-INDUCED PROTEIN STRUCTURAL CHANGES AND PROTEIN ABUNDANCE IN PLANTS

Tuesday 8th July 2025 09:30

Ive De Smet (VIB-UGent, Belgium)

ive.desmet@psb.vib-ugent.be

Plants have developed various cellular, physiological and morphological solutions to deal with environmental stress. Environmental changes, such as temperature, induce changes in gene expression and protein abundance. However, many protein functional changes are regulated by post-translational modifications (PTMs), binding to other molecules, or conformational changes. The structure of a protein can be affected by several factors, including binding to other molecules, protein modifications, and fluctuations in its direct environment. Such structural changes may alter the functions of proteins, signal their degradation, or lead to their relocalisation to cellular organelles or subcellular structures. While already several molecular mechanisms associated with high temperature are known, protein degradation and associated E3 ligases have hardly been studied in the context of high temperature in plants. In addtion, protein structural alterations upon elevated temperature are hardly explored in plants. Here, I will present our work on high temperature-induced protein structural changes and protein abundance using mass spectrometry-based techniques, including combining limited proteolysis with mass spectrometry (LiP-MS). This expands our knowledge of high temperature signalling beyond the well-studied pathways and can contribute to ensuring food security under a changing climate.

C1.3 THE ROLE OF THE ER PROTEOSTASIS MACHINERY IN LIPID HOMEOSTASIS

Tuesday 8th July 2025 10:00

Colin Adrain (Queen’s University, United Kingdom)

C.Adrain@qub.ac.uk

The endoplasmic reticulum (ER) is a key site of membrane protein biogenesis and protein and lipid quality control. The ER harbours several “insertase” complexes that mediate the integration of integral membrane proteins into the ER membrane. The ER Membrane complex (EMC) is a recently identified insertase for certain key classes of membrane protein. The EMC has also been found to make extensive interactions with the ERAD (ER-associated degradation) machinery. Our recent work identifies an evolutionarily conserved role for the EMC in triglyceride storage and lipid droplet homeostasis in animals and a novel role played by the ERAD machinery in the regulation of the lower part of the sterol biogenesis pathway.

C1.4 EXPLORING LYSOSOMAL DYSREGULATION IN CELLULAR SENESCENCE AND AGEING

Tuesday 8th July 2025 14:00

Bernadette Carroll (University of Bristol, United Kingdom)

bernadette.carroll@bristol.ac.uk

In healthy cells, a dynamic balance between biosynthesis, degradation and recycling supports growth. This is controlled, at least in part by the pro-growth mammalian target of rapamycin complex 1 (mTORC1) and the degradative autophagy-lysosome pathway. mTORC1 is activated by nutrients and energy to control protein translation, lipid and nucleotide synthesis while autophagy involves the sequestration of cytoplasmic contents in both selective and non-selective (bulk) ways to deliver them to the lysosome for degradation. Importantly, there is extremely tight reciprocal control between mTORC1 and the autophagy-lysosome pathway to maintain proteostasis and homeostasis. We are studying the mechanisms controlling the localisation and activity of these processes and how rewiring of this equilibrium contributes to cellular senescence (a tumour suppressor mechanism of cell cycle arrest) and cancer.

C1.5 THE N-DEGRON PATHWAY OF PROTEOLYSIS REGULATES HISTONE METHYLATION DYNAMICS TO COORDINATE PLANT DEVELOPMENT AND STRESS ADAPTATION

Tuesday 8th July 2025 14:30

d.gibbs@bham.ac.uk

The N-degron pathways are a set of conserved eukaryotic degradation pathways that target proteins for ubiquitin-mediated proteolysis based on the chemical nature and identity of their N-terminus. In plants, the PROTEOLYSIS6 (PRT6) N-degron pathway has emerged as a key regulator of diverse processes. In particular, it coordinates development and stress-responses through the oxygen- and nitric oxide-dependent control of several functionally discrete substrates, including transcription factors (ERFVIIs, ZPR2) and the polycomb protein VRN2. VRN2 is a flowering plant homolog of animal Suz12, a core subunit of the conserved polycomb repressive complex 2 (PRC2) that catalyses the tri-methylation of histones (H3K27me3) to epigenetically silence gene expression. Our work to date suggests that post-translational control of VRN2 abundance via its N-degron allows it to function as a “sensor subunit” that connects PRC2 activity to the perception of diverse environmental and positional cues. Supporting this, we have shown that VRN2 directly couples hypoxic (i.e., low-oxygen) signals from the environment to the epigenetic control of root and leaf development and plays a key role in establishing longer term abiotic stress tolerance and memory. In parallel, we have identified a second histone modifying protein - an H3K27 demethylase, which counterbalances PRC2 activity - that is targeted to genes in an oxygen-and N-degron-dependent manner. Taken together, our work suggests that the PRT6 N-degron pathway influences global gene expression patterns to coordinate plant growth and environmental stress adaptation through controlling the stability and recruitment of a suite of antagonistic histone modifiers and transcription factors.

C1.6 REDOX REGULATED AUX/IAA MULTIMERIZATION MODULATES AUXIN RESPONSES

Tuesday 8th July 2025 15:00

Dipan Roy (Durham University, United Kingdom)

dipan.roy@durham.ac.uk

Reactive oxygen species function as key signals in plant adaptation to environmental stresses like drought. Roots respond to transient water unavailability by temporarily ceasing branching through the acclimative response xerobranching. In this study, we report how a xerobranching stimulus triggers rapid changes of ROS levels in root nuclei, triggering redox-dependent multimerization of the auxin repressor protein IAA3. Mutations in specific cysteine residues of IAA3 disrupt redox-mediated multimerization and interaction with co-repressor TPL, thereby attenuating IAA3 mediated target gene repression. Other AUX/IAA proteins also vary in their redox mediated multimerization, revealing a regulatory mechanism that connects dynamic changes in cellular redox status to auxin signalling. Our study reveals how ROS, auxin and water availability intersect and shape root adaptive responses, thereby maintaining phenotypic plasticity in plants.

Daniel J Gibbs (University of Birmingham, United Kingdom)

C1.7 HARNESSING STRESS RESILIENCE

PATHWAYS FOR THERAPEUTICS

Tuesday 8th July 2025 16:00

Ritwick Sawarkar (University of Cambridge, United Kingdom)

rs2099@cam.ac.uk

Mammalian cells experiencing proteotoxic stress downregulate the expression of thousands of active genes and upregulate a few stressresponse genes. The strategy of downregulating gene expression has conceptual parallels with general lockdownin the global response to the coronavirus disease 2019 (COVID-19) pandemic. The mechanistic details of global transcriptional downregulation of genes, termed stress-induced transcriptional attenuation (SITA), are only beginning to emerge. The reduction in RNA and protein production during stress may spare proteostasis capacity, allowing cells to divert resources to control stress-induced damage. Given the relevance of translational downregulation in a broad variety of diseases, the role of SITA in diseases caused by proteotoxicity should be investigated in future, paving the way for potential novel therapeutics.

C1.8 GLYCATION: “SUGAR COATING” PEPTIDES IN PLANT SIGNALLING

Tuesday 8th July 2025 16:30

Ulrike Bechtold (Durham University, United Kingdom), GEMMA MILNE (Durham University, United Kingdom), AMELIA ANDERSON (Durham University, United Kingdom), Steven L Cobb (Durham Univesrity, United Kingdom)

ulrike.bechtold@durham.ac.uk

Glycation refers to the non-enzymatic post-translational modifications of proteins formed through interaction with reducing carbohydrates and reactive carbonyls. In mammalian systems, glycated proteins and peptides have the potential to serve as effectors of intracellular signalling pathways and contribute to protein degradation triggering cell death and inflammatory responses. The impact of glycation in plants has been overlooked, yet high carbonyl content in plant tissues especially under stress, has prompted research into the role of glycation. How glycated peptides are recognised, if and how they move within plants and their general physiological role, is not yet understood. We are developing a method that allows us to trace exogenously applied glycated and non-glycated peptides in Arabidopsis leaf extracts and link these to downstream responses. Fluorinated peptides are synthesised using Solid Phase Peptide Synthesis and subsequently glycated with D-ribose. Glycated and non-glycated peptides were fed to mature Arabidopsis leaves and assessed for their capacity to induce reactive oxygen species (ROS), and plant extracts were analysed by 19 F NMR for the presence of peptides in planta. Only glycated peptides elicited a rapid mitochondrial ROS burst followed by a delayed burst in the chloroplast. Detection of both non-glycated and glycated fluoropeptides in plant extracts, showed that glycated peptides were significantly more degraded compared to their nonglycated equivalents. This implies that glycation serves as a specific metabolic signal, potentially interacting with signalling pathways. These findings lay the foundation for further investigations into the role of glycation in plant physiology and its potential implications for plant stress responses.

C1.9 STUDY ON THE ROLE OF VACUOLAR PROCESSING ENZYMES (VPE) IN AUTOPHAGIC BODY DEGRADATION DURING

CARBON STARVATION-INDUCED AUTOPHAGY

Tuesday 8th July 2025 16:45

Karolina Wleklik (Adam Mickiewicz University Poznań, Poland), Małgorzata Pietrowska-Borek (Poznań University of Life Sciences, Poland), Katarzyna Nuc (Poznań University of Life Sciences, Poland), Szymon Stefaniak (Adam Mickiewicz University Poznań, Poland), Sławomir Borek (Adam Mickiewicz University Poznań, Poland)

karolina.wleklik@amu.edu.pl

Autophagy is the evolutionarily well-conserved process during which cell components are degraded and recycled. One of the crucial, but poorly understood steps of autophagy is autophagic body degradation in vacuole. To this day, no enzyme involved in this autophagy stage in plants has been identified. However, vacuolar processing enzymes (VPE) constitute great candidates as they are key vacuolar enzymes that activate other hydrolases. Our team is addressing this hypothesis by conducting studies on isolated embryonic axes of white lupin (Lupinus albus L.) and Andean lupin (Lupinus mutabilis Sweet) cultured in vitro under various carbon (sugar) and nitrogen (asparagine) conditions. Sugar starvation induces autophagy, whereas asparagine (Asn) slows down autophagic body breakdown. So far, we detected a significantly higher VPE activity in sugar-starved axes (-S) than in sucrose-fed axes (+S), which was lowered in -S axes fed with asparagine (-S+Asn) and treated with autophagy inhibitors that interrupt this process at different stages. Ultrastructure observations, using a VPE inhibitor, showed an accumulation of autophagic bodies in the vacuoles of the -S axes. We performed the RNA-seq analysis and identified five transcripts of genes encoding VPE in each lupin species, within which four were most similar to the γVPE and one to the γVPE isoform of Arabidopsis thaliana. The RT-qPCR analysis revealed that only two γVPE-like genes showed higher levels of transcripts in the -S axes than in the +S axes. This may indicate that only given VPE participate in autophagic body degradation during sugar starvationinduced autophagy in lupin embryonic axes.

C1.10 A NOVEL CLASS OF SMALL MOLECULE ACTIVATORS OF GCN2, AN AMINO ACID-SENSING PROTEIN KINASE

Wednesday 9th July 2025 09:00

Simon Cook (Babraham Institute, United Kingdom)

simon.cook@babraham.ac.uk

GCN2 is an evolutionarily conserved serine/threonine protein kinase that acts as a sensor of amino acid deficiency and phosphorylates eIF2α; this inhibits global translation initiation but allows expression of ATF4 and activation of the integrated stress response (ISR). Here we show that we show that eight different inhibitors of the RAF protein kinases (RAFi) paradoxically activate GCN2 leading to eIF2αdependent (and ERK1/2-independent) ATF4 and CHOP expression. The GCN2 kinase inhibitor A-92, GCN2 RNAi, GCN2 knock-out or ISRIB (an

eIF2α antagonist) all reverse RAFi-induced expression of ATF4 and CHOP indicating that RAFi require GCN2 to activate the ISR. RAFi also activate full-length recombinant GCN2in vitroand in cells. Activation of the ISR by RAFi is abolished by a GCN2 kinase dead mutation, whilst a M802A gatekeeper mutant is activated at lower RAFi concentrations, demonstrating that RAFi bind directly to the GCN2 kinase domain; this is supported by mechanistic structural models of RAFi interacting with GCN2. RAFi may therefore serve as novel probes for GCN2 function in the ISR and proteostasis. Our results may also be relevant to the clinical use of RAFi in cancer.

C1.11 ER-ASSOCIATED DEGRADATION

AND NUCLEAR SORTING CONTROL THE FATE OF TWO PROTEASOME TRANSCRIPTIONAL ACTIVATORS FOR INTRACELLULAR ORGANELLE COMMUNICATION DURING PROTEOTOXIC STRESS

Wednesday 9th July 2025 09:30

Suayb Üstün (Ruhr-University of Bochum, Germany)

suayb.uestuen@rub.de

Proteotoxic stress, characterized by the accumulation of damaged proteins, poses a significant challenge to cellular homeostasis. To mitigate proteotoxicity eukaryotes employ the proteasome that is regulated by proteasome activators, e.g. transcription factors that promote gene expression of proteasome subunits. As proteotoxicity originates in different compartments, cells need to perceive signals from various locations. Understanding which components integrate signals to address proteotoxicity is essential to develop strategies to cope with proteotoxicity but remain elusive. Here, we identify that the proteasome autoregulatory feedback loop acts as a gatekeeper to facilitate the communication between nucleus and chloroplast. We reveal that the ER-associated degradation (ERAD) controls NAC53 and NAC78 proteasomal degradation while ER-associated nuclear sorting (ERANS) mediates nuclear targeting of both proteasome activators. While both transcription factors activate the proteasome gene expression, they repress photosynthesis-associated nuclear genes during proteotoxicity through association with a conserved ciselement. Our data implicate a general trade-off between proteasome function and energy metabolism unravelling an unprecedented mechanism of how eukaryotic cells cope with proteotoxicity. Collectively, our discoveries provide a novel conceptual framework in which the proteasome autoregulatory feedback loop coordinates subcellular proteostasis and the trade-off between growth and defence.

C1.12 CARBAMYLATION IMPINGING ON UBIQUITINATION IN THE NF-kB PATHWAY

Wednesday 9th July 2025 09:45

George Weston (University of Durham, United Kingdom)

george.m.weston@durham.ac.uk

Carbon dioxide (CO 2 ) is fundamental to biological processes throughout the biosphere. While much is known about the impact of CO2 on the overall physiology of an organism, much less is known about how its interaction with specific biomolecules may affect their function. Identifying proteins that bind CO2 is imperative to understanding these broader CO2 -regulated molecular processes. Carbamylation is a non-enzymatic reversible post-translational modification where CO2 binds to a lysine ε-amino group. A chemical proteomics tool using a triethyloxonium (TEO) ion to trap carbamates allows identification through mass spectrometry. Using this method and 13 C-NMR, ubiquitin has been shown to bind CO2 through the N-terminus and the ε-amino group on lysines 6, 33, 48 and 63. CO2 binding to lysine 48 was demonstrated to reduce ubiquitin conjugation and subsequent activation of the NF-KB pathway. This mechanism is proposed as one method by which elevated CO2 reduces inflammation. Three lysines (11, 27, 29) within ubiquitin do not form observable carbamates. Through computational molecular dynamics simulations, we aim to understand why lysines have different prevalences for carbamate formation and investigate the change in properties and structural impacts of this modification. Understanding how select lysines in ubiquitin do or do not interact with CO2 can influence our broader understanding of protein-CO2 interactions.

C2 - BIOMOLECULAR CONDENSATES IN PLANTS AND ANIMALS

ORGANISED BY: MONIKA CHODASIEWICZ (KING ABDULLAH UNIVERSITY OF SCIENCE AND TECHNOLOGY)

C2.1 BIOMOLECULAR CONDENSATES SUPPORT PLANT-ENVIRONMENT INTERACTIONS

Wednesday 9th July 2025 11:00

Xiaofeng Fang (School of Life Sciences Tsinghua University, China)

xffang@tsinghua.edu.cn

Plants, unable to move on their own, have evolved more rapid and complex mechanisms to perceive and respond to environmental changes during interactions with their surroundings. The phase separation of biomacromolecules within cells exhibits sensitivity to the surrounding physical and chemical environment. In my talk, I will explore the possibility of phase separation as a mechanism for plants to respond to environmental changes. My laboratory has developed methods and techniques to investigate the phase separation of proteins involved in environmental signal response. Our recent work has revealed that phase separation plays a significant role in water and heat stress. Phase separation is expected to become a new direction in the study of plant-environment interactions, providing new perspectives on how plants respond to environmental changes.

C2.2 TRIM PROTEINS AS REGULATORS OF NUCLEAR CONDENSATION AND HUMAN CONDENSATOPATHIES

Wednesday 9th July 2025 11:30

Hari R. Singh (Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany), Vineeta Sharma (BCH Boston, United States), Anna Hadarovich (CSBD Dresden, Germany), Jik Nijssen (Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany), Andrei Pozniakovski (Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany), Agnes Toth Petroczy (CSBD Dresden, Germany), Amar J Majmudar (BCH Boston, United States), Anthony Hyman (Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany)

hari.r.singh@mpi-cbg.de

How biomolecular organization from the molecular to the mesoscale gives rise to cellular function remains a central question in cell biology. We identify the human TRIM protein family—rich in intrinsically

disordered regions (IDRs) and largely understudied—as key players in mesoscale nuclear organization. Using imaging and multi-scale analysis, we show that TRIM proteins form condensates whose properties correlate with IDR content and structural complexity. Disease-causing variants in TRIM8 disrupt these condensates, leading to altered protein concentration and loss of co-condensation with partners such as ubiquitin and TAK1. These findings establish TRIM8 syndrome as a bona fide human condensatopathy. More broadly, we are using TRIM proteins as a model to explore machine learning approaches for predicting protein condensation behavior and for extracting generalizable features from mesoscale localization patterns. Our study provides a framework for probing the role of mesoscale organization in health and disease.

C2.3 DECIPHERING UBP1C FUNCTION: PHASE SEPARATION, RNA BINDING, AND ITS ROLE IN PLANT STRESS RESPONSES

Wednesday 9th July 2025 12:00

Malavika MuraleeDharan (King Abdullah University of Science and Technology, Saudi Arabia), Monika Chodasiewicz (King Abdullah University of Science and Technology, Saudi Arabia), Israel Maruri Lopez (King Abdullah University of Science and Technology, Saudi Arabia)

malavika.muraleedharan@kaust.edu.sa

Plants, due to their sessile nature, are equipped with intricate molecular mechanisms to respond to environmental stresses including the formation of stress granules (SGs) – membrane-less organelles that sequester translationally repressed mRNAs and proteins during stress. Assembly of SGs are through a phenomenon known as liquidliquid phase separation (LLPS), mediated by multivalent protein and RNA interactions. Although the predominance of SGs as a survival mechanism has been established, understanding the general composition and its molecular drive remains poorly understood. Our research focuses on unraveling the molecular intricacies of plant SGs, with a particular emphasis on the Oligouridylate binding protein 1c (Ubp1c), a known SG-associated protein. Ubp1c, characterized by its tri-RNA-Recognition Motifs (RRMs), has previously been identified as a key player in SGs formation, yet its precise role and molecular characteristics remain elusive. Using a multi-faceted approach, we explore the contributions of Ubp1c RRM domains to SG dynamics and potential RNA regulation by the protein. Deletion constructs targeting Ubp1c’s RRMs revealed the indispensability for these domains for localization to SG. Our findings further highlight how Ubp1c’s modular domains mediate both RNA binding and LLPs, hypothesizing

the facilitation of Ubp1c to recruit specific mRNAs to SGs, thereby influencing SG RNA composition and functionality. Ongoing work aims to characterize RNA and protein composition of SGs in Ubp1c mutants and explore how Ubp1c-mediated RNA sequestration influences mRNA stability and translational control during stress.

C2.4 IMPORTANCE OF STRESS GRANULES IN STRESS TOLERANCE

Wednesday 9th July 2025 12:15

Monika Chodasiewicz (Monika Chodasiewicz, Saudi Arabia), Itzell Hernandez-Sanchez (KAUST, Saudi Arabia), Ibrahim Tarbiyyah (KAUST, Saudi Arabia), Israel Maruri-Lopez (KAUST, Saudi Arabia)

monika.chodasiewicz@kaust.edu.sa

Plants are sessile organisms that had to develop molecular mechanisms to deal with changes in their environment. One of such mechanism is formation of stress-induced condensates called Stress Granules (SGs). SGs are liquid-liquid phase separation (LLPS) biomolecular condensates composed of proteins, mRNA and metabolites. The main function of the SGs is protective sequestration of their components. When analyzed the composition of SGs in plants we realized high similarity to SGs described in mammalian and yeast cells suggesting that there is conservation of SGs across different species. Therefore, research on SGs in plants might be beneficial for understanding the response of whole organism into stressful conditions. With the use of cell biology, biochemistry, molecular biology and omic approaches, our group is interested to uncover the mechanism of SGs formation/disassembly but also the true role of SGs in stress signaling and tolerance. Recent research in our lab shows that by manipulation of key SG proteins or their biophysical properties we can affect the overall SG dynamics leading to improved stress tolerance. During my talk, I will focus on RBP proteins that are close homologues of TIA from mammalian and are well known SGs markers in plants.

C2.5 THE MOLECULAR REGULATION OF STEM CELL HOMEOSTASIS IN THE ARABIDOPSIS ROOT MERISTEM

Wednesday 9th July 2025 15:00

Yvonne Stahl (Institute for Molecular Biosciences Plant Developmental Genetics Goethe University, Germany) y.stahl@bio.uni-frankfurt.de

Plants can continuously develop new organs thanks to pluripotent stem cells in meristems. In Arabidopsis roots, stem cell niche (SCN) maintenance is crucial for growth and development. This is regulated by interactions among transcription factors, phytohormones, peptide ligands, and receptors. However, the exact molecular regulation of stem cell differentiation remains unclear.

At the center of the SCN, the quiescent centre (QC) preserves the surrounding stem cells, known as initial cells, which give rise to all the different root tissues. TFs like WUSCHEL-RELATED HOMEOBOX 5 (WOX5) and PLETHORAs (PLTs) in the SCN maintain the QC and

control the fate of distal columella stem cells (CSC). Both WOX5 and PLTs are essential for maintaining the root meristem, coordinating QC quiescence, and determining CSC fate.

Notably, PLTs, particularly PLT3, contain intrinsically disordered prion-like domains (PrDs) that are necessary for complex formation with WOX5 and recruitment to nuclear bodies (NBs) in CSCs. The subcellular partitioning of PLT-WOX5 complexes to NBs, possibly through liquid-liquid phase separation, seems to be relevant for CSC fate determination.

Furthermore, the occurrence of unique cell-type specific TF complexes of WOX5, PLT3, and BRASSINOSTEROIDS AT VASCULAR AND ORGANIZING CENTER (BRAVO) can be modeled by integrating experimental data on protein abundances and specific binding affinities.

This new regulatory model suggests that the cell-type specific and PrD dependent formation of TF complexes may be instrumental in cell fate determination. This could integrate external cues with stem cell regulation on a molecular level shedding light on plant growth and adaptability to environmental challenges.

C2.6

ARE STRESS GRANULES EMERGING AS NOVEL SIGNALING HUBS IN PLANT RESPONSES TO STRESS?

Wednesday 9th July 2025 15:30

Emilio Gutierrez-Beltran (Universidad de Sevilla-CSIC, Spain), Jorge Solis-Miranda (Universidad de Sevilla-CSIC, Spain), David Delgado-Romero (Universidad de Sevilla-CSIC, Spain), Itzell Hernandez-Sanchez (KAUST, Saudi Arabia), Monika Chodasiewicz (KAUST, Saudi Arabia), Panagiotis N. Moschou (Institute of Molecular Biology and Biotechnology, Greece) egutierrez@ibvf.csic.es

Stress Granules (SGs) are a type of biomolecular condensates formed through liquid-liquid phase separation (LLPS) and composed of RNAs and proteins that arise in the cytoplasm in response to both environmental and internal signals 1 . The formation of SGs minimizes stress-related damage and promotes cell survival, although the molecular mechanisms underlying pro-survival effects of SGs remain to be established 2 . The last past few years, SGs are emerging as an important concept in signalling. In fact, our recent results suggest that SGs might act as a key signalling hub in the plant stress response. In this line, we have recently found that in the model plant Arabidopsis thaliana, Tudor staphylococcal nuclease (TSN) is an intrinsically disordered protein acting as a scaffold for a large pool of signalling proteins, including the evolutionarily conserved energy-sensing SNF1-related protein kinase 1 (SnRK1) complex and two modules of well-conserved mitogen-activated protein kinases (MAPKs) 1,3 . In accordance with the enrichment of kinases into SGs, we have found that protein phosphorylation events are required for modulating activity of SGs-associated proteins, suggesting a key role of this post-translational modification for the plant stress response 4 . Our recent findings indicate that SGs may serve as platform for integrating phosphoregulatory signalling events to control specific biological processes.

C2.7 BACTERIA EXPLOIT PLANT

PROCESSING BODIES TO ATTENUATE HOST TRANSLATION DURING INFECTION

Wednesday 9th July 2025 16:00

Manuel Gonzalez-Fuente (Ruhr-University of Bochum, Germany), Nico Schulz (Ruhr-University of Bochum, Germany), Alibek Abdrakhmanov (Gregor Mendel Institute Vienna BioCenter, Austria), Gaiea Izzati (Center for Plant Molecular Biology University of Tübingen, Germany), Shanshuo Zhu (Ruhr-University of Bochum, Germany), Gautier Langin (Ruhr-University of Bochum, Germany), Paul Gouguet (Ruhr-University of Bochum, Germany), Mirita Franz-Wachtel (Ruhr-University of Bochum, Germany), Boris Macek (Proteome Center Tübingen, Germany), Anders Hafrén (Swedish University of Agricultural Sciences, Sweden), Yasin Dagdas (Gregor Mendel Institute Vienna BioCenter Austria, Austria), Suayib Üstün (Ruhr-University of Bochum, Germany)

manuel.gonzalezfuente@rub.de

Compartmentalization of transcripts in biomolecular condensates allows rapid and cost-efficient responses to environmental stimuli. Processing bodies (P-bodies) are dynamic ribonucleoprotein condensates formed by phase separation in the cytosol. P-bodies are involved in translational arrest and mRNA decay and regulate several developmental processes and stress responses. Pathogens have evolved strategies to modulate the host protein degradation for their own benefit, however little is known about how they impact protein synthesis. We show that pathogenic bacteria Pseudomonas syringae pv. tomato (Pst) induces the formation of P-bodies to attenuate the host translation through two effectors with liquid-like properties. Moreover, we found that autophagy and repression of the ER stress response are required for the Pst-mediated induction of P-bodies and attenuation of translation. Altogether, our discoveries provide novel insights on how host translation is attenuated by bacteria to dampen plant immunity, and uncover unknown connections between ER stress responses and autophagy with P-body dynamics.

C2.8 MECHANISM MODULATING HUR LOCALIZATION IN STRESS GRANULES AND ITS IMPACT ON CELLS STRESS RESPONSE

Wednesday 9th July 2025 16:15

Sujitha Sali (King Abdullah University of Science and Technology, Saudi Arabia), Shahryar Khattak (King Abdullah University of Science and Technology, Saudi Arabia), Sergio Di Marco (King Abdullah University of Science and Technology, Saudi Arabia), Imed Gallouzii (King Abdullah University of Science and Technology, Saudi Arabia)

sujitha.sali@kaust.edu.sa

Cells employ specialized mechanisms to regulate mRNA translation in response to diverse stress stimuli, ensuring the maintenance of cellular homeostasis. One such response involves the formation of bimolecular called Stress Granules (SGs) through Liquid-Liquid Phase Separation (LLPS), a process majorly driven by RNA binding proteins (RBPs), the central scaffold proteins. Among these, Human antigen R (HuR) stands out as a ubiquitously expressed RBP which aggregates into SGs and serves as a well‐established mRNA stabilizer crucial for determining cell fate. The multifunctional role of HuR is intricately regulated through post translational modifications, including PARylation, wherein poly ADP-ribose (PAR) polymers are generated by PAR polymerase enzymes (PARPs). Although, extensive research has been conducted on the parylation of RBPs within SGs and its impact on SG dynamics, a significant gap still remains to be uncover.

In this study, we aim to uncover the potential role of HuR parylation and its association with other trans-acting factors in regulating the function of SGs. Our investigation reveals that PBM (PAR binding motif) within the HuR nucleocytoplasmic shuttling (HNS) domain, plays a crucial role in mediating the localization of HuR within SGs under conditions of cellular stress. We further hypothesize that parylation of HuR facilitates its association with other RBPs, contributing to the recruitment of mRNAs and other critical factors into the SGs. Overall, our study provides novel insights into the mechanism governing HuR localization within SGs. Understanding the role of HuR in SGs opens new avenues for developing targeted therapeutic strategies for alleviating stress associated diseases.

C3: TIP GROWTH IN PLANT BIOLOGY

ORGANISED BY: KRIS VISSENBERG (UNIVERSITY OF ANTWERP), JOSÉ A. FEIJO (UNIVERSITY OF MARYLAND)

C3.1 MECHANOSENSATION IN THE CELL WALL

Tuesday 8th July 2025 14:00

Nicolas MINC (Institut Jacques Monod CNRS UMR7592, France)

nicolas.minc@ijm.fr

The Cell Wall (CW) is a thin and rigid sugar-made layer encasing the plasma membrane. It provides mechanical integrity to bacterial, fungal and plant cells and define their shapes and modes of growth. Using super-resolution imaging to map CW thickness around live and growing fission yeast cells, we deciphered the mechanisms controlling CW dynamics during tip growth. We uncovered a homeostatic mechanism controlling wall thickness at growing cell tips, which impinges on cell viability and growth regulation. This mechanism implicates the integral membrane CW mechanosensor Wsc1, which features long extracellular domains embedded into the CW matrix. Using devices to apply local mechanical stresses onto the CW, or to create local damages in the CW we further establish how Wsc1 can dynamically probe local surface forces applied onto the CW, and promote its repair. Those data contribute to establish mechanisms and functions of CW mechanosensing.

C3.2

UNRAVELING

THE MOLECULAR BASIS OF ROS-MEDIATED CELL WALL BIOMECHANICS DURING ARABIDOPSIS

Tuesday 8th July 2025 14:30

Yentl Meul (University of Antwerp, Belgium), Ruimin Zhu (University of Münster, Germany), Ana Cunha (University of Antwerp, Belgium), Sébastjen Schoenaers (University of Antwerp, Belgium), Jörg Kudla (University of Münster, Germany), Kris Vissenberg (University of Antwerp, Belgium)

yentl.meul@uantwerpen.be

Our research aims to elucidate the role of reactive oxygen species (ROS) in regulating cell wall (CW) biomechanics during plant growth, bridging a critical gap in the growth regulatory pathway. Understanding these growth regulatory processes is essential for plant biology, particularly in plant-pathogen interactions and stress responses. By integrating ROS signaling with CW integrity pathways,

we want to create a mechanistic framework that could form the basis for future fundamental and agricultural advancements.

Using a microfluidics setup and automated pumping system, we quantified the oscillatory dynamics of growth, cytoplasmic calcium, extracellular pH, ROS, and CW charge in wild-type and mutant root hairs of Arabidopsis thaliana. These mutants were affected in transmembrane and cytoplasmic receptor-like kinases and ROS-generating proteins. Additionally, we examined the effects of modulating ROS presence on the oscillatory dynamics and CW integrity by adding ROS and ROS scavengers to growing root hairs through live-cell imaging.

To further dissect the growth regulatory network, we used complementary approaches to analyze interactions among the key proteins, conducted kinase activity assays, and reconstituted pathways in HEK cells. Finally, we modeled potential protein complexes within this ROS-related growth regulatory pathway, linking it to the recently identified CW integrity sensing module that regulates root hair growth.

C3.3 THE RELATION BETWEEN SECRETION AND GROWTH RATE IN ROOT HAIRS

Tuesday 8th July 2025 14:45

Stephanie Afonso (Institut Jean-Pierre Bourgin - IJPB, France), Alexis Peaucelle (Institut Jean-Pierre Bourgin - IJPB, France), Herman Höfte (Institut Jean-Pierre Bourgin - IJPB, France), Kalina T. Haas (Institut Jean-Pierre Bourgin - IJPB, France)

tephanie.afonso@inrae.fr

A central question in plant biology is how cells expand while maintaining the integrity of their cell walls. According to the classical Lockhart model, cell expansion is driven by turgor pressure and regulated by the extensibility of the cell wall. Although this model does not explicitly account for it, the deposition of new cell wall material is thought to occur in response to expansion through an unspecified mechanosensing feedback mechanism.

In this study, we investigated the oscillatory dynamics of exocytosis inArabidopsis thalianaroot hairs and its relationship with cell growth. Additionally, we explored how calcium regulates cell growth through the spatiotemporal control of exocytosis and actin dynamics. To achieve this, we used microfluidics to deliver rapid and reversible pharmacological perturbations, allowing us to track their effects at short timescales. Our findings support a causal relationship between secretion and growth rate.

Furthermore, we provide new insights into the recently proposed dual role of Rapid Alkalinization Factor 22 (RALF22) in both the structural organization of the cell wall and the feedback signaling that coordinates cell wall expansion.

C3.4 A PECTIN-BINDING RALF PEPTIDE WITH BOTH A STRUCTURAL AND SIGNALING ROLE IN THE PERIODIC ASSEMBLY OF THE PLANT CELL WALL

Tuesday 8th July 2025 15:00

Sébastjen Schoenaers (University of Antwerp, Belgium), Francis Lee (University of Lausanne, Switzerland), Martine Gonneau (INRAE Institut Jean-Pierre Bourgin (IJPB), France), Elvina Faucher (INRAE Institut Jean-Pierre Bourgin (IJPB), France), Thomas Levasseur (INRAE, France), Elodie Akary (INRAE Institut Jean-Pierre Bourgin (IJPB), France), Yentl Meul (University of Antwerp, Belgium), Naomi Claeijs (University of Antwerp, Belgium), Kalina Haas (INRAE Institut Jean-Pierre Bourgin (IJPB), France), Steven Moussu (University of Lausanne, Switzerland), Caroline Broyart (University of Lausanne, Switzerland), Daria Balcerowicz (University of Antwerp, Belgium), Hamada AbdElgawad (University of Antwerp, Belgium), Andrea Bassi (Politecnico di Milano, Italy), Daniel S. C. Damineli (University of São Paulo, Brazil), Alex Costa (University of Milan, Italy), José A. Feijó (University of Maryland, United States), Celine Moreau (INRAE, France), Estelle Bonin (INRAE, France), Bernard Cathala (INRAE, France), Julia Santiago (University of Lausanne, Switzerland), Herman Höfte (INRAE Institut JeanPierre Bourgin (IJPB), France), Kris Vissenberg (University of Antwerp, Belgium)

ebastjen.schoenaers@uantwerpen.be

Secreted Rapid ALkalinization Factor (RALF) peptides have emerged as key components controlling cell wall integrity. However, the inner workings of the RALF pathway remain enigmatic. We show that RALF22, a root hair expressed RALF, has a dual signaling and structural role during cell growth. RALF22 loss-of-function root hairs are short and frequently burst due to loss of wall integrity. Exogenous RALF22 treatment induces a FERONIA-dependent root hair growth arrest and a FER-independent increase in cell wall porosity. Our data show that this duality is the result of RALF22 interacting with (1) the LLG1/FER transmembrane receptor complex to regulate downstream signaling and (2) the integral cell wall proteins LRX1 and LRX2 to regulate pectic cell wall assembly. In the root hair cell wall, RALF22 forms periodic circumferential rings which colocalize with rings of blockwise demethylated homogalacturonan (HG) and LRX1. Polycationic RALF22 and RALF22-LRX1 bind to and induce the condensation of polyanionic HG in a charge dependent manner.

In vivo, the LLG1-RALF22-FER and RALF22-LRX1-pectin interactions are mutually exclusive. As such, we suggest a model in which FER and polyanionic HG compete for RALF22 to sense and regulate pectic cell wall organization and integrity and, as a result, cell growth. Consistent with this model, our most recent findings indicate that FER rapidly senses and responds to changes in the degree of pectin methylesterification in the growing root hair cell wall.Together, our results reveal a novel mechanism in which RALF22 simultaneously regulates periodic pectin assembly through LRX1/2 and cell wall sensing through LLG1/FER.

C3.5 THE FAST AND THE TINY: DYNAMICS OF ROOT HAIR EXPANSION

Tuesday 8th July 2025 16:00

Kalina T Haas (INRAe, France)

kalina.haas@inrae.fr

Understanding how plant cells grow remains a fundamental question in plant biology. At the subcellular level, growth is driven by cell wall expansion, which requires dynamic modifications in the chemistry and architecture of polymer networks. Tip-growing root hairs exhibit rapid oscillatory growth accompanied by periodic fluctuations in intra- and extracellular pH, Ca²+, and reactive oxygen species (ROS). Investigating these second-scale pulsations provides insight into the molecular events underlying growth regulation.

In this presentation, we will explore how spatial periodicity in cell wall assembly and architecture is orchestrated by dynamic cellular processes and biochemical oscillations. To achieve this, we employ single molecule iamging to uncover key changes in cell wall composition and structure during growth. Additionally, we will demonstrate how real-time interrogation of rapid signaling events— through microfluidics-mediated perturbation, biosensing, and highspeed time-lapse imaging—enhances our understanding of the mechanisms coordinating cell wall expansion.

C3.6 EXPLORING THE ROLE OF PHOSPHOLIPASE C2 (PLC2) AND ITS ALLELIC DIVERSITY IN ROOT DEVELOPMENT AND PHOSPHATE HOMEOSTASIS

Tuesday 8th July 2025 16:30

Sofía C Somoza (University of Padua, Italy), Arianna Capparotto (University of Padua, Italy), Daniele Castelli (University of Padua, Italy), Wolfgang Busch (Salk Institute for Biological Studies, United States), Marco Giovannetti (University of Torino, Italy)

sofiacristina.somoza@unipd.it

Phosphorus is an essential nutrient that plays a fundamental role in plant development, but its supply chain is fragile, and it is relatively immobile, usually present in low concentrations in the soil. To optimise inorganic phosphate usage, it is crucial to gain a deeper understanding of the molecular mechanisms regulating plant phosphate homeostasis. Recent studies suggest that inositol phosphates may act as key molecules buffering cellular responses to phosphate. Additionally, a GWAS study conducted in our lab identified Phosphoinositidespecific Phospholipase C2 (PLC2) as a candidate regulating root responses to phosphate in legumes. PLC2 is a key enzyme in inositol phosphate biosynthesis, hydrolysingphosphatidylinositol-4,5bisphosphate(PIP2) to generatediacylglycerol(DAG) andinositol1,4,5-trisphosphate(IP3).

UsingLotus japonicusas a model legume, we observed that PLC2 localises to the plasma membrane, accumulating preferentially at emerging root hair tips. Furthermore,plc2insertional mutant root hairs exhibited an altered localisation pattern of PIP2, its substrate, along with an impaired endocytosis, supporting PIP2’s role in membrane trafficking.

To investigate how the allelic diversity of PLC2 inL. japonicuscorrelates with root phenotypic variation, we selected natural accessions carrying different SNPs in thePLC2promoter. GUS staining revealed differential expression patterns in roots influenced by phosphate availability. Moreover, the differentPLC2promoters were able to complement theplc2phosphate phenotype in different levels.

C3.7 DECODING THE CONVERSATION BETWEEN THE PLASMA MEMBRANE AND CELL WALL IN CONTROLLING

POLLEN TUBE GROWTH DURING FERTILIZATION

Tuesday 8th July 2025 16:45

Hao WANG (South China Agrcultural University, China)

wanghaohw@gmail.com

Plant fertilization relies on precisely regulated pollen tube growth, driven by the interplay between membrane dynamics and cell wall expansion. We previously identified an unconventional exocytic pathway in which Golgi-derived secretory vesicles (GDSVs) bypass the trans -Golgi network (TGN) to polar exocytose Nicotiana tabacumpectin methylesterase 1 (NtPPME1), modulating cell wall rigidity during rapid pollen tube growth. However, the mechanisms coordinating this unconventional exocytosis with membrane dynamics and signaling, crucial for maintaining pollen tube integrity, remain unclear. Here, using cryo-FIB-SEM and 3D tomography, we morphologically identified GDSVs as a distinct vesicle population accumulating at the pollen tube tip. Additionally, we demonstrated that tobacco LORELEI-like-GPI-anchored protein 4 (NtLLG4), a key signaling molecule controlling plasma membrane dynamics and integrity, acts as a receptor to recognize NtPPME1 and regulate its polar secretion via GDSVs to regulate cell wall rigidity. Furthermore, we systematically elucidated the trafficking signal determinants mediating NtPPME1 unconventional polar exocytosis across various intracellular organelles. Our findings reveal a crucial mechanism that coordinates cell wall rigidity with membrane signaling to maintain pollen tube integrity during plant fertilization, and greatly advance our understandings of GDSV-mediated unconventional exocytosis in regulating polar cell growth and morphogenesis.

C3.8 ONE COMPLEX, TWO WORLDS: DIVERGENT ROLES OF PARALOGOUS SUBUNITS OF THE EXOCYST COMPLEX IN POLLEN AND SPOROPHYTIC CELLS

Tuesday 8th July 2025 17:00

Martin Potocký (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Klára Batystová (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Samuel Haluška (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Anna Bartáková (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Přemysl Pejchar (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Edita Janková-Drdová (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Vedrana Markovic (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Michal Hála (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Viktor Žárský (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Lukáš Synek (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic)

potocky@ueb.cas.cz

The exocyst complex is an evolutionarily conserved hetero-octameric tethering complex crucial for polarised secretion in eukaryotic cells. In higher plants, exocyst subunits frequently exist as multiple paralogs with specialised expression patterns, predominantly in male gametophyte (pollen) or sporophytic tissues. Here, we systematically investigate the functional diversification of Arabidopsis exocyst subunit paralogs, focusing mainly on SEC15, EXO70 and EXO84 isoforms. SEC15 paralogs illustrate an intriguing phenomenon: SEC15a functions canonically at the pollen tube tip, essential for pollen maturation and efficient fertilisation, yet also contributes secondarily to plasmodesmatal functions in sporophytic tissues. Conversely, SEC15b primarily supports canonical sporophytic processes, including root hair elongation and seed coat mucilage deposition, but unexpectedly also influences pollen tube elongation despite minimal expression there. Similarly, EXO70A2 is the principal isoform for pollen-specific exocytosis, effectively substituting sporophyte-expressed EXO70A1, but not vice versa, revealing partial redundancy coupled with unique functional specialisation. We propose that these paralogous shifts in subunit specialisation may reflect adaptive mechanisms facilitating plant diversification. By combining evolutionary analyses, genetics, live-cell imaging, biochemistry and in silico approaches, our data thus shed new light on the dual functionality of exocyst subunits and their crosstalk between the sporophyte and male gametophyte, highlighting the exocyst complex as a valuable model linking cellular specialisation with evolutionary adaptation.

C3.9 BALANCING TIP-GROWTH IN POLLEN GERMINATION OF ARABIDOPSIS THALIANA

Wednesday 9th July 2025 09:00

Philipp Denninger (TU Munich, Germany)

philipp.denninger@tum.de

Polar growth is crucial for many cellular and developmental processes and requires the polar accumulation of growth factors at a specific site within the cell. Tip-growth is an extreme form of polar growth that needs a fine-tuned balance of cell expansion and integrity. This balance is achieved by multiple pathways connected by feedback

loops. However, the molecular mechanisms behind these feedback loops are not understood. We use pollen germination as a model to study how this dormant cell establishes ade novopolar growth domain and initiates tip-growth after cell activation. The RhoGTPases RHO OF PLANTS (ROPs) are central molecular switches that regulate tipgrowth. ROP activity is, amongst others, regulated by activating ROP GUANINE NUCLEOTIDE EXCHANGE FACTORS (ROPGEFs). Even though multiple ROPGEFs are present in pollen grains, we show that specific ROPGEFs are crucial for pollen germination and tip-growth initiation. Further, we show that a kinase cascade of PDKs and AGCVIII kinases restricts pollen germination by phosphorylating multiple proteins required for pollen germination. Using phosphoproteomics, we identified novel AGCVIII kinase-dependent phosphorylation sites of ROPGEFs that restrict their activity and thus balance cell growth and integrity to prevent premature pollen germination.

C3.10 THE ARABIDOPSIS RECEPTOR-

Wednesday 9th July 2025 09:30

Daria Balcerowicz (University of Antwerp, Belgium), Sébastjen Schoenaers (University of Antwerp, Belgium), Karolien De Wael (University of Antwerp, Belgium), Philipp Denninger (Technical University of Munich, Germany), Kris Vissenberg (University of Antwerp, Belgium) daria.balcerowicz@uantwerpen.be

Pollen germination and tube elongation are essential for fertilisation in flowering plants. While receptor-like cytoplasmic kinases (RLCKs) play crucial roles in various signalling pathways, their functions in pollen development remain largely unexplored. Here, we identify DELAYED BURST1 (DEB1), a pollen-specific receptor-like cytoplasmic kinase (RLCK) class VII, as a key positive regulator of pollen germination. Loss of DEB1 function leads to impaired pollen germination and increased sensitivity to moisture. Under humid in vitro conditions, deb1 pollen grains form oscillatory cytosolic Ca²+ gradients but fail to accumulate active ROP-GTPases at the future germination site. This defect is suppressed when deb1 pollen germinates on a cellulose membrane or upon exogenous application of methyl jasmonate, a jasmonic acid precursor. Furthermore, 24-epibrassinolide can break deb1 pollen dormancy but does not promote deb1 pollen tube growth in vitro, suggesting that DEB1 plays a dual role in regulating pollen germination and acting as a pollen-specific component in brassinosteroid-induced tube elongation. These findings provide new insights into the molecular control of pollen function, highlighting DEB1 as a crucial factor in reproductive success.

C3.11 SIGNALING IN POLLEN TUBE TIP GROWTH: HOW TO TRACE AND MANIPULATE CA++ DYNAMICS

Wednesday 9th July 2025 09:45

marta.belloli@botinst.uzh.ch

Pollen tubes (PTs) are among the fastest-growing cells on Earth, elongating at an astonishing rate through polarized tip growth. This growth direction is carefully regulated by both biochemical and physical stimuli from the surrounding environment. While several biochemical factors contributing to PT growth have been identified, the integration of mechanical properties with the intracellular processes that control tip extension remains unclear.

In this study, we aim to elucidate the mechanical and biochemical principles underlying PT growth and navigation using a system that combines microfluidics (Lab-on-a-Chip) and transgenic biosensor lines. Specifically, we focus on intercellular events and biochemical properties by engineering transgenicArabidopsis thalianalines that express light-inducible switches and biosensor proteins specifically in PTs. Our goal is to construct a photo-activatable system that allows for the controlled modulation of Ca² concentration at the PT tips.

The integration of these tools, alongside live imaging, enables us to track PT responses to various stimuli in real time. A deeper understanding of pollen tube dynamics will not only shed light on the mechanisms fundamental to plant productivity, growth, and development, but also inspire the creation of novel tools. Collaborations with mechanical engineering, micro- and nanorobotics could lead to the development of autonomously growing and navigating soft robots, with potential applications in drug delivery systems, laparoscopic surgery, and diagnostics.

C3.12 INTEGRATION OF ION DYNAMICS INTO MEMBRANE POTENTIAL IN POLLEN TUBES AND ITS CONSEQUENCES FOR CHEMOTROPISM PLANT FERTILIZATION.

Wednesday 9th July 2025

10:00

Jose Feijo (University of Maryland- College Park, United States)

jfeijo@umd.edu

Pollen tubes (PT) are excellent models for studying processes involved in apical growth and cell polarity. Their growth relies on a choreography of extracellular ion fluxes and intracellular ion gradients of Cl- , Ca2+ , H+ and K+ that create a unique electrochemical environment at the growing tip. We hypothesize that the membrane potential differences between the tip and the shank should be central for sensing the minute gradients that lead to chemotropism and fertilization. I will present new data suggesting causality of the bioelectrical state of pollen tubes based on potassium regulation and chemo-sening and attraction by ovule secreted attractant proteins.

Marta Belloli (University of Zurich, Switzerland), Hannes Vogler (University of Zurich, Switzerland), Ueli Grossniklaus (University of Zurich, Switzerland)

POSTER SESSIONS

Friday 11th July 2025

18:00-20:00

C3.13 ALL ROADS LEAD TO ROS: SPATIO-TEMPORAL REGULATION OF POLLEN NADPH OXIDASES

Přemysl Pejchar (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Eliška Škrabálková (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Roman Pleskot (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Martin Potocký (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic)

pejchar@ueb.cas.cz

NADPH oxidases (termed Rboh in plants) play important roles in plant response to stress and are essential for plant development and cell expansion, including tip growth of pollen tubes, an essential component of plant reproduction. However, the detailed mechanisms of Rboh regulation and Rboh-derived reactive oxygen species (ROS) function in cellular morphogenesis remain mysterious. Crucially, all Rboh are transmembrane proteins, yet their regulation brought about by the surrounding lipidic environment, as well as peripherally attached protein partners, remains virtually unknown. Here, we performed an analysis of several pollen-expressed Rboh genes with the particular focus on the evolutionary distinct, pollen-specific RbohH/J family. We used tobacco pollen tubes as a model system and a combination of advanced microscopy, biochemical, genetic and computational approaches to describe in detail localization, interaction partners and the membrane-centric regulation of Rboh in tip-growing cells.

C4: OPEN CELL

ORGANISED BY: ARI SADANANDOM (UNIVERSITY OF DURHAM)

C4.1 THE ARABIDOPSIS SUMO CELL ATLAS REVEALS DIVERGENCE IN CELLTYPE AND SUBCELLULAR LOCATION OF ITS COMPONENTS TO FINE-TUNE STRESS RESPONSES

Wednesday 9th July 2025 11:00

Ari Sadanandom (Department of Biosciences Durham University, United Kingdom)

ari.sadanandom@durham.ac.uk

SUMOylation is essential in plant and animal cells, but it remains unknown how SUMO components act in concert to modify specific targets in response to environmental stresses. In this study we characterise every SUMO component in the Arabidopsis root to create the first complete SUMO Cell Atlas in eukaryotes. This unique resource reveals wide spatial variation, where SUMO proteins and proteases have sub-functionalized in both their expression and subcellular localisation. During stress SUMO conjugation is mainly driven by tissue specific regulation of the SUMO E2 ligase. Stress-specific modulation of the SUMO pathway reveals unique combinations of Proteases being targeted for regulation in distinct root tissues by salt, osmotic and biotic signals. Our SUMO Cell Atlas resources reveal how this PTM influences cellular and tissue scale adaptations during plant development and stress responses. We provide the first comprehensive study elucidating how multiple stress inputs can regulate an entire PTM system.

C4.2 CRACKING THE CODE OF INFECTION: MAPPING THE PHOSPHORYLATION NETWORK BEHIND INFECTION-RELATED DEVELOPMENT IN RICE BLAST

Wednesday 9th July 2025 11:30

Frank L.H. Menke (The Sainsbury Laboratory University of East Anglia, United Kingdom), Neftaly Cruz-Mireles (The Sainsbury Laboratory University of East Anglia, United Kingdom), Miriam Osés-Ruiz (The Sainsbury Laboratory University of East Anglia, United Kingdom), Paul Derbyshire (The Sainsbury Laboratory University of East Anglia, United Kingdom), Neha Sahu (The Sainsbury Laboratory University of East Anglia, United Kingdom), Lauren S. Ryder (The Sainsbury Laboratory University of East Anglia, United Kingdom), Mark Jave Bautista (The Sainsbury Laboratory University of East Anglia, United Kingdom), Jan Sklenar (The Sainsbury Laboratory University of East Anglia, United Kingdom), Xia Yan (The Sainsbury Laboratory University of East Anglia, United Kingdom), Dan MacLean (The Sainsbury Laboratory University of East Anglia, United Kingdom), Nicholas J. Talbot (The Sainsbury Laboratory University of East Anglia, United Kingdom)

Frank.Menke@tsl.ac.uk

Fungal pathogens continue to pose substantial threats to global food security, causing some of the most devastating crop diseases worldwide. We present a pioneering investigation into the infectionrelated development of the rice blast fungus,Magnaporthe oryzae, employing a quantitative mass spectrometry-based phosphoproteomic approach. Our study maps 8,005 phosphosites on 2,062 fungal proteins, providing a detailed landscape of the phosphorylation events that orchestrate plant infection. This reveals a profound re-wiring of phosphorylation-based signalling cascades during fungal infection, shedding light on the dynamic molecular responses elicited byM.oryzae. To unravel the broader significance of these findings, we undertook a comparative analysis of phosphosite conservation across 41 fungal species, revealing phosphorylation signatures linked to plant-associated fungal lifestyles, biotrophic and hemibiotrophic fungal infections. As the Pmk1 MAP kinase is a key orchestrator of plant infection in many plant pathogenic fungi, we then used parallel reaction monitoring to identify Pmk1 MAPK substrates. Our investigation defines 32 putative substrates of Pmk1, revealing a complex network of regulatory interactions. This led to identification of a novel regulator, Vts1, which undergoes Pmk1-dependent phosphorylation and is indispensable for the manifestation of rice blast disease. Vts1 is a SAM domain protein that plays an essential function in appressorium morphogenesis, septin aggregation and re-polarisation. Using an analogue-sensitive Pmk1 mutant, parallel reaction monitoring, and subsequent site-specific mutagenesis, we show that a single Pmk1-dependent phosphorylation event is necessary for its function as a virulence determinant during rice blast disease.

C4.3 UNRAVELING ABA’S MOLECULAR

SIGNATURE: INSIGHTS INTO ITS FUNCTION IN BARLEY SEED GERMINATION

Wednesday 9th July 2025 12:00

Ewa Sybilska (Institute of Biology Biotechnology and Environmental Protection University of Silesia in Katowice, Poland), Bahareh Sadat Haddadi (Deepartment of Life Science Aberystwyth University, United Kingdom), Luis A. J. Mur (Deepartment of Life Science Aberystwyth University, United Kingdom), Manfred Beckmann (Deepartment of Life Science Aberystwyth University, United Kingdom), Szymon Hryhorowicz (Institute of Human Genetics Polish Academy of Science, Poland), Joanna Suszynska-Zajczyk (Institute of Human Genetics Polish Academy of Science Dept. of Biochem. Biotech. PULS, Poland), Monika Knaur (Institute of Human Genetics Polish Academy of Science, Poland), Andrzej Pławski (Institute of Human Genetics Polish Academy of Science Dept. of GES GO PUMS, Poland), Agata Daszkowska-Golec (Institute of Biology Biotechnology and Environmental Protection University of Silesia in Katowice, Poland)

ewa.sybilska@us.edu.pl

Abscisic acid (ABA) regulates seed germination and plant responses to abiotic stress, however, its molecular mechanisms of action are still not fully understood. We used an integrative approach, combining transcriptomic, metabolomic, and spatial transcriptomic analyses, to investigate ABA effects on germinating barley (Hordeum vulgare) embryos. Our results showed that ABA primarily acts as a transcriptional repressor, inhibiting carbohydrate metabolism, lignin biosynthesis, cell wall organization, and photosynthesis while activating stress responses and phytohormonal signaling. Metabolomic profiling revealed strong correlations between differentially expressed genes and metabolites related to ABA metabolism and phytohormone pathways, including gibberellins, jasmonates, brassinosteroids, salicylic acid, and auxins. A comparison of transcriptomic profiles between ABA-treated barley embryos and developing seeds revealed that, while ABA regulates a subset of processes common to both stages, most transcriptional changes are unique to the germination phase. This demonstrated that ABA induces a distinct molecular response finely tuned to the regulation of seed germination. Spatial transcriptomics overcame RNA-seq limitations by localizing ABA-regulated gene expression across embryo tissues, revealing significant tissue-specific differences. The results highlight the importance of local regulatory mechanisms during germination. Integration of obtained datasets uncovered a ‘molecular signature’ of ABA effects in germinating embryos, offering new insights into its role in barley seed germination. These findings have potential implications for breeding strategies to enhance germination efficiency and crop resilience under environmental stress. This work was supported by the National Science Center, Poland project SONATA BIS10 ‘(QUEST) Quest for climate-smart barley–the multilayered genomic study of CBC function in ABA signaling’ (2020/38/E/NZ9/00346).

C4.4 DIFFERENTIAL EMISSION OF BIOGENIC VOCS AND REACTIVE ALDEHYDES UNDER HEAT AND ROOT ANOXIA IN WINTER WHEAT

Wednesday 9th July 2025 12:15

Kinga Benczúr (HUN-REN ATK, Hungary), Csaba Éva (HUNREN Centre for Agricultural Research Martonvásár, Hungary), Andrea Jara Quispe (Hungarian University of Agriculture and Life Sciences Budai Campus Budapest, Hungary), Krisztina Balla (HUN-REN Centre for Agricultural Research Martonvásár, Hungary), Gabriella Szalai (HUN-REN Centre for Agricultural Research Martonvásár, Hungary), Tibor Janda (HUN-REN Centre for Agricultural Research Martonvásár, Hungary), Imre Majláth (HUN-REN Centre for Agricultural Research Martonvásár, Hungary)

benczur.kinga@atk.hun-ren.hu

Biogenic volatile organic compounds (BVOCs) from plants are extremely diverse. One of the best known classes of BVOCs are the terpenes, which are responsible for the odour of plants. However, there are several other organic compounds that have a high vapour pressure at room temperature. Stress factors also affect BVOC emissions from plants.

The detection and analysis of reactive carbonyl species (RCS), including aldehydes, is extremely challenging, due to the high reactivity of these compounds, which are often present in the form of covalent adducts with DNA, proteins or other biomolecules. This knowledge is rather limited for leaves and cereals. Our study focuses on the free fraction of the BVOCs under different abiotic stress conditions (heat, flooding, their combination) in winter wheat. Plants emit BVOCs from the leaves, so the free forms of the compounds should measure this fraction. We measured the extracted compound using triple-quad GC-MS coupled with SPME technique. The SPME fiber was PDMS, the carrier gas was He and the thermal program was started at 40°C and ended at 250°C.

The analysis revealed a large number of BVOCs, including acetaldehyde, propionaldehyde, isobutyraldehyde, n-butanal, methyl vinyl ketone, 2,4-hexadienal, n-hexanal, n-heptanal, pentenal, octanal, nonanal, and 1-penten-3-ol, cis-2-penten-1-ol, 7-octen-4-ol, 1-octen-5-ol, cyclohexene, tetrahydrolinalool, which showed significant changes under heat and flood stress. Our method may open up perspectives for similar researches to detect BVOC and RCS from cereal leaves. The study was funded by the Hungarian National Research, Development and Innovation Office (Grant Agreement No. K145879).

C4.5 OSSIFICATION ACROSS SCALES GUIDES EMERGENT MULTIFRACTAL BIOMINERAL PATTERN IN THE SKULL

Wednesday 9th July 2025 15:00

Jaqueline Tabler (Max Planck Institute of Molecular Cell Biology and Genetics, Germany)

tabler@mpi-cbg.de

The mineral pattern in the skull forms intricate, dynamic, lace-like designs as osteoblasts spread across the head. These patterns emerge

from fine-scale dynamics, but uncovering the underlying mechanisms is challenging without tools to quantify such complexity. To address this, we developed multifractal methods to measure self-similarity in these patterns. Using these tools, we constructed toy models suggesting that a collagen gradient alone is sufficient to generate the multifractal patterns of developing bone. Through live imaging, physical perturbations, and additional mathematical modeling, we confirmed that this collagen gradient arises from a self-propagating differentiation wave. More broadly, our mathematical framework for pattern quantification provides a generalizable approach for studying cross-scale interactions that drive spatial pattern formation, offering new ways to explore the fundamental mechanisms underlying spatiotemporal dynamics in living systems.

C4.6 EXPERIMENTAL APPROACHES TO UNDERSTAND OXIDATIVE PROTEIN FOLDING AND PROTEIN QUALITY CONTROL IN ANIMAL CELL BIOLOGY

Wednesday 9th July 2025 15:30

Adam Benham (Durham University, United Kingdom)

a.benham@durham.ac.uk

The Endoplasmic Reticulum directs the folding and trafficking of the majority of proteins that are secreted from cells to their external environment. A key step in this process is the formation of disulphide bonds, which is chiefly mediated by transport of electrons and oxidising equivalents to client proteins through the ERO1-PDI oxidoreductases. In some circumstances, proteins can fail to fold properly and can misoxidise or be targeted for degradation, resulting in a molecular stress response and proteostatic disease. In this talk, I will discuss the molecular, proteomic and imaging tools that we are using to understand the cellular response to redox stress and to uncover new candidates and pathways that control the secretory network and protein fidelity.

C4.7 A NEW CELL TYPE IN THE GUT OF VERTEBRATES?

Wednesday 9th July 2025 16:00

Jehan-Hervé Lignot (UMR MARBEC, France), Pope Robert (National Biodefense Analysis and Countermeasures Center, United States), Secor Stephen (University of Alabama, United States)

jehan-herve.lignot@umontpellier.fr

How vertebrates that ingest their prey whole and dissolve the skeleton can process high amounts of calcium and phosphorus passing through the intestine? This was assessed using captive Burmese pythons facing different diets: a normal diet (calcium and phosphorus provided from entire rodents); a low-calcium and phosphorus diet (rodents with no bones: ‘boneless prey’), and a calcium-rich diet (boneless rodents supplemented with intraperitoneal injection of calcium carbonate, CaCO3). The intestinal mucosa was analysed using microscopy techniques (alizarin red S and peroxidase staining, EDX analyses). Blood calcium and hormone levels (parathyroid hormone, PTH and

calcitonin) were also analysed from fasting pythons and snakes repeatedly fed with either a normal prey or a boneless rat. Results revealed the presence of specialised cells along the intestine involved in the production of calcium and phosphorus particles (fed snakes). A multi-layered particle made of calcium, phosphorus and iron-rich nucleation elements in the centre is usually observed in the apical crypt of these cells. In fasting snakes, crypts are empty. When snakes are fed with a boneless prey, the particles are not observed, although iron elements are located within the crypts. When fed with a boneless meal supplemented with calcium, large particles fill the crypts. When snakes are fed repeatedly with a low-calcium diet, blood calcium level drops but calcitonin and PTH levels increase. So far this cell type was found in some Boidae, a Colubrid and the Gila monster, these vertebrates eating their entire prey. Therefore, a broader and thorough evolutionary analysis is needed.

C4.8 TUDCA ATTENUATES STRUCTURAL CHANGES IN THE HEARTS OF MICE FED A LOW-PROTEIN DIET

Wednesday 9th July 2025 16:15

Maria das Graças S Carvalho (Universidade Estadual de Campinas, Brazil), Lucas L Maldonado (Unicamp, Brazil), Israelle N Freitas (Unicamp, Brazil), Antonio Thiago P Campos (Unicamp, Brazil), Mariana C da Silva (Unicamp, Brazil), Hernandes F de Carvalho (Unicamp, Brazil), Carlos L Cesar (Unicamp, Brazil), José Antonio D Garcia (Unifenas, Brazil), André A de Thomaz (Unicamp, Brazil), Ana Paula C Davel (Unicamp, Brazil), Everardo M Carneiro (Unicamp, Brazil), Aline M dos Santos (Unicamp, Brazil)

mariasc9292@gmail.com

Cardiovascular diseases and protein malnutrition are public health problems that require attention. In this context, understanding the effects of low-protein diets on the heart and the therapeutic potential of TUDCA is essential. C57Bl/6 mice were divided into four groups: control (C), control + TUDCA (CT), restricted (R) and restricted + TUDCA (RT). For 16 weeks, they received normalprotein or low-protein diets and, in the last 15 days, were treated with TUDCA (300 mg/kg) or PBS. Animals in group R had lower body weight and lower serum concentration of total proteins. However, we did not observe any change in relation to heart/body weight. Morphometric analysis revealed cardiomyocyte hypertrophy in group R, which was reduced by TUDCA in group RT. Similar results were observed in interstitial and perivascular collagen deposition. The TUNEL assay indicated the highest rate of cell death in group R, reduced in RT. Structural alterations in the sarcomere and in the organization of type 2 myosin were evident. The length of sarcomeres, myofibrils and A and I bands was shorter in the R group, but in the RT group these structures presented measurements similar to those of the control. In addition, R mice exhibited greater structural disorganization and an increase in the termination points between the myofibrils. Thus, the low-protein diet induces hypertrophy, collagen accumulation, apoptosis and sarcomeric alterations in the heart, while TUDCA exerts a therapeutic effect by reducing these alterations. Keywords:Cardiomyocytes; myosin type 2; fibrosis, hypertrophy, myofibrils.

C4.9 DESIGNING PLANT SYSTEMS FOR A MORE EFFICIENT AND SUSTAINABLE INVESTIGATION OF P53 ACTIVITY

Thursday 10th July 2025

09:00

Miguel De Lucas (Department of Biosciences Durham Univeristy, United Kingdom)

miguel.de-lucas@durham.ac.uk

p53 is a tumour suppressor conserved from sea anemones, worms, insects to vertebrates, but is not conserved in plants. Upon limited DNA-damage, p53 induces cell cycle arrest activating the DNA repair machinery. Under excessive DNA-damage p53 induces cell death. Mutations inTP53occur in more than 50% of human cancers, indicating its importance in cancer suppression.

Traditional p53 research involves the use of patient biopsies, (transgenic) animal models, cancer cell cultures, or tedious and expensive cell transfection experiments. While these methods collectively boosted our understanding of how p53 operates and led to identification of effective cancer treatment therapies, each approach has its own practical and ethical considerations that often limit p53 research to specialists’ groups in high-income countries.

We have developed an alternative to animalexperimentation for the study of p53 using Arabidopsis expressing p53 under a conditional expression promoter. In this talk I will introduce our results demonstrating that p53 expression in plants is suitable for investigating central mechanisms of p53 regulation and function. We believe that implementing plants for p53 research will reduce animal experimentation, bureaucratic burden, experimental costs while broadening its study to underrepresented countries. Importantly, this has the potential to identify novel aspects of p53 function with applications in cancer prevention and treatment.

C4.10 MECHANISMS OF ROOT BRANCHING UNDER HETEROGENOUS WATER AVAILABILITY

Thursday 10th July 2025

09:30

Poonam Mehra (University of Nottingham, United Kingdom)

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Water scarcity is a threat to agriculture, given the impact of climate change. Root branching is an agronomically important trait that determines foraging capacity of plants. To adapt to heterogenous soil water availability, roots exhibit remarkable plasticity in their branching patterns. Discovering how plant root adapts to water availability is vital for futureproofing crops.Xerobranching serves as a valuable model for studying root adaptive mechanisms in response to fluctuating soil water availability. A xerobranching response is triggered when a growing root tip loses contact with soil moisture (e.g. in an air-gap) leading to suppression of branching until the root tip re-enters moist soil (Mehra et al., 2022). Our recent research has uncovered that xerobranching utilizes Reactive Oxygen Species (ROS) to inhibit root branching. Lack of moisture triggers nuclear ROS accumulation within the basal meristem and elongation zone of growing root tips. ROS induces multimerization of auxin repressor protein IAA3/SHY2 (Roy

et al., 2024 bioRxiv). Mutations in specific cysteine residues in IAA3/ SHY2 disrupt its redox-mediated multimerization and interaction with co-repressor TPL, but not with auxin response partner ARF7 and auxin receptor TIR1. ROS-mediated oligomerization of IAA3/SHY2 is required for efficient ARF-mediated target gene repression during xerobranching and lateral root emergence. Our findings demonstrate that AUX/IAA proteins vary in their redox mediated multimerization, revealing a new auxin response regulatory mechanism that directly connects ROS sensing to auxin signalling. Our study reveals how ROS, auxin and water stress intersect to shape adaptive responses in roots and maintain their phenotypic plasticity.

C4.11 THE ROLE OF VAMP714 IN PIN RECYCLING AND PIN POLARITY MAINTENANCE IS ESSENTIAL FOR POLAR AUXIN TRANSPORT

Thursday 10th July 2025 10:00

Julien Agnessens (Department of Biosciences Durham University, United Kingdom)

julien.agneessens@durham.ac.uk

Auxin gradients in plant root tissues are critical for the growth and development of the root. PIN proteins which are responsible for the efflux of auxin from the cell to the extracellular environment play a central role in establishing these gradients and are polarly distributed at the plasma membrane (PM) in some cell types. Through my research on VAMP714, a SNARE protein involved in the vesicle trafficking of PINs, I will describe the set of tools I used in order to understand how vesicle trafficking coordinates PIN sorting and PIN polarity. Using methods to investigate protein-protein interactions is essential to connect the different regulators of PIN trafficking and allowed the identification of CTL1, a choline transporter, as an interactor of VAMP714. Interestingly, choline regulates VAMP714 subcellular localization suggesting that CTL1 and VAMP714 belong to a same vesicle trafficking pathway regulating PIN sorting at the PM.

Former studies have shown that polar sorting of PINs is not sufficient to explain PIN polarity. Indeed, PIN polarity is maintained only if PINs are in domains of the PM where their lateral diffusion is reduced. Cell walls have an important role in that process. Interestingly, VAMP714 regulates the subcellular localization of the cellulose synthase CESA3. Consistently, FRAP measurements indicate that PIN lateral diffusion is increased in the vamp714 background. Altogether, this suggests that VAMP714 regulates polar auxin transport through PM sorting of PINs at the PM alongside elements of the cellulose synthase machinery that in turn stabilize PINs in their polar domain.

C4.12 IDENTIFICATION OF ARABIDOPSIS PROTEINS INVOLVED IN NUCLEOTIDE EXCISION REPAIR

Thursday 10th July 2025 10:15

Syed Zain Kashif (Department of Molecular Biology and Genetics Koc University, Turkey), Onur Oztaş (Department of

Molecular Biology and Genetics Koc University, Turkey) skashif22@ku.edu.tr

The intricate DNA repair mechanisms organisms employ to rectify damage induced by environmental factors, such as UV rays, play a pivotal role in maintaining genomic stability. UV-induced damage leads to bulky lesions which are removed primarily by two Nucleotide excision repair (NER) pathways i.e., Global Genome Repair (GG-NER) and Transcription-Coupled Nucleotide Excision Repair (Tc-NER). In mammals Tc-NER involves the recruitment of CSA and CSB repair proteins when RNA polymerase halts at the damage site during transcription, resulting in transcription arrest followed by the formation of a repair bubble. This study aims to identify the proteins engaged in transcription-coupled DNA repair in Arabidopsis, offering insights into repair dynamics using the XR-seq method. Key proteins in mammalian Tc-NER are CSA and CSB for damage recognition and XPF\XPG serve as endonucleases responsible for DNA excision. Arabidopsis harbors homologs of key NER repair proteins CSA (AtCSA1 and AtCSA2), CSB (Chr24, Chr8), and XPF\XPG endonucleases (UVH3, UVH1, and ERCC1). Utilizing the XR-seq methodology allows the generation of genomewide DNA repair maps at a single nucleotide level resolution. The main steps in XR-seq include Cell lysis, Immunoprecipitation, Adapter ligation, and Sequencing. We performed XR-seq for CSB homologs (Chr24 and Chr8) in Arabidopsis. Data shows the repair dymanics on transcribed strands for Chr24 and Chr8 knockouts compared to the normal wild type. Comparative protein alignments of these homologs also underscore potential functional differences. This research contributes to a comprehensive understanding of plant DNA repair processes and how they maintain genome integrity.

C4.13 DECIPHERING THE MECHANICAL CODE OF DNA AND ITS IMPACT ON CELLULAR PROCESSES

Thursday 10th July 2025

11:00

Aakash Basu (Department of Biosciences Durham University, United Kingdom)

aakash.basu@durham.ac.uk

Mechanical deformations of DNA are ubiquitous in Biology and occurs as part of critical processes involved in the reading, repair, copying, and packaging of genetic information. Therefore, such processes may be regulated by the local mechanical pliability of DNA to accommodate physical deformations. We have developed highthroughput technology to measure how local sequence impacts local DNA bendability via a “mechanical code”. We show that via the mechanical code, genomes encoded regulatory information impacting diverse cellular processes such as gene expression, nucleosome organization and remodelling, transcription factor binding, and DNA supercoiling by topoisomerases. We are currently exploring how chemical alterations to DNA such as via epigenetic modifications or DNA damage may alter the mechanical code, resulting in downstream functional consequences. We are also investigating how variations in DNA mechanics impact the genome-wide variations in DNA supercoiling, ultimately allowing environmental factors that control supercoiling to impact broad cellular gene expression programmes in complex ways. Overall, we advance our understanding of how physical forces have impacted the evolution of genomes.

C4.14 EVOLUTIONARY APPROACHES TO UNDERSTANDING CELL AND DEVELOPMENTAL BIOLOGY

Thursday 10th July 2025 11:30

Tom Bennett (School of Biology University of Leeds, United Kingdom)

t.a.bennett@leeds.ac.uk

In this talk, I will discuss the use of phylogeny, protein sequence analysis and ancestral protein reconstruction, and how these tools can deepen and broaden our understanding of cell and developmental biology in any experimental system. I will exemplify these techniques by discussing my lab’s work on strigolactone signalling and auxin transport in plants, and how the interplay of these two processes regulates the shoot branching of a plant. I will discuss our efforts to try and understand the polar plasma membrane localization of PIN auxin efflux transporters in individual cells, and how this can be regulated by strigolactone signalling acting specifically in the nucleus. Overall, I aim to illustrate how evolutionary approaches can help us to better refine the questions we ask in our research, as well as providing us with interesting new avenues for investigation.

C4.15 REGULATION OF CYTOKINESIS BY WNT SIGNALLING IN THE C. ELEGANS EMBRYO

Thursday 10th July 2025 12:00

Tim Davies (Department of Biosciences University of Durham, United Kingdom), Edward O’Neill (Department of Biosciences University of Durham, United Kingdom)

timothy.r.davies@durham.ac.uk

Accurate cytokinesis, the physical division of one cell into two, is essential for the development of all multicellular organisms. It has long been known that animal cells divide using a highly conserved molecular apparatus, including coordination of the microtubule spindle and actomyosin contractile ring.

We previously developed a sensitised C.elegans model, in which contractile ring f-actin is depleted via a temperature-sensitive formin mutant. In this model, the lack of contractile ring f-actin prevents cytokinesis in the well-studied zygote. Surprisingly, we showed that other cells in the early embryo are still able to divide in this sensitised system. One of these, the EMS cell, is known to receive a Wnt signal from the adjacent germline cell.

Here we performed a targeted RNAi screen and demonstrate that Wnt signalling promotes successful cell division in this sensitised background, and that this occurs via a transcriptionally independent mechanism. To determine the mechanism by which Wnt signalling contributes to division we screened the localisation and behaviour of a range of cytokinetic and cytoskeletal proteins in control and wnt(RNAi) embryos. This demonstrated that Wnt signalling increases both centrosome separation and cortical myosin-II flow, leading us to propose a model in which Wnt signalling promotes cytokinesis via an ‘astral relaxation’ model.

C4.16 VESICULAR SALT TRANSPORT MECHANISMS ARE CRUCIAL FOR CALCIFICATION IN SEA URCHIN LARVAE

Thursday 10th July 2025 12:15

Smilla L. Tetzlaff (CAU Kiel, Germany), Marian Y. Hu (CAU Kiel, Germany)

smillatetzlaff@gmx.de

Biomineralization is an evolutionary ancient process found in many marine organisms including the sea urchin larva that form a delicate calcium carbonate skeleton. Calcium and carbonate ions are taken up into vesicles via endocytosis of seawater by the calcifying Primary Mesenchyme Cells (PMCs). Here the amorphous precursor is formed and ultimately exocytosed. However, calcium and carbonate ions only make up about 4.70 % and 0.23 % of the seawater ion composition respectively. To promote calcification, the substrates must be concentrated and seawater and its redundant ions e.g. sodium and chloride removed. However, the underlying mechanisms remain unknown.

Using the sea urchin larva, we investigated the role of the Na-K-Cl (NKCC) cotransporter in promoting salt transport in PMCs. Single cell transcriptomic analyses demonstrated this ion transporter to be mainly expressed within these calcifying cells. Using in vivo confocal microscopy in combination with the specific NKCC inhibitor azosemide we investigated its role in the process of spicule formation during early development. Larvae treated with azosemide showed impaired spicule formation and developed strikingly shorter spicules compared to control conditions. Tracking of calcium incorporation using the calcium-binding dye calcein confirmed reduced mineral deposition rates in the presence of azosemide. Gene expression analyses of this transporter revealed an upregulation during recalcification of the larval skeleton.

These findings suggest that the NKCC cotransporter plays a crucial role for calcification and shed light onto novel vesicular mechanisms of mineralization in echinoderms that are important ecosystem engineers in marine habitats.

C4.17 LIPOPHAGY: A PROCESS MORE RELEVANT THAN JUST GETTING FUEL

Friday 11th July 2025 09:30

Marina Garcia Marcia (Institute of Functional Biology and Genomics (IBFG) University of Salamanca-CSIC, Spain) marinagarciamacia@usal.es

Autophagy is the cellular clearing and recycling program that degrades cytoplasmic content in lysosomes. This process takes place in all cells and is further induced during cellular stress. Besides its crucial role as a quality control mechanism, autophagy is also involved in a host of other functions such as growth and differentiation, metabolic regulation and as an alternative energy source through a type of selective autophagy called lipophagy. Lipophagy is the most effective way to mobilize fatty acids (FAs) which prevents FAmediated toxicity and is the preferred mechanism to generate energy during starvation. Lipophagy selectively degrades lipid droplets (LD).

LDs are organelles formed by cholesterol and triacylglycerols (TG) surrounded by a phospholipid membrane serving as dynamic hubs of cellular lipid metabolism by sequestering excess of FAs. Lipophagy has mapped autophagy as an emerging player in lipid metabolism. Thus, understanding how this catabolic process happens in different scenarios can help to understand deeper lipid metabolism, we will show how to measure lipophagy in different contexts and its biological meaning.

C4.19 WHAT’S NEW IN THE WORLD OF FLOW CYTOMETRY

Friday 11th July 2025 10:15

Daniel Vocelle (Michigan State university, United States)

vocelled@msu.edu

Flow cytometry has seen transformative advancements in the past four years, revolutionizing its applications in modern research. Despite these innovations, many researchers remain anchored in traditional approaches, unaware of the tools now available to enhance their work. This presentation will explore cutting-edge advancements that increase the impact, novelty, and reproducibility of research. Key highlights include:

Spectral Cytometry:

-Simultaneous measurement of up to 50 fluorophores, simplifying complex multicolor experiments.-Phenotyping using cellular autofluorescence, reducing dependency on dyes for delicate samples.Enhanced resolution of ratiometric dyes for precise ion flux and signaling studies.

Imaging Cytometry:

-High-throughput imaging (13,000 images/second) with automated analysis for phenotyping and rare event detection.-AI/ML integration to classify cancers based on cellular morphology, advancing precision medicine.-Fluorescent image-based cell sorting to study intracellular processes like protein localization.

Small/Large Particle Cytometry:

-Characterization of extracellular vesicles with unprecedented accuracy for biomarker discovery.-Resolution capabilities from 20nm to 1000nm, expanding insights into cell-to-cell communication.

Future Cytometry:

-Deep UV lasers (260nm–355nm) for label-free biomolecule detection, enabling novel discoveries.-Fluorescent lifetime cytometers to study protein-protein interactions through temporal fluorescence. This presentation will equip attendees with a comprehensive understanding of how these advancements can elevate their research and unlock new possibilities.

C4.20 FROM LIGHT TO LIMESTONE: PHYSIOLOGICAL LINKS BETWEEN

REEF CORAL PHOTOSYNTHESIS AND CALCIFICATION VIA PH REGULATION

Friday 11th July 2025 10:30

Alexander Venn (Centre Scientifique de Monaco, Monaco), Lucas Crovetto (Centre Scientifique de Monaco, Monaco), Eric Tambutté (Centre Scientifique de Monaco, Monaco), Sylvie Tambutté (Centre Scientifique de Monaco, Monaco) avenn@centrescientifique.mc

The ecological success of scleractinian reef-building corals is often attributed to the high growth rates of their calcium carbonate skeletons through the process of calcification. However, this capacity is increasingly threatened by multiple environmental stressors, including ocean acidification and thermal stress. Light plays a crucial role in enhancing coral calcification rates, a phenomenon known as light-enhanced calcification (LEC), which has been widely observed in both laboratory and field studies. Certain research suggests that LEC may provide resilience to coral calcification under unfavorable environmental conditions, such as reduced seawater pH.

The physiological mechanisms underlying LEC remain debated, but many hypotheses focus on the symbiotic relationship between scleractinian corals and dinoflagellate algae of the family Symbiodiniaceae , which influence calcification through their photosynthetic activity. Our research investigates the link between light and coral calcification by examining how symbiont photosynthesis affects trans-epithelial pH regulation, from the growing front of the coral skeleton, through the coral tissues, and into the surrounding seawater.

To achieve this, we employ a combination of live tissue imaging using confocal microscopy and pH-sensitive microelectrodes to measure both intracellular and extracellular pH across the complex spatial structure of coral tissues. Our findings reveal that Symbiodiniaceae photosynthetic activity drives pH gradients within coral tissues, which correlate with enhanced calcification rates and mitigate the effects of ocean acidification. In contrast, the impacts of acidification are more pronounced in darkness or in coral tissue regions lacking symbionts. However, energy-dependent pH regulation mechanisms enable corals to sustain calcification even under these challenging conditions.

C4.21 KLF2 EXPRESSION REGULATES

Friday 11th July 2025 10:45

growth over proliferation, independent of nuclear size, suggesting that senescence or DNA damage were not driving factors. AQP1, a water channel protein and potential downstream target of KLF2, was significantly upregulated in KLF2-overexpressing cells, implicating it in size regulation. Furthermore, single-cell analysis revealed a positive correlation between GFP fluorescence (KLF2 expression) and cell area, reinforcing KLF2’s direct role in size determination. Morphological analysis suggested that KLF2 expression restores the elongated shape characteristic of ECs under laminar flow, potentially contributing to vascular homeostasis. These findings establish KLF2 as a key regulator of endothelial size and morphology, implicating AQP1 in this process. Future studies will explore additional KLF2regulated pathways with potential therapeutic implications for vascular diseases such as atherosclerosis.

David H An (Harvard University, United States), Guillermo García-Cardeña (Brigham and Women’s Hospital Harvard Medical School, United States)

davidan@college.harvard.edu

Atherosclerosis develops in regions of blood vessels exposed to disturbed flow, where endothelial cells (ECs) exhibit cuboidal morphology and suppressed expression of Kruppel-like factor 2 (KLF2), a key transcription factor in vascular homeostasis. While KLF2’s role in endothelial size regulation has been demonstrated in zebrafish, its effects in human ECs remain unclear. To investigate, we conducted a gain-of-function study using human umbilical vein endothelial cells (HUVECs) transduced with murine KLF2 (mKLF2) or GFP control vectors under static conditions. KLF2-overexpressing cells were 22% larger in surface area (95% CI: 15%-26%) and exhibited an elongated morphology. Unlike control cells, which increased in number by 29% over 48 hours (95% CI: 9%-48%), KLF2-expressing cells prioritized

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PLANT BIOLOGY ABSTRACTS

P1: ACCELERATING PROGRESS IN PLANT SCIENCE VIA AI APPROACHES

ORGANISED BY: JOHANNES KROMDIJK (UNIVERSITY OF CAMBRIDGE), ZORAN NIKOLOSKI (MAX PLANCK INSTITUTE OF MOLECULAR PLANT PHYSIOLOGY)

P1.1 PLANTCONNECTOME: KNOWLEDGE GRAPH ENCOMPASSING >70,000 PLANT ARTICLES

Tuesday 8th July 2025 09:00

Marek Mutwil (University of Copenhagen, Denmark)

mutwil@plen.ku.dk

Predicting gene function is indispensable to our understanding of biology. However, these predictions hinge on large collections of experimentally characterized genes, the compilation of which is not only labor-intensive and time-consuming but rendered nearimpossible given the volume and diversity of scientific literature. Here, we tackle this challenge by deploying the textmining capacities of Generative Pre-trained Transformer (GPT) to process over 70,000 plant biology articles. Our approach unveiled over 5,000,000 functional relationships between a wide array of biological entities—genes, metabolites, tissues, and others—with a remarkable accuracy of over 85%. We encapsulated these findings in PlantConnectome, a userfriendly database, and demonstrated its diverse utility by providing insights into gene regulatory networks, protein-protein interactions, as well as developmental and stress responses. We believe that this innovative use of AI in the life sciences will significantly accelerate and direct research, drive powerful gene function prediction methods and help us keep up to date with the rapidly growing corpus of scientific literature.

P1.2 PL@NTNET AS A FOUNDATION MODEL

Tuesday 8th July 2025 09:45

David Rousseau (Université d’Angers, France), Simon Ravé (Université d’Angers, France), Pejman Rasti (Université d’Angers, France), Alexis Joly (INRIA, France), Jean-Chistophe Lombardo (INRIA, France)

david.rousseau@univ-angers.fr

Foundation models have revolutionized artificial intelligence by providing versatile, pre-trained architectures that can be adapted to various downstream tasks. In the realm of plant biodiversity, Pl@ ntNeth as emerged as a large-scale, AI-driven plant identification system. In this presentation, we investigate the potential of using

Pl@ntnet as base for various computer vision tasks beyond species identification, combining it with generalist foundation models positionned upstream or downstream in the pipeline to enable zeroshot possiblity. We test our method on publicly available datasets and which allow comparison with existing supervised and other zero-shot methods.

P1.3 KINETICGP, A COMPUTATIONAL FRAMEWORK FOR GENOMIC PREDICTION OF LEAF PHOTOSYNTHESIS TRAITS

Tuesday 8th July 2025 10:00

Rudan Xu (University of Potsdam, Germany), John Ferguson (University of Essex, United Kingdom), David Hobby (University of Potsdam, Germany), Milad Rahimi‐Majd (University of Potsdam, Germany), Philipp Wendering (University of Cambridge, United Kingdom), Johannes Kromdijk (University of Cambridge, United Kingdom), Zoran Nikoloski (University of Potsdam, Germany)

xu2@uni-potsdam.de

Photosynthesis is the workhorse for growth of all crops and is one of the key targets for improving agricultural productivity. Its efficiency differs both between and within species, with responses intensively measured under varying CO2 concentrations and light intensities (represented by A-Ci and A-Q curves). While many published kinetic models of photosynthesis were used to simulate photosynthetic response and to propose different hypotheses, their kinetic parameters were collected from literature or estimated in different species. Yet, the differences in kinetic parameters of enzymes involved in photosynthesis between different genotypes are not fully explored. Moreover, photosynthetic traits are the integrated outcome of genetic factors, environmental conditions, and their complex interactions that renders their accurate prediction from genetic markers challenging. To address these problems, we parameterized a kinetic model for C4 photosynthesis allowing accurate simulation of A-Ci or A-Q curves measured for 68 inbred lines from a maize population grown in two seasons. The genotype-specific kinetic parameters were then used to train a machine learning model capable of predicting parameter values for genotypes with only genomic data available. The predicted parameters were used to simulate photosynthesis for unseen genotypes and seasons by integrating environmental conditions. The photosynthetic rates simulated at saturating light using our approach, KineticGP, outperformed the predictions of baseline genomic models for unseen genotypes across seasons.

P1.4 A FOUNDATIONAL LARGE LANGUAGE MODEL FOR EDIBLE PLANT GENOMES

Tuesday 8th July 2025 14:00

Marie Lopez (InstaDeep, United Kingdom)

m.lopez@instadeep.com

Significant progress has been made in the field of plant genomics, as demonstrated by the increased use of high-throughput methodologies that enable the characterization of multiple genomewide molecular phenotypes. These findings have provided valuable insights into plant traits and their underlying genetic mechanisms, particularly in model plant species. Nonetheless, effectively leveraging them to make accurate predictions represents a critical step in crop genomic improvement. We present AgroNT, a foundational large language model trained on genomes from 48 plant species with a predominant focus on crop species. We show that AgroNT can obtain state-of-the-art predictions for regulatory annotations, promoter/ terminator strength, tissue-specific gene expression, and prioritize functional variants. We conduct a large-scale in silico saturation mutagenesis analysis on cassava to evaluate the regulatory impact of over 10 million mutations and provide their predicted effects as a resource for variant characterization. Finally, we propose the use of the diverse datasets compiled here as the Plants Genomic Benchmark (PGB), providing a comprehensive benchmark for deep learning-based methods in plant genomic research.

P1.5 A GENERIC 3D PIPELINE FOR UNSUPERVISED LEAF SEGMENTATION OF INDIVIDUAL HORTICULTURAL CROPS

Tuesday 8th July 2025 14:45

David Rousseau (Université d’Angers, France), Herearii Metuarea (Université d’Angers, France), Oumaima Karia (INRAe, France), Helin Dutagaci (Eskişehir Osmangazi Universiy, Turkey)

david.rousseau@univ-angers.fr

Accurate 3D leaf segmentation is fundamental for plant phenotyping, growth modeling, and precision agriculture. However, existing approaches often rely on supervised learning, requiring extensive annotated datasets, which limits their scalability across diverse plant species and structures. To overcome this limitation, we propose a generic, unsupervised 3D pipeline for leaf segmentation, eliminating the need for manual annotations while ensuring robustness across various plant morphologies. Our pipeline leverages geometric and structural analysis of 3D point clouds to identify and segment individual leaves. It integrates spatial clustering, normal estimation, curvature-based segmentation, and connectivity analysis, enabling the detection of leaves even in the presence of occlusions and complex canopy structures. We validate our approach on diverse individual horticultural plant datasets, demonstrating its ability to generalize across species and acquisition protocol with various 3D sensors.

P1.6 AI-BASED METABOLOME PREDICTIONS TO STUDY COMPLEX PLANT TRAITS

Tuesday 8th July 2025 15:00

Pierre PETRIACQ (University of Bordeaux, France), Thomas DUSSARRAT (University of Bielefeld, Germany), Sylvain PRIGENT (INRAE, France), Yves GIBON (INRAE, France), Rodrigo GUTIERREZ (PUC, Chile)

pierre.petriacq@inrae.fr

Since the late 2010s, artificial intelligence (AI), including machine learning and deep learning, has transformed life science research by enhancing the computational analysis of biological processes, natural product discovery, and ecosystem understanding. The surge in highthroughput omics data has made AI-based analyses essential for deciphering complex datasets, with phenotyping facilities becoming crucial in advancing plant sciences.

This presentation focuses on plant metabolism and the role of omics-based predictive analytics in systems biology. By using plant metabolomes as an integrative system, machine learning tools have been employed to address critical areas such as plant resilience to extreme environments and plant-soil interactions. These AI-driven approaches have provided deeper insights into the complex biological systems governing plant life. For instance, metabolic profiles of 24 plant species from the Atacama Desert could predict plant growth elevation with 79% accuracy using only 39 compounds, revealing a shared metabolic toolkit for coping with extreme conditions like freezing temperatures, water deficit, and intense solar radiation.

The presentation also discusses future challenges and opportunities in using AI in plant sciences, offering strategies to advance AI-based predictions of complex plant traits. It highlights AI’s potential to revolutionise our understanding of plant biology and its applications in agriculture and environmental conservation.

P1.7 METABOLOMIC ANALYSIS OF CAMELLIA: UNLOCKING PHENOTYPIC INSIGHTS AND INDUSTRIAL APPLICATIONS

Tuesday 8th July 2025 15:15

Fafa Ikram Hocini (INRAE - Chanel Parfums Beauté, France), Vincent Cocandeau (Chanel Parfums Beaute, France), Sylvain Prigent (INRAE, France), Nicola Fuzzati (Chanel Parfums Beaute, France), Yves Gibon (INRAE, France), Aurélien Rey (Chanel Parfums Beaute, France), Pierre Petriacq (INRAE, France)

ikram.hocini@inrae.fr

Artificial intelligence (AI) encompasses methods and algorithms that allow machines to perform tasks typically requiring human intelligence, such as image recognition, complex data analysis, and decision-making. Machine learning (ML), a central component of AI, relies on analysing large datasets to identify patterns and make predictions. Unlike traditional methods based on predefined rules, ML enables algorithms to learn from data and improve over time. In plant sciences, ML offers new opportunities for optimising varietal

selection, predicting the biological activity of plants relevant to humans, and anticipating their applications in health, cosmetics, or agriculture.

The Camellia genus, known for its polyphenols and oils in cosmetics and its aesthetic value in horticulture, serves as a key example where ML can be impactful. The goal of its study is to identify promising varieties by optimising selection based on their compounds of interest and aesthetic traits. One major challenge is the long wait of 3 to 7 years for the camellia to flower, a critical phase for validating phenotypic attributes. ML applied to predictive metabolomics provides a solution by training models on leaf metabolomic profiles to predict floral characteristics before flowering. This method has achieved prediction accuracies of over 80% for flower shape and colour, revealing key families of metabolites involved.

Beyond accelerating varietal selection, this method could be used to predict biological activities of interest to humans, presenting new possibilities in health, cosmetics, and agriculture.

P1.8 EFFICIENT PARAMETER ESTIMATION FOR A LARGE-SCALE C4 PHOTOSYNTHESIS MODEL USING NEURAL NETWORKS

Tuesday 8th July 2025 16:00

Philipp Wendering (University of Cambridge, United Kingdom)

pw543@cam.ac.uk

Large-scale kinetic models of photosynthesis offer precise, timeresolved predictions of photosynthesis, gas exchange, and metabolic processes. Thereby, they provide the means to determine factors limiting photosynthesis under different environmental conditions. However, their use is currently limited by the lack of efficient approaches to estimate the hundreds of kinetic parameters that may differ between genotypes. Here, we present an artificial neural network, which can efficiently predict parameters of a large-scale photosynthesis model from A/CO2 and A/light curves. The model was trained on a diverse artificial dataset comprising parameter samples and associated curve simulations from a dynamic C4 photosynthesis model. Model training was guided by considering both the predicted parameters and resulting curve simulations. To increase the efficiency of curve simulations during the training process, we trained a surrogate neural network to predict A/CO2 and A/light curves directly from the model parameters and environmental inputs. Despite the high sensitivity of the ODE model to changes in parameter values, over 99% of the predicted parameter vectors could be used directly by the kinetic model. Therefore, the developed framework presents a fast and precise approach for parameter estimation in large-scale photosynthesis models, based on minimal datasets. Further, the flexible structure of the model allows for an easy adjustment in the number of relevant parameters as well as the environmental input.

P1.9 ADVANCED MATHEMATICAL MODELLING OF HYPERSPECTRAL DATA TO QUANTIFY THE OPTICALLY INACTIVE SECONDARY METABOLITES EUGENOL AND METHYL EUGENOL IN THE MEDICINAL PLANT HOLY BASIL

Tuesday 8th July 2025 16:45

Hathairut Jindamol (Forschungszentrum Jülich, Germany), Björn Thiele (Forschungszentrum Jülich, Germany), Nathalie Wuyts (Forschungszentrum Jülich, Germany), Mark Müller-Linow (Forschungszentrum Jülich, Germany), Panita Chutimanukul (National Science and Technology Development Agency, Thailand), Kriengkrai Mosaleeyanon (National Science and Technology Development Agency, Thailand), Theerayut Toojinda (National Science and Technology Development Agency, Thailand), Uwe Rascher1 (Forschungszentrum Jülich, Germany), Laura Verana JunkerFrohn2 (Forschungszentrum Jülich, Germany)

h.jindamol@fz-juelich.de

The quantification of secondary metabolite content is crucial for the industrial production of high-quality essential oil from medicinal plants, i.e. to determine an optimal harvest time to achieve the desired quality. Spectral reflectance measurements provide a potential technique to perform non-destructive and real-time monitoring of secondary metabolite content. However, not all secondary metabolites are optically active in the range of hyperspectral sensors. In this study, a method for the non-destructive quantification of eugenol (Eu) and methyl eugenol (MeEu) in holy basil (Ocimum tenuiflorum L.) was developed by combining leaf-level hyperspectral measurements with mathematical modelling based on partial least squares regression (PLSR). To generate a wide range dataset of secondary metabolite content, three experiments investigating developmental variation, osmotic stress response and secondary metabolism induction by methyl jasmonate were conducted with two commercial cultivars. Hyperspectral point measurement (350-2500 nm) of individual leaves were combined with destructive quantification of Eu and MeEu by gas chromatography-mass spectrometry. We observed variation of Eu and MeEu concentrations between cultivars, treatments, and leaf ages. PLSR modelling based on the full wavelength spectrum resulted in quantification of Eu and MeEu with R2 of 0.62 and 0.70, respectively, with RMSEP of 1.10 and 0.98. We explain the high correlation by an indirect quantification of these compounds based on associated changes in plant secondary metabolism. This study demonstrated that hyperspectral data combined with PLSR provides a promising technique for the non-destructive quantification of foliar secondary metabolites for industrial applications even in absence of specific absorption feature within the measurement range.

P1.10 AI-DRIVEN

MULTI-OMICS ANALYSIS OF PLANT-PLANT COMMUNICATION IN TOMATO, USING FEATURE EXTRACTION AND STATISTICAL MACHINE LEARNING

Tuesday 8th July 2025 17:00

Mariachiara Cangemi (University of Naples Federico II, Italy), Daniela D’Esposito (Institute for Sustainable Plant Protection (IPSP) - CNR, Italy), Francesca Palomba (Institute for Sustainable Plant Protection (IPSP) - CNR, Italy), Simona Gargiulo (Institute for Sustainable Plant Protection (IPSP) - CNR, Italy), Maurilia Maria Monti (Institute for Sustainable Plant Protection (IPSP) - CNR, Italy), Michelina Ruocco (Institute for Sustainable Plant Protection (IPSP) - CNR, Italy), Salvatore Cuomo (University of Naples Federico II, Italy), Francesco Loreto (University of Naples Federico II, Italy), Alessandro Bottino (University of Naples Federico II, Italy)

mariachiara.cangemi@unina.it

A non-destructive multi-omic approach was adopted to integrate phenome (imaging phenotyping and physiological gas exchange) and volatilome analyses (detection of Volatile Organic Compounds, VOCs) to investigate plant-plant communication in tomato (Solanum lycopersicum). A wild-type (WT) and a mutant (MT) for a gene putatively encoding for an odor receptor were analyzed. WT and MT plants (receivers) were closed in containers, together with WT plants previously subjected to water stress (emitters). The VOCs released by the emitters are supposed to function as chemical signals, enhancing defensive mechanisms (priming) of neighboring plants against future stressors. After 24 hours, a subset of WT and MT receivers was subjected to water stress to evaluate the priming effect. The preliminary analysis of phenomic data reveals differences between stressed and non-stressed plants, hindering the detection of the priming response. The Principal Component Analysis of volatilome data confirms this separation and further distinguishes between WT and MT plants. Statistical and supervised machine learning methodologies can significantly enhance the analysis of complex datasets. To this end, we are implementing models capable of identifying common latent components across -omic analyses, rigorously selecting the most informative features, improving both the interpretability and robustness of the analysis. This approach has proven particularly effective for datasets with limited sample sizes and is expected to enable the identification of potential critical biomarkers and distinctive response patterns. The innovative integration of multiomics and artificial intelligence techniques opens new avenues for studying plant communication while advancing both fundamental knowledge and applied research strategies.

P1.11 BATTLING OBSTACLES TOWARDS FULLY AUTOMATED POLLEN ANALYSIS USING MACHINE LEARNING AND PALEOECOLOGICAL REFERENCE COLLECTIONS.

Tuesday 8th July 2025 17:15

Robin Von Allmen (Department of Ecology and Genetics Uppsala University, Sweden), Björn Gedda (Pollenlabor Naturhistoriska Riksmuséet, Sweden), Anneli Ekblom (Department of Archeology Anicent History and Conservation Uppsala University, Sweden), Sandra O Brügger-Camara (Department of Environmental Sciences University of Basel, Switzerland), Joachim R De Miranda (Department of Ecology Swedish University of Agricultural Sciences, Sweden), Mario Vallejo-Marín (Department of Ecology and Genetics Uppsala University, Sweden)

robinvonallmen@hotmail.com

The robust structure of the pollen exine, the outer membrane, render pollen grains an ideal proxy to study the floral composition in samples of various origin; from sediment and ice cores, to fossils in amber. Despite being laborious and requiring long-standing expertise, analysis of pollen assemblages across these diverse deposition contexts remains mostly manual. Machine Learning approaches on the other hand, have the potential to reach expert level identification for trained pollen types, but have not been applied to different research fields and sample origins. We developed a database rendered for Machine Learning of one hundred pollen types by digitizing and manually annotating a palaeoecological reference collection of pollen grains in Sweden. The database was used to train an Object Detection model (ODM) and a Classification model (CM) using a Transfer Learning approach. The assembled pipeline, consisting of the ODM, CM and a filter layer with customizable parameters, was then applied to fossil pollen assemblages in sediment and ice cores, as well as modern pollen assemblages collected from insects and Hirst-type air pollen traps. This pipeline can effectively recreate the same overall vegetation pattern as manual pollen analysis, offering a promising alternative to manual palynology in the future.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

P1.12 AN ECO-PHYSIOLOGICAL INVESTIGATION OF INDOOR PLANTS PHOTOSYNTHETIC CO2 SEQUESTRATION CAPACITY FOR IMPLEMENTING ARTIFICIAL INTELLIGENCE (AI) PREDICTIVE MODELS

Alessio Tei (Institute of BioEconomy - National Research Council of Italy (IBE-CNR), Italy), Francesca Rapparini (Institute of BioEconomy - National Research Council of Italy (IBE-CNR), Italy), Luisa Neri (Institute of BioEconomyNational Research Council of Italy (IBE-CNR), Italy), Gabriele Bernardini (Department of Construction Civil Engineering and Architecture - Marche Polytechnic University, Italy), Marco D’Orazio (Department of Construction Civil Engineering and ArchitectureMarche Polytechnic University, Italy), Federico Brilli (Institute for Sustainable Plant ProtectionNational Research Council of Italy (IPSP-CNR), Italy)

lessio.tei@ibe.cnr.it

The deterioration of indoor air quality (IAQ) poses a serious health risk because of the high concentration levels of CO2 and air pollutants. Within the frame of our project ‘NEUROPLANT’ (NEURal netwOrks trained with measurements of pollutants removal by PLANTs and their associated microbiome at different spatial and temporal scales), this study explores the air phytoremediation potential of plants as an eco-sustainable solution to improve IAQ. We assessed the capacity of three common indoor plant species (i.e. Schefflera actinophylla, Spathiphyllum wallisii and Epipremnum aureum) to reduce ambient CO2 concentration through photosynthesis. The dynamic response of CO2 assimilation to short-term increasing levels of light and CO2 was measured in leaves of potted plants, that were previously acclimated to chamber high and low light levels. In the short-term photosynthetic efficiency increased in response to elevated CO2 concentrations and high light intensity, whereas long-term exposure to high light likely induced photoinhibition. This suggests that the ability of indoor plant species to improve ambient CO2 assimilation, and in turn IAQ, can be dramatically enhanced by high ambient CO2 concentration, but only to a limited extent by high light levels. Data allowed us to identify key parameters of photosynthetic performance for developing and training an air phytoremediation model, based Long-Short-Term-Memory Recurrent Neural Network (LSTM RNN) artificial intelligence (AI), able to predict the impact of different plant species on IAQ in real indoor settings. This will assist architects and policymakers in designing and optimizing plant-based air purification systems for sustainable improvement of IAQ.

P2: POISONOUS PLANTS

ORGANISED BY: ROSLYN GLEADOW (MONASH UNIVERSITY), ELIZABETH NEILSON (UNIVERSITY OF COPENHAGEN)

P2.1 REHABILITATING GRASS PEA, FROM POISONOUS PLANT TO A MODEL FOR SUSTAINABLE AGRICULTURE

Tuesday 8th July 2025 09:00

Cathie Martin (John Innes Centre, United Kingdom), Jasmine Staples (John Innes Centre, United Kingdom), Peter Emmrich (John Innes Centre, United Kingdom), Anne Edwards (John Innes Centre, United Kingdom)

Cathie.Martin@jic.ac.uk

Grass pea is a grain legume known for its resilience to drought, salt and waterlogging and its high protein content. Despite these advantages and over 2000 years of cultivation, grass pea currently faces limited use globally, due to its association with neurolathyrism caused by its content of β-L-ODAP neurotoxin, and can be classified as an orphan crop. Using a resequenced diversity panel of 354 accessions collected by ICARDA from across the world, together with recombinant inbred lines, we have assessed a number of nutritional traits, including β-LODAP content, methionine and cysteine levels in seed proteins, and the presence of condensed tannins (which limit iron bioavailability), using a combination of bioinformatics and direct analysis of nutrients.

The resulting data will be described and how these nutritional traits can contribute to pre-breeding aimed at improving the nutritional value of grass pea and adding value to the existing germplasm collections.

Through these efforts, our work aims to improve the nutritional status of communities in LMICs consuming grass pea, enhance agricultural resilience to climate change, and ensure not only the sustainable conservation and utilization of grass pea genetic resources but also the development of new low toxin varieties suitable for cultivation as a low input, sustainable source of protein, across the world.

P2.2 THE INS AND OUTS OF GLUCOSINOLATE SEED LOADING

Tuesday 8th July 2025 09:30

Deyang Xu (University of Copenhagen, Denmark)

dyxu@plen.ku.dk

The green transition dictates an urgent need to change from animalbased towards plant-based protein sources in our diet. Rapeseed is the world’s third-largest oilseed crop. The rapeseed press cake that contains 30-40% protein with an excellent amino acid composition

is unexploited as plant-based protein food for human consumption due to the presence of anti-nutritional glucosinolates. In the model plant Arabidopsis thaliana, we recently discovered that the funiculus, which connects the silique septum in the mother plant with theseed, is a highly active production site for seed-bound glucosinolates. Additionally, we identified three funiculus-localized transporters UMAMIT29,-30 and -31, as glucosinolate exporters in Arabidopsis. UMAMIT stands for Usually Multiple Amino acids Move In and out Transporter and was believed to be a family of only amino acid transporters. We found that UMAMIT exporters and previously identified GLUCOSINOLATE TRANSPORTERs (GTRs) importers form a transporter cascade that is both essential and sufficient for moving glucosinolates across at least four plasma membrane barriers along the seed loading route. Mutating both importer and exporter genes eliminates seed glucosinolates while maintaining the defense compounds in the rest of the plant. We are translating this transport engineering technology to rapeseed. By addressing today’s farming challenge in growing rapeseed after the EU’s ban on selected neonicotinoids in 2013, this crop has great potential for becoming an attractive protein crop for human consumption. Development of the already-existing, locally-grown rapeseed into a novel protein crop will contribute to sustainable agriculture in the green transition.

P2.3 HARNESSING LOCAL DIVERSITY IN THE WILD PLANT CHENOPODIUM ALBUM TO DEVELOP RESILIENT FOOD CROPS

Tuesday 8th July 2025 10:00

Pablo D. Cárdenas (University of Copenhagen, Denmark) pdcardenas@plen.ku.dk

Our global agrifood system depends on a narrow selection of domesticated crops, leaving it highly vulnerable to pests, diseases, and climate change. Yet, thousands of resilient wild plant species have potential as future crops. However, most remain unsuitable for agriculture due to poor agronomic performance and the presence of anti-nutritional, bitter defense compounds. Here, we introduceChenopodium album, a widespread and locally abundant wild species, as a proof-of-concept for rapid crop domestication. Historically consumed in Denmark during the Iron Age and still foraged in parts of the world,C. albumshows promise as a nutritious crop. However, high levels of saponins and limited agronomic knowledge currently hinder its cultivation. To address this, we established a collection of localC. albumaccessions and generated a highqualityde novogenome assembly. Metabolomic profiling revealed its saponin composition, allowing us to propose a biosynthetic pathway involving β-amyrin synthase, CYP716-family cytochrome P450s, and glucuronic acid transferases, enzymes that catalyze the initial steps of oleanolic acid-derived saponin biosynthesis. For future targeted trait improvement, we are developing both transient

and stable transformation systems forC. album, to enable editing of genes involved in saponin biosynthesis and domestication. Parallel efforts include phenotyping under field conditions and establishing a speed-breeding pipeline to accelerate life cycle and selection inC. album. Altogether, our work provides a framework for thede novodomestication of local wild plants, showcasingC. albumas a model to unlock new plant biology and diversify food sources for a resilient and nutritious agrifood system.

P2.4 THE POISONOUS PLATE OF CLIMATE CHANGE

Tuesday 8th July 2025 10:15

Ros Gleadow (Monash University, Australia)

ros.gleadow@monash.edu

Increasing carbon dioxide, high temperatures, extreme weather, rising sea levels and increasing aridity will affect plant composition as well as their growth. Over 30% of crop plants are cyanogenic, capable of some level of cyanide release primarily as a herbivore deterrent. Cassava is highly productive and an important food security crop. It is also the only staple that, under certain conditions, can kill you. A monotonous cassava diet is associated with a type of permanent paralysis called Konzo, particularly in children. Most cyanogenic plants upregulate the production of cyanogenic glucosides when subject to stressful environmental conditions, leading to higher potential toxicity, in addition to the concentration effect from the overall biomass being less. It is proposed that the biosynthesis and recycling of these nitrogen-containing specialised metabolites help plants to manage their nitrogen and mitigate stress. Indeed, cassava (and sorghum) may have become more toxic with domestication. In this talk, I will discuss the possible underlying mechanisms as to why cassava, in particular, is so cyanogenic and why this may be exacerbated by climate change, using examples from field and controlled environment studies. I will propose strategies for reducing the harm , emphasising the need for education.

P2.5 ONE BEAST’S HOST PLANT IS ANOTHER BEAST’S POISON. ECOLOGICAL

CONSEQUENCES OF STEROIDAL GLYCOSIDE DIVERSITY IN SOLANUM DULCAMARA

Tuesday 8th July 2025 14:00

Nicole M. Van Dam (Leibniz Institute for Vegetable and Ornamental Crops, Germany), R.Adam Anaia (Institute for Biodiversity Friedrich Schiller University Jena German Centre for Integra, Germany), Ilaria Chiocchio (University of Bologna, Italy), Rebekka Sontowski (IGZ Friedrich Schiller University iDiv, Germany), Bart Swinkels (Radboud Institute for Biological and Environmental Sciences, Netherlands), Fredd Vergara (Leibniz Institute for Vegetable and Ornamental Crops Friedrich Schiller University, Germany) vandam@igzev.de

Bittersweet nightshade (Solanum dulcamara) plants produce a large variety of steroidal glycosides (SGs). Minor chemical differences, for example the level of saturation in the steroidal moiety, are associated with differences in resistance to herbivores and pathogens. Liquid Chromatography-quadrupole Time of Flight – Mass Spectrometry metabolomic analyses showed that both total leaf SG levels and SG diversity are associated with herbivore preference and leaf damage. We analysed the metabolomes of leaves and roots of selected chemotypes with saturated and unsaturated SG profiles in their leaves. In addition, we assessed the expression a GLYCOALKALOID METABOLISM25 (GAME25) homologue. In tomato, GAME25 is coding for a short-chain dehydrogenase responsible for the reduction of the C-5,6 double bond in dehydrotomatidine, which results in the formation of tomatidine. We found that differences in leaf SG chemodiversity were associated with the expression of SdGAME25. In contrast to leaves, roots of the same saturated and unsaturated individuals were more similar in their SG profiles and SdGAME25 expression levels. This implies that leaf and root SG chemodiversity in S. dulcamara are under differential selection pressures by aboveground and belowground interactions with herbivores and pathogens. In a common garden experiment, we manipulated the frequencies of these two S. dulcamara chemotypes to create different levels of SG plot chemodiversity. We found that both fruit and seed production as well as herbivore damage were affected by individual and plot diversity level. This suggest that herbivores as well as herbivore community composition may maintain chemodiversity as observed in natural S. dulcamara populations.

P2.6

METABOLOMICS-BASED APPROACH TO

DISTINGUISH

SPECIALTY COFFEE BEANS FROM DIFFERENT ORIGINS AND PROCESSING PRACTICES BASED ON THEIR BIOACTIVE CHEMICAL PROFILE

Tuesday 8th July 2025 14:30

Paula C.P. Bueno (Leibniz Institute for Vegetable and Ornamental Crops, Germany), Daniela A. Chagas-Paula (Federal University of Alfenas, Brazil), Willem G. Araujo (MG Technical Assistance and Rural Extension Corporation, Brazil), Adriana Giongo (Leibniz Institute for Vegetable and Ornamental Crops, Germany), Alexandr L Teixeira (EMBRAPA Coffea, Brazil)

bueno@igzev.de

Coffee trees ( Coffea spp.)are highly susceptible to changes in environmental conditions and agricultural practices. Concurrently, it is also one of the most valued, consumed and traded crops worldwide due to its economic relevance and health effects. Coffee drink is recognized for its psychostimulant effects and antioxidant properties, which are linked to its chemical composition, rich in alkaloids, phenolic compounds and diterpenes. These bioactive compounds are not only associated with beneficial health effects but also play an important role in ecological interactions and plant performance. From the quality perspective, the chemical composition of unroasted green beans and the accumulation of non-volatile and bioactive compounds will determine the sensorial profile and value in the market. Reversely, their relative composition is highly influenced by the genetic background, geographical origin, corresponding environmental growing conditions, agricultural practices and postharvesting processing. Aiming to underscore the complex interplay between all these factors, we employed metabolomics to access the

content of major coffee’s bioactive compounds in Brazilian specialty coffee beans produced in different locations. De-pulping processing increased the sensory score by 1.5% and the content of chlorogenic acid derivatives by 5.8%. Altitude, ferulic acid,p-coumaric acid, sweetness, and acidity were predictors distinguishing the samples. Higher-quality coffees were linked to higher-altitude regions and increased soil organic carbon stock. Theobromine, theophylline, ferulic acid, and p-coumaric acid were linked with sustainable management practices and coffee quality. These findings provide novel insights for coffee quality assessment with a focus on their bioactive compounds and sustainable agricultural practices.

P2.7 INDEPENDENT EVOLUTION OF BENZOXAZINOIDS BIOSYNTHESIS: ENZYMES WANTED, DEAD OR ALIVE

Tuesday 8th July 2025 14:45

Matilde Florean (Max Planck Institute for Chemical Ecology, Germany), Tobias Köllner (Max Planck Institute for Chemical Ecology, Germany), Hedwig Schultz (Max Planck Institute for Chemical Ecology, Germany), Katrin Luck (Max Planck Institute for Chemical Ecology, Germany), Benke Hong (Westlake University, Canada), Veit Grabe (Max Planck Institute for Chemical Ecology, Germany), Jens Wurlitzer (Max Planck Institute for Chemical Ecology, Germany), Yoko Nakamura (Tohoku University, Japan), Sarah E O´Connor (Max Planck Institute for Chemical Ecology, Germany), Tobias G. Köllner (Max Planck Institute for Chemical Ecology, Germany) mflorean@ice.mpg.de

Benzoxazinoids (BXD) are indole-derived defensive compounds produced by several, evolutionarily distant plant families. While their biosynthesis has been well-characterized in the grasses (monocots), the biosynthetic pathway in basal and core eudicots has remained largely unresolved. We employed integrated metabolomic and transcriptomic analyses to elucidate BXD biosynthesis in Consolida orientalis (Ranunculaceae, basal eudicots), Aphelandra squarrosa (Acanthaceae, core eudicots), and Lamium galeobdolon (Lamiaceae, core eudicots). Heterologous expression of candidate genes in Nicotiana benthamiana identified multiple independently evolved enzymes - three bifunctional flavin-dependent monooxygenases, six cytochrome P450s, two UDP-glycosyltransferases, a 2-oxoglutaratedependent dioxygenase, and an O-methyltransferase - catalyzing the conversion of indole to DIMBOA-Glc. Interestingly, in A. squarrosa and L. galeobdolon, no efficient indole-producing enzymes were found. Instead, we identified in all core eudicots, including these species, an alternative indole biosynthetic mechanism involving a catalytically dead paralog of the tryptophan synthase β-subunit (TSB). This pseudoenzyme hijacks the tryptophan synthase α-subunit (TSA), enabling indole production through functional mimicry of the native TSB–TSA interaction, but without further conversion of indole to tryptophan. These findings reveal a remarkable diversity and evolutionary plasticity in BXD biosynthesis across monocots, basal eudicots and core eudicots, and provide an example of the role of pseudoenzymes in metabolic innovation.

P2.8 CHEMICAL WARFARE IN DEGRADED ECOSYSTEMS: THE CHEMICAL SPACE OF ALLELOPATHIC EMPETRUM NIGRUM

Tuesday 8th July 2025 15:00

Elizabeth Neilson (The University of Copenhagen, Denmark), Ingvild Ryde (The University of Copenhagen, Denmark), Kari Anne Bråthen (The University of Copenhagen, Denmark), Ingibjörg Jónsdóttir (University of Iceland, Iceland)

en@plen.ku.dk

The ecologically important Empetrum nigrum L. is an evergreen dwarf shrub with a wide distribution across the northern hemisphere. This species possesses strong allelopathic capacities that can negatively influence the performance and survival of other plant species. Two E. nigrum subspecies (ssp. nigrum and ssp. hermaphroditum) are prevalent in the Icelandic highlands, and their allelopathic nature may influence long-term land degradation. Using an untargeted LC-MS metabolomic approach, different chemical constituents were assessed in E. nigrum leaves, specifically comparing variation in populations, subspecies and sex (i.e. ssp. nigrum; male and female plants). Over 1000 different metabolic features were detected in E. nigrum, with GNPS2 feature-based molecular networking and SIRUS compound predictions classifying the majority of features as phenylpropanoids, especially flavonoids and bibenzyls. Other detected classes include polyketides, terpenoids and alkaloids. Notably, Random Forest analysis identified several molecular features that vary between the different subspecies and sexes. These metabolites may account for the measured differences in allelopathic capacity when assayed against the germination and developmental response of the palatable grass species Festuca richardsonii. These resultsindicate that variation in Empetrum chemical constituents may be an important driver forplant-plant interactions and ecosystem processes, and the relative abundance of Empetrumsubspecies and sexes within populations may play a role in retarding the recovery of degraded ecosystems.

P2.9 THE POISONOUS BENEFITS: PLANT TOXINS AS SUSTAINABLE BIOPESTICIDES

Tuesday 8th July 2025 15:15

Søren Bak (University of Copenhagen, Denmark) bak@plen.ku.dk

As agriculture confronts the urgent need to reduce reliance on synthetic pesticides, nature offers powerful inspiration: plants themselves. Across millions of years, plants have evolved sophisticated chemical defense strategies, including the production of toxins like saponins, which selectively target pests while preserving the plant’s own tissues. Our research investigates how these natural compounds can be harnessed as sustainable biopesticides, aligning with EU intention to halve synthetic pesticide use by 2030 and achieve zero toxicity by 2050.

We combine molecular biology, membrane biophysics, and ecological insight to uncover how plant-produced toxins function—particularly saponins, which disrupt pest membranes without harming the plant. Our studies reveal how plants store these toxins safely and activate them upon attack, offering a blueprint for next-generation

biopesticide design. We also address societal and legal barriers to adoption, recognizing that success requires not only scientific innovation but also policy support and public engagement. By learning from nature, we can develop environmentally friendly plant protection products that safeguard food security, reduce pollution, and support a circular bioeconomy. This work exemplifies how interdisciplinary research—spanning biology, law, and anthropology— can drive the transition to sustainable agriculture.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

P2.10 VARIATION IN TOXICITY BETWEEN THE LAYERS OF EDIBLE SEEDS OF CYCAS ANGULATA IN NORTHERN AUSTRALIA

Roslyn Gleadow (Monash University, Australia), Georgia Lloyd (Monash University, Australia), Kira Maher (Monash University, Australia), John Bradley (Monash University, Australia)

ros.gleadow@monash.edu

Indigenous peoples familiar with cycads recognise their toxicity and hold the knowledge to safely process and prepare the seed for consumption. In different parts of Australia, Indigenous groups have processed different parts of the cycad seed. It is not known whether differences in seed layer preference relate to known differences in the toxicity or nutritional benefit of the seed layers or to the different social and cultural histories of Indigenous groups. Previous research on cycad seed toxins has been contradictory, primarily due to the focus on individual toxins, overlooking the broader chemical profile of each layer. This study simultaneously measured the concentrations of three major cycad toxins—azoxyglycosides (AZGs), β-methylamino-L-alanine (BMAA), and the sterol glycoside, β-sitosterol β-D-glucoside (BSSG) across the four seed layers in the culturally significant species C. angulata. Results show significant variation in the type and concentration of toxins across seed layers. The study challenges earlier dispersal theories due to a different chemical profile in the different layers. This study supports the detailed processing knowledge of Yanyuwa and Noongar and highlights the importance of interpreting Indigenous cycad use beyond the purely utilitarian perspective.

P3: PEPG - BRIDGING THE GAP: CONNECTING PHOTOSYNTHESIS RESEARCH FROM CONTROLLED ENVIRONMENTS TO THE FIELD

ORGANISED BY: LIANA ACEVEDO-SIACA (WAGENINGEN UNIVERSITY), SILVERE VIALET-CHABRAND (WAGENINGEN UNIVERSITY)

P3.18 DEEP LEARNING-BASED DATA DRIVEN YIELD ESTIMATION FOR CAPSICUM GROWN IN GLASSHOUSES

Tuesday 8th July 2025 09:00

Oula Ghannoum (Western Sydney University, Australia)

o.ghannoum@westernsydney.edu.au

Crop photosynthesis and yield are determined by many variables including light energy, CO2, water, and mineral nutrients as the main inputs, as well as various environmental factors. Predicting crop performance in semi-controlled indoor environments such as glasshouses that use natural light, requires complex modelling. Deep learning-based models are superior compared to statistical and mathematical models for handling multivariate, non-linear data for multistep predictions in agriculture. Specifically, transformer-based models are foremost tools which also use GPT based intelligent chatbots. Here, we explore the use of Transformer based sequence to sequence modelling to predict Capsicum crop yield in multi steps based on light, crop inputs such as fertigation, environmental variables such as temperature, humidity, CO2 concentration, and historical yield. We use data pre-processing to clean and standardise data, data engineering techniques for feature selection, multi-head attention with positional encoding for input data and multi-head attention-based decoding to predict yield. The proposed model learns complex light patterns together with crop input and environmental data for near future yield prediction. It predicts yield of next one to seven days given last one to two weeks input window. We showcase the use of new deep learning-based models for complex glasshouse yield prediction, and photosynthetic rate prediction will be our next target for replacing labour-intensive measurements and excessively demanding process models.

P3.1 CONCURRENT TEMPERATURE AND IRRADIANCE FLUCTUATIONS PROMOTE STOMATAL OPENING, ENHANCE NET CO2 ASSIMILATION AND INTERACT

WITH RESPIRATORY PROCESSES.

Tuesday 8th July 2025 09:30

Samikshya Shrestha (Wageningen University and Research, Netherlands), Sarah R. Berman (Wageningen University and Research, Netherlands), Maarten L.J. Wassenaar (Wageningen University and Research, Netherlands), Tom Van den Berg (Wageningen University and Research, Netherlands), Evi Mavrou (Wageningen University and Research, Netherlands), Leo F.M. Marcelis (Wageningen University and Research, Netherlands), Elias Kaiser (Wageningen University and Research, Netherlands), Silvere Vialet-Chabrand (Wageningen University and Research, Netherlands)

samikshya.shrestha@wur.nl

Leaf temperature (T leaf ) fluctuates concurrently with irradiance under fluctuating sunlight, but the separate transient effects of these entangled factors on photosynthesis (A) and stomatal conductance (gs ) are unknown. Furthermore, it is not known to what extent acclimation to fluctuating irradiance affects responses to T leaf fluctuations. Cucumber plants were grown under constant or fluctuating light (FL). Leaf gas exchange was measured under concurrent fluctuations in Tleaf and irradiance, fluctuations in only Tleaf or only irradiance, or constant Tleaf and irradiance. Fluctuations were implemented using a dimmable LED and infrared lamp. High Tleaf or irradiance were imposed twice for 15 min and were separated by phases of low Tleaf or irradiance. Stepwise increases in Tleaf caused transient reductions in A, and caused gs to increase initially and decrease thereafter, with cumulative effects in the second step of Tleaf increase. Concurrent increases in Tleaf and irradiance promoted stomatal opening and increased photorespiration transiently, compared to increases in irradiance only. Leaves acclimated to FL showed larger transient increases in A and gs under high irradiance and T leaf . Our study suggests that Tleaf fluctuation triggers a mechanical advantage for enhancing stomatal opening under sunflecks, and that acclimation to sunflecks allows leaves to better exploit them.

P3.2

SAVING FACE: UTILISING

GROWTH CHAMBERS TO STUDY

Tuesday 8th July 2025 09:45

Robert S Caine (University of Sheffield, United Kingdom), Muhammad S Khan (University of Sheffield, United Kingdom), Yixiang Wang (University of Sheffield, United Kingdom), Colin P Osborne (University of Sheffield, United Kingdom), Holly L Croft (University of Sheffield, United Kingdom)

b.caine@sheffield.ac.uk

Anthropogenic CO 2 emissions are leading to rising global temperatures and increasingly extreme weather events. High vapour pressure deficit (VPD), which often occurs during heatwaves, reduces stomatal opening, which could negate crop photosynthetic gains associated with higher atmospheric CO2 concentrations. Studying the interactive effects of increased CO2 and VPD using free-air concentration enrichment (FACE) under field conditions is challenging due to technical difficulties associated with regulating temperature and moisture content. To bypass this limitation, we conducted high-VPD (3.14 kPa) heatwave experiments on spring wheat (Triticum Aestivum) at high temperatures (37 °C) and low relative air humidity (50%) in climate-controlled growth chambers set to ambient (450 ppm) or elevated (720 ppm) CO2 concentration. We find that elevated CO2 concentration combined with highVPD treatment leads to higher saturating light photosynthesis and maximum rate of rubisco carboxylation (Vcmax ), but this is also associated with much greater evaporative demand than might be expected. Transpiration and thermal profiling within chambers revealed high CO2 grown plants often had higher levels of waterflux and cooler leaves than ambient CO2 equivalent plants, and overall this resulted in higher plant water usage. Light-shift assays showed that photosynthetic performance was tightly linked with stomatal performance during heatwaves at either CO2 concentration, with stomatal conductance only reducing by 37-38% during complete darkness for both CO 2 treatments, which could have considerable implications for future water-use efficiency. Together, our results highlight that high CO2 and rising VPD together could aid photosynthetic performance, but this will be at the expense of higher water usage.

P3.19 SINK LIMITATIONS TO PHOTOSYNTHESIS; HOW (AND WHEN) THE END JUSTIFY THE MEANS

Tuesday 8th July 2025 10:00

Mauricio Tejera Nieves (Jan IngenHousz Institute, Netherlands)

mauricio.tejera@jan-ingenhousz-institute.org

Research on the photosynthetic response to environmental factors is mostly centred on light energy capture and carbon assimilation. Our understanding of how environmental factors impact photosynthate consumption (sink activity), and how these changes in sink activity

affect the photosynthetic response is more limited. At the leaf level, consumption of photosynthates and sink limitations are usually quantified in terms of triose phosphate utilization (TPU). A big limitation to understanding the role of sink limitations on the photosynthetic response to environmental factors is the timeconsuming steady state measurements needed to quantify TPU. Here, I present multi-species evidence supporting the Dynamic Assimilation Technique (DAT) as reliable and accurate non-steady state approach to the quantification of TPU and other biochemical limitations. I will further discuss the potential of using DATs approaches to estimate TPU proxies under 60 seconds using abrupt changes in CO2 concentrations. Field research suggested that the seasonal dynamics of carbon assimilation extend beyond concurrent environmental factors, and sink activities strongly interacted with plant development to ultimately limits photosynthesis. As we integrate multiple environmental factors in control environment experiments, plants’ internal carbon balance remains challenging to control and a potential source of variation. Experimental manipulation of sink strength in control environments suggested cross-level response in plant development, carbon partitioning and carbon assimilation. Results call for further consideration of carbon balance and sink limitations in photosynthetic research, and the development of rapid methods for leaf-level sink activity quantification.

P3.20 PLANT GROWTH ON THE BRIDGE BETWEEN CARBON ASSIMILATION AND WATER DYNAMICS

Tuesday 8th July 2025 14:00

Kathy Steppe (Ghent University, Belgium)

Kathy.Steppe@UGent.be

Photosynthesis is a vital driver of plant growth and, under wellwatered conditions, is inherently shaped by environmental factors such as light, temperature and CO2. Recent advances in sensor technology and plant cuvette design enable detailed, real-time monitoring and modelling of dynamic photosynthetic responses under controlled conditions. These insights are not only key to mechanistic understanding but also serve as inspiration for optimizing plant growth in novel plant production systems. Yet, plant growth involves more than just the fixation of atmospheric carbon. It is a biophysical process also strongly governed by plant-water relations. Next-generation measurements and growth models must incorporate the dynamics of water transport and the crucial role of internal water storage pools in sustaining turgor pressure, especially under changing environmental conditions. This turgor-driven perspective is essential to fully understand how growth occurs, particularly under drought stress. To further complete this picture, we must also consider the often-overlooked recycling of internally respired CO2, which becomes increasingly relevant under drought stress when stomatal closure limits atmospheric CO2 uptake. Together, these processes highlight the intricate interplay between carbon and water relations in plants. Plants grow in a carbon-water world, and bridging the gap between controlled-environment experiments and real-world conditions requires embracing this complexity.

P3.3 CIRCADIAN RHYTHM AND PHOTOSYNTHESIS IN CONTROLLED ENVIRONMENT AGRICULTURE: LIMITS AND OPPORTUNITIES

Tuesday 8th July 2025 14:30

Cédric Dresch (Futura Gaïa Technologies, France), Véronique Vidal (Avignon Université, France), Séverine Suchail (Avignon Université IMBE, France), Huguette Sallanon (Avignon Université, France), Florence Charles (Avignon Université, France), Vincent Truffault (Futura Gaïa Technologies, France)

cedric.dresch@futuragaia.com

In Plant Factories with Artificial Lighting (PFAL), the photoperiod can be reduced to save electricity, but a large daily reduction leads to a decrease in plant growth and Light Use Efficiency (LUE). The reduction in plant growth is linked to the decrease in the total amount of light provided to the plant, known as the Daily Light Integral (DLI). The loss in LUE is linked to photoperiod duration and the plant’s circadian rhythm. When the photoperiod matches the circadian rhythm, plants enter circadian resonance, maximizing LUE because photosynthetic capacity and light availability are synchronized. When the photoperiod is reduced, the circadian resonance state can be disrupted, altering LUE. To better characterize the link between photoperiod duration and LUE, we carried out two experiments, in which we studied the carbohydrate contents, photosynthesis, stomatal conductance and photosystem II efficiency. In the first experiment, lettuces were grown under a photoperiod inducing a periodic 4-hour mismatch with the circadian rhythm. This mismatch did not disrupt the circadian regulation of stomatal conductance, photosystem II efficiency, or sugar metabolism. In the second experiment, larger periodic mismatches of 6 and 12 hours were induced to reduce energy consumption by 12.5% or 25%. The 12.5% modality was the better compromise between agronomical parameters and energy savings. With 25% energy savings, the circadian regulation of stomatal conductance was altered, leading to a significant reduction in LUE. These findings highlight the need to consider circadian rhythms in photoperiod management within PFAL to optimize LUE and reduce energy consumption.

P3.4 THE ROLE OF INFLORESCENCE PHOTOSYNTHESIS IN THE HIGH FECUNDITY OF AN AGRICULTURAL WEED, AVENA FATUA

Tuesday 8th July 2025 14:45

Soualihou Soualiou (School of BEES University College Cork, Ireland), Lucía G Cornejo (School of BEES University College Cork, Ireland), Rossana Henriques (School of BEES University College Cork, Ireland), Astrid Wingler (School of BEES University College Cork, Ireland)

ssoualiou@ucc.ie

Avena fatua (common wild oat) is a weed affecting the yield of cereals, such as wheat and barley. Its combination of rapid growth and tall statue (high competitive ability) with abundant seed production (high

fecundity) make it particularly problematic. Based on the hypothesis that inflorescence photosynthesis contributes to carbon capture for seed production, we explored photosynthetic gene expression in inflorescence organs and the impact of source-sink manipulation on seed formation. Initial analysis of mRNA-Seq comparing inflorescence organs (glume, lemma, palea and awn) to leaves shows higher expression of genes involved in fatty acids synthesis (lipoxygenase), sucrose and secondary metabolism (carbohydrate accumulation and distribution and lignin and flavonoids synthesis) but lower expression of genes related to RuBisCO activity and photochemical efficiency. Defoliation, shading of the inflorescence and de-awning of plants reduced total seed weight by 13, 32 and 38 %, respectively. This indicates that inflorescences, and particularly the awn, contribute more to seed carbon gain than the leaves. Additionally, inflorescence shading and de-awning resulted in a significant delay in stem senescence and higher leaf photosynthesis, suggesting that leaf and stem senescence is determined by source-sink interactions. Extended photosynthetic lifespan of the leaves could increase stem reserves to sustain longer seed filling when photoassimilates in the leaves and stems are depleted in the absence of inflorescence photosynthesis. Altogether, A. fatua exhibits remarkable inflorescence photosynthesis, contributing to seed carbon assimilation, thus supporting high fecundity.

P3.5 BRIDGING WITH CARE: DOES FAR-RED LIGHT INFLUENCE PHOTOSYNTHESIS IN FIELD CONDITIONS?

Tuesday 8th July 2025 15:00

Maarten Wassenaar (Wageningen University WUR, Netherlands), Pieke Van de Weerd (Wageningen University, Netherlands), Wim Van ieperen (Wageningen University, Netherlands)

maarten.wassenaar@wur.nl

Far-red light is abundant in natural sunlight, particularly in shaded leaves within plant canopies. Although traditionally excluded from photosynthetically active radiation (PAR), recent studies suggest that far-red can enhance leaf photosynthesis (An) and reduce mesophyll conductance (gm ) at low light intensities. This triggered an interesting debate: should PAR be redefined?

Previous research, however, was conducted on plants grown in artificial ‘white’ lighting in climate chambers, with spectral conditions differing significantly from natural sunlight. Furthermore, these studies used unrealistic low far-red fractions in control treatments, raising questions about their applicability to field conditions. To address this, we grew tomato plants under a simulated sunlight spectrum (400-750 nm) at 300 mmol PAR m-2 s-1 . We measured An and gm in 25-days-old leaves under normal, increased, and decreased (field-unrealistic) far-red fractions in sunlight PAR. We used a LI6800 and LI7800 Stable Isotope Analyzer system to monitor An and gm over 3-4 diurnal cycles, measuring at 5 min-¹, under constant and sinusoidal diurnal intensity patterns.

Our results show that increasing far-red—mimicking the shift from unshaded to shaded leaves in the field—did not significantly affect An or gm . However, removing far-red, comparable to previous studies, reduced An and gm throughout light periods regardless of light intensity variation.

These findings suggest that while far-red plays a role in photosynthesis, its effect in realistic field conditions may be less pronounced than

previously thought. However, its role can be significant in protected cultivations, where low fractions of far-red frequently occur.

P3.12 STOMATAL CONDUCTANCE AND LIGHT INTERCEPTION TRANSLATE FROM CONTROLLED CONDITIONS TO FIELD AND

Tuesday 8th July 2025 16:00

Francois Tardieu (LEPSE INRAE France, France), Claude Welcker (LEPSE INRAE France, France)

francois.tardieu@inrae.fr

Inverse modelling allows estimation of stomatal conductance (by inverting the Penman Monteith equation), providing result well related to gas exchange indoor and in the field. Plant architecture, which determines radiation interception efficiency, can also be estimated both in the field and indoor, with good genetic correlations. Both have good heritabilities, present a large genetic variability in maize and can be predicted from genomic information. Furthermore, and unexpectedly, they were found to be well-related to yield measured in a multi-site field experiment: high stomatal conductance increased yield in favourable environmental scenarios only, whereas plant architecture increased yield in all scenarios. The consequences of these findings were analysed for 50 years of maize breeding in a multi site field experiment and in indoor platforms. While selecting for yield, breeders indirectly improved architectural traits and allelic frequencies at QTLs related to architecture changed with generations of selection. Conversely, stomatal conductance was similar in varieties released in 1950 and 2010, and allelic frequencies did not change. This is probably because selection for yield only favours traits that positively affect yield in nearly all experiments. Genomic selection for traits may be an alternative avenue. Stomatal conductance and plant architecture could be inferred in different fields, based on genotypic values obtained indoor and on environmental conditions in each considered field. Genomic prediction resulted in adequate ranking of genotypes for the tested traits, thereby opening the way for genomic selection.

P3.13 PHOTOSYNTHESIS TO SUCCESSIVE WATER STRESSES IN WHEAT AND BARLEY: GROWTH ROOM TO GREENHOUSE

Tuesday 8th July 2025 16:30

Shukanta Saha (University of Manchester, United Kingdom), Giles N. Johnson (University of Manchester, United Kingdom)

shukanta.saha@postgrad.manchester.ac.uk

Food security is hampered by increasing drought and flooding. Although each stress individually has been well studied, little is known about the response of cereal crops to successive water stresses. We have compared physiological responses of wheat and barley cultivars to cycles of drought and flooding in both growth

room and greenhouse.Plants were subjected to control (80% soil moisture content [SMC]), drought (30% SMC) or flooding treatments for 15 days. Following that, previously stressed plants were exposed to a further stress – drought followed by flooding (D-F) or flooding followed by drought (F-D) for a further 15 days. These cereals showed contrasting responses to single drought or flooding and to D-F or F-D in growth room. We observed that exposure to the first stress stimulated the inhibition of photosynthesis induced by further stress. Importantly, preceding exposure to flooding increased the inhibition of photosynthesis induced by subsequent drought in both wheat and barley. Barley is more tolerant to successive water stresses retaining photosynthetic capacity and PSII efficiency following single as well as double water stress, with only F-D double stress inhibiting photosynthesis and only via a stomatal limitation. The greater root growth of barley may be important in this tolerance. By contrast, wheat may increase its chances of survival by having the flexibility to reengineer the leaf, even if it is unable to maintain its growth and final yield. However, In greenhouse experiment, due to the changes of responses to flooding in barley induced the photosynthetic inhibition to subsequent stresses.

P3.14 TESTING PROXIES FOR HIGHTHROUGHPUT PHENOTYPING OF CO2 ASSIMILATION AND STOMATAL CONDUCTANCE KINETICS UNDER FLUCTUATING LIGHT

Tuesday 8th July 2025 16:45

Elahe Javadi Asayesh (Wageningen university and research, Netherlands), Elias Kaiser (Wageningen university and research, Netherlands), Liana Acevedo-Siaca (Wageningen university and research, Netherlands), Leo Marcelis (Wageningen university and research, Netherlands)

elahe.javadiasayesh@wur.nl

Quantifying the kinetic traits of CO2 assimilation (A) and stomatal conductance (gs ) under fluctuating irradiance relies on leaf-level gas exchange measurements, which are slow and pose a bottleneck for large-scale studies. Unlike leaf gas exchange, measuring chlorophyll fluorescence and leaf temperature is rapid. We evaluated proxies for high-throughput phenotyping (HTP) of non-steady-state A and gs We examined non-steady-state and steady-state responses of nine species to stepwise changes in irradiance through leaf gas exchange and chlorophyll fluorescence measurements (LI-6800). We quantified the rates of change (time to 50% (t50 ) and 90% (t90 ) of the final steady-state value) of A, gs , photosystem II operating efficiency (ΦPSII ), and leaf temperature (Tleaf ) to irradiance changes. Photosynthetic traits in response to irradiance changes, including the speed of response, varied significantly among species. We found significant positive correlations for t50 and t90 between A and ΦPSII (r2 = 0.70 and r2 =0.33, respectively). Additionally, t90 of gs and Tleaf correlated significantly after increasing (r2 =0.45) and decreasing (r2 =0.61) irradiance. The relationships between the parameters were partially species-dependent. Our findings suggest that the rates of change in PSII and Tleaf can be used as proxies for dynamic A and gs , which may enable rapid HTP methods to estimate the speed of these kinetics.

P3.15 GREEN CONVERSATIONS: HARNESSING PLANT COMMUNICATION TO CONTROL GROWTH LIGHT INTENSITY

Tuesday 8th July 2025

17:00

Tracy Lawson (University of Illinois at Urbana-Champaign, United States), James Stevens (University of Essex, United Kingdom), Phillip Davey (University of Essex, United Kingdom), Piotr Kasznicki (University of Essex, United Kingdom), Tanja A Hofmann (University of Essex, United Kingdom)

tlawson@essex.ac.uk

The cumulated rate of photosynthesis determines plant growth and yield and is linked directly to light intensity throughout the day. Previous studies have shown that photosynthetic carbon assimilation is not constant throughout the day but tends to decrease toward the end of the photoperiod, even when light intensity is constant as in Controlled Environment Agriculture (CEA). There is an increasing interest in CEA with the potential to increase crop production per unit land, contributing to resilient food systems and increasing nutrient supply amidst challenges of climate change, population growth and urbanization. However, the high energy costs associated with the use of LED lighting systems in completely CEA systems has raised concerns over the viability of such crop growth environments. Here we have developed and demonstrated a novel real-time plant biofeedback system based on measurements of chlorophyll fluorescence that allows the crops to directly ‘communicate’ with the input lighting system to optimise lighting requirements. Here we show that the decrease in photosynthesis efficiency later in the day led to a reduced demand for light by the plants, which resulted in increased yield by 10% and reduced energy consumption by 18%, whilst also delivering reduction in carbon footprint.

P3.16

COMMON AND INDEPENDENT

GENETIC BASES OF CARBON- AND WATER-RELATED LEAF TRAITS ON A

Tuesday 8th July 2025 17:15

Eva Coindre (Univeristé de Montpellier, France), Eva Coindre (Univeristé de Montpellier, France), Sarah Etou (INRAE, France), Romain Boulord (INRAE, France), Llorenç CabreraBosquet (INRAE, France), Maëlle Lis (INRAE, France), Mélyne Falcon (INRAE, France), Gautier Sarah (INRAE, France), Baptiste Pierre (INRAE, France), Dominique This (Institut Agro Montpellier, France), Roberto Bacilieri (INRAE, France), Agnès Doligez (INRAE, France), Thierry Simonneau (INRAE, France), Benoît Pallas (Institut Agro Montpellier, France), Vincent Segura (INRAE, France), Aude Coupel-Ledru (INRAE, France)

eva.coindre@umontpellier.fr

Water scarcity, impacted by climate change, threatens grapevine production and quality. To select varieties more adapted to constraining conditions, a key lever could be to explore genetic progress margins around the well-known trade-off between carbon gain and water loss. A major bottleneck that hampers such

advances is the lack of methods for measuring fine functioning traits on thousands of plants as required for genetic analyses, and easily usable in field settings. To overcome this limitation, we deployed an original approach to predict photosynthesis, water-use efficiency and other constitutive leaf traits using high-throughput measurements of poro-fluorometry and near-infrared spectroscopy on a grapevine diversity panel of 250 cultivars grown both in a greenhouse with different watering regimes, and in the vineyard. All these cultivars were resequenced, yielding 1.6M genomic variants, which were used to perform genome-wide association studies with single-locus linear mixed-model and LocalScore algorithms. We found large genetic variability for all traits studied in the greenhouse, with genomic heritability ranging from 0.14 to 0.38. Thirty-six QTLs were detected, with some co-localizations, such as a main genomic region associated with net photosynthesis, electron transport rate, and transpiration. Interestingly, additional regions were detected, specifically associated with either photosynthesis or transpiration, highlighting genetic margins to maintain photosynthesis under drought together with a lower water use. Our findings provide valuable insights into how photosynthesis responds to multiple environmental factors in field settings. This is particularly relevant for perennial crops such as grapevine, where cumulative effects of adverse conditions over years deserve major attention.

P3.17 EFFECT OF SALT STRESS ON THE PHOTOSYNTHETIC ACTIVITY OF FOUR AMARANTHUS CRUENTUS CULTIVARS

Tuesday 8th July 2025 09:00

Adrien Luyckx (Université Catholique de Louvain, Belgium), Stanley Lutts (Université Catholique de Louvain, Belgium), Muriel Quinet (Université Catholique de Louvain, Belgium)

adrien.luyckx@uclouvain.be

Amaranthus sp. (amaranths) is a genus of plants in Amaranthaceae family. Several species, like A. cruentus, are minor crops cultivated for either seed production or for their edible leaves. They are renowned for their tolerance to biotic and abiotic stress and their excellent nutritional quality, making them promising crops in challenging environmental conditions. Soil salinity is one of the main abiotic stress constraining crop growth, mostly in (semi-)arid regions. Most of the crops used today are glycophyte (i.e. salt sensitive); finding salttolerant cultivars or new species is therefore a priority for sustainable agriculture. Photosynthetic activity of Amaranthus cruentus (red amaranth, a plant with C4-type photosynthesis) was studied in response to a moderate saline stress (75 mM in irrigation water) in controlled conditions. Analysis of photosynthesis parameters, recorded with an infrared gas analyzer coupled with a fluorimeter (IRGA), showed a deleterious effect of salt stress on the light-independent reactions of photosynthesis (net carbon assimilation), but not on the light-dependent reactions (electron transport rate and quantum yield of photosystem II). Transpiration and stomatal conductance were also affected by salt. Transcriptomic and proteomic analysis were also performed on leaves. Differentially expressed genes and differentially accumulated proteins involved in metabolic pathways related to photosynthesis were used to explain photosynthetic activity data. Finally, chlorophylls and carotenoids content in leaves were compared to IRGA and -omics data.

POSTER SESSIONS / PECHA KUCHA

Tuesday 8th July 2025 15:15-15:30

P3.6 IS CLIMATE CHANGE AFFECTING THE NUTRITIONAL QUALITY OF OUR FOOD?

Jiata U Ekele (Liverpool John Moores University, United Kingdom), Richard J Webster (Liverpool John Moores University, United Kingdom), Fatima Perez de Heredia (Liverpool John Moores University, United Kingdom), Katie E Lane (Liverpool John Moores University, United Kingdom), Abdulmannan Fadel (United Arab Emirates University, United Arab Emirates), Rachael C Symonds (Liverpool John Moores University, United Kingdom)

J.U.Ekele@2024.ljmu.ac.uk

Global climate change, characterised by rising atmospheric CO 2 and increasing temperatures, has profoundly affected ecosystems, biodiversity, water resources, and human health. Extreme weather events, desertification, and ocean acidification threaten global stability, while agricultural systems face shifting growth patterns, altered pest dynamics, and declining crop nutritional quality. Rising CO2—from pre-industrial levels of ~200 ppm to over 400 ppm today, potentially exceeding 550 ppm by 2050— modifies plant physiology, altering photosynthesis and biomass accumulation, disrupting carbon-nitrogen balance, and reducing bioactive compound synthesis. Combined with high temperatures, these changes pose risks to global food security and nutrition. This study examines the physiological and biochemical responses of kale, rocket, and spinach to elevated CO2 and temperature. Crops are grown in controlled chambers under ambient (400 ppm) and elevated CO2 (1000 ppm) conditions, with photosynthetic performance monitored using MultispeQ v2.0 at key growth stages. Growth parameters, including leaf number, plant height, leaf area, biomass accumulation, carbon-nitrogen ratio, and inorganic carbon content, are determined. Biochemical analyses quantify flavonoid, phenolic, and protein content, antioxidant activity, vitamin A and E, polyphenols (HPLC), and minerals (ICP). Bioavailability and digestibility are assessed using Caco-2 cell models. Preliminary results from this study indicate that elevated CO2 may enhance photosynthesis but modulates nutrient composition, with potential trade-offs between biomass accumulation and bioactive compound synthesis. Altered sugar, mineral, and vitamin content could affect global diabetes and micronutrient deficiencies. Further hightemperature analysis is underway to clarify climate stress interactions. Findings aim to inform climate-resilient crop production and food security strategies.

P3.7 BEYOND THE BOUNDARY: A NEW ROAD TO IMPROVE PHOTOSYNTHESIS BY WIND

Killian Dupont (Wageningen University Research, Netherlands), Tom Van den Berg (Wageningen University and Research, Netherlands), Jiayu Zhang (Wageningen University and Research, Netherlands), Arnold Moene (Wageningen University and Research, Netherlands), Silvere Vialet-Chabrand (Wageningen University and Research, Netherlands)

killian.dupont@wur.nl

Plants interact with their microclimate, simultaneously responding to and influencing it. A key element in this interaction is the leaf boundary layer: a stagnant air layer enveloping the leaf, creating a resistance for heat and gas exchange within canopy air. Its thickness, altered mainly by airflow and leaf size, determines the leaf-to-air interaction. Field crops typically experience wind speeds of 0-8 m s-1 at the canopy top, with wind gusts up to 20 m s-1 . Conversely, indoor-grown crops always encounter low wind speeds (0-1 m s-1 ). These low speeds, especially with larger leaves, restrict heat and gas exchange, impacting photosynthesis and transpiration. Although the effect of the leaf boundary layer on plant exchange processes has been defined, its magnitude remains poorly characterized and is frequently underestimated. This review re-examines its role, underlying processes are further explained by using an existing modelling approach informed with published physiological parameters, and the potential impact on leaf photosynthesis is quantified. This model suggests that in greenhouses, a 0.4 m s-1 increase in wind speed could boost diurnal photosynthesis by 23%, although with possible detrimental side effects. Leaves in the field wider than 8 cm may experience thick boundary layers 50% of time with stronger effects within the canopy. The role of the boundary layer needs to be reevaluated, but this will require new tools, methods and models to make a breakthrough in understanding this overlooked process.

P3.8 ACCLIMATION TO HIGHER PPFD INCREASES PHOTOSYNTHETIC CAPACITY AND NPQ KINETICS WITHOUT IMPACTING PHOTOSYNTHETIC LIGHTUSE EFFICIENCY AND PHOTOSYNTHETIC INDUCTION RATE

Bingjie Shao (Wageningen UniversityResearch, Netherlands)

bingjie.shao@wur.nl

Crops often grow under naturally fluctuating irradiance, requiring photosynthesis to react dynamically adjust to these fluctuations. However, to what extent acclimation to different growth PPFD (photosynthetic photon flux density) affects this dynamic response remains unclear. To elucidate this, three widely cultivated horticultural crops (cucumber, tomato, and sweet pepper) were grown under three PPFD levels (100, 300, and 600 μmol m-2 s-1 ). Leaf morphology, pigmentation, steady-state and dynamic photosynthesis, gas exchange, and chlorophyll fluorescence were analyzed. Higher growth PPFD significantly affected plant morphology, increased leaf pigment concentration and steady-state photosynthetic traits, but had little effect on quantum yield of CO2 assimilation and photosynthetic induction rate. Only cucumber leaves grown under 600 μmol m-2 s-1 exhibited a slower photosynthetic induction rate, due to a reduced stomatal opening speed, despite unchanged steady-state stomatal conductance. NPQ capacity was also unaffected by growth PPFD, but NPQ induction rate significantly increased, while NPQ relaxation rate was

much less affected with different growth PPFD. These results indicated that acclimation to different PPFD strongly influences steady-state photosynthesis but has minimal effects on dynamic photosynthesis. Our findings enhance the understanding of photosynthetic acclimation to light, provide insights for optimizing supplemental lighting and light control in greenhouse, and offer data for modeling photosynthesis under both steady and fluctuating irradiance.

P3.9 IMPACT OF FLUCTUATING LIGHT ON PHOTOSYNTHETIC CAPACITY AND PERFORMANCE IN TOMATO: A NATURAL VARIATION APPROACH

Keshav Jayasankar (Wageningen University and Research, Netherlands), Yuxi Niu (Wageningen University and Research, Netherlands), Herbert Van Amerongen (Wageningen University and Research, Netherlands), Jeremy Harbinson (Wageningen University and Research, Netherlands) keshav.jayasankar@wur.nl

The irradiance of natural daylight constantly fluctuates on the seconds to the hours scale, and it is unsurprising that photosynthesis acclimates differently under a fluctuating irradiance compared to one where the irradiance is constant. Understanding the response and acclimation of photosynthesis to fluctuating irradiance is essential for understanding crop carbon gain and crop productivity. The acclimatory responses of photosynthesis have however been shown to be species dependent. Understanding the differences in acclimation can better inform how plants adapt to fluctuating irradiance, which can be used to develop crops that adapt well to similar environments. We investigated the long-term effect of fluctuating light on five different species of tomato. The species were subject to multiple irradiance fluctuations to understand how the photosynthetic capacity and short-term photosynthetic response acclimates (referred to as ‘performance’). The performance was measured by how fast CO2 assimilation responds to a step increase and step decrease in irradiance, while the photosynthetic capacity was measured via an Irradiance Response Curve. To investigate the effects of these fluctuations on the light-reaction side of photosynthesis, PSII and PSI electron transport, rate constant of linear electron transport and antennae size were measured . The observed effect of the fluctuating light on the differences in capacity and performance of the 5 species of tomato provides insight into differences in limitations and tradeoffs of photosynthesis.

P3.10 IMPACT OF CADMIUM AND ZINC ON THE PHYSIOLOGY OF INDUSTRIAL HEMP AND EVALUATION OF THE PROTECTIVE EFFECT OF SILICON IN HYDROPONIC SOLUTION

Nolan Regnier (UCLouvain, Belgium) nolan.regnier@uclouvain.be

Heavy metals (HMs) such as cadmium (Cd) and zinc (Zn) disrupt photosynthesis and plant physiology. This study assesses their impact on hydroponically grown industrial hemp (Cannabis sativa) and examines the potential role of silicon (Si) as a protective agent, the

latter being known to improve resistance to biotic and abiotic stresses. Various experimental conditions were established, including controls, exposure to Cd and Zn, and treatment with silicon. Physiological effects were assessed by analysing the light response curve, gas exchange and chlorophyll fluorescence, while pigment content was compared using a proteomic approach. The results show a significant decrease in electron transport, net CO2 assimilation, PSII effective quantum yield, transpiration and stomatal conductance. These perturbations reflect stomatal closure as well as altered electron transport under metal stress. In addition, analysis of light saturation highlights a reduction in maximum CO2 uptake and PSII quantum efficiency, as well as an increase in dark respiration in the face of HM stress. Cd and Zn exposure led to a reduction in chlorophyll and carotenoid levels, indicating pigment degradation. The increase in the chlorophyll a/b ratio under metal stress reflects a specific inhibition of chlorophyll b. Contrary to expectations, silicon supplementation did not mitigate the effects of pollutants. These results highlight the negative impact of HMs on the physiology of industrial hemp and reveal the ineffectiveness of silicon as a protective agent in this context. Proteomic analysis provides additional information on the differential accumulation of proteins and the mechanisms underlying the effects of Cd and Zn.

P3.11 MEXPLORING CHLOROPHYLL DYNAMICS IN STAY-GREEN WINTER WHEAT USING A PROTEIN-TURNOVER MODEL TO ASSESS BREEDING PROGRESS AND STRATEGIES.

Emilio Villar Alegria (Albrecht Thaer Institut für Agrar- und Gartenbauwissenschaften Humboldt Universität zu Berlin, Germany), Tsu-Wei Chen (Albrecht Thaer Institut für Agrarund Gartenbauwissenschaften Humboldt Universität zu Berlin, Germany)

emiliovillaralegria@gmail.com

Chlorophyll (Chl) synthesis and degradation govern light-harvesting capacity and photosynthetic efficiency in winter wheat. Stay-green (SG) cultivars exhibit prolonged Chl retention, extending postanthesis photosynthesis and assimilate transport. However, whether this trait results from enhanced synthesis or reduced degradation remains unclear, challenging breeding strategies. To investigate the mechanisms underlying Chl dynamics, we apply a proteinturnover model focusing on three key parameters: maximum synthesis rate (Smax), aging effect (td) reducing synthesis over time, and degradation rate (Dr). We assess these dynamics in 60 winter wheat genotypes spanning recent German breeding history, using periodic SPAD measurements over five weeks of leaf life under constant and fluctuating light and temperature conditions. Our results reveal that modern cultivars maintain greenness longer due to higher Smax, lower td, and reduced Dr, demonstrating distinct mechanisms driving improved chlorophyll retention. Notably, these parameters do not show a strong correlation with each other, suggesting they can be selected independently in breeding strategies. Smax shows the greatest independence from environmental variation, making it a promising target for future breeding strategies aimed at enhancing chlorophyll retention regardless of changing environmental conditions. Our findings provide functional insights into SG mechanisms from a high-throughput and easily accessible measurement, guiding breeding strategies to improve wheat productivity and resilience under climate change. Future work will extend the model to include subsequent steps in photosynthesis, such as proteins involved in electron transport and carboxylation, offering a more comprehensive understanding of leaf photosynthetic dynamics.

P4: CYTOPLASMIC GENETICS: FROM SHAPING PLANT TRAITS TO DRIVING SPECIATION

ORGANISED BY: KIN PAN CHUNG (WAGENINGEN UNIVERSITY), PASCAL TOUZET (UNIVERSITÉ DE LILLE), TOM THEEUWEN (JAN INGENHOUSZ INSTITUTE)

P4.1 REGULATION OF PHOTOSYNTHESIS BY THE PROTONMOTIVE FORCE: TARGETS FOR ENGINEERING ‘IMPROVING’ PHOTOSYNTHESIS

Wednesday 9th July 2025 09:00

Deserah D Strand (Jan Ingenhousz Institute, Netherlands) deserah.strand@jan-ingenhousz-institute.org

The light reactions of photosynthesis supply ATP and NADPH to downstream metabolism in the chloroplast. The chloroplast must balance the supply of ATP and NADPH with the energetic demands of metabolism, and disruptions in this balance may lead to inefficiency or photodamage, with potential implications for plant growth and development. This seminar will discuss recent data showing the response of the photosynthetic electron transport to changes in demands from central metabolism and the implications this has for plant metabolic engineering strategies.

P4.2 PHENOMICS OF CLOCK AND GROWTH PLASTICITY IN BARLEY: A TANGO OF TWO GENOMES

Wednesday 9th July 2025 09:30

Eyal Fridman (Institute of Plant Sciences Agricultural Research Organization (ARO) The Volcani Center, Israel), Eyal Bdolach (Institute of Plant Sciences Agricultural Research Organization (ARO) The Volcani Center, Israel), Manas R. Prusty (Institute of Plant Sciences Agricultural Research Organization (ARO) The Volcani Center, Israel), Lalit D. Tiwari (Institute of Plant Sciences Agricultural Research Organization (ARO) The Volcani Center, Israel), Schewach Bodenheimer (Institute of Plant Sciences Agricultural Research Organization (ARO) The Volcani Center, Israel), Adi Doron-Feigenbaum (Institute of Plant Sciences Agricultural Research Organization (ARO) The Volcani Center, Israel), Eiji Yamamoto (Kazusa DNA Research Institute, Japan), Khalil Kashkush (Department of Life Sciences Ben-Gurion University, Israel), Eyal Fridman (Institute of Plant Sciences Agricultural Research Organization (ARO) The Volcani Center, Israel)

fridmane@volcani.agri.gov.il

In plants, the role of chloroplasts and mitochondria (plasmotype) in controlling circadian clock plasticity and overall plant robustness has not been elucidated. It is not also clear what is the relationship between plasticity of circadian clock rhythms and fitness of the plants under changing environments, a timely topic in the scenarios of current and future climatic change. We developed and implemented the SensyPAM high content phenomics platform for photosynthesis rhythmicity measurements, combined with field trials, to explore consequences of domestication and genetic diversity on clock output and its thermal plasticity, using barley as a model crop. Our studies identified drivers of the clock (DOC) loci that control the loss of clock plasticity between wild and cultivated populations; in these loci we identify significant signature of selection in the barley Pangenome (Prusty et al., 2021). In the wild populations, we identified and experimentally validated key DOCs, including the chloroplast genome in which barley alleles of the rpoC1, a member of the RNA polymerase complex, are modulating the clock plasticity in barley and when overexpressed in Arabidopsis (Tiwari et al., 2024). Population genetic analysis shows a non-random association of alleles for chloroplasticrpoC1 and nuclear DOC loci, thereby indicating the adaptive value of clock plasticity before domestication. These findings led us to the first built of a cytonuclear multiparent population (CMPP) in crops, which captures the segregation of ten wild organelles and nuclear genomes in the background of an elite cultivar (will be presented in more detail in another talk).

P4.3 TRNA INTRONS ARE NOVEL INTRINSIC ANTITERMINATORS IN PLANT CHLOROPLASTS

Wednesday 9th July 2025 09:45

Vanessa F. Loiacono (Max Planck Institute of Molecular Plant Physiology, Germany)

Loiacono@mpimp-golm.mpg.de

Transcription termination is the final stage in RNA synthesis that culminates in the disassociation of the transcribing RNA polymerase (RNAP) complex from the DNA template and release of the nascent RNA molecule. Terminators define 3' borders of genes (or operons) and prevent read-through transcription into downstream sequences, avoiding to the detrimental expression of cryptic proteins or antisense transcripts.

Transcription termination in plant chloroplasts differs from classical prokaryotic mechanisms. Although it is believed to rely solely on secondary structures folding in the 3' UTRs of genes, plastid ‘intrinsic’ terminators lack typical bacterial motifs of GC-rich hairpins followed by a poly-U tract. Additionally, chloroplast terminators do not efficiently terminate transcription eitherin vivoorin vitro. By screening for potential termination signals in plastid genomes, we noticed that tRNA genes are nearly universally interrupted by introns when co-transcribed with downstream genes. We hypothesized that the presence of the intron prevents premature transcription termination at highly structured tRNA domains. By removing tRNA introns from the plastid genome, we demonstrate that, in the absence of the intron, RNAP processivity is impaired, resulting in premature termination of RNA synthesis from operons. This, in turn, leads to mutant phenotypes due to low accumulation of the gene product(s) from the downstream cistron(s).

We propose that introns evolved in chloroplast genomes (i) to adapt to modern RNAPs more sensitive to structured sequences than their prokaryotic counterparts, and (ii) to facilitate the incorporation of tRNA genes into operons, thus increasing gene density and providing additional opportunities for co-regulation.

P4.4

WHAT CAN WE LEARN FROM GENETIC VARIATION FOR CYTONUCLEAR INTERACTIONS?

Wednesday 9th July 2025 10:00

Tom Theeuwen (Jan IngenHousz Institute, Netherlands), Jeremy Harbinson (Wageningen University Research, Netherlands), Mark Aarts (Wageningen University Research, Netherlands)

tom.theeuwen@jii.org

Evolution adapted photosynthesis to many different environmental conditions, even within plant species. The resulting genetic architecture underlying photosynthesis can 1) point at novel genes as targets for improvements, 2) generate new mechanistic insights and 3) pave the way to novel breeding methods. So far, the impact of variation in chloroplast and mitochondrial genomes are largely ignored due to the difficulty in separating their effect from nuclearderived variation. Therefore, we developed methods to study how genetic variation for cyto-nuclear interactions responds to dynamic environmental conditions.

Using haploid-inducer lines we developed an efficient method to generate new organelle-nuclear combinations, with the resulting genotypes referred to as cybrids. A large cybrid panel representing species wide organelle variation inArabidopsis thalianareveals variation for a large range of chlorophyll fluorescence-derived photosynthetic traits. We found that genetic variation in theNdhGgene can result in increased photosynthetic performance. Follow up work revealed that NDH mediated cyclic electron flow has a trade-off on photosystem II efficiency, which impacts the biomass significantly. On the nuclear side, a segregating population between two genotypes, revealed a dozen QTLs connected to photosynthetic traits. Interestingly, these were caused by several different processes and heavily dependent on the dynamic light regime.

All together it shows that there is ample room for improvement of photosynthetic traits, not only in the nuclear genome but also hidden in the organellar genomes. These findings are now extended to novel methods on how genetic variation can be used to identify when photosynthesis is limiting yield in crops.

P4.5 DEVELOPMENT OF PLANT ORGANELLAR GENOME EDITING TECHNOLOGIES

Wednesday 9th July 2025 11:00

Shin-ichi Arimura (University of Tokyo)

d

Chloroplasts and mitochondria retain their own genomes, encoding essential genes for energy production and agricultural traits. Developing precise modification technologies for these organellar genomes is crucial for both basic research and practical applications. We have established TALEN-based gene editing for chloroplast and plant mitochondrial genomes by designing expression vectors with organellar targeting signals. These enzymes successfully edited organellar DNA, achieving homoplasmy and stable inheritance. Importantly, the nuclear-introduced vectors can be eliminated through Mendelian segregation, while the edited organellar genomes persist via maternal inheritance. This approach may classify gene-edited plants as non-GMO in certain countries, including Japan, facilitating agricultural applications.Using this strategy, we have knocked out genes responsible for cytoplasmic male sterility in mitochondrial genomes and introduced single-nucleotide changes conferring antibiotic and herbicide resistance. Furthermore, we recently enhanced Rubisco function by modifying RbcL. TALEN-based editing has been applied to various plants and crops, including Arabidopsis, rice, rapeseed, potato, and tomato. Despite these advancements, further exploration of cytoplasmic genomes and improvements in editing technologies remain essential to unlock their full potential for plant and agricultural innovations.

P4.6 INHERITANCE BEYOND THE NUCLEUS: UNCOVERING THE SECRETS OF PLASTID DNA INHERITANCE

Wednesday 9th July 2025 11:30

Femke Van den Berg (Wageningen University Research, Netherlands), Kin Pan Chung (Wageningen University Research, Netherlands)

femke.vandenberg@wur.nl

In addition to the nucleus, certain plant organelles also possess their own DNA. One such organelle, plastids, harbour the genome derived from ancient cyanobacterial endosymbionts.

Plastid DNA is typically inherited maternally, meaning it is transmitted exclusively through the female parent. However, the underlying mechanisms governing maternal inheritance remain poorly understood. One theory suggests that a plastid exclusion mechanism prevents plastids from entering sperm cells, thereby restricting the transmission of paternal plastids. Notably, this exclusion mechanism can be disrupted by specific environmental conditions. It has been shown that chilling stress significantly increases the frequency of paternal plastid transmission.

Besides the environmental factor, we have also identified a genetic factor that regulates plastid inheritance. InNicotiana tabacum, the endonuclease DPD1 is responsible for plastid DNA degradation during pollen development. Whendpd1mutant serves as the paternal

parent, a higher paternal plastid transmission rate is observed. Despite these recent findings, the full extent of genetic and environmental influences on plastid inheritance remains to be elucidated.

In my research, I aim to uncover additional factors, both genetic and environmental, that influence plastid inheritance. Specifically, I will develop a high-throughput crossing and screening pipeline to facilitate the study of plastid inheritance inArabidopsis thaliana. Both forward and reverse genetic screens will be conducted to identify genes regulating plastid inheritance. Ultimately, our research will shed light on the molecular mechanisms underlying maternal inheritance.

P4.7 THE RELATIONSHIP BETWEEN THE REPRODUCTIVE SYSTEM AND MITOCHONDRIAL GENOME STRUCTURE IN THE GYNODIOECIOUS SPECIESSILENE VULGARISAND ITS RELATIVES

Wednesday 9th July 2025 11:45

Helena Štorchová (Institute of Experimental Botany Czech Academy of Sciences, Czech Republic) storchova@ueb.cas.cz

The model systemSilene vulgarisand its relatives from the Behenantha section provide a unique opportunity to explore the relationship between gynodioecy and mitochondrial (mt) genome structure. Complete mt genome sequences from severalS. vulgarispopulations revealed the highest intraspecific mt genome diversity reported in any angiosperm, characterized by extensive intergenic regions, hundreds of repeats, and multiple subgenomes.

The taxonomic diversity withinBehenanthaoffers an ideal framework for studying the origins and evolution of this extraordinary mt genome variation. This section includes both gynodioecious and hermaphroditic species, such asSilene fabaria, which is closely related toS. vulgarisyet exhibits a profoundly different mitogenome. While similar in size,S. fabariamt genome forms a single circular molecule with only a few large repeats, in contrast to the multipartite structure ofS. vulgaris.

The high mt genome diversity and frequent intramolecular rearrangements also impact essential mt genes. Some genes display variable transcription start sites or lack stop codons in certainS. vulgarisgenotypes. Hundreds of nucleus-encoded proteins regulating organellar gene expression must adapt to this intraspecific mt genome variability in gynodioecious species. The recently publishedS. vulgarisnuclear genome now enables the analysis of neo/ subfunctionalization in organellar RNA-binding proteins, particularly pentatricopeptide repeat (PPR) proteins, which are associated with extreme mt genome variation.

P4.8 KNOCKING OUT A FUNCTIONAL GENE IN TOBACCO MITOCHONDRIA

Wednesday 9th July 2025 12:00

Joachim Forner (Max Planck Institute of Molecular Plant Physiology, Germany)

Forner@mpimp-golm.mpg.de

Targeted modification of the plant mitochondrial genome has been a long-standing desired goal of the research community and only in recent years it has become feasible. Key to this are transcription activator-like effectors (TALEs), or more precisely base editors and nucleases (TALENs) that build on these. TALENs are protein-only, freely programmable site-specific DNA endonucleases. TALEN-encoding transgenes can be delivered to the nucleus via classical transformation techniques, while the resulting proteins can be easily targeted to the mitochondria by adding an N-terminal mitochondrial presequence. Using TALENs, we have now managed to completely remove thenad9gene from the mitochondrial genome ofNicotiana tabacum, creating a full knock-out. While the removal ofnad9was coupled to genome rearrangements via recombinations in most of the lines, we also succeeded in isolating a few lines with a clean deletion, without any additional alterations in the mitochondrial genome.

The mutant plants lack the entire complex I in their respiratory chain, but are viable. They display a distinct phenotype, most notably delayed germination and growth as well as altered leaf and flower morphology. They are also male sterile. By allotopic expression ofnad9in the nucleus, we could fully rescue thenad9knock-out phenotype, including reversion to male fertility. We thus have created an artificial cytoplasmic male sterility (CMS) system.

P4.9

DISRUPTION OF CYTONUCLEAR COEVOLUTION IN THE PLASTID RIBOSOME MAY LEAD TO GENETIC INCOMPATIBILITY AND REPRODUCTIVE ISOLATION

Wednesday 9th July 2025 15:00

Karen Barnard-Kubow (James Madison University, United States), Ava Wehr (James Madison University, United States), Alfredo López-Caamal (University of Virginia, United States), Bryson Scoffield (James Madison University, United States), Laura Galloway (University of Virginia, United States)

barnarkb@jmu.edu

Understanding the process by which new species form is critical for understanding the generation of biodiversity. Coevolution between the nuclear and organelle genomes and subsequent disruption of this coevolution when hybridization occurs between genetically divergent lineages is a potentially powerful, yet understudied, mechanism of speciation. Campanula americana, an herbaceous species in the Campanulaceae, has been found to exhibit elevated rates of plastid genome evolution and strong cytonuclear incompatibility. However, the underlying genetics of the cytonuclear incompatibility in this system are unknown. Using a combination of newly sequenced C. americana and publicly available plastid genomes and RNAseq on green and white leaf tissue pairs from variegated plants we exmained the genetic changes leading to cytonuclear incompatibility. We found elevated rates of nucleotide diversity in genes involved in plastid genome regulation, in particular the ribosomal protein subunits, within C. americana and also across the Campanulaceae as a whole. We also found that while transcription of the plastid encoded RNA polymerase (cpRPO) is upregulated in white tissue relative to green, the target genes of this polymerase are downregulated. These findings suggest the cytonuclear incompatibility in this system is a result of reduced functioning of the plastid ribosome, which in turn prevents

sufficient expression of plastid genes essential to plastid development and photosynthesis.

P4.10 THE BARLEY CYTONUCLEAR MULTI-PARENT POPULATION (CMPP) AS A NOVEL RESOURCE FOR DISSECTING CYTONUCLEAR INTERACTIONS

Wednesday 9th July 2025 15:30

Schewach Bodenheimer (Plant Sciences Institute Volcani Agricultural Research Organization (ARO), Israel), Eyal Bdolach (Plant Sciences Institute Volcani Agricultural Research Organization (ARO), Israel), Avital Beery (Plant Sciences Institute Volcani Agricultural Research Organization (ARO), Israel), Shengming Yang (USDA-ARS Cereals Research Unit Edward T. Schafer Agricultural Research Center, United States), Ruth S. B. Alfaro (Department of Botany and Plant Sciences University of California Riverside, United States), Daniel Koeing (Department of Botany and Plant Sciences University of California Riverside, United States), Eyal Fridman (Plant Sciences Institute Volcani Agricultural Research Organization (ARO), Israel)

fridmane@volcani.agri.gov.il

Crop wild relatives hold great potential for enhancing the genetic diversity of cultivated crops, particularly for traits critical to yield stability under environmental stress. While existing mapping populations primarily emphasize nuclear diversity, the importance of cytonuclear interactions (CNIs) between cytoplasmic and nuclear genomes in shaping complex agronomic traits remains underexplored. Here, we introduce the barley Cytonuclear Multi-Parent Population (CMPP), an innovative interspecific resource consisting of 924 doubled haploid lines organized into ten subfamilies, each exhibiting segregation of both nuclear and cytoplasmic genomes. Through comprehensive field trials (2022–2024), we demonstrate significant effects of cytoplasmic origin on key spike and grain traits, notably Thousand Grain Weight (TGW) and Fruiting Efficiency at maturity (FEm), as well as on trait stability indices. Utilizing a WGS-derived genotype, we distinguished cytoplasmic effects from nuclear genetic drift, confirming genuine cytoplasmic contributions. Genomewide epistasis mapping identified 16 cytonuclear quantitative trait loci (cnQTL) which show cytoplasm-dependent nuclear effects, highlighting their importance in trait variation. Cross-validation runs of genomic prediction models that incorporate subfamily and cytoplasm-specific interactions showed that for most traits, this approach reaches the accuracy equivalent to using the full genotypic matrix as predictor, despite using only a fraction (<1.5%) of input variables, therefore significantly reducing the computational impact of the analysis. The CMPP thus represents a novel genetic infrastructure for exploring cytonuclear interactions, promoting molecular characterization, and supporting future crop breeding strategies.

P4.11 ENDOSYMBIOTIC GENE TRANSFER AS A MUTAGENIC PRESSURE DURING PLANT EVOLUTION

Wednesday 9th July 2025 15:45

Enrique Gonzalez-Duran (Max Planck Institute of Molecular Plant Physiology, Germany), Ralph Bock (Max Planck Institute of Molecular Plant Physiology, Germany)

duran@mpimp-golm.mpg.de

During eukaryotic evolution, genes encoded in the genomes of plastids and mitochondria have relocated to the nuclear genome, a process known as endosymbiotic gene transfer (EGT). Although EGT is a well-known enabler of eukaryotic evolution, it proceeds at different speeds across eukaryotic lineages, and among plants and algae. In order to elucidate the forces governing these speed variations, we set out to investigate the effects of genetic and environmental factors on EGT frequencies in tobacco (Nicotiana tabacum), a plant species in which EGT from plastids to the nucleus can be reproduced experimentally. We discovered that EGT increases up to 20-fold in the male germline of tobacco plants after inactivation of individual pathways for repair of double-strand breaks (DSB) in the nuclear DNA. Furthermore, we observed that EGT frequencies increase even further (34-fold) in higher-order mutants, in which the defects in DSB repair have been combined with mutations affecting other candidate EGTcontrolling processes. We predict that additional interventions (e.g., stress conditions triggering plastid rupture) may result in extreme EGT levels, at which EGT could become a mutagenic stressor that threatens the stability of the nuclear genome. We propose that the need to suppress EGT and/or its mutagenic effects may have shaped the evolution of diverse plant features, including stress responses and the genome structure of plants.

P4.12 WHAT IS THE ROLE OF THE ORGANELLES IN THE SPECIATION PROCESS OF SILENE NUTANS?

Wednesday 9th July 2025 16:00

Pascal Touzet (University of Lille, France)

pascal.touzet@univ-lille.fr

Silene nutans (Caryophyllaceae) is composed of 4 distinct genetic lineages which are strongly reproductively isolated: inter-lineage hybrids are chlorotic and exhibit high mortalities. The asymmetry in the reproductive isolation in reciprocal crosses suggested the involvement of cyto-nuclear incompatibilities in hybrid breakdown. Using hybrid capture and high-throughput DNA sequencing, we analyzed diversity patterns in the genic content of the organellar genomes in the four S. nutans lineages. Because organellar genomes are usually co-transmitted, we assessed whether both genomes could be involved in the speciation process.

P5: FROM THE MICRO TO THE MACRO: FINE TUNING STOMATA TO MAXIMISE GLOBAL CROP RESILIENCE

ORGANISED BY:

ROBERT S CAINE (UNIVERSITY OF SHEFFIELD), CASPAR CHATER (ROYAL BOTANIC GARDENS, KEW)

P5.1 THE IMPORTANCE OF STOMATAL PHYSIOLOGY FOR ADAPTION: LESSONS FROM WILD PLANT SPECIES

Wednesday 9th July 2025 09:00

John N Ferguson (University of Essex, United Kingdom)

jfergu@essex.ac.uk

The availability of water is the most important limitation to net primary productivity. This is reflected by the plethora of adaptive mechanisms that plants have evolved to balance water use with carbon fixation via photosynthesis. Stomata are integral to this tradeoff and ~98% of water used by plants passes through them. Despite their importance to this end, there have been relatively few studies that have demonstrated the role of stomatal physiology in conferring local adaptation. In this presentation, I will describe two studies that explore natural variation of water use and photo physiology without directly focusing on stomatal biology. Firstly, a study focusing on water use in Arabidopsis thaliana (Arabidopsis) and secondly a study on photophysiology in Hordeum spontaneum (wild barley). Despite not directly focusing on stomatal biology, both studies highlight the importance of stomatal constraints to water use as key to local adaptation. In Arabidopsis, we highlight stomatal- and root-mediated regulation of water use as key to facilitating adaptation to warm environments. In wild barley, we highlight how uncoupling stomatal conductance from photosynthesis is key to facilitating adaptation to dry environments. Finally, I will discuss how these findings can be used to guide crop development.

P5.2 THE MOLECULAR MECHANISMS

Ive De Smet (VIB-UGent, Belgium)

ivsme@psb.vib-ugent.be

Plants continuously respond to changing environmental conditions to prevent damage and maintain optimal performance. To regulate gas exchange with the environment and to control abiotic stress relief, plants have pores in their leaf epidermis, called stomata. Multiple environmental signals affect the opening and closing of these stomata. High temperatures promote stomatal opening (to cool down), and drought induces stomatal closing (to prevent water loss). Here, I will present our work on the high-temperature-associated kinase TARGET OF TEMPERATURE 3 that directly controls the activity of plasma membrane H+-ATPases to induce stomatal opening. OPEN STOMATA 1, which regulates stomatal closure to prevent water loss during drought stress, directly inactivates TARGET OF TEMPERATURE 3 through phosphorylation. Taken together, this signalling axis harmonizes stomatal opening and closing under high temperatures and/or drought. In addition, I will show how our high temperature phosphoproteomes of different plant species allows identifying additional components of this complex signalling module. In the context of global climate change, understanding how different stress signals converge on stomatal regulation allows the development of climate-change-ready crops.

P5.3

BARLEY DOUBLE MUTANT IN ARABIDOPSIS OST1 HOMOLOGS IS IMPAIRED IN STOMATAL REGULATION

Wednesday 9th July 2025 09:45

Ebe Merilo (University of Tartu, Estonia), Kajal Samantara (University of Tartu, Estonia), Eliisabeth Laul (Centre of Estonian Rural Research and Knowledge, Estonia), Egon Meigas (University of Tartu, Estonia), Dmitry Yarmolinsky (University of Tartu, Estonia), Kristiina Laanemets (Centre of Estonian Rural Research and Knowledge, Estonia)

ebe.merilo@ut.ee

Stomatal pores on leaves determine water loss of plants and carbon assimilation in photosynthesis. These key physiological processes affect biomass production, stress sensitivity and water use efficiency of plants and are also addressed in breeding. ABA signaling network described for Arabidopsis is conserved in land plants; the module of ABA-activated kinase OST1 leading to anion channel activation and stomatal closure developed during evolution of early land plants.

Climate change associated rise in atmospheric vapour pressure deficit (VPD) results in OST1-mediated stomatal closure in Arabidopsis. Here, we measured stomatal VPD- and ABA-sensitivity of barley double mutants defective in two barley genes homologous to Arabidopsis OST1. Double mutants showed higher stomatal conductance and reduced VPD- and ABA-sensitivity compared with wildtype Golden Promise (GP) in gas exchange experiments. Net assimilation rate and stomatal density were only mildly affected in double mutants compared with GP. These results show that as in Arabidopsis, OST1 is involved in determining stomatal openness and sensitivity to ABA and abiotic environmental factors. The effect of alleviating ABA signalling pathaway on stress tolerance and yield is discussed regarding breeding plants for different water availability conditions.

P5.4 MOLECULAR EVIDENCE FOR STOMATAL ADAPTIVE EVOLUTION OF DROUGHT TOLERANCE IN WILD CEREALS

Wednesday 9th July 2025 10:00

Yuanyuan Wang (Western Sydney University, Australia), Guang Chen (Central Laboratory Zhejiang Academy of Agricultural Sciences, China), Fanrong Zeng (Collaborative Innovation Centre for Grain Industry College of Agriculture Yangtze University, China), Peter Franks (School of Life and Environmental Sciences The University of Sydney, Australia), Pilar Catalán (High Polytechnic School of Huesca University of Zaragoza, Spain), Eviatar Nevo (Institute of Evolution University of Haifa, Israel), Zhong-hua Chen (School of Science Western Sydney University, Australia)

Yuanyuan.Wang@westernsydney.edu.au

The drought tolerance of wild cereal progenitors has declined through domestication in the pursuit of higher productivity. Restoring this trait is critical for global food security, yet it requires deeper genetic insights. In this study, we investigated the molecular basis of drought adaptation in wild barley (Hordeum spontaneum), wild emmer wheat (Triticum dicoccoides), and  Brachypodium species collected from contrasting dry and moist habitats at Evolution Canyon, Israel (ECI).

We found that local environmental conditions have shaped the stomatal and photosynthetic traits of these wild cereals, with distinct adaptive signatures between xeric and mesic habitats. We present the genomic and transcriptomic evidences contributing to these differences. Further, we examined the role of polyploidy in drought responses using allotetraploid  Brachypodium hybridum  (Bh) and its diploid progenitor  B. stacei (Bs). Genes related to stomatal regulation and immune response in the S-subgenome were under positive selection, highlighting their importance in environmental adaptation. Bh employed a drought escape strategy, exhibiting higher photosynthetic capacity, lower WUEi, and earlier flowering than Bs, driven by a tightly co-regulated circadian rhythm gene network.

We functionally characterized African Slope-specific differentially expressed genes in barley. Silencing  DRN1 (Disease-Related Nonspecific Lipid Transfer 1),  NPQ4 (Nonphotochemical Quenching 4), and BRH1 (Brassinosteroid-Responsive Ring-H1 ) confirmed their role in drought tolerance. These findings underscore the genetic mechanisms underlying drought adaptation in wild cereals and the evolutionary significance of polyploidy in environmental resilience. Our study provides valuable genetic insights for breeding climate-resilient cereal crops in an era of increasingly frequent drought events.

P5.5 STOMATA AND THE INTEGRATION OF LIGHT QUALITY SIGNALS IN SEEDLING ESTABLISHMENT

Wednesday 9th July 2025 10:15

Ashley J Pridgeon (University of Bristol, United Kingdom), Mathilda Gustavsson (University of Bristol, United Kingdom), Lionel Hill (John Innes Centre, United Kingdom), Keara A. Franklin (University of Bristol, United Kingdom)

ashley.pridgeon@bristol.ac.uk

Following germination, seedlings must rapidly adapt to their surrounding environment. Perception of light quality via specialised photoreceptors signals the availability of sunlight for photosynthesis. Water availability and light quantity/quality are among the key factors that determine the likelihood of seedling survival. Plants regulate gas exchange through stomata on both short-term scales (through rapid movement) and long-term scales (through changes in cell size and stomatal density). Even though we know a great deal about the contribution of stomata to the ability to withstand stress in mature plants, their role in seedling establishment is much less clear.

In this study we investigate how exposure to different light qualities affect the regulation of stomatal movements in Arabidopsis thaliana seedlings. These light qualities include white light (light wavelengths between 400-700nm) supplemented with low dose ultraviolet B (UVB – between 280-315nm), and white light supplemented with far red light (FR – between 725-735nm). These light conditions were chosen to simulate aspects of direct sunlight (which contains light within the UV part of the spectrum) and surrounding vegetation (which selectively transmits and reflects far red light) respectively. We find that both signals have effects on stomatal movements, and we investigate the underlying mechanisms mediating these stomatal responses.

PHOSPHORYLATION OF

-AMYLASE 1 MODULATES GUARD CELL STARCH DYNAMICS ACROSS LAND PLANTS

Diana Santelia (ETH Zurich, Switzerland)

dsantelia@ethz.ch

β-amylases (BAM, EC 3.2.1.2) are key enzymes of plastidial starch turnover extensively studied in Arabidopsis thaliana. One isoform of the Arabidopsis BAM family, BAM1, is predominantly expressed in guard cells (GCs), where it promotes GC starch degradation for rapid stomatal opening at dawn and under blue light. The function of BAM1 orthologous genes from other plant species remains underexplored. Our research uncovers significant BAM1 duplications across the Poaceae family, suggesting sub- and neo-functionalization. Intriguingly, a conserved phosphorylation motif in the N-terminal region of BAM1 orthologs from eudicot species, which possess kidney-shaped stomata, is absent in corresponding BAM1 orthologs from the monocot Poaceae family, which possess dumbbell-shaped stomata. The presence/absence of this BAM1 phosphorylation motif across plant taxa seem to underpin the differences in GC starch turnover dynamics, in turn influencing stomatal responses to environmental cues. Our findings advance the understanding of GC

starch metabolism and its regulatory mechanisms, offering insights into the evolutionary adaptation of stomata. They also provide a basis for future research directions in stomatal regulation, helping plants cope with environmental stresses.

P5.7 EFFECTS OF RED AND BLUE LIGHT PROPORTIONS ON STOMATAL DYNAMICS: DISTINGUISHING THE ROLES OF PHYSIOLOGY AND DEVELOPMENT

Wednesday 9th July 2025

11:45

Yixiang Shan (University of Sheffield, United Kingdom), Muhammad Khan (University of Sheffield, United Kingdom), Holly Croft (University of Sheffield, United Kingdom), Colin Osborne (University of Sheffield, United Kingdom) y.shan@sheffield.ac.uk

Spectral light quality can regulate both the physiology and development of stomata. The combination of red and blue light promotes stomatal development through phytochrome and cryptochrome responses. In dynamic light responses, red light indirectly regulates stomatal opening by stimulating chloroplasts, while blue light rapidly triggers stomatal opening via phototropinmediated signal transduction. However, the net effects of these responses on stomatal dynamics, whether through stomatal physiological responses or leaf structural development, has not been well distinguished. In a controlled-environment growth chamber experiment, six treatments with different R:B ratios ranging from 0.45 to 2.06 were combined with a fixed photon flux to study the changes in stomata conductance and anatomical properties during flowering in tomato (Solanum lycopersicum). The results showed that as the R:B ratio increased, the time required to complete stomatal opening and closing both became shorter. Correspondingly, the maximum stomatal conductance decreased with increasing R:B ratio. When the R:B ratio was at the minimum of 0.45, stomatal conductance reach the largest value under saturating light. Anatomical results showed that lower R;B ratio makes stomatal conductance at steady state a larger proportion of the maximum determined by anatomy. The R:B ratio had a significant effect on the linear relationship between anatomical potential stomatal conductance and actual diffusive conductance. The experiment demonstrates that stomatal responses are modulated by adjusting the R:B ratio of light in controlled environments, with a larger proportion of blue light promoting wider stomatal opening via physiological mechanisms, and minimal contribution from anatomical changes.

P5.8 THE RATIO OF CI- INDEPENDENT AND CI- DEPENDENT CONTRIBUTIONS TO THE STOMATAL RED LIGHT RESPONSE ACCLIMATE TO THE LIGHT ENVIRONMENT

Wednesday 9th July 2025 12:00

Tomas E Van den Berg (Wageningen University, Netherlands), Elias Kaiser (Elias.kaiser@wur.nl, Korea (South)), Jurriaan Schmitz (University of Twente, Netherlands)

Tom.vandenberg@wur.nl

The stomatal red light response changes stomatal conductance (gs) proportionally to photosynthesis, is partly driven by the chloroplast plastoquinone redox state (1-qL) and can be manipulated to change water-use-efficiency. It consists of leaf internal [CO2] (Ci) dependent and independent contributions. Ci-independent response in Arabidopsis thaliana is suggested to be larger than the Ci- dependent response for physiological Ci, but it is unclear to what extent environmental acclimation could change this ratio. • We tested how Ci-independent responses changed under two different light acclimation states in Arabidopsis plants with intrinsically different levels of 1-qL by different content of Photosystem II Subunit S (PsbS) with red light response curves of gs. • Acclimation to higher light intensity reduced 1-qL levels at the higher red light intensities for Col-0 but not for the mutants and the acclimation induced reduction of 1-qL did not affect the slope of 1-qL versus gs at the same Ci,. gs of Col-0 was however increased, indicating that the Ci- independent response remained the same and the Ci- dependent red light response increased with acclimation to higher light intensity. • The ratio of the Ci dependent and Ci-independent responses to red light can acclimate to the needs of the plant through homeostasis.

P5.9 DROUGHT-INDUCED TRADE-OFFS: STOMATAL CLOSURE, GROWTH, AND WATER USE IN ARABIDOPSIS ECOTYPES

Wednesday 9th July 2025 12:15

Nitkamon Iamprasertkun (University of Sheffield, United Kingdom), Colin Osborne (University of Sheffield, United Kingdom), Holly Croft (University of Sheffield, United Kingdom), Stephen Rolfe (University of Sheffield, United Kingdom)

niamprasertkun1@sheffield.ac.uk

Stomatal regulation balances water use and carbon assimilation, directly influencing plant resilience under drought. Investigating natural variation in stomatal responses provides insights into how plants fine-tune water use strategies. This study examines the growth responses, potential trade-offs, and the influence of climate origin on trait variation under drought in 53 Arabidopsis ecotypes from diverse geographical origins. Plant projected area, chlorophyll fluorescence, and rosette temperature (stomatal regulation proxy) were monitored over time, revealing ecotypic variation in stomatal regulation and growth maintenance under drought. While all ecotypes employed a conservative strategy under drought, closing stomata to conserve water and reducing photosynthetic efficiency, they varied in the timing and intensity of their responses. A trade-off in stomatal conductance (gs) was observed in 42% of ecotypes, with those exhibiting higher gs under well-watered conditions experiencing a greater reduction under drought, indicating increased sensitivity to drought. Limited water availability led to a stronger trade-off between vegetative and reproductive growth, whereas in well-watered, sufficient resources allowed both to develop freely. Rather than distinct strategies, NMDS analysis revealed that drought responses followed a continuum of water-use strategies, ranging from risky-fast to safety-slow. Environmental origin played key roles in shaping drought responses, as ecotypes from regions with wider temperature ranges (p < 0.05) were more likely to adopt a safety-slow strategy, whereas warmer winter ecotypes (p < 0.05), mediterranean, tended toward a risky-fast approach. These findings highlight the diversification of stomatal and

growth strategies within a single species, providing insights into how plants optimize water use under stress.

P5.10 STOMATAL COUPLING WITH MESOPHYLL DEMANDS FOR CO2 – A ROAD MAP TO IMPROVED PHOTOSYNTHESIS AND WATER USE EFFICIENCY

Wednesday 9th July 2025 09:00

Tracy Lawson (University of Essex, United Kingdom), Mengjie Fan (University of Essex, United Kingdom), Martin Battle (University of Essex, United Kingdom), Piotr Kasznicki (University of Essex, United Kingdom), Mauro G Sangtos (Federal University of Pernambuco, Brazil)

tlawson@essex.ac.uk

In order for leaf photosynthesis to take place CO2 must enter the leaf through adjustable pores, called stomata, and at the same time water is lost through these pores which also aids in cooling of the leaf. Stomata respond to a range of environmental stimuli in order to maximize CO2 uptake for photosynthesis, however the consequential loss of water is an order of magnitude greater. As a strategy to improve both carbon assimilation and water use we are also exploring the speed of stomatal responses to changes in environmental signals. It is clear that stomatal responses that are rapid and in tune with mesophyll demands for CO2 have greater A and water use efficiency. Exploring a range of different sorghum cultivars, we demonstrated an extremely tight coupling and high water use efficiency. What is not clear is the signals that co-ordinate stomatal behaviour with assimilation rate. Here we explore photosynthetic and stomatal responses to various signals including light intensity and spectra in order to elucidate mesophyll signals. We also present a novel epidermal transfer experiment to evaluate the effect of different photosynthetic strategies on stomatal responses. Elucidating the signals that co-ordinate stomata with mesophyll could provide novel unexploited targets to improve plant resilience for future crop performance.

P5.11 CUTTING-EDGE SOLUTIONS FOR REAL-TIME,

STOMATAL IMAGING AND ANALYSIS

Wednesday 9th July 2025 15:30

Fabien Miart (MIAtecs, France)

fabien.miart@live.fr

Stomata regulate plant water balance, carbon exchange, and defense mechanisms, while also affecting bioactive compound production. Their density and behavior impact crop resilience, productivity, and adaptation to climate change, making stomatal analysis essential in plant breeding, agroindustry, pharmacology, and forestry. However, conventional imaging methods remain labor-intensive and timeconsuming.

We offer real-time, high-throughput solutions for automated stomatal analysis, from density assessments to morphological and open/closed status evaluations. Designed for greenhouses, growth chambers, and

field applications, our two complementary technologies redefine stomatal imaging:

STOMmini– A smartphone-based tool capable of analyzing up to 1,000 stomata per image, depending on species and magnification. It provides automated measurements of density, size, shape, and clustering index, offering instant insights into stomatal organization. PHENOM– A portable, modular microscope for real-time stomatal imaging. It delivers high-resolution imaging and can be seamlessly deployed across diverse environments.

Both solutions are non-destructive and integrate AI-driven automation, transforming stomatal analysis from a tedious manual task into a scalable, high-throughput process. Validated across multiple crops, our approach empowers researchers and breeders with unprecedented precision, from whole-leaf assessments to singlestoma resolution.

P5.12 SCALING UP: HARNESSING THERMAL AND OPTICAL DRONE TECHNOLOGIES FOR FIELD-SCALE ASSESSMENT OF WHEAT STOMATAL WATER FLUXES AND PHOTOSYNTHETIC CAPACITY

Wednesday 9th July 2025 15:45

Holly Croft (University of Sheffield, United Kingdom), Robert S Caine (University of Sheffield, United Kingdom), Pete M Berry (ADAS, United Kingdom), Kate E Storer (ADAS, United Kingdom)

h.croft@sheffield.ac.uk

The global demand for food is expected to increase, as populations grow and dietary patterns change, which will be compounded by a changing climate. Monitoring within-field crop performance in real-time will be crucial for sustainably enhancing agricultural productivity. Leveraging remote sensing (RS) technologies to model plant physiological traits and fluxes over space and time offers an opportunity for targeted management strategies.

In this study, key crop biochemical, physiological and structural trait measurements were collected in winter wheat (Triticum aestivum) across 24 plots at a variable nutrient (Nitrogen, Sulphur and Sugar) application field trial in Yorkshire, UK. Ground measurements included: Leaf Area Index (LAI), leaf-level gas exchange (photosynthesis, stomatal conductance), leaf chlorophyll/nitrogen and hyperspectral reflectance. Thermal and multispectral drone imagery was sampled between 10-12 GMT at a height of 10 m, giving a pixel size of 0.34 cm and 0.52 cm, respectively.

Results showed that combined nitrogen and sulphur application most positively impacted wheat performance, while sugar treatment often hindered performance. Nitrogen treatment resulted in larger stomatal size, which was strongly linked with higher LAI (R2 =0.83; P<0.001) and grain yield (R2 =0.85; P<0.001). Drone-acquired thermal data presented a good inverse relationship with stomatal conductance (R2 = 0.6; P < 0.01), capturing variations in water fluxes within and between plots. Optical data correlated strongly with photosynthetic traits (e.g. maximum carboxylation rate; Vcmax , R2 =0.76; P<0.001) and grain yield (R2 =0.94; P<0.001). This work demonstrates the potential of drone-based RS techniques in the spatially-continuous modelling of wheat performance; guiding fertilisation and irrigation strategies and maximising future yields.

P5.13 LARGE SCALE QUANTIFICATION

OF STOMATAL PATTERNING REVEALS POSITION SPECIFIC SPATIAL HETEROGENEITY AND FUNCTION

Wednesday 9th July 2025 16:00

Mengjie Fan (University of Essex NIAB, United Kingdom),

Keri Anne Moss (University of Essex, United Kingdom), Piotr Kasznicki (University of Essex, United Kingdom), Pratham Jindal (University of Essex, United Kingdom), Philip Davey (University of Essex, United Kingdom), Tracy Lawson (University of Essex, United Kingdom), Philippe P Laissue (University of Essex, United Kingdom) fan_mengjie@hotmail.com

Spatial heterogeneity in stomatal distribution across leaf surfaces significantly impacts photosynthetic efficiency and water utilization in plants. However, comprehensive quantification of this variability and its functional consequences remains limited in monocot crop species due to methodological constraints. A novel, efficient technique for in situ imaging and quantification of stomatal patterning across extensive leaf areas (>15cm2) was applied to examine spatial variation between leaf surfaces in Barley genotypes with varying stomatal density. Large scale quantitative analysis of stomatal revealed distinctive distribution patterns between leaf surfaces and toward leaf tip. This non uniform stomatal distribution proved fundamental for interpreting gas exchange measurements from both surfaces and their implications for carbon assimilation and transpirational water loss. These findings highlight the critical importance of understanding stomatal patterning function relationships for developing future crop varieties with enhanced water use efficiency.

P5.14 STOMATAL DISTRIBUTION BETWEEN LEAF SURFACES AND ITS RELATIONSHIPS WITH YIELD

Wednesday 9th July 2025 16:15

Hanna Hõrak (University of Tartu Institute of Technology, Estonia), Sára Babincová (University of Tartu Institute of Technology, Estonia), Ingmar Tulva (University of Tartu Institute of Technology, Estonia), Pirko Jalakas (University of Tartu Institute of Technology, Estonia), Kajal Samantara (University of Tartu Institute of Technology, Estonia), Patricia K Obinwanne (University of Tartu Institute of Technology, Estonia), Ingrid Bender (Centre of Estonian Rural Research and Knowledge, Estonia), Anne Ingver (Centre of Estonian Rural Research and Knowledge, Estonia), Ilmar Tamm (Centre of Estonian Rural Research and Knowledge, Estonia), Liina Jakobson (Centre of Estonian Rural Research and Knowledge, Estonia), Ebe Merilo (University of Tartu Institute of Technology, Estonia), Hanna Hõrak (University of Tartu Institute of Technology, Estonia)

hanna.horak@ut.ee

Stomata arise during leaf epidermal development as specialised structures for gas-exchange. Stomatal numbers, apertures and distribution between leaf surfaces can affect plant water balance, growth and yield. While the mechanisms that govern the formation

of stomata on the abaxial (lower) leaf surface are well-studied, how stomata develop on the adaxial (upper) leaf surface is poorly understood. How the distribution of stomata between leaf sides (stomatal ratio) is determined and adjusted in response to plant growth environment also remains unclear.

We addressed the effects of environmental conditions on adaxial and abaxial stomatal patterns in Arabidopsis thaliana. Acclimation to dry air or warm temperatures in Arabidopsis leaves manifests in substantial changes in stomatal density, small changes in stomatal ratio and minor, if any, changes in stomatal index. Thus, acclimation to growth environment may be mostly mediated by changes in cell expansion and less by alterations in leaf developmental program. We also explored the relationships between stomatal anatomical traits and yield in crops. In spring wheat that has relatively more stomata on the adaxial leaf surface, higher adaxial but not abaxial stomatal density was negatively associated with yield, especially under dry and warm conditions. In tomato that has less stomata on the adaxial than abaxial leaf surface, higher stomatal ratios were positively associated with yield. Thus, manipulation of adaxial stomatal densities and stomatal ratios may increase yield in both monocot and dicot crops. Understanding how adaxial stomatal development is controlled and how stomatal ratios are regulated is necessary to achieve this goal.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

P5.15 STOMATAL ANATOMICAL BASIS FOR CROP WATER USE EFFICIENCY

Yazen Al-Salman (Wageningen University Research, Netherlands)

yazen.al-salman@wur.nl

Water use efficiency (WUE) is gaining importance as a key trait to grow crops under water limited conditions. Stomata, the small pores on the leaf surface that govern water and carbon dioxide exchange, exert a key influence on WUE through their conductive capacity (gs). gs maximum and minimum is determined by the size and density of stomata, and operational gs by density and the operational pore. All these structural features are related based on allometric relationships that take into account the cost of investment in these features for the benefit of higher gas exchange rates. However, the effect these relationships have on WUE especially at different scales has not been fully explored. I present a simple modeling analysis of the effect of stomatal anatomy on WUE, and attempt to scale it using crop models by integrating it with optimality coefficients. Stomatal operational pore (aop) changes in response to environmental conditions. In leaves with high densities, maximum operational pores per surface area is smaller compared to lower density leaves, but high density leaves experience higher rates of increase in gs, and hence photosynthesis, for small changer in aop, making them more sensitive to environmental changes. Attempting to link these anatomical variations to stomatal sensitivity can provide more basis for incorporating stomatal variation in crop models and provide a mechanistic basis for selecting for genetic traits such stomatal density.

P5.16 INFLUENCE OF STOMATAL CHARACTERISTICS ON WINTER WHEAT GRAIN YIELD

Elena Ivandi (University of Tartu, Estonia), Ebe Merilo (University of Tartu, Estonia), Reine Koppel (Centre of Estoninan Rural Research and Knowledge, Estonia), Hanna Hõrak (University of Tartu, Estonia)

elena.ivandi@ut.ee

Stomata are small microscopic pores that regulate plant gas diffusion and water loss. An increase in food requirements and changes in climate conditions affect global food security. In addition, rising air temperatures and increases in droughts affect changes in stomatal traits and cause stress in plants. Wheat (Triticum aestivum), the most widely cultivated food crop, supplies one-fifth of the total calories of the world’s population. Therefore, it is important to understand how stomata respond to environmental stress factors. So far, it has been found that in wheat the adaxial surface has more stomata compared to the abaxial surface. Still, less is known about the relationship between stomatal traits and grain yield and how stomata behave in different environmental conditions. Field trials were carried out with 25 winter wheat varieties in two years (2023-2024) to investigate stomata anatomical characteristics and their impact on crop formation. Trials in growth chambers with nine winter wheat varieties were conducted under controlled conditions to investigate abaxial and adaxial stomatal sensitivity to changes in relative air humidity. Field trial results showed positive correlations between grain yield and leaf adaxial stomatal density in 2024 and also as two-year averages. In both years, stomatal densities and stomata guard cell length had a negative relationship. In growth chamber trials, adaxial side stomata were more sensitive to changes in air humidity than abaxial side stomata. By understanding how stomatal traits are related to grain yield, we could breed more suitable wheat varieties for changing climate conditions.

P5.17 THE EFFECT OF STOMATAL DENSITY ON NOCTURNAL AND DIURNAL BEHAVIOUR OF RICE PLANTS AT DIFFERENT CANOPY LEVELS.

Yifan Dong (University of Nottingham, United Kingdom), Lorna McAusland (Univerisity of Nottingham, United Kingdom), Ranjan Swarup (Univerisity of Nottingham, United Kingdom), Erik Murchie (Univerisity of Nottingham, United Kingdom)

stxyd9@exmail.nottingham.ac.uk

Stomatal pores regulate the CO2 uptake for photosynthesis and water loss through transpiration during daytime. Stomatal closure is normally thought to occur at night to minimize water loss in the absence of carbon uptake. Previous studies have found that overexpressing the rice epidermal patterning factor (OsEPF1) gene creates plants with reduced stomatal density, resulting in lower stomatal conductance and improved water use efficiency. However, measurements were conducted during the daytime on a single leaf basis. There remain uncertainties on the performance of OsEPF1 lines in terms of nocturnal stomatal behaviour, which has often been overlooked in traditional plant physiological studies. Many plant

species maintain partially open stomata during nighttime and in fact nocturnal transpirational water loss can be substantial. Here, we focus on the regulation of nighttime stomatal behaviour and whether the rice OsEPF1 would reduce nocturnal stomatal conductance further. Stomatal development has complex gene regulatory networks and it is unknown whether elevating the expression of EPF1 would equally impact different levels of the canopy where contrasting environmental conditions occur. This study also aims to investigate how different canopy positions are affected by overexpression of OsEPF1 in terms of reduced stomatal conductance and how this impacts WUE throughout the plant.

P5.19 THE HUNT FOR NEW GENES INVOLVED IN ADAXIAL STOMATAL DEVELOPMENT

Pirko Jalakas (Institute of Technology University of Tartu, Estonia), Nele M B”rziąa (Institute of Technology University of Tartu, Estonia), Patricia K Obinwanne (Institute of Technology University of Tartu, Estonia), Hanna H rak (Institute of Technology University of Tartu, Estonia)

pirko.jalakas@ut.ee

Stomatal pores mediate CO2 uptake for photosynthesis and water loss via transpiration. While most plants are hypostomatous with stomata present only on the lower (abaxial) leaf surface, model plant Arabidopsis is an amphistomatous plant that has a substantial number of stomata also on the upper (adaxial) leaf surface. Knowledge on stomatal development mostly originates from studies focused on abaxial stomata and very little is known of adaxial stomatal formation. Here, we screened the HEM (Homozygote EMS mutants) collection from the Versailles Arabidopsis stock center to find new genes involved in adaxial stomatal development. In the initial round, we pre-screened the collection by sampling one leaf per one plant per mutant line for adaxial and abaxial stomatal impressions. We found several potential lines with altered stomatal traits on adaxial and/ or abaxial leaf sides. The second round of re-testing is underway to verify the altered stomatal traits. Based on the mutant lines re-tested thus far, we have identified several lines that have increased adaxial stomatal density, increased number of precursors on the adaxial leaf side, and/or increased stomatal ratio. Of the verified lines, no obvious candidate mutation has been identified based on the available sequence data accessible in the ATHEM database. Further work is required to determine which new genes associated with adaxial stomatal formation might be mutated in these lines.

P5.20 IMPORTANCE OF STOMATAL PATCHINESS IN THE BIOLOGICAL RESPONSE TO WATER STRESS

Guillaume FORGET (University of Bordeaux, France), Sylvain DELZON (University of Bordeaux INRAE UMR BIOGECO, France), Régis BURLETT (University of Bordeaux INRAE UMR BIOGECO, France), Jérôme JOUBES (University of Bordeaux CNRS UMR LBM, France), Tracy LAWSON (School of Life Sciences University of Essex, United Kingdom) guillaume.forget@u-bordeaux.fr

Droughts are increasing in frequency and intensity across all biomes, affecting plant survival and productivity. During drought, the stomatal response, although effective against water loss, is detrimental to CO2 uptake, highlighting the trade-off between transpiration and assimilation. Stomatal patchiness, defined by a non-uniform distribution of stomatal openings across the leaf surface, represents an emerging collective behaviour that optimises gas exchange in response to environmental stimuli. Advanced imaging techniques, such as thermal and chlorophyll fluorescence imaging, have become essential methods to visualise and quantify this phenomenon. This research investigates dynamics of stomatal patchiness along drought, examining both long-term and short-term stomatal responses using dual imaging. Our results show consistent patterns in thermal and quantum efficiency in relation to stomatal conductance, with both measures showing variability at the onset of stress, indicating some plasticity in the face of changes in water potential optimising gas exchange. Stomatal patchiness emerges as a complex, multiscale phenomenon characterised by the fragmentation of macroscale leaf patches into distinct unit patches. This hierarchical organisation is manifested by intra-patch dynamics as a short-term response to environmental conditions, but decreases in the long term as water stress increases. The relationship between patch-level behaviour and overall leaf physiology highlights the biological significance of this spatial heterogeneity in plant water regulation strategies, leading to a better understanding of the mechanisms underlying drought resistance. Understanding stomatal patchiness and its role in drought response is crucial for developing strategies to enhance plant resilience to water stress in the context of climate change.

P5.21 STOMATAL KINETICS: LINKING GENETICS TO PHYSIOLOGY AND ENVIRONMENT SCENARIO

Maria Papanatsiou (University of Glasgow, United Kingdom), Anna Amtmann (University of Glasgow, United Kingdom), Anna Palombo (University of Glasgow, United Kingdom)

maria.papanatsiou@glasgow.ac.uk

Stomata enable CO2 uptake, transpiration and release of organic volatiles. Plants have evolved complex regulatory systems to open and close stomata in response to environmental signals1 . However, the speed of stomatal responses does not always match the frequency of natural environment fluctuations, which leads to sub-optimal CO2 assimilation or unnecessary water loss2

Previous work provided proof-of-principle that better kinetic synchronization resulted in biomass gains and water use efficiency3 . Translation from model to crop requires identification of the endogenous genetic loci determining stomatal kinetic traits, and labto-field translation requires understanding of benefits and trade-offs in diverse environments.

Taking advantage of LICOR-IRGA technology4 in our GasPP Facility5,6 , we recorded stomatal conductance in 200 fully-sequenced Arabidopsis accessions. Using modelling, GWAS algorithms and advanced bioinformatics, we have mapped the dynamic traits to genetic variation, and prioritised candidate genes by linkage, coexpression, cellular localisation and functional annotation. The analysis revealed that individual kinetic parameters such as rates of opening and closing are independently controlled by different loci and distinct advantages in different combinations of light and humidity. This research provides a foundation for adjusting stomatal kinetics to optimise plant performance for a variety of environment scenarios.

1. Schroeder, J. I., et al. Annual review of plant physiology and plant

molecular biology 52, 627–658 (2001).

2. Lawson, T. & Blatt, M. R. Plant Physiology 164, 1556–1570 (2014).

3. Papanatsiou, M. et al. Science 363, 1456–1459 (2019).

4. Busch, F. A. et al. Plant, cell Environment. 47, 3344–3364 (2024).

5. https://www.gla.ac.uk/schools/molecularbiosciences/research/ gaspp/

6. https://phenomuk.org/platform/

P5.22 GROWTH AIR HUMIDITY, STOMATAL DENSITY, AND LEAF SIDES

Ingmar Tulva (University of Tartu, Estonia), Pirko Jalakas (University of Tartu, Estonia), Elena Ivandi (University of Tartu, Estonia), Hanna Hõrak (University of Tartu, Estonia)

ingmar.tulva@ut.ee

The mechanisms governing differences between leaf surfaces in stomatal formation are poorly understood. By theoretical considerations, preferential allocation of stomata to upper leaf surface may increase photosynthetic potential, at the cost of water stress susceptibility. In a series of experiments with Arabidopsis plants grown under moderately altered RH, we demonstrated that 1) mutations affecting stomatal openness and density can be combined with no interference; 2) growing under low RH results in increased stomatal density (SD) SD due to diminished leaf expansion; 3) changes in stomatal index are subtle but lead to consistent increase in adaxial/ abaxial stomatal density ratio under reduced RH; 4) above-ground growth was negatively affected by both low RH and increased SD, but not increased stomatal conductance per se; 5) a significant proportion of stomata on the abaxial (but not adaxial) leaf side of the epf1/2 mutant lines remain partially developed, more so in the low RH treatment; 6) while stomatal size stays in negative relationship with SD within any given genotype, the drastically increased SD in epf1/2 mutants is not associated with decreased stomatal dimensions. We argue that stomatal formation, including allocation between leaf sides, is little affected by water preservation considerations in our experimental conditions and is more geared towards maximising CO2 assimiation, while stomatal formation itself is a costly burden on the plant. Selection towards greater amphistomaty could be a more promising path for agricultural plants than overall greater stomatal density.

P7: PLANT PHENOMICS: BEYOND THE PLATFORMS

ORGANISED BY: BERTRAND MULLER (INRAE)

P7.19 EXAMPLES OF USING SYNTHETIC DATA FROM BIOPHYSICAL AND STRUCTURAL MODELS TO TRAIN ALGORITHMS FOR PLANT AND CROP PHENOTYPING

Thursday 10th July 2025 09:00

Scott Chapman (School of Agriculture and Food Sustainability

The University of Queensland, Australia)

cott.chapman@uq.edu.au

Opportunities for increased rate of progress in the use of phenotyping have greatly been enhanced by improvements in machine-learning (ML) models for both image analytics and for time-series type analyses. These two classes of ML problems have great utility in plant phenotyping where solutions have been constrained by difficulties in generating sufficient training data. In image analytics, training data is expensive as annotation of images is labour-intensive. For this class of ML problems, transfer learning and domain adaptation concepts permit synthetic images to be converted to ‘real’ images at low cost, with these images being used to enhance the ML algorithms to identify plant parts and organs. Synthetic data from bio-physical models also has a role in ML. In our work, we use bio-physical models to train ML algorithms to invert satellite reflectance data and estimate crop traits such as crop leaf area index and biomass over time more efficiently than do benchmark naïve inversions based on brute-force parameterisation. In designing further improvements to ML models, we also apply techniques referred to as ‘physics-informed machine learning’ (PIML) which aim to further constrain the ML inversion models to behave within known biological relationships.

APPROACHES

Thursday 10th July 2025 09:30

Francois Tardieu (LEPSE INRAE France, France), Claude Welcker (LEPSE INRAE France, France), Jugurta Bouidghaghen (Arvalis, France)

francois.tardieu@inrae.fr

Breeding for resilience to climate change requires considering adaptive traits such as stomatal conductance and growth responses

to environmental conditions, but these traits are difficult to select for. 50 years of maize breeding increased yield two-fold in dry fields, but affected neither stomatal conductance nor growth sensitivity to drought, in opposition to plant architecture that was improved with generations of selection. Stomatal conductance measured indoor was nevertheless positively related to grain yield, but in fields with favourable conditions only. Plant architecture had a positive effect in all conditions. Hence, selection for yield probably favoured traits that positively affect yield regardless of environmental conditions, such as plant architecture, but not traits with unstable effect on yield. New methods of selection are therefore required to improve these traits. Robotized indoor phenotyping allows measuring them at high throughput for speed breeding, but is often considered as non-relevant for field conditions. We show that adaptive traits can be inferred in different fields, based on genotypic values obtained indoor and on environmental conditions in each considered field. The modelling of environmental effects allowed translation from indoor to fields, but also from one field to another field. Indeed, values of considered traits matched between indoor and field conditions. Genomic prediction resulted in adequate ranking of genotypes for the tested traits, although with lesser precision for elite varieties presenting reduced phenotypic variability. Hence, it distinguished genotypes with high or low values for adaptive traits, conferring either spender or conservative strategies for water use under future climates.

P7.6 PHOTOSYNTHESIS PHENOTYPING UNDER FUTURE FIELD CONDITIONS: THE ROLE OF CO₂ AND LIGHT COMPETITION.

Thursday 10th July 2025 09:45

Onno Muller (Forschungszentrum Juelich, Germany)

o.muller@fz-juelich.de

Field phenotyping platforms have been developed in Free Air CO2 Enrichment (FACE) experiments (BreedFACE) and integrated into Agri-Photovoltaic systems as part of the German Plant Phenotyping Network and the BioökonomieREVIER project. These platforms modify key drivers of photosynthesis, such as CO2, light, and water. In this study, we report on the photosynthetic response to changing environmental conditions within these platforms.

Photosynthesis was quantified using both active and passive chlorophyll fluorescence (ChlF). Active ChlF was measured using the Light-Induced Fluorescence Transient (LIFT) method, while spectrally derived Solar-Induced Fluorescence (SIF) was obtained using the FLOX system. In winter wheat and sugar beet, we observed seasonally dependent acclimation of ChlF to elevated CO2

levels (600 ppm) in BreedFACE. In chlorophyll-deficient soybean, acclimation to reduced light availability under Agri-Photovoltaics resulted in an increase in chlorophyll content per leaf area and enhanced non-photochemical quenching.

Additionally, we report on positioning systems that facilitate highthroughput field phenotyping, utilizing custom-built mobile bridges and rail systems in BreedFACE and Agri-Photovoltaics, respectively. While this study focuses on photosynthesis, these universal positioning systems enable broader applications by integrating additional methods and plant traits to assess plant growth under future field conditions.

P7.7 HOW THE REPRODUCTIVE TRANSITION ORGANIZES THE DIVERSITY OF CANOPY ARCHITECTURE IN MAIZE

Thursday 10th July 2025 10:00

Kristian Johnson (INRAE UMR759 LEPSE, France), Aurélien Besnier (INRAE UMR759 LEPSE, France), Christian Fournier (INRAE UMR759 LEPSE, France), Randall J Wisser (INRAE UMR759 LEPSE, France)

kristian.johnson@inrae.fr

The reproductive transition defines a shift in the production of leaves to inflorescences. In maize, the timing of this transition determines what the final number of leaves will be and where the female inflorescence (the ear) will be positioned along the stem, which together shape the canopy architecture. Although specific relationships between reproductive transition and canopy organization have been carefully dissected, previous studies have focused on individual organs and examined only a few genotypes. We aim to develop a more comprehensive model relating dynamics in the development of all phytomer components (stem and leaf) and explore genotypic variation in the effect of the floral transition on canopy architecture. In a highthroughput phenotyping platform, we experimented with variation in the timing of reproductive transition—natural genetic variation and variation induced by a nightbreak treatment—to demonstrate that the influence of reproductive transition on canopy organization is robust. Final organ dimensions and leaf number were determined by dissection, whereas stem and leaf development were tracked over the course of the experiment with computer vision. Understanding the interaction between the reproductive transition and canopy architecture is crucial for phenotyping diversity in maize and important for mechanistic modeling of radiation capture and crop yield.

P7.8 INFLUENCE OF SECONDARY GROWTH, APOPLASTIC BARRIERS AND DEVELOPMENTAL ANATOMY ON ROOT HYDRAULIC PROPERTIES:

}IN SILICO ANALYSIS

Thursday 10th July 2025 10:15

Marco D’Agostino (UCLouvain, Belgium), Rémy Schoppach (-, Belgium), Adrien Heymans (SLU, Sweden), Valentin Couvreur (UCLouvain, Belgium), Guillaume Lobet (Uclouvain, Belgium)

marco.dagostino@uclouvain.be

The efficiency of water uptake by plants from the soil is shaped by root system architecture and influenced by anatomical features, such as hydrophobic barriers and aerenchyma formation. While root architecture determines the spatial distribution of roots, root anatomy influences local hydraulic properties like radial and axial conductances. Water movement through root tissues occurs via apoplastic and cellto-cell pathways. Apoplastic flow can be blocked by hydrophobic barriers like lignin and suberin, while cell-to-cell flow is regulated by plasmodesmata and aquaporins. These features collectively define radial conductivity and axial conductance, which are crucial for estimating a plant’s water uptake capacity.While these hydraulic properties have been extensively studied in monocotyledons, there is a knowledge gap regarding woody dicotyledons. Dicots present significant anatomical differences, including secondary growth and different hydrophobic deposition patterns, which can substantially impact hydraulic dynamics.Here we use computational models to investigate how anatomical features influence root hydraulic properties in tomato (used as a model species). We characterized the root anatomy of 30-day-old tomato plants and developed a secondary growth module to a generator of root anatomy. We also monitored suberin and lignin deposition in the endodermis and exodermis, establishing a spatiotemporal atlas of their maturation, coupled with recent litterature data. We used a hydraulic solver of root anatomy hydraulics to estimate local hydraulic properties and conducted in silico analysis to assess the impact of various factors on root hydraulic conductance and water uptake profiles.This research provides valuable insights into the hydraulic dynamics of dicotyledonous roots.

P7.9 ENHANCING VARIETY EVALUATION: INTEGRATING PHENOTYPING, MODELING, AND ENVIROTYPING FOR ADAPTATION TOSPECIFICAGROENVIRONMENTAL SCENARIOS

Thursday 10th July 2025 11:00

Boris Parent (INRAE-LEPSE, France)

boris.parent@inrae.fr

As agricultural practices diversify and climatic variability increases, traditional variety evaluation methods struggle to capture genotypespecific advantages across diverse agro-environments. The historical focus on a limited number of elite varieties does not align with the need for locally adapted cultivars tailored to specific climate scenarios and management practices.

This talk explores how integrating phenotyping, modeling, and envirotyping can improve the evaluation and prediction of genotype performance under variable agro-climatic conditions. Key approaches include (i) model-based envirotyping to cluster environments based on plant-perceived conditions, (ii) crop modeling with highthroughput phenotyping-derived variety parameters, and (iii) genomic prediction for new genotypes in unexplored conditions. While these methods have been academically demonstrated, their application to operational variety evaluation remains underdeveloped.

By trying to bridge this gap, we could refine registration and recommendation processes to better align with the needs of farmers and climate-resilient agriculture.

P7.10 WITHIN-FIELD CROP GROWTH HETEROGENEITY FROM A MULTI-YEAR CROP ROTATION PERSPECTIVE

Thursday 10th July 2025 11:30

Tom Kenda (Earth and Life Institute UCLouvain, Belgium), Xavier Draye (Earth and Life Institute UCLouvain, Belgium), Pierre Defourny (Earth and Life Institute UCLouvain, Belgium)

tom.kenda@uclouvain.be

To identify optimal combinations of species, genotypes and management practices, plant scientists are considering moving their experiment from controlled environment to the fields. One of the major challenge is to address the spatial and temporal variability of environmental conditions within fields, which have a significant impact on plant growth in farmers’ fields.

This study aims to characterise the within-field spatial and temporal variability of crop growth. To achieve this, it will (1) develop a method to represent the spatial heterogeneity of crop growth across different seasons and crop types, (2) establish criteria to distinguish heterogeneous fields from homogeneous ones, and (3) identify some of the drivers of heterogeneity (4) while investigating how these patterns evolve over time. To do so, we leverage on 8 years of Leaf Area Index time series derived from the Sentinel-2 satellite over 45 000 parcels across the Walloon region (Belgium).

The results of the study are used to adapt the method of Blackmore (2000) to delineate management zones. These zones correspond to the following: (1) high productivity stable zone across years, (2) low productivity stable zone or (3) unstable zone across years.

The versatility of the method extends its applicability to different agricultural settings and crops at very low (or no) cost to the end user. The resulting maps could guide dynamic agricultural practices towards greater sustainability, including irrigation, fertilisation and spraying management, and could also provide opportunities for new soil sampling designs and targeted in-field phenotyping.

P7.11 PHENOTYPING PLANT RESPONSES TO LIGHT QUALITY WITH COLOR GRADIENTS

Thursday 10th July 2025 11:45

Pierre Lejeune (University of Liège, Belgium), Anthony Fratamico (GDTech S.A., Belgium), Frédéric Bouchez (University of Liège, Belgium), Pierre Tocquin (University of Liège, Belgium), Claire Périlleux (University of Liège, Belgium)

plejeune@uliege.be

Background

The increasing demand for local food production is fueling high interest in the development of controlled environment agriculture. In particular, LED technology brings energy-saving advantages together

with the possibility to manipulate plant phenotypes through light quality control. However, optimizing light quality is required for each cultivated plant and specific purpose.

Findings

In this work, it is shown that the combination of LED gradient setups with imaging-based, non-destructive plant phenotyping constitutes an interesting screening tool with the potential to improve speed, logistics, and information output. To validate this concept, an experiment was performed to evaluate the effects of Red:Blue ratio on seven plant species: Arabidopsis thaliana, Brachypodium distachyon, Euphorbia peplus, Ocimum basilicum, Oryza sativa, Solanum lycopersicum, and Setaria viridis. Plants were exposed during thirty days to the light gradient and showed significant, but speciesdependent, responses in terms of dimension, shape, and color. A time series analysis of phenotypic descriptors highlighted growth changes but also transient responses of plant shapes to the Red:Blue ratio. A workflow for generating simple intuitive graphical representation of complex phenotypic data is proposed.

Conclusion

This approach, which generated a large reusable dataset, can be adapted for addressing specific needs in crop production or fundamental questions in photobiology.

P7.12

TIME TO FLOWERING AND FLOWERING DURATION IN MUNGBEAN ARE UNRELATED PHYSIOLOGICAL TRAITS WITH INDEPENDENT GENETIC CONTROLS

Thursday 10th July 2025 12:00

Caitlin E Dudley (Ueensland Alliance for Agriculture and Food Innovation The University of Queensland, Australia), Shanice Van Haeften (Queensland Alliance for Agriculture and Food Innovation The University of Queensland, Australia), Samir Alahmad (Queensland Alliance for Agriculture and Food Innovation The University of Queensland, Australia), Eric Dinglasan (Queensland Alliance for Agriculture and Food Innovation The University of Queensland, Australia), Lee T Hickey (Queensland Alliance for Agriculture and Food Innovation The University of Queensland, Australia), Hannah Robinson (Hochschule Geisenheim University Department of Plant Breeding, Germany), Thomas Noble (Queensland Department of Primary Industries, Australia), Christine Beveridge (School of Agriculture and Food Sustainability Faculty of Science The University of Queensland, Australia), Michael Udvardi (Queensland Alliance for Agriculture and Food Innovation The University of Queensland, Australia), Karen Massel (Queensland Alliance for Agriculture and Food Innovation The University of Queensland, Australia), Elizabeth A Dun (School of Agriculture and Food Sustainability Faculty of Science The University of Queensland, Australia), Millicent R Smith (Queensland Alliance for Agriculture and Food Innovation The University of Queensland, Australia)

c.dudley@uqconnect.edu.au

Mungbean (Vigna radiataL.), a valuable sub-tropical grain legume, typically exhibits an extended, asynchronous flowering window, complicating harvest and increasing vulnerability to abiotic stress. To facilitate breeding efforts, we conducted multi-environment trials

across four field experiments in Queensland, Australia (2022-2023), evaluating days to flowering (DTF) and the novel trait flowering duration (FD). Extensive phenotypic variation was observed for DTF (35-70 days after sowing) and FD (20-60 days after sowing), with genotype-by-environment interactions influencing both traits, particularly FD. No relationship was evident between DTF and FD across environments. Genome-wide association studies identified eight quantitative trait loci (QTL) for DTF and one for FD, with no overlapping QTL, further demonstrating that these traits are genetically independent. The accumulation of early or late alleles at DTF QTL explained variations in flowering time, providing actionable insights for breeding programs.

To further dissect flowering mechanisms, controlled environment studies under varying photoperiods (short, neutral, and long) assessed how photoperiod influences flowering initiation, duration, and overall behaviour across a diverse panel of breeding germplasm and genebank accessions. These experiments, combined with shoot tip dissection examined shifts in flowering characteristics underpinning resilience and adaptability and the transition from vegetative to reproductive stages in mungbean.

Our integrated field and controlled-environment approach offers novel pathways to improve mungbean for enhanced food security, environmental sustainability, and climate resilience. This foundational understanding of mungbean flowering traits provides a mechanistic basis for developing varieties with synchronised and optimised flowering patterns, crucial for improving adaptation to diverse agricultural environments under climate change.

P7.13 FROM LIGHT TO BIOMASS: USING DYNAMIC PHOTOSYNTHESIS DATA TO IMPROVE BIOMASS PREDICTIONS

Thursday 10th July 2025 12:15

Junita Solin (Jan IngenHousz Institute, Netherlands), Tom Theeuwen (Jan IngenHousz Institute, Netherlands), Martin Boer (Wageningen University Research, Netherlands), Fred Van Eeuwijk (Wageningen University Research, Netherlands)

junita.solin@jan-ingenhousz-institute.org

Genetic variation in photosynthesis suggests opportunities for yield improvement and breeding strategies. When photosynthesis limits yield is still an open question. Photosynthesis has been extensively studied under low-throughput, growth-chamber experiments, but only recently imaging platforms have allowed us to measure photosynthesis continuously, under dynamic environmental conditions. In contrast to agronomic traits such as plant height or projected leaf area, which typically follow well-defined patterns and are directly related to yield, photosynthetic variables exhibit more complex patterns. This complexity presents challenges in longitudinal modelling and linking photosynthesis to yield.

Using the phenotyping platform in NPEC (Netherlands Plant Ecophenotyping Centre), we could phenotype the photosynthetic activity of 394 Arabidopsis inbreds every 15 minutes during the daytime (8.00-20.00) over 12 days. The climate chamber is set to a series of dynamic lighting and temperature treatments that mimic natural field conditions. We used smoothing splines to estimate the temporal and genetic trajectories of various photosynthesis variables. Our early results show that dynamic photosynthesis variables changed diurnally with the amplitude varying for different genotypes. Following the smoothing, we extracted curve parameters and used them to predict biomass, our proxy for yield. Overall, this framework will provide an

effective approach to leverage temporal photosynthesis variables to predict end-point traits while also understanding the key processes of photosynthesis that may limit biomass or yield.

P7.14 ARTIFICIAL INTELLIGENCE IN PLANT PHENOTYPING – TOWARDS ENDTO-END GXEXM MODELLING

Friday 11th July 2025 09:30

Ioannis N Athanasiadis (Chair of Artificial Intelligence Wageningen University and Research, Netherlands)

Ioannis.Athanasiadis@Wur.Nl

Artificial intelligence methods are a key enabler in high throughput phenotyping. With AI, we can phenotype plants at large scale, more accurately, and often faster than humans. However, there have been fewer attempts in incorporating AI in modelling genotype by environment by management interactions. This talks offers a reflection on how AI methods can advance GxExM modelling, starting with some motivating examples from the PHENET project: How AI can improve estimating yields in multi-environment breeding trials? How hybrid models, combining neural networks with process based models, can improve phenology estimation models? And finally how machine vision advances can be combined with 3d structural models towards crop growth digital twins? We conclude with a research agenda for the years to come and some open problems in this emerging field.

P7.15 GENERIC NON-SUPERVISED VEGETATION FOREGROUND EXTRACTION BASED ON MONOCULAR RGB IMAGING; APPLICATION TO ARBO AND VITICULTURE

Friday 11th July 2025 10:00

David Rousseau (Université d’Angers, France), Herearii Metuarea (Université d’Angers, France), Abdoul-Djalil Ousseini (INRAe, France), Morgane Roth (INRAe, France), Eric Duchêne (INRAe, France), Jacem Ben-Hamden (INRAe, France)

david.rousseau@univ-angers.fr

Automated vegetation analysis is crucial for precision agriculture, particularly in arboriculture and viticulture, where accurate plant segmentation enhances monitoring, yield estimation, and disease detection. Traditional vegetation segmentation approaches often rely on supervised learning, requiring extensive labeled datasets, which are costly and time-consuming to produce. In this presentation, we introduce a generic, non-supervised vegetation foreground extraction method designed for tree and vine crops, eliminating the need for labeled data while maintaining high segmentation accuracy despite operating in a non-controlled environment. In the literature, vegetation foreground extraction is mostly based on LIDAR or Stereo Vision which enables it to cope with the non uniform lighting. We demonstrate the possibility to achieve high quality without the need of such 3D sensors via the sole use of monocular RGB imaging and by leveraging on the state-of-the-art in deep learning foundation models.

P7.16 INCREASING WHEAT PHENOTYPIC PREDICTION THROUGH A UNIFIED FRAMEWORK INTEGRATING HIGHTHROUGHPUT PHENOTYPING, GENOMICS, AND CROP GROWTH MODEL

Friday 11th July 2025 10:15

Shouyang Liu (Nanjing Agricultural University, China), Dong Cai (Nanjing Agricultural University, China), Chen Zhu (Nanjing Agricultural University, China), Jianhui Wu (Northwest AF University, China), Dejun Han (Northwest AF University, China), Yanfeng Ding (Nanjing Agricultural University, China), Dong Jiang (Nanjing Agricultural University, China), Benoit De Solan (ARVALIS, France), Fred Baret (INRAE, France), Samuel Buis (INRAE, France), Pierre Martre (INRAE, France)

shouyang.liu@njau.edu.cn

Accurately predicting phenotypic variation across diverse genotypes and environments is vital for accelerating crop improvement. Process-based crop growth models can capture complex genotype–by–environment interactions, yet estimating genotype-specific parameters typically relies on labor-intensive measurements. Here, we developed a data assimilation pipeline that integrates highthroughput phenotyping with the SiriusQuality wheat model to predict phenology and yield. In multi-year trials (six years) involving seven wheat varieties in France, we simultaneously assimilated the dynamics of the fraction of intercepted photosynthetically active radiation, heading dates, and final yield. This enabled single-step estimation of 12 key genotypic parameters controlling both phenology and yield. We compared a Bayesian inference method with a lookup table (LUT)-based inversion approach and found the LUT method to be faster and more accurate in both simulated and field experiments. We then applied this framework to multi-environment trials in China with 565 varieties across 13 site–year experiments. Using leave-neenvironment-out cross-validation, we calibrated six phenological parameters and achieved prediction errors of about three days for heading and flowering dates. A genome-wide association study of these phenological parameters (including Phyllochron, Response of vernalization rate to temperature, and Daylength response of leaf number) identified major quantitative trait loci (QTL). We further built a GBLUP-based model that incorporated these QTL to estimate the phenological parameters. Overall, our study establishes a robust framework that integrates high-throughput phenotyping, a crop growth model, and genomic data. This approach offers a powerful tool for enhancing the accuracy and efficiency of large-scale multienvironment germplasm evaluations.

P7.17

Friday 11th July 2025 10:30

Lamis Abdelhakim (PSI (Photon Systems Instruments), Czech Republic), Hans Tietze (University of Potsdam, Germany), Barbora Pleskačová (PSI (Photon Systems Instruments), Czech Republic), Ayelet Kurtz-Sohn (Agricultural Research Organization, Israel), Eyal Fridman (Agricultural Research Organization, Israel), Klára Panzarová (PSI (Photon Systems Instruments), Czech Republic), Zoran Nikoloski (University of Potsdam, Germany)

Abdelhakim@psi.cz

Harvest-related traits are key agronomic traits for cereal crops. Understanding the influence of abiotic stress on yield and the ability to find the most predictive traits for final yield are important for understanding and characterizing crop resilience strategies. Using a high spatial and temporal phenotyping approach with multiple imaging sensors we monitored the growth dynamics of plants and assessed their physiological responses throughout development until reaching the maturity stage under control and drought conditions. Here we present a dataset comprising 145 traits over 70 time points under two conditions for six barley lines including elite, cultivated, and wild lines. We applied advanced data analysis using machine learning approaches for effective integrative visualisation and subsequent modelling. The main objectives of this study were to identify distinct traits that differentiate drought-stressed from well-watered plants and to accurately predict harvest traits. Using a classification model, we observed an accurate separation between control and drought treatments and ranked the tolerance levels of different lines. For the harvest prediction models, we evaluated all time points under different watering regimes compared with models using only early time points and determined the importance of traits. Finally, we analysed the variance components of highly predictive traits and identified which traits are mostly driven either by genetic, environmental or time components. With the applied modelling approach, we were able to predict the harvest-related traits and pinpoint the most predictive traits at specific time points. Identifying predictive traits early in the developmental stage can help breeders find stress-tolerant traits of interest.

P7.18 UNMANNED AERIAL SYSTEM (UAS)-BASED PHENOTYPING FOR SELECTION OF SPINACH VARIETIES

Friday 11th July 2025 10:45

Juan Enciso (Texas AM AgriLife Research, United States), Ittipon Khuimphukhieo (Kalasin University, Thailand), Jose Carlos Chavez (Texas AM AgriLife Research, United States), Carlos Avila (Texas AM AgriLife Research, United States), Ainong Shu (University of Arkansas, United States), Waldo Ojeda (University of Chaping, Mexico)

Juan.Enciso@ag.tamu.edu

Unmanned aerial systems (UAS) have emerged as an efficient tool to perform crop growth analysis and yield prediction. The objectives of this study were to assess if the fusion between vegetation indices (VIs) and textural features (TFs) could improve the spinach biomass prediction ability using year-cross validation. In addition, we further leveraged the UAS feature to perform spinach growth analysis. A 2-year experiment (Exp.1 and Exp.2) was conducted using a randomized complete block design. One UAS flight mission was carried out before harvest, and yield was manually harvested at

Exp. 1, while nine flight missions were implemented in addition to four biomass samples for the Exp. 2. The UAS data and fresh yield of spinach from the Exp. 2 were used to establish machine learning models, and also to perform growth analysis, while the data from Exp. 1 was used to validate the accuracy of the prediction models. A fusion of vegetation indices and textural features significantly improved the prediction ability of the models using year-cross validation. Among the four models, lasso regression showed the highest prediction accuracy. In addition, normalized difference red edge index (NDRE) − based growth nondestructively revealed the timing when yield decay happened. Moreover, a significant correlation between the maximum NDRE growth rate and yield was observed, suggesting that NDRE at the early growth stages reflects the final spinach yield. Our study highlights the potential of UAS, along with machine learning and growth function, to predict yield and to describe the growth of spinach.

P7.4 EXPLORING AVENUES TO INCREASE THE RELEVANCE OF HIGH-THROUGHPUT PLANT PHENOTYPING

Friday 11th July 2025 11:30

Hendrik Poorter (Horticulture and Product Physiology Wageningen University and Research, Netherlands)

h.poorter@gmail.com

Traditional plant phenotyping for physiology, morphology, chemical composition and plant or seed biomass is labor-intensive and difficult to scale up. Like other scientific fields, it has benefited from automation, both in controlled environments and in the field. For practical reasons – particularly the need to handle the large numbers of plants required for genetic analysis - choices generally have been to measure plants fast and non-destructively. As a result, the traits being measured have shifted from ‘hard-core variables’ such as CO2 uptake rates or total plant biomass, to proxies like fluorescence or digital biomass. In this talk, I will discuss some of the implications of this shift for interpretating experimental results.

Another challenge is the gap that often exists between results obtained in controlled conditions and those observed in the field. This issue becomes even more pressing when using expensive highthroughput phenotyping equipment. Addressing this discrepancy requires greater attention from the phenotyping community. We will also explore strategies to bridge this gap.

P7.20 HIGH-THROUGHPUT PHENOTYPING

RADIATION USE EFFICIENCY OF WHEAT CROPS IN THE FIELD

Friday 11th July 2025 12:00

Chen Zhu (Nanjing Agricultural University, China), Shouyang Liu (Nanjing Agricultural University, China), Dong Jiang (Nanjing Agricultural University, China), Yanfeng Ding (Nanjing Agricultural University, China), Fred Baret (INRAE, France), Pierre Martre (INRAE, France)

chenzhu@njau.edu.cn

Optimizing radiation use efficiency (RUE) is essential for increasing wheat crop yields. Conventional RUE measurements rely on the dynamics of above-ground biomass (AGB) and intercepted photosynthetic active radiation (IPAR). It therefore suffers from low throughput, hindering large-scale phenotyping of RUE for crop improvement. In this study, we propose a high-throughput phenotyping method utilizing multi-view RGB cameras to estimate RUE in wheat crops in the field. Initially, a deep semantic segmentation model assesses the green fraction (GF) from zenith angle 0° and 45° RGB images, denoted as GF(0°) and GF(45°). Subsequently, employing the digital plant phenotyping platform from our prior work, we generate a synthetic dataset with 10,000 simulations, including GF(0°) and GF(45°), along with the corresponding green area index (GAI) and fraction of intercepted PAR (FIPAR). This synthetic dataset facilitates training a Gaussian Process Regression model to estimate GAI and FIPAR based on GF(0°) and GF(45°). Consequently, the accumulation of intercepted PAR is computed from FIPAR dynamics, and AGB is estimated from GAI using the allometric growth law developed in our previous work. Finally, RUE is estimated by fitting a linear regression between biomass dynamics and accumulated IPAR. Our high-throughput phenotyping method for RUE was implemented on a wheat population exceeding 500 genotypes across three sites. This approach successfully identified key genes strongly associated with the photosynthetic process, validating the reliability of our algorithm. In summary, our algorithm, requiring observations from only two RGB cameras, significantly enhances feasibility and throughput for application in wheat breeding programs.

P7.21 FROM BIOCHEMISTRY TO COMPUTER VISION: ADVANCING NON-DESTRUCTIVE

TOMATO STRESS MONITORING WITH AI

Friday 11th July 2025 12:15

Giorgia Del Cioppo (University of Molise, Italy), Sylvain Poque (University of Helsinki - National Plant Phenotyping Infrastructure (NaPPI), Finland), Simone Scalabrino (University of Molise, Italy), Kristiina Himanen (University of Helsinki - National Plant Phenotyping Infrastructure (NaPPI), Finland), Gabriella Stefania Scippa (University of Molise, Italy), Dalila Trupiano (University of Molise, Italy)

g.delcioppo@studenti.unimol.it

Tomato (Solanum lycopersicum) is among the world’s most important crops, yet its cultivation is increasingly threatened by climate change. Traditional destructive analyses can accurately classify stress symptoms, but novel Artificial Intelligence driven approaches offer promising solutions for early abiotic stress detection through computer vision. This study integrates image-derived traits with laboratory-based physiological parameters within a machine learning framework to classify, identify, and quantify the responses of two dwarf tomato cultivars (Microtom and Tiny Tim) under longterm drought and salinity conditions, at increasing intensities. RGB and PAM chlorophyll fluorescence imaging were combined with biochemical assays, including pigment content (chlorophylls and carotenoids), malondialdehyde (MDA) content, relative water content (RWC), and electrolyte leakage (EL). Notably, color indices exhibited significant shifts in pixel distribution peaks across treatments, highlighting their sensitivity to stress-induced physiological changes. Moreover, cultivar-specific differences at 7 and 14 Days After Stress

(DAS) suggested genetic variability in stress responses. Based on these multi-source features, various decision tree-based models were trained, tested, and evaluated. The binary presence/absence classifier achieved the highest accuracy (precision=0.87, recall=0.97, F-measure=0.92), outperforming more complex models designed to differentiate and quantify stressors. As classification complexity increased, image-derived features—particularly geometrical (e.g., area, perimeter), colorimetric (e.g., chroma indices), and fluorescencebased traits (e.g., NPQ)—became more influential, while laboratoryderived attributes (e.g., RWC) had reduced importance. These findings underscore the potential of digital traits as reliable, non-destructive indicators for early stress monitoring in tomato plants. Future research will refine and generalize this AI-based framework to enhance its robustness, scalability, and applicability in field studies.

P7.22 INTEGRATING 3D SENSING AND AUTONOMOUS ROBOTICS FOR ENHANCED GRASSLAND MONITORING

Friday 11th July 2025 12:30

Louis Lemaire (Université de Liège, Belgium), Martin Houry (Haute École de Namur-Liège-Luxembourg, Belgium)

llouis.llemaire@gmail.com

Grasslands are challenging to characterize due to their homogeneous visual texture and diverse species composition, complicating automated data collection for precision livestock farming adoption. Current methods lack detailed spatial information, hindering effective grassland management. Recent advancements in industrial grade field sensing technologies and 3D data processing provide new opportunities for automated phenotyping.

We propose an integrated pipeline for grassland phenotyping using an autonomous unmanned ground vehicle (UGV) powered by Robot Operating System 2 (ROS2). The UGV follows predefined waypoints using NAV2 to scan the grassland, capturing geo-referenced data. This platform is designed to be easy to replicate, deploy and use, allowing compatibility with a variety of sensors based on specific needs. It features IP67-certified components, USB and Ethernet connectivity for data transfer, and approximately 8 hours of battery life for active operation.

Our current work focuses on combining RGB-D frames into a colorized point cloud using a precise positioning device and registration algorithms to assess sward height, LAI, biomass, and vegetation indices while integrating species composition. Future work will incorporate predictive modeling to assess climate and management impacts on grassland health. Additionally, 3D rendering will simulate virtual environments to optimize acquisition parameters before real data collection. A semantic segmentation pipeline will be developed using synthetic training data to spatially classify plant species and objects of interest.

This approach integrates data acquisition, simulation, and predictive modeling to enhance grassland monitoring and management, enabling data-driven precision agriculture for sustainability and productivity.

P7.23 PREDICTING BIOTIC STRESS OF WHEAT USING VISIBLE AND NEAR-INFRARED SPECTROSCOPY, SPECTRAL INDICES AND MULTIVARIATE APPROACHES

Friday 11th July 2025 12:45

François Stevens (Walloon Agricultural Research Centre, Belgium), Louise Leclère (Agriculture territory and technologies integration Unit Walloon Agricultural Research Centre, Belgium), Yannick Curnel (Agriculture territory and technologies integration Unit Walloon Agricultural Research Centre, Belgium), Viviane Planchon (Agriculture territory and technologies integration Unit Walloon Agricultural Research Centre, Belgium), Maxime Troiani (Earth and Life Institute Université catholique de Louvain, Belgium), Pierre Defourny (Earth and Life Institute Université catholique de Louvain, Belgium), Vincent Baeten (Quality and authentication of agricultural products Unit Walloon Agricultural Research Centre, Belgium), Philippe Vermeulen (Quality and authentication of agricultural products Unit Walloon Agricultural Research Centre, Belgium)

f.stevens@cra.wallonie.be

Agriculture is increasingly under pressure from climate and biodiversity crises but has also the potential to adapt and to mitigate them. Wheat, a staple crop worldwide, is particularly vulnerable to biotic stresses caused by fungal pathogens. Developing effective strategies to monitor and manage these diseases is critical for enhancing the resilience and sustainability of agriculture.

This study explores the potential of visible and near-infrared (Vis-NIR) diffuse reflectance spectroscopy to detect biotic stresses in wheat under field conditions. Intensive field campaigns were conducted in Wallonia, Belgium, including experimental trials and farmers’ fields. At key growth stages, the overall plant health status of field plots was visually assessed, and Vis-NIR spectra were collected using a portable spectrometer.

Three different data treatment approaches were tested (1) calculation of established vegetation indices known to reflect plant health, (2) development of novel indices optimized for specific disease detection using genetic algorithms and (3) use of multivariate classification methods (PLS-DA, SVM-DA) on spectral variables or on a selection of spectral indices to distinguish between severity classes.

The results demonstrate that biotic stresses induce distinct changes in wheat spectral properties, which could be leveraged for disease detection. Before heading stage, disease detection is possible, but uncertainty is high. Between heading and the end of flowering, the performances of detection are better, with a good accuracy on most field trials and on the farmer’s fields. By linking plant physiological responses to near-infrared spectral data, this study confirms the potential for improved disease monitoring from proximal or remote platform.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

P7.1 AUTOMATED X-RAY-BASED SPIKE ANALYSIS FOR GRAIN CHARACTERIZATION

Sajid Ullah (Photon Systems Instruments, Czech Republic)

sajidullah124@gmail.com

Grain yield is a key determinant of cereal crop productivity, with spike morphology playing a crucial role in its assessment. Traditional spike characterization methods are often labor-intensive and time-consuming, limiting their scalability for large-scale breeding programs. To address this challenge, we present an advanced imagebased tool leveraging deep learning methodologies for non-invasive, high-throughput spike phenotyping. The system utilizes a U-Net model trained on 200 annotated spike images, incorporating data augmentation techniques such as rotation and scaling to enhance robustness. With the Dice coefficient as the loss function and the Adam optimizer, the model was trained for 60 epochs with early stopping to prevent overfitting. Additionally, adaptive thresholding and the Segment Anything Model (SAM) were evaluated, achieving Dice coefficients of 0.95 and 0.98, respectively, demonstrating the effectiveness of automated spike segmentation. The post processing of segmented grains extracts key morphological traits, including spike length, grain number, grain width, grain length, and grain area, facilitating precise yield analysis. This innovation enhances the efficiency of crop breeding research by providing an accurate, nondestructive, and scalable solution for spike trait analysis.

P7.2 DIGITAL PHENOTYPING FOR PLANT MONITORING AND SELECTION UNDER ENVIRONMENTAL CONSTRAINTS:

APPLICATIONS FOR ECOSYSTEM SERVICES AND NATURE-BASED SOLUTIONS

Daniela Di Baccio (Research Institute on Terrestrial Ecosystems National Research Council of Italy (IRETCNR), Italy), Elianalanfranca Tassi (Research Institute on Terrestrial Ecosystems National Research Council of Italy (IRET-CNR), Italy), Andrea Scartazza (Research Institute on Terrestrial Ecosystems National Research Council of Italy (IRET-CNR), Italy), Alice Vezzosi (Research Institute on Terrestrial Ecosystems National Research Council of Italy (IRET-CNR), Italy), Francesca Bretzel (Research Institute on Terrestrial Ecosystems National Research Council of Italy (IRET-CNR), Italy), Irene Rosellini (Research Institute on Terrestrial Ecosystems National Research Council of Italy (IRET-CNR), Italy), Meri Barbafieri (Research Institute on Terrestrial Ecosystems National Research Council of Italy (IRET-CNR), Italy)

daniela.dibaccio@cnr.it

Plants are the source of energy, food, feed, and bio-based products; they directly or indirectly contribute to human well-being providing ecosystem services (ESs). Photosynthesis regulates essential ecological processes supporting ESs, including non-material benefits as recreation and cultural identity. Aboveground, most of these functions reside in the leaf multispectral properties and the canopy architecture. Such functions and the appearance assumed by the vegetation canopy represent the phenotype, that depends on the interaction mechanisms between the genotype and the environment. In the last decades, plant genomics has remarkably advanced: now the bottleneck of research is to connect the plant genetic characteristics to their phenome throughout phenotyping studies. In this work, we tested two phenotyping platform systems (Phenospex MicroScan and TraitFinder) for improving the monitoring plant growth and production, evaluating their potentiality as ecosystem servicers and predicting effects/impacts on the environments. Some plant species were chosen as models for the identification of phenotypic traits that are proxies of the plant response to salt stress and environmental pollutants such as the traditional heavy metals and the emergent earth rare elements. Lactuca sativa and Raphanus sativus were representative of the agroecosystem, Arbutus unedo and Pinus halepensis of the Mediterranean environment and Phytolacca americana was chosen because it is an invasive neophyte species (native to North America) tolerant to various adversities. The potential of using the PlantEye Multispectral 3D System in the study of ecophysiological processes lying environmental changes and in the development of indices to be used for their description and managing are discussed.

P7.3 SUNLIT INSIGHTS: TRANSFERRING HYPERSPECTRAL IMAGING FROM LAB TO FIELD

Ivan Kashkan (Photon Systems Instruments s.r.o., Czech Republic), Nuria D. Diego (UPOL, Czech Republic), Klára Panzarová (Photon Systems Instruments s.r.o., Czech Republic)

kashkan@psi.cz

Hyperspectral imaging has long been a key tool for non-destructive plant phenotyping. Photon System Instruments (PSI) integrates hyperspectral (HS) cameras into phenotyping pipelines, using them as essential data sources to assess plant health and developmental stages in controlled environments. However, research shows that plant responses to environmental stress can vary significantly between laboratory and field conditions, even in genetically identical plant lines, affecting the accuracy of yield and nutritional predictions.

To address this challenge, PSI developed an advanced HS image processing pipeline, tested on a comprehensive dataset of Calendula flowers. This system together with a series of pHS image preprocessing steps features a deep learning classifier based on a 1D convolutional neural network, which effectively captures key spectral signatures of each plant pixel despite variations in lighting—an issue that has long hindered the application of field HS imaging for phenotyping. The model achieves high classification accuracy, successfully distinguishing between 10 Calendula lines in field conditions.

This study highlights the advantages of high-speed, high-precision HS imaging, enabling rapid data collection while compensating for environmental variability and noise. Compared to traditional methods like manual sampling, spectrophotometry, or RGB imaging, this approach offers greater reliability, accuracy, and efficiency in field-based plant phenotyping. As a result, this pipeline significantly improves the transition of high-throughput, precise HS phenotyping from laboratory research to real-world field applications.

P8: GRAVITROPISM AND PLANT ARCHITECTURE

ORGANISED

BY:

MARTA DEL BIANCO (ITALIAN SPACE AGENCY)

P8.6 THE DYNAMICS OF ROOT GRAVITROPISM AND THE ENIGMAS OF THE UNDERLYING AUXIN SIGNALING PATHWAYS

Thursday 10th July 2025 09:00

Matyáš Fendrych (Czech Academy of Sciences, Czech Republic)

matyas.fendrych@natur.cuni.cz

Roots navigate in the darkness of soil by detecting the gravity vector. During gravitropic response, cells in the root tip communicate with the cells in the elongation zone using the phytohormone auxin. To achieve gravitropic bending, the root needs to detect the change of the gravity vector, redirect the flux of the auxin, transport it to the responding cells which in turn need to adapt their growth rate to the new concentration of auxin. The primary root of many plant species can respond to the change of gravity direction with a remarkable speed. In Arabidopsis thaliana roots, this fact led to the discovery of a cytoplasmic rapid auxin response module that operates in parallel to the long-studied TIR1/AFB nuclear auxin response signaling. I will show how the rapid and nuclear auxin response pathways interact during the course of the gravitropic response of Arabidopsis root, and I will present our current understanding of the molecular nature of the cytoplasmic, AFB1-dependent auxin signaling. Further, I will discuss the existence of the cytoplasmic auxin signaling pathway in other species, particularly in grasses. Possibly, the ability to respond quickly might be important during root navigation through heterogeneous soil environments and during early seedling establishment.

P8.7 TOWARDS THE FORMULATION OF A UNIVERSAL THEORY OF ROOT GRAVITROPISM

Thursday 10th July 2025 09:30

Marta Del Bianco (Marta Del Bianco, Italy), Suruchi Roychoudhry (University of Leeds, United Kingdom), Katelyn Sageman-Furnas (Duke University, United States), Iftekhar Showpnil (Ohio Wesleyan University, United States), Chris Wolverton (Ohio Wesleyan University, United States), Jiri Friml (Institute of Science and Technology Austria (ISTA), Austria), Stefan Kepinski (University of Leeds, United Kingdom)

marta.delbianco@asi.it

Research on gravitropism has been dominated by two main ideas: that gravity is perceived through the sedimentation of starch-rich plastids within specialised gravity-sensing cells (Starch-statolith hypothesis), and that tropic growth is driven by auxin asymmetry across the graviresponding organ (Cholodny-Went hypothesis). Our recent work on gravity-dependent, non-vertical growth in lateral organs in Arabidopsis, has highlighted the importance of a third, even older concept in gravitropism: angle dependence. However, the mechanistic basis of how statolith sedimentation, and eventually Cholodny-Went driven auxin asymmetry, translates into angle dependent gravitropic behaviour remains unexplored. Here, using a combination of cutting edge vertical confocal imaging with time lapse tracking software, we characterize for the first time the dynamics of gra visensing in the columella of the Arabidopsis primary roots. We observed that statolith sedimentation across individual tiers of columella cells occurs according to the angle of displacement from the vertical axis. We also demonstrate how statolith sedimentation leads to angle dependent PIN3/7 polarization in specific columella domains. This detail analysis shows that different PINs/columella tiers play distinct roles in establishing the asymmetric auxin gradient at different angles. Our findings provide a fundamental framework to further explore the mechanisms that regulate angle dependent gravitropic responses in both primary and lateral organs, with major implications for crop improvement.

P8.8 EXPLORING THE DYNAMICS OF ACTIN NETWORKS AND

AUXIN SIGNALLING IN PROPRIOCEPTION PROCESS IN ARABIDOPSIS

Thursday 10th July 2025 09:45

Kinza Khan (University of Clermont Auvergne, France), Jérôme Franchel (University of Clermont Auvergne, France), Félix Hartman (University of Clermont Auvergne, France), Nicole Brunel (University of Clermont Auvergne, France), Mélanie Decourteix-Volle (University of Clermont Auvergne, France), Valerie Legue (University of Clermont Auvergne, France), Jason Reed (University of North Carolina at Chapel Hill, United States), Bruno Moulia (University of Clermont Auvergne, France), Nathalie Leblanc-Fournier (University of Clermont Auvergne, France)

Kinza.khan@uca.fr

The ability of plant organs to sense their local curvature and driving the progressive establishment of organ straightening is known as proprioception. This is a key mechanism in achieving correct shape and regulating the growth dynamics in combination with gravisensing and light perception. In this study, we aim to explore molecular

players driving proprioception inArabidopsis. Previous experiment using myosin-XI mutants suggested a role of actin in this process. The proprioceptive insensitivity in this mutant could be either due to the disruption of their cargo function or due to the modification of tension in actin cables. To explore the role of actin filaments we analyzed actin network with confocal microscopy. In wild type, during the gravitropicupward-curving-phase, these long actin bundles deviate from their straight-alignment and become wavy. During the de-curving-phase, these actin bundles regain their straight configuration. Then we produced RNAi-villin plants where actin configuration was specifically altered in fibre cells in stem. Using computational phenotypic tool, these lines appeared to be insensitive to proprioception confirming the importance of actin filament in controlling plant posture. We are exploring the actin configuration in both mutants and how it could modify the growth pattern and auxin action during plant movements.

P8.9 DIVERSITY AND FORMSTRUCTURE-FUNCTION RELATIONSHIPS IN PLANT HINGES

Thursday 10th July 2025 10:00

Arooj Sajjad (Technische Universität Darmstadt, Germany), Simon Poppinga (Technische Universität Darmstadt, Germany)

arooj.sajjad@tu-darmstadt.de

Plants move in a variety of ways, e.g. to align themselves with sunlight or the earth’s gravitational field, to catch prey, to attract pollinators, and to attach themselves to structures in the environment. Plant movements are often enabled by joint-like structures, commonly referred to as “plant hinges” in the literature. Unlike technical hinges, which rely on rigid body movements that are maintenance-intensive and prone to failure, plant movement systems employ functionally robust, flexible mechanisms known as compliant mechanisms. The most well-known plant hinge, the pulvinus, controls leaf movement through hydraulic mechanisms, as observed in legume species such asMimosa pudica, and has been extensively studied. However, there are many other types of plant hinges that allow for a variety of motions that can differ greatly in kinematics, actuation, and reversibility. Examples include motile sepals in various orchids (Orchidaceae) and lever mechanisms in sages (Salvia, Lamiaceae). Interestingly, the hinges in most motile plant structures have not been investigated regarding their form-structure-function relationships. We present a still-in-progress overview and phylogeny of plant hinges and exemplify their functional principle(s) with an in-depth analysis of a technical ball-and-socket joint analogy from the plant kingdom, i.e., the anther hinge of a Liliaceae species. Our analyses provide, from a structural-mechanical viewpoint, an in-depth understanding of hinged structures in the plant kingdom, which we will use in future biomimetic approaches where fine-tuned compliant mechanisms are required.

P8.10 ROS REGULATES THE ROOT HALOTROPISMIC RESPONSE IN ARABIDOPSIS ECOTYPES AND HALOPHYTE SCHRENKIELLA PARVULA

Thursday 10th July 2025 10:15

rengin.ozgur@ege.edu.tr

To survive in saline environments, plants have evolved adaptive strategies such as halotropism—a directional root growth response that helps to avoid high-salinity zones. This process involves intricate signaling networks, including hormonal regulation, ion transport, and reactive oxygen species (ROS) signaling. ROS function both as signaling molecules and stress mediators, guiding root growth direction while mitigating salt-induced damage. To investigate the role of ROS metabolism in halotropism, we conducted five-day experiments using different Arabidopsis thaliana ecotypes (Col-0, Wt5, and Uod-7) and the extreme halophyte Schrenkiella parvula under 200 mM NaCl. ROS levels were manipulated using ascorbic acid (to reduce ROS), rotenone (to increase mitochondrial ROS), and DPI (to inhibit NADPH oxidase activity). DPI suppressed root growth but did not significantly affect root orientation in any genotype compared to 200 mM NaCl alone. Rotenone enhanced halotropic orientation across all genotypes, though its effect was similar to that of 200 mM NaCl. Ascorbic acid produced varied effects: in Col-0, it redirected roots toward the NaCl source; in Wt-5, it intensified the response without altering orientation; and in Uod-7, it mitigated the response without affecting directionality. In S. parvula, ascorbic acid significantly increased halotropism without changing its direction. This study is the first to explore ROS-mediated root orientation during halotropism in the extreme halophyte S. parvula and A. thaliana ecotypes, providing new insights into the crucial role of ROS in plant stress adaptation.

P8.11 CONTROL OF THE ROOT ANGLE IN BARLEY

Thursday 10th July 2025 11:00

Gwendolyn Kirschner (The James Hutton Institute, United Kingdom)

gwendolyn.kirschner@hutton.ac.uk

The root angle is crucial for shaping root system architecture and therefore access to soil resources. Throughout their life, roots maintain a specific angle in relation to the gravity vector, which depends on the root type, its developmental stage, and environmental conditions. The angle is maintained by a balance between opposing gravitropic and anti-gravitropic cues, mediated in Arabidopsis lateral roots by the phytohormones auxin and cytokinin.

To date, it is unknown if a similar mechanism controls the root angle in crop plants, which often have a root architecture that is more complex than the one of Arabidopsis. This is especially interesting because individual roots with the same genetic background, the same age and in the same developmental stage can have different angle setpoints, like the seminal roots in barley. To uncover how these roots can regulate their individual root angle set-points, we compared the transcriptomes of seminal roots with different angle set-points and identified differentially expressed genes correlating with specific angles. Gene expression of cytokinin oxidases/dehydrogenases (CKXs) correlated with the root angle suggests a root angle regulation by cytokinin in barley.

Understanding how the root angle is set in individual barley roots will allow us to precisely engineer a root system adapted to specific, otherwise unfavourable soil environments.

Rengin Ozgur Uzilday (Ege University, Turkey), Nil Demircan (Ege University, Turkey), Baris Uzilday (Ege University, Turkey)

STRESS RESILIENCE

Thursday 10th July 2025 11:30

Muhammad A Farooq (University of Bologna, Italy), Martina Bruschi (University of Bologna, Italy), Manar Makoul (Justus Liebig University, Germany), Francisco Pinto (International Maize and Wheat Improvement Center, Mexico), Chunyi Liu (University of Bologna, Italy), Xinying Zheng (University of Bologna, Italy), Cristian Forestan (University of Bologna, Italy), Matteo Bozzoli (University of Bologna, Italy), Matthew Reynolds (International Maize and Wheat Improvement Center, Mexico), Rod J Snowdon (Justus Liebig University, Germany), Silvio Salvi (University of Bologna, Italy), Eric Ober (NIAB, United Kingdom), Roberto Tuberosa (University of Bologna, Italy), Marco Maccaferri (University of Bologna, Italy)

awaisfarooq724@gmail.com

Root growth angle (RGA) plays a critical role in drought resilience by regulating water/nutrient uptake. This study deciphers the genetic basis of RGA in tetraploid wheat, comparing cultivars (CVS) and Triticum turgidum landraces (TDL) to pinpoint breeding targets for drought adaptation. We characterize RGA diversity, haplotype stacking, in durum wheat using GWAS (90K SNP array), KASP validation, and multi-omics (transcriptomics, gene ontology. CVS (61.44°–77.05°) showed lower RGA diversity and plasticity than TDL (57.63°–78.24°), with 7 high-confidence QTLs in CVS versus 13 in TDL. KASP-validated QTLs on 2A (QRGA.ubo.2A.2), 6A (QRGA. ubo.6A.2), and 7A (QRGA.ubo.7A.2) revealed haplotype-specific alleles for narrow (steep) and wide (shallow) RGA, demonstrating stacking potential for trait optimization. Narrow RGA improved deepwater uptake under terminal drought while indirectly supporting yield. Multi-omics implicated conserved phosphorus-response pathways (PHR1, CLE14) and ROS-hormonal interplay (auxin, ALMT1) in RGA regulation, with narrow RGA genotypes enhancing phosphorus foraging in deficient soils. Co-localized QTLs for yield, biomass, and grain quality underscored RGA’s pleiotropic impact on resource efficiency.

P8.13 CULTIVATING PLANTS IN

ROTATIONAL

SYSTEMS:

INSIGHTS INTO THE INTERACTION BETWEEN GRAVITY PERCEPTION, METABOLISM AND AGRONOMIC PERFORMANCE IN PFALS

Thursday 10th July 2025 11:45

Vincent Truffault (Futura Gaïa Technologies, France), Cédric Dresch (Futura Gaïa Technologies, France), Manon Petigny (Université Clermont-Ferrand, France), Nathalie LeblancFournier (Université Clermont-Ferrand, France) vincent@futuragaia.com

Plant Factories with Artificial Lighting (PFAL) are a sustainable alternative to conventional agriculture for producing plants used in food, cosmetics, pharmaceuticals, and nutraceuticals. Standard PFALs rely on horizontal cultivation layers, requiring a high number of lamps to ensure uniform lighting, leading to high light-related energy consumption. To reduce energy consumption, an innovative rotational cultivation system has emerged. The rotation is slow, and plant physiology in the context of growing in a continuous slow rotation has not been studied before. The present work aims to provide insights into physiology, metabolism, morphology and agronomical performance of lettuce or basil plants grown in a rotational cultivation system. The position of statoliths in basil grown in the rotational cultivation system consistently aligned with the gravity vector, suggesting the plants’ ability to perceive changes in gravity orientation. This was consistent with the observed changes in plant morphology. Photosynthesis of lettuce was affected by changes in stomatal conductance and photosystem II efficiency. The profile of primary and secondary metabolites differed from those of control lettuces grown in a horizontal cultivation layer, notably in terms of polyphenol content. Despite these physiological and metabolic modifications, yield remained unchanged, and similar values of Water and Light Use Efficiencies (WUE and LUE) were found between lettuces grown in the rotational and horizontal cultivation systems. This study provides new insights into plant physiology and agronomic performance under slow rotational cultivation in PFALs, with implications for understanding plant responses to altered gravity perception, such as in microgravity environments.

P8.14 LINKING GENOME DIVERSITY TO ROOT ARCHITECTURE AND GROWTH DYNAMICS IN PERENNIAL RYEGRASS

Thursday 10th July 2025

12:00

Shane Fagan (Queens University Belfast, United Kingdom), Trevor Gilliland (Queens University Belfast, United Kingdom), Lisa Black (Agri-Food Biosciences Institute, United Kingdom), Gillian Young (Agri-Food Biosciences Institute, United Kingdom), Adam Gauley (Agri-Food Biosciences Institute, United Kingdom), Paul Williams (Queens University Belfast, United Kingdom)

sfagan03@qub.ac.uk

Global warming is predicted to cause an increased incidence in both, summer droughts, and excessive rainfall and flooding events in winter and early spring months. Existing plants can be adapted to survive and produce high yields in these future climates, through the enhancement of existing characteristics responsible for combating drought and excess water presence. This project investigates the genes responsible for regulating key perennial ryegrass (PRG) root architecture traits such as root length, while identifying the genetic loci responsible. A diverse set of PRG genotypes were compared from an initial screen of 200, which possessed varied root phenotypes. Rhizoboxes and RNA sequencing were used to analyse phenotypic and transcriptomic data. Phenotyping methods including 3D structural analysis using CT scanning and photographic analysis using a range of 2D imaging software are being employed. Near-isogenic-lines (NILs) are being developed to select for the activations or suppression of key identified genes, to analyse their effects on PRG root architecture. Future work will identify the presence of single nucleotide polymorphisms (SNPs) through whole genome sequencing. This will be used in combination with transcriptomic data to correlate SNPs presence in certain genes to variations in their transcription levels across different PRG genotypes.

Correlated SNPs presence and variations in RNA-sequencing data will then be jointly correlated to alterations in PRG root architecture across NILs. Understanding the underpinning gene networks responsible for variations in both abiotic resistance and root architecture will allow for the identification of genetic markers which can be targeted to inform future breeding strategies.

P8.15 UNDERSTANDING AND MANIPULATING ROOT SYSTEM ARCHITECTURE FOR AGRICULTURE ON EARTH AND BEYOND

Thursday 10th July 2025 12:15

James PB Lloyd (University of Western Australia, Australia)

james.lloyd@uwa.edu.au

The angle at which roots grow is adjusted by gravity and other environmental cues and whether roots grow shallow or deep is extremely important in agriculture as shallow roots allow for better nutrient (P) absorption while deeper roots lead to more drought tolerant plants. Thus tailoring the root system architecture is of great interest in agriculture. Gravity being a key factor in how roots grow raises some interesting questions with regards to growing plants away from earth, a key aim in the recently established Australia Research Council Centre of Excellence in Plants for Space. The impact of lateral root angle in agriculture on earth and beyond will be explored in this talk. What will the root system architecture look like in 17% of Earth gravity when growing crops on the moon? How can synthetic biology be used to engineer optimal roots structure for agriculture on earth and beyond? This talk will outline how synthetic gene circuits can be used to engineer plant development and could be used to sense and integrate environmental signals to create a tailored growth change

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

P8.1 DETERMINING THE ROLE OF AUXIN IN PHYLLOTAXIS PATTERNING IN THE MOSS PHYSCOMITRIUM PATENS

Priyanka Patra (ENS de Lyon, France), Lidor Shaar-Moshe (University of Haifa, Israel), Brendan Lane (John Ines Centre Norwich, United Kingdom), Rob Bellow (John Ines Centre Norwich, United Kingdom), Laure Mancini (ENS de Lyon, France), Elsa Véron (ENS de Lyon, France), Carlyne Golding (ENS de Lyon, France), Grégory Mouille (Institut Jean-Pierre Bourgin Versailles, France), Aline Voxeur (Institut Jean-Pierre Bourgin Versailles, France), Richard Smith (John Ines Centre Norwich, United Kingdom), Siobhan Brady (UC Davis, United States), Teva Vernoux (ENS de Lyon, France), Yoan Coudert (ENS de Lyon, France)

priyanka.patra@ens-lyon.fr

Phyllotaxis, the spatial arrangement of lateral organs in plants, is a critical determinant of plant architecture. While well-studied in flowering plants, the mechanisms governing phyllotaxis in bryophytes remain poorly understood. This study investigates the molecular and cellular mechanisms regulating phyllotaxis in the moss Physcomitrium patens, with a specific focus on the role of auxin and cell wall dynamics.

Using a combination of genetic, biochemical, and molecular approaches, we analyzed auxin transport mutants exhibiting aberrant shoot development. Quantitative phyllotaxis analysis revealed significant morphological alterations, suggesting that auxin transport disruption fundamentally impacts organ positioning. To understand the mechanistic basis of these changes, we conducted comprehensive analyses of cellular responses to auxin transport perturbation. Transcriptome profiling and cell wall compositional analyses uncovered that compromised auxin transport triggers cascading changes in cell wall biosynthesis, specifically altering the levels of critical components like cellulose and pectin.

Building on these insights, we investigated a cellulose biosynthesis mutant, which definitively demonstrated that cell wall composition alterations directly influence phyllotaxis. These findings reveal a tightly coupled mechanism where auxin signaling orchestrates cell wall remodeling, ultimately governing shoot architecture. By elucidating this mechanism in a basal land plant lineage, our research provides critical insights into the evolutionary conservation of phyllotaxis regulation across plant diversity.

This work represents the first comprehensive analysis of phyllotaxis mechanisms in Physcomitrium patens , bridging critical gaps in our understanding of plant developmental biology and offering new perspectives on the fundamental processes controlling plant morphogenesis.

P8.2 DELINEATING THE REGULATORY MECHANISMS OF THE TRANSCRIPTION FACTORS OSETTIN1 AND OSETTIN2 IN RICE FLORAL DEVELOPMENT AND FERTILITY

Amartya Sarkar (Indian Institute of Science, India), Heeba Anjum (Indian Institute of Science, India), Usha Vijayraghavan (Indian Institute of Science, India)

amartyas@iisc.ac.in

Developmental regulators of angiosperm vegetative to reproductive growth transition, inflorescence architecture, and floral development, together influence reproductive success. Rice (Oryza sativa) is a cereal model where determinate florets are made on the spikelet, the final branch on the inflorescence. The identity and patterning of floret organs, along with timely termination of the meristem requires the E class gene, OsMADS1 which is a master regulator of other transcription factors and signalling pathways, including various auxin pathway genes. Among the downstream targets of OsMADS1 are OsETTIN1 and OsETTIN2 which encode auxin response factors (ARFs). The regulatory roles of OsETTINs for floral fertility are still unknown. In the current study, transgenic lines silenced for either OsETTIN1 or OsETTIN2 were studied. The osettin1kd and osettin2kd plants had increased height coupled with delayed flowering transition. In florets, variable stamen number with defective anthers and reduced pollen viability, carpels with elongated styles and reduced stigmatic papilla are some notable phenotypes in both knockdown genotypes. These stamen and carpel defects underlie the poor seed setting and demonstrate roles for OsETTINs in rice fertility. Comparative transcriptomics of osettin1kd vs WT panicle stages which represents florets undergoing organogenesis revealed 5937 differentially deregulated genes. Gene Ontology (GO) enrichment analysis indicate several downstream genes associated with auxin signalling, transport, and hormone metabolism. Altogether, we gain new insights on developmental roles for OsETTIN1 and OsETTIN2 in vegetative plant architecture and floral development and decipher its downstream pathways in the developing florets.

P8.3 PLASTOCHRON REGULATION IN MAIZE: SPATIAL TRANSCRIPTOMICS REVEALS TRANSCRIPTIONAL CHANGES IN THE PLASTOCHRON1 MUTANT.

Lotte Van de Vreken (VIB-UGent Center for Plant Systems Biology, Belgium), Stan Werbrouck (VIB-UGent Center for Plant Systems Biology, Belgium), Hilde Nelissen (VIB-UGent Center for Plant Systems Biology, Belgium) lovre@psb.ugent.be

The maize plastochron1 ( pla1 ) mutant exhibits a shortened plastochron (accelerated leaf initiation) and reduced plant growth. This remarkable phenotype suggests a role for PLA1 in regulating leaf initiation and growth in the maize shoot apical meristem (SAM). The SAM is a highly complex structure where stem cells gradually differentiate into plant organs in a spatially coordinated manner. However, the transcriptional mechanisms by which PLA1 influences these developmental processes remain unclear. To investigate how PLA1 affects plant architecture at the molecular level, we applied spatial transcriptomics to visualize the expression of 500 genes in

wild-type and pla1 mutant shoot apices. Our analysis showed that PLA1 is expressed at the boundary between undifferentiated and differentiated cells, suggesting a role in regulating cell division and organ initiation. Developmental trajectory analysis tracing transcriptional changes from stem cells to differentiated cells revealed overlaps of PLA1 with stem cell markers such as Knotted1 and differentiation markers such as YABBY14, further supporting its regulatory function. Comparisons between wild-type and pla1 mutants revealed significant transcriptional changes, particularly in auxin metabolism, indicating an important role for PLA1 in (hormonal) regulation of the SAM. These findings provide novel insights into the transcriptional regulation of the maize meristem SAM and plastochron regulation, showcasing spatial transcriptomics and its downstream data-analysis as a valuable tool for studying plant development.

P8.4 FLORAL ORGAN SHAPE AND FUNCTION: STUDIES ON RICE CLASS B TRANSCRIPTION FACTORS OSMADS2 AND OSMADS4 AND THEIR ROLES IN LODICULE, STAMEN AND CARPEL DEVELOPMENT

Ritabrata Basak (Indian Institute of Science, India), Mohamed Zamzam (Indian Institute of Science, India), Heeba Anjum (Indian Institute of Science, India), Usha Vijayraghavan (Indian Institute of Science, India)

ritabratab@iisc.ac.in

In rice florets, the identity of lodicules, homologous to petals, requires the PISTILLATA-like gene paralogs OsMADS2 and OsMADS4 Disrupting OsMADS2 leads to abnormal malformed lodicules, while disruption of both paralogs (osmads2-/- osmads4kd) exacerbated lodicule abnormalities along with other defects, notable being male and female sterility, panicle-enclosure, increased meristem size, organ number, and interestingly parthenocarpy. Here, we investigated mechanisms underlying the developmental roles of these PI-like factors. The deregulated transcriptome in osmads2-/panicles highlights cell-cycle control, osmotic regulation and cellwall biosynthesis as downstream pathways contributing to osmads2-/floret phenotypes. We assessed the spatial profile of cell division in organ primordia and found inner organs in osmads2-/- osmads4kd florets have more cells in the S-phase that are drastically different in their spatial distribution altered along the proximal-distal axis of lodicules. These findings align with the abnormal lodicule size and shape. The reduced osmolality of osmads2-/- lodicules is consistent with abnormal vasculature patterning and the reduced expression of aquaporin genes in osmads2-/- panicles.

Given the unexpected carpel sterility of osmads2 -/- osmads4kd florets, we examined the carpel expression domains of both genes. We discover distinct spatial patterns of OsMADS2 and OsMADS4 transcripts in developing carpels, suggesting previously unknown sub-functionalized roles in carpel development. Transcriptomes of osmads2-/- osmads4kd panicles identify unique and shared targets of OsMADS2 and OsMADS4, emphasizing their unequal redundancies for normal floral development. Together, we provide new insights into the complex and dynamic regulatory networks controlled by OsMADS2/4 during the early stages of rice floral development.

P8.5 LAZY BUT EFFECTIVE: THE ROLE OF LAZYGENES IN REGULATING LATERAL ROOT GRAVITROPIC SETPOINT ANGLE (GSA)

Suruchi Roychoudhry (University of Leeds, United Kingdom), Adam Binns (University of Leeds, United Kingdom), Stefan Kepinski (University of Leeds, United Kingdom) s.roychoudhry@leeds.ac.uk

Overall plant architecture (consisting of the number, spacing and angle of secondary root and shoot branches) determines the efficiency of crops to capture essential resources such as water and nutrients below-ground, and light above-ground. Plant architecture is critically regulated by gravitropic growth, and recently, members of the highly conserved LAZYgene family have been demonstrated to play crucial roles in regulation of branching angle, a key determinant of plant architecture. Our previous work identified a novel dominant point mutation in LAZY4, (described as lazy4D) through an EMS mutagenesis screen in the model plant, Arabidopsis. Lateral roots in the lazy4Dmutant demonstrate steeper rooting, a highly desirable trait, that maximises nitrogen uptake, drought tolerance and carbon sequestration in cereal crops, making LAZY4 (and related LAZY genes) attractive targets for gene-editing to engineer deeper rooting in crop plants. However, the mechanistic basis for LAZY4dependentregulation of root angle remains uncharacterised. Using live cell bioimaging and molecular genetic techniques, we determined that lazy4D influences root growth angle in a dose-dependent manner, and further, that root LAZYs interact with D6PK proteins to regulate PIN polarisation and/or activity to regulate lateral root growth angle. Further we show that an MKK-MPK31,2 phosphorylation module is required forLAZY4, but notlazy4d dependent regulation of growth angle. Collectively, our work sheds novel insights into the molecular mechanisms that underpin thelazy4D (and more broadly,LAZY) dependent regulation of root and shoot branching angle in flowering plants.

SOCIETY FOR EXPERIMENTAL BIOLOGY PRESENTS:

AIMING TO IMPROVE DIVERSITY IN BIOSCIENCE AWARDS

SEBIOLOGY.ORG #SEBCONFERENCE

SEB AWARDS

Increase both nominations and nominators from historically marginalised groups for SEB awards

Expand the action of the task force to include other Societies and bioscience awards

Everyone (members and non-members) can get involved. No previous

1. Join the SEB Awards Nomination Task Force

2. Suggest the name of someone deserving of a bioscience award for the SEB Task Force

3. Nominate someone in your own right

Oxygen Sensors for Respirometry

P9 - PLANT ENGINEERING STRATEGIES FOR ACHIEVING SUSTAINABILITY GOALS: FROM MODELS TO LAB TO FIELD

ORGANISED BY: MEGAN L. MATTHEWS (UNIVERSITY OF ILLINOIS), JOHNATHAN NAPIER (ROTHAMSTED RESEARCH)

P9.1 ENGINEERING PHOTOSYNTHETIC CARBON METABOLISM FOR IMPROVED CROP PRODUCTIVITY

Wednesday 9th July 2025 09:00

Christine Raines (University of Essex, United Kingdom)

rainc@essex.ac.uk

Increasing world population, plateauing crop yields and climate change present a challenge to provide sufficient food for the planet. For this reason we need to explore all of our options and deploy new technologies. Over the last 10 years a number of studies have provided evidence demonstrating that improving photosynthesis can result in improved yield. This talk will focus on improvements in the RuBP regeneration phase of the Calvin-Benson-Bassham cycle and also electron transport. I will summarise some of the results of successful studies using genetic engineering of steps in the photosynthetic process that led to increases in yield. These results provide clear evidence for the potential of increased photosynthesis to contribute to improving our crop plants.

P9.2 A SEARCH FOR GENES TO ENGINEER THE CHLOROPLAST COMPARTMENT OF CELLS

Wednesday 9th July 2025 09:30

Enrique Lopez-Juez (Dept. Biological Sci. Royal Holloway University of London, United Kingdom), Priyanka Mishra (Dept. Microbiol. Cell Biol. Indian Institute of Science, India), Masab U Khan (Dept. Biological Sci. Royal Holloway University of London, United Kingdom), Anisha Uppal (Dept. Biological Sci. Royal Holloway University of London, United Kingdom)

e.lopez@rhul.ac.uk

An ability to engineer the total chloroplast complement of cells could be transformational, in relation to attempts to engineer

photosynthesis, including its alternative metabolic versions. Detailed analyses of chloroplast biogenesis during leaf development have revealed stages of plastid proliferation, biogenic machinery assembly and eventually greening (synthesis of photosynthetic components). Those analyses have also demonstrated our very limited knowledge of the drivers of chloroplast biogenesis, with currently known ones involved primarily in the greening phase. Particularly well understood are the GOLDEN-LIKE 1 and 2 (GLK1 and GLK2) transcription factors. The total chloroplast content of photosynthetic leaf cells, their chloroplast compartment, is remarkably constant even in plants which carry mutations in chloroplast division genes. glk1,2 double mutants in Arabidopsis are pale, with chloroplasts in similar numbers (to those in the wild type) but smaller, with less developed internal photosynthetic membranes, and creating a smaller chloroplast compartment within the cells harbouring them.

In order to search for novel genetic factors involved early in chloroplast biogenesis, we have carried out genetic screens for loss- and gain-offunction suppressor mutants of the Arabidopsis glk1,2 double mutant.

In at least two of those cases, identification of the responsible gene and isolation of mutants carrying that specific mutation alone has produced plants with an increased degree of greening and an enlarged chloroplast compartment of cells.

These newly-identified genes may open the door to uses in crop plants.

P9.3 THE HEAT IS ON: SCALING IMPROVEMENTS IN PHOTOSYNTHETIC THERMAL TOLERANCE FROM THE LEAF TO CANOPY TO PREDICT CROP YIELDS IN A

CHANGING CLIMATE.

Wednesday 9th July 2025 09:45

Amanda P Cavanagh (University of Essex, United Kingdom), Megan L Matthews (University of Illinois at Urbana Champaign, United States)

a.cavanagh@essex.ac.uk

Crop production must increase to sustain a growing global population, and this challenge is compounded by increased growing season temperatures and extreme heat events that are already causing

significant yield losses in staple crops. Therefore, there is an urgent need to develop strategies to adapt crops to withstand the impacts of a warmer climate. Temperature-sensitive vegetative processes fundamentally related to yield, like photosynthesis, will be impacted by warming throughout the growing season, thus strategies to enhance their resilience hold promise to future-proof crops for a warmer world.

Here, we summarize three major strategies to enhance C3 photosynthesis above the thermal optimum: enhanced Rubisco activation, modified photorespiration, and increased rates of RuBP regeneration. We highlight recent experimental evidence demonstrating the efficacy of these strategies, and then employ a mechanistic modelling approach to predict the benefit of these engineering strategies on leaf-level carbon assimilation and soybean yield at elevated temperatures. Our approach highlights that thesethree engineering targets, particularly when combined, can enhance photosynthetic rates and yield under both ambient and elevated temperatures.By targeting multiple aspects of photosynthetic metabolism, we can develop crops that are better equipped to withstand the challenges of a warming climate and contribute to future food security.

P9.4 A NEW TWIST ON THE USUAL SUSPECTS: STRATEGIES FOR PHOTOSYNTHETIC IMPROVEMENT IN RICE

Wednesday 9th July 2025 10:00

Samuel H Taylor (Lancaster University, United Kingdom), Supreeta Vijaykumar (Lancaster University, United Kingdom), Yu Wang (Nanjing University, China), Hsiang Chun Li (International Rice Research InstituteNational Taiwan University, Philippines), Stephen P Long (University of Illinois at Urbana-Champaign, United States), Elizabete Carmo-Silva (Lancaster University, United Kingdom)

s.taylor19@lancaster.ac.uk

To explore opportunities for engineering improved photosynthesis in rice, Rubisco enzyme kinetics and activation were re-parameterised, and activity of enzymes involved in RuBP-regeneration and sucrose synthesis re-scaled in a digital twin of photosynthetic metabolism (e-Photosynthesis). By contrast with soybean and potato, the new digital twin of rice photosynthesis is consistent with higher leaf-level investment in photosynthetic enzymes. Despite this, optimisation of CO2 assimilation using an evolutionary algorithm to reallocate protein among enzymes resulted in reallocation to Rubisco across a wide range of [CO2 ]. As [CO2 ] increased, so too did reallocation to Calvin Cycle enzymes previously identified by e-Photosynthesis as important limits on RuBP-regeneration in tobacco and potato. From these results, alternative sets of target enzymes were identified for strategic overexpression, targeting improvement of photosynthesis under three conditions: low [CO2 ] consistent with abiotic stress, nonstressed current conditions, and future, higher [CO2 ]. Some target enzymes have already been overexpressed in planta, so achieved increases in enzyme concentrations were used to constrain in silico evaluation of strategies. Improvements to photosynthesis were similar among strategies at high [CO2 ] and modest compared with complete optimisation of protein allocation. Despite all strategies increasing both Rubisco and RuBP-regeneration enzymes, benefits to CO 2 assimilation were greatest at low [CO2 ]. In rice, a realistic expectation

seems to be that rather than step-changes under yield potential conditions, photosynthetic improvement will be most beneficial under conditions where [CO2 ] diffusion is limiting, consistent with real-world conditions of mild abiotic stress.

P9.5 ENGINEERING ROOT TRAITS FOR CLIMATE CHANGE MITIGATION

Wednesday 9th July 2025 11:00

Wolfgang Busch (Salk Institute for Biological Studies, United States)

wbusch@salk.edu

Climate change will soon profoundly and negatively affect the vast majority of our planet’s biota, including most human beings. Despite the importance and urgency of addressing this problem, we still lack technologies to globally address the root cause of climate change –increased levels of CO2 in the atmosphere. Since plants are central agents in the earth’s carbon cycle, fixing atmospheric carbon that then mostly gets released when they decompose, engineering plant traits that affect the decomposition rate of plant derived carbon molecules can potentially lead to a large and globally significant drawdown of atmospheric CO2 . In particular, root systems and the rhizosphere are of interest for such approaches as soils are enormous carbon sinks. Since plants first colonized the earth’s land surfaces, their carbon depositions have built up three times more carbon in the soil than is contained in the atmosphere. Specific root traits are important contributors to the accumulation and permanence of carbon in the soil. These include root depth, root biomass and the levels of refractory carbon compounds in root tissues. I will present our efforts in using natural variation, genome wide association mapping, chemical genetics and functional genomics approaches in the model plant Arabidopsis thaliana and several crop species to identify genetic and molecular mechanisms that regulate these traits and how we attempt to utilize this knowledge to enhance traits relating to carbon accumulation and permanence in soils in crops.

P9.6 EPIGENOMIC REGULATIONS OF RICE RESPONSES TO COMBINED HEAT AND SALINITY STRESS

Suraj Patil (Savitribai Phule Pune University, India), Shrushti Joshi (Savitribai Phule Pune University, India), Vinay Kumar (Savitribai Phule Pune University, India)

m

Rice (Oryza sativa L.) is a staple for over half the global population, yet its production potential has stagnated. Climate change and environmental challenges, such as rising temperatures and sea levels, are increasing soil salinity and atmospheric heat, particularly in coastal rice-growing areas. Combined heat and salinity stress are expected to significantly reduce rice yield and quality. Our study employs a multiomics approach, integrating DNA methylation, miRNAomics, and transcriptomics, to investigate the molecular mechanisms underlying rice responses to both individual and combined heat and salinity stresses. After screening of 16 Indica rice varieties with respect to

physiological, biochemical and molecular responses to individual and combined stress, we identified Karjat 6 as the most responsive variety. Using a time-dependent heat stress cycle and 100mM salinity treatment administered hydroponically, we observed distinct patterns of reactive oxygen species scavenging enzymes and ion accumulation. Further analysis using Enzymatic Methyl-Sequencing (EM-Seq), small RNA sequencing, and transcriptomics revealed differentially expressed genes associated with distinct methylation patterns. The combined stresses exerted additive effects, with notable epigenetic markers, such as Guanine nucleotide-binding protein, MADS-box, WRKY112, and Salt stress-induced proteins, uniquely responsive under combined conditions. Additionally, Os-miR167h-5p and Os-miR408-3p were identified as top miRNAs in response to combined stress. we further demonstrated the functional significance of these epigenetic markers in enhancing rice tolerance to combined stress. This research provides key insights into the molecular adaptations of rice and contributes significantly to the field of plant stress biology.Keywords:Combined stress, DNA methylation, EM-Seq, Transcriptomic, miRNAomicsEmail for correspondence: suraj.patil1999@gmail.com

P9.7 IDENTIFICATION AND FUNCTIONAL CHARACTERIZATION OF SALT-RESPONSIVE MICRORNAS INGLYCINE MAXL

Wednesday 9th July 2025 11:45

Shrushti Joshi (Savitribai Phule Pune University, India), Suraj Patil (Savitribai Phule Pune University, India), Vinay Kumar (Savitribai Phule Pune University, India)

shru1604@gmail.com

Soybean plants, in particular, experience hindered growth and reduced yield due to salt stress-induced osmotic imbalance, mineral deficiencies, and the toxicity of specific ions, leading to oxidative stress. Our study aims to elucidate the molecular responses and adaptive strategies of soybeans to salt stress, focusing on miRNAmediated post-transcriptional regulation. We conducted experiments utilizing two distinct Indian soybean cultivars: the salt-tolerant MAUS47 (Parbani Sona) and the salt-sensitive Gujosoya-2. These cultivars underwent short-term NaCl stress (100 mM) at the trifoliate stage. Our results reveal distinct methods of scavenging reactive oxygen species and ion accumulation between the two cultivars. The saltsensitive variety exhibited a higher intake of Na+ at the expense of essential K+ , P+ , and Mg2 + ions, potentially decreasing yield and delaying growth. Small RNA sequencing during salt stress identified 450 miRNAs from various families, with miR159, miR3522, miR166, miR396, and others displaying significant differential expression. Notably, miR5371-3p emerged as the top-responsive miRNA to salinity stress in our sensitive cultivar. Further investigation unveiled that miRNA5371-3p play a crucial role in conferring sensitivity to soybean against salinity stress. Artificial miRNA5371-3p were prepared to knock down miRNA5371-3p expression and transformed in sensitive cultivar usingAgrobacterium. Validation through PCR confirmed successful plant transformation. The targets were validated using RLM-RACE. Further the transgenic plants were functionally validated by observing their biochemical and molecular responses. Keywords: Soybean, salt stress, miRNA, artificial miRNA, RLM-RACE, Small RNA seq

P9.8 MADS GATEKEEPERS: OVULE PROTEIN COMPLEXES ENSURE FERTILIZATION-DEPENDENT FRUIT SET IN TOMATO

Wednesday 9th July 2025 12:00

Tzahi Arazi (ARO Volcani Institute, Israel), Jackson Khedia (ARO Volcani Institute, Israel), Hawi D Kenea (ARO Volcani Institute, Israel), Oscar Castaneda-Méndez (Michigan State University, United States), Victoria Kwarteng (ARO Volcani Institute, Israel), Daniel Feder (Instituto de Investigação e Inovação em Saúde, Portugal), Erich Grotewold (Michigan State University, United States)

tarazi@volcani.agri.gov.il

The process of fruit set, which transforms an arrested flower ovary into a rapidly growing fruit, is essential for achieving maximum crop yield. Fruit set is typically initiated by fertilization of the ovules inside the arrested ovary. However, because pollen maturation occurs within a narrow temperature range, climate change is expected to severely impair fruit set, leading to major yield losses. Understanding the regulation of ovary arrest is therefore crucial for developing climateresilient crops. Previously, we identified SlAGL6 as a key regulator of ovary arrest, but its molecular mechanism remained unclear. Here, we demonstrate that SlAGL6 suppresses parthenocarpy specifically from the ovules, as reintroducing SlAGL6 into its loss-of-function mutant using an ovule-specific promoter restored ovary arrest. A yeast two-hybrid screen identified SlMBP3 and SlMBP22 as highconfidence interactors of SlAGL6 in planta. CRISPR/Cas9-mediated knockout of SlMBP3 and SlMBP22, combined with genetic interaction analysis, revealed that SlMBP3 cooperates with SlAGL6 and SlMBP22 to suppress parthenocarpy. Consistent with that, protein interaction assays and AlphaFold-based structural predictions suggest that these proteins form a Flower Quartet-like Complex (FQC), with SlAGL6 essential for complex assembly. Our findings provide a mechanistic framework for ovary arrest regulation, demonstrating that ovuleexpressed FQCs function in a partially redundant manner to prevent parthenocarpy. This knowledge offers new breeding strategies to enhance fruit set under suboptimal conditions, helping to mitigate climate change-induced yield losses and safeguard food security.

P9.9 EXPLORING METABOLIC ENGINEERING STRATEGIES FOR ENHANCED CROP YIELD USING CONSTRAINT-BASED MODELING

Wednesday 9th July 2025 15:00

Sanu Shameer (Indian Institute of Science Education and Research Thiruvananthapuram, India)

sshameer@iisertvm.ac.in

Improving the efficiency of converting light energy into organic biomass has been identified as a key factor required to increase crop yield. Classical kinetic models of photosynthesis have helped identify rate limiting steps of photosynthesis and have helped engineering efforts on this front. However, kinetic models are computationally expensive and depend on detailed information about kinetic laws,

metabolite, and enzyme concentrations, which limits their scope. In contrast, constraint-based models of leaf metabolism are less datareliant and can account for the entire leaf metabolism, making them a promising alternative for studying steady-state leaf metabolism. In my talk I will describe how constraint-based modeling works and how such models can be used to study metabolism in C3 and CAM leaves. I will also discuss our recent efforts in using this modeling approach to search for potential strategies to increase efficiency of tomato leaf metabolism. Our analysis revealed that a switch in the activity of glutamine synthetase (GS) from the chloroplast to the mitochondria could help a leaf achieve higher productivity. To further explore this prediction, transgenic tomato plants over-expressing GS in leaf mitochondria were generated. These plants exhibited faster growth rate and increased fruit yield. Leaf metabolomic profiling and enzyme activity analysis also showed GS activity in mitochondria played a role in enhancing the synthesis and export of sugar from the leaves. These findings increase our confidence in the use of constraint-based modeling as a viable approach for designing engineering strategies aimed at improving crop productivity.

P9.10 UNRAVELLING YIELD CONSISTENCY IN WINTER WHEAT (TRITICUM AESTIVUM L.): INSIGHTS FROM MULTI-ENVIRONMENT TRIALS AND SIMULATION MODELING

Wednesday 9th July 2025 15:30

Tien-Cheng Wang (Humboldt University of Berlin, Germany), Tsu-Wei Chen (Humboldt University of Berlin, Germany)

wangtien@student.hu-berlin.de

Understanding crop yield requires navigating the intricate interaction between genotype and environments (GxE), which presents challenges for accurate predictions due to the plant’s plastic responses. To study the environmental impacts on grain yield, we addressed two questions: Q1) Do environmental factors affect the consistency (R2 trait ) of trait performance? Q2) Can physiological relationships between traits across field environments be represented by simulation (APSIMwheat)? To explore the GxE effect on trait performance of yield (R2 yield ), we utilise a multi-environment trials (MET) dataset featuring 220 genotypes and 45 environments over three years, five locations and three managements. The management includes combinations of two treatments: total nitrogen fertiliser application (high-HN: 220 kg N ha-1 , low-LN: 110 kg N ha-1 ) and fungicide application (with-WF, without-NF). Resulting three managements are HN_WF, HN_NF and LN_NF. R2 trait is calculated using standardised major axis (SMA) regression between two environments grouped by three environmental factors: management, location and year. Trait-trait Pearson correlation (r) was calculated between nine traits in both field and simulation dataset. Our results reveal: 1) R2 trait increases with trait complexity – higher for grain yield, grain number and weight, but lower for straw dry matter and spike number. Further grouping by management improves R2 trait . 2) APSIM-Wheat simulations highlight discrepancies in dry matter allocation to grain yield and straw dry matter at maturity between fields and simulation. These insights into R2 trait enhance our understanding of GXE in yield formation and inspiration for designing field trials for trait evaluation.

P9.11 MAPPING MECHANICAL INPUT TO STRUCTURAL REMODELLING OUTPUT IN ARABIDOPSIS STEMS

Wednesday 9th July 2025 15:45

Samuel E Mason (Imperial College London, United Kingdom), Tom Masselter (University of Freiburg, Germany), Evie E Quinlan (Imperial College London, United Kingdom), Daniel Khosravinia (Imperial College London, United Kingdom), Angela E Kedgley (Imperial College London, United Kingdom), Olga Speck (University of Freiburg, Germany), Thomas Speck (University of Freiburg, Germany), Naomi Nakayama (Imperial College London, United Kingdom) s.mason22@imperial.ac.uk

The climate crisis is increasing the likelihood of plant shoot failure due to mechanical overload, which is often presented as lodging. Currently up to 50% of UK oilseed rape yield can be lost when plant stems fail due to environmental conditions such as wind and rain. This crop failure rate will likely increase as extreme weather becomes more frequent, with disproportionate impact on the Global South. In this study, the model plant Arabidopsis thaliana, a relative of many common Brassicaceae crops, was used to understand stem remodelling in response to controlled magnitudes of wind load. Wind load inputs were quantified using hot wire anemometry. Plant remodelling outputs were measured using techniques such as uniaxial bending tests, histology and 3D laser scanning. We found that the force exerted by Arabidopsis stems during bending falls within a gap in the sensitivity range of commercially available uniaxial mechanical testing devices; thus, we designed and built a custom rig. The rig was designed to be open-source, affordable, user-friendly and easily manufacturable using 3D-printed parts. Using this, Arabidopsis stem bending tests were completed and methods developed to systematically link the mechanical inputs to plant remodelling outputs. Experimental data informs on failure loads/modes, plant strength and stability. The data will be built into computational models to understand internal stress and strain, to simulate environmental conditions that cannot be tested experimentally, and to predict remodelling response.

P9.12 BREEDIT: A MULTIPLEX GENOME EDITING STRATEGY TO IMPROVE COMPLEX QUANTITATIVE TRAITS IN MAIZE

Wednesday 9th July 2025 16:00

Arthur Beauchet (VIB-PSB, Belgium), Christian Lorenzo (VIB-PSB, Belgium), Pieter Wytynck (VIB-PSB, Belgium), David Blasco Escamez (VIB-PSB, Belgium), Matilde Sanches (VIB-PSB, Belgium), Wout Vandeputte (VIB-PSB, Belgium), Stijn Seynnaeve (VIB-PSB, Belgium), Dirk Inzé (VIB-PSB, Belgium), Hilde Nelissen (VIB-PSB, Belgium) arbea@psb.ugent.be

Growth and yield are complex quantitative traits that imply multiple molecular pathways of which the interplay is highly complex. To decipher the molecular networks and gene combinations that contribute to these relevant agronomic traits, we developed a flexible pipeline called BREEDIT (an acronym of breeding and gene

editing) that combines multiplex gene editing with directed crossing schemes to integrate higher order edits per generation. This strategy allowed us to target entire gene families or multiple components of regulatory pathways involved in leaf growth and yield parameters to bypass redundancy and enabling the detection of novel additive or synergistic gene combinations. In our plant population, almost every plant was unique with a complex mosaics of INDELs or SNPs that are homozygous, heterozygous or biallelic, making statistical analysis impossible. Using high-throughput phenotyping in seedling and mature plants, we generated quantitative data and used AI models to detect intricate patterns in highly complex datasets, to decipher the underlying relationships and determine the causative gene combinations. In parallel, we fixed mutants from our segregating lines using haploid inducer lines to validate the gene-edit combinations responsible for a given phenotype. We are currently exploiting our AI model to test the best gene edit combinations from these fixed mutants in the field.

P9.24 ENGINEERING A NIN-LIKE PROTEIN INTO A MASTER REGULATOR OF NITROGEN-FIXING NODULATION

Thursday 10th July 2025 09:00

Rene Geurts (Wageningen University & Research)

rene.geurts@wur.nl

Rhizobium-induced nitrogen-fixing nodule symbiosis is an ecologically and economically important trait in legumes and some related species. A critical step in this symbiosis is the transcriptional activation of the NODULE INCEPTION (NIN) gene, which encodes as a master regulator of nodule organogenesis and functioning. NIN is homologous to nitrate-sensing NIN-LIKE PROTEIN (NLP) transcription factors, which control lateral root formation in response to exogenous nitrate sources. NIN acquired evolutionary adaptions to allow it to function in nodulation. However, which of these are critical remains elusive. We aim to dissect the evolution of the NIN gene, ultimately aiming to engineer NIN-induced nodulation in non-leguminous crops.

P9.25 THE PHYLLOSPHERE MICROBIOME: UNCOVERING THE SECRETS OF SIGNAL PEPTIDES AND METABOLITES

Thursday 10th July 2025 09:30

Tacha-Marie Joubert (Stellenbosch University, South Africa), Sahar Esgandari (Stellenbosch University, South Africa), Itumeleng Petro Moroenyane (Stellenbosch University, South Africa)

tjoubert@sun.ac.za

The phyllosphere, the above-ground surface of plants, is home to a diverse microbiome that significantly influences plant health and productivity. This project investigates the intricate relationships between the phyllosphere microbiome, signal peptides, and metabolites, focusing on their roles in modulating plant defense mechanisms and promoting symbiotic interactions.

Using a multi-omics approach, we explore how signal peptides facilitate communication between phyllosphere microorganisms and their host plants, affecting the production and exchange of metabolites crucial for plant growth and stress tolerance. Our research reveals that specific metabolites, such as isoprenoids, are synthesized and degraded by phyllosphere bacteria, potentially acting as signaling molecules that modulate plant responses to environmental stresses. This study contributes to the development of novel strategies for microbiome management, leveraging the phyllosphere microbiome to enhance plant health and productivity. By deciphering the complex interplay of signal peptides and metabolites, we aim to unlock new avenues for sustainable agriculture practices that promote ecosystem resilience and reduce chemical pesticide use.

Our findings have significant implications for understanding the phyllosphere microbiome’s role in plant health and for developing innovative, microbiome-based solutions for agriculture. This research paves the way for future studies on manipulating the phyllosphere microbiome to improve crop resilience and sustainability.

P9.26 CONTROLLED BACTERIAL RELEASE VIA ENCAPSULATION: A STRATEGY TO IMPROVE MAIZE GROWTH UNDER WATER DEFICIT

Thursday 10th July 2025 09:45

Tiago S Lopes (University of Aveiro, Portugal), Paula AAP Marques (University of Aveiro, Portugal), Etelvina Figueira (University of Aveiro, Portugal)

tslopes@ua.pt

As climate change intensifies throughout the 21st century, droughts are expected to become more frequent and severe, posing a major threat to agricultural productivity and global food security. Innovative strategies are needed to improve water management and promote plant growth under stress conditions.This study investigates bacterial encapsulation as a novel approach to enhance plant resilience. Specifically, it evaluates the efficacy of encapsulating plant growth promoting rhizobacteria (PGPR) in an alginate-starch matrix and its effect on maize (Zea mays) under water stress. The capsules were characterised in terms of size, morphology, structural integrity and resistance to assess their ability to protect the bacteria and provide controlled release.The effectiveness of encapsulation in mitigating water stress was assessed using physiological and biochemical parameters. The results indicate that encapsulation preserved bacterial viability under drought conditions and facilitated their gradual release into the environment. Maize plants exposed to encapsulated PGPR showed increased root and shoot biomass under water deficit.In shoots, encapsulated bacteria increased metabolic activity (ETS), antioxidant response (catalase activity) and photosynthetic pigment concentration. In roots, osmolyte accumulation (sugars and proline), metabolic activity (ETS) and antioxidant response (catalase) increased. These changes contributed to improved plant adaptation to drought by promoting.

P9.27 MODELING OF ZEA MAYS QUANTIFIES

THE

COSTS,

BENEFITS, AND SYNERGIES OF BIOENGINEERING SYMBIOSES WITH RHIZOBIA AND ARBUSCULAR MYCORRHIZAL FUNGI

Thursday 10th July 2025

10:00

Joshua AM Kaste (University of Illinois Urbana-Champaign, United States), Rourou Ji (University of Illinois UrbanaChampaign, United States), Patrick Sydow (The Pennsylvania State University, United States), Ruairidh JH Sawers (The Pennsylvania State University, United States), Megan L Matthews (University of Illinois Urbana-Champaign, United States)

kaste2@illinois.edu

Engineering staple crops like Zea mays to associate with N2 -fixing rhizobia or to enhance existing associations with arbuscular mycorrhizal fungi (AMF) are two strategies being pursued to improve the sustainability of food production by reducing the need for synthetic fertilizers. The effectiveness of such strategies may vary depending on soil nutrient conditions in the field as well as the developmental stage of the plant. We developed the first metabolic models describing the symbiotic nutrient exchange between a plant and AMF and validated its predictions by comparing them with empirical data from a field study comparing plants with and without AMF. Measured and predicted growth rate benefits – 31% vs. 19%, respectively – aligned closely, and predicted carbon allocation from the plant host to AMF mirrored prior literature estimates. Next, we developed a model quantifying the costs of N2 -fixation by rhizobia on a hypothetical Zea mays plant engineered to harbor rhizobia in nodules. Our model predicts relative growth rate penalties ranging from 12.8 to 3.4%, depending on developmental stage, associated with obtaining organic nitrogen from rhizobia rather than synthetic fertilizer. These penalties are lower than those previously predicted for legumes due to the lower nitrogen content of Zea mays biomass, making the potential symbiosis with rhizobia in Zea mays especially economically viable. Finally, we built a model of the plant in association with both rhizobia and AMF and found that, under conditions of moderate to severe nutrient deprivation, these strategies are predicted to have substantial synergy with one another.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

P9.13 MUSANAC46 TRANSCRIPTION FACTOR REGULATES STRESS INDUCED LEAF SENESCENCE OF BANANA PLANT BY MODULATING AUTOPHAGY AND CHLOROPHYLL CATABOLISM

Subham Bhakta (Bhabha Atomic Research Centre Affiliated To Homi Bhabha National Institute, India), Himanshu Tak (Bhabha Atomic Research Centre Affiliated To Homi Bhabha National Institute, India), Anand Ballal (Bhabha Atomic Research Centre, India), Sudhir Singh (Bhabha Atomic Research Centre Affiliated To Homi Bhabha National Institute, India)

subhambhakta7@gmail.com

Stress-induced senescence significantly affects plant productivity, influencing growth and development. In model plants, stress-related NAC transcription factors are key mediators of senescence, but their mechanisms remain unclear in crop plants. Banana, a crucial tropical fruit crop, faces significant yield loss (30%) due to stress-induced early senescence, exacerbated by climate change. To address this challenge in this study we have investigated the role of the NAC transcription factor ‘MusaNAC46’ in banana plants. Transcriptional analysis revealed that MusaNAC46 expression is up regulated under salt and drought stress conditions. Overexpression of MusaNAC46 (MusaNAC46-OX) induced premature senescence, while knockout (MusaNAC46-KO) lines showed delayed senescence, confirming its regulatory role in senescence. Chlorophyll content in MusaNAC46-OX leaves was significantly lower compared to controls, whereas MusaNAC46KO leaves exhibited enhanced chlorophyll levels. Ultrastructural analysis through transmission electron microscopy showed degraded chloroplasts and autophagic bodies in MusaNAC46-OX leaves. Gene expression analysis revealed upregulation of chlorophyll catabolic genes, nonyellow colouring (NYC) and pheophytinase (PPH), and autophagy-related genes such as ATG5, ATG8B, and ATG12 in MusaNAC46-OX lines, while these genes were downregulated in knockout lines. A dual luciferase assay demonstrated that MusaNAC46 directly interacts with the promoters of NYC, PPH, ATG5, ATG8B, and ATG12. Additionally, LC-MS analysis showed increased ABA levels and H2O2 accumulation in MusaNAC46-OX leaves, indicating the involvement of MusaNAC46 in stress-induced senescence. In conclusion, modulating the levels of MusaNAC46-like proteins could provide a strategy to control senescence in plants.

P9.14 THE EFFECTS OF TRICHODERMA HARZIANUM, STRAIN KHB, AS AN ELICITOR ON SILYMARIN PRODUCTION AND GROWTH OF SILYBUM MARIANUM (L.) GAERTN HAIRY ROOT CULTURES

Sahar Esgandari Gharabaghlou (Stellenbosch University, South Africa), Nox Makunga (Stellenbosch University, South Africa), Tahereh Hasanloo (Agricultural Biotechnology Research Institute of Iran)

sahar@sun.ac.za

Milk thistle (Silybum marianum) is well known for its medicinal value, particularly for treating liver and gallbladder conditions, owing to its active flavonolignan complex, silymarin. Due to difficulties in seed availability, alternative biotechnological methods, such as hairy root culture, have been introduced. This study investigates the use of Trichoderma harzianum strain KHb as an elicitor to enhance silymarin production and biomass growth in S. marianum hairy root cultures induced with Agrobacterium rhizogenes AR15834.

Hairy roots were cultivated in shake flasks with varying concentrations (0.5, 1, 2, and 4 mg 50 mL ¹) of T. harzianum culture filtrate and sampled at different exposure times (12, 24, 48, 72, 96, and 120 h). The roots were collected, freeze-dried, and their dry weight recorded. Silymarin was extracted using methanol and quantified via high-performance liquid chromatography. Results demonstrated that supplementation with 2 mg/50 mL T. harzianum led to the highest silymarin yield, increasing from 0.26 mg g ¹ DW in controls to 0.45 mg g ¹ DW after 48 h—approximately a 1.73-fold enhancement. Biomass production also improved significantly under elicited conditions. Our findings suggest that T. harzianum is an effective elicitor for boosting both secondary metabolite accumulation and biomass in S. marianum hairy root cultures. This strategy offers a promising biotechnological alternative for producing silymarin, supporting the development of sustainable, high-yield production systems for pharmaceutical applications. Further optimisation and scaling studies could help meet growing demand for this valuable phytochemical.

P9.15 MITIGATING MICROBIAL DYSBIOSIS UNDER ENVIRONMENTAL STRESS: ENGINEERING PLANT-MICROBE INTERACTIONS FOR SUSTAINABLE REMEDIATION.

Anele Ndlovu (Stellenbosch University, South Africa), Itumeleng Moroenyane (Stellenbosch University, South Africa)

anelendlovu@sun.ac.za

Microbial dysbiosis, a threat to crop production, is indirectly worsened by abiotic stressors like drought and nutrients deficiency. The plantmicrobe interactions, both in the rhizosphere and endosphere are partially maintained by various plant signalling molecules including root exudates, salicylic acid and signalling peptides. Alterations to the production of any of these signalling molecules due to environmental stress may be linked to microbial composition shifts. Hence, this study aims to delve deeper into the impacts of abiotic stress on soybean plant-microbe interactions. The roles played by beneficial

microorganisms and signalling molecules in tackling the issue of microbial dysbiosis and alleviating the impacts of climate change will also be studied. Beneficial microbes might serve as effective biofertilizers to relieve plants from abiotic stresses with the help of exogenously applied signalling molecules. Salicylic acid may aid in relieving water stress. On the other hand, root exudation could be essential in the maintenance of microbial diversity while signalling peptides may relieve both abiotic and biotic stresses in plants. Therefore, thorough research on how the plant holobiont responds to environmental stress conditions will be done to devise more effective strategies of alleviating abiotic stress and maintaining eubiosis.

P9.16 DECIPHERING THE ROLE OF PLASTOCHRON1 IN TRANSIT AMPLIFYING CELLS IN MAIZE YIELD THROUGH SPATIAL TRANSCRIPTOMICS AND ENZYMATIC CHARACTERIZATION

Büşra Çelik (VIB, Belgium), Lotte Van de Vreken (VIB, Belgium), Stan Werbrouck (VIB, Belgium), Kirin Demuynck (VIB, Belgium), Lennart Hoengenaert (VIB, Belgium), Griet Coussens (VIB, Belgium), Stijn Aesaert (VIB, Belgium), Timothy Villers (VIB, Belgium), Hilde Nelissen (VIB, Belgium) busra.celik@psb.vib-ugent.be

Ectopic expression of a cytochrome P450 enzyme-encoding gene PLASTOCHRON1(PLA1/ZmCYP78A1) leads to increased biomass and seed yield potential by extending the duration of cell division, as demonstrated by multi-year and multi-location field trials. The expression pattern of PLA1 in the maize shoot apical meristem resembles a boundary region between meristematic and differentiated cells, where cells divide more rapidly and begin transitioning. We refer to these PLA1-expressing cells as transit amplifying cells (TACs), in analogy with similar cell types in animal systems. However, the precise mechanism of enzymatic reaction of PLA1 and its surrounding gene network in TACs remain unclear. To address these gaps, we utilize targeted spatial transcriptomics in the maize shoot apex to spatially map gene distribution and apply multiplex genome editing to investigate the genetic interactions of PLA1 co-expressing genes in TACs. Additionally, we use a cell-free protein expression system to stably and purely synthesize PLA1 for target binding assays to identify its substrate-product pair. These findings will advance both fundamental and applied research, deepening our understanding of growth, cell differentiation, and leaf initiation in the shoot apical meristem; and they will facilitate the fine-tuning of key growth genes through genetic engineering and the utilization of enzymatic characteristics to enhance crop traits.

P9.18 GREEN TO THE FULLEST: GENES CONTROLLING THE TOTAL CHLOROPLAST COMPARTMENT OF PHOTOSYNTHETIC CELLS

Declan Perry (Royal Holloway University of London, United Kingdom), Suresh Leonel (Royal Holloway University of London, United Kingdom), Hequan Sun (Xi’an Jiaotong University, China), Enrique Lopez-Juez (Royal Holloway University of London, United Kingdom)

declan.perry.2013@live.rhul.ac.uk

The population of chloroplasts within a plant mesophyll cell is present within the cytoplasm as a distinctive monolayer, which can be referred to as the chloroplast compartment. The opportunity to engineer the “chloroplast index”, the proportion of the cell taken up by the chloroplast compartment, has significant applications towards food security. However, our understanding of the governing genetic factors responsible for its regulation was completely lacking until the identification of the REC genes, whose loss results in cells with a REduced Coverage or chloroplast index (Larkin et al. 2016,PNAS 113, E1116 E1125). To uncover novel genetic regulators responsible for the control of the chloroplast compartment, two genetic screens have been initiated. Within Arabidopsis thaliana, 35S activation tagging and chemical mutagenesis by ethyl methanesulfonate (EMS), are being used to discover suppressor mutations of the rec phenotype. 35S activation tagging mutagenesis and EMS putative suppressor mutants demonstrating an enhanced greening phenotype have been identified, their cellular phenotype having been quantified. Bulked segregant analysis through next generation sequencing has been achieved to identify the position of a rec EMS suppressor mutation. The end goal is to utilize this knowledge into enhancing the plastid compartment within specific cell types of crop plants, for improving the photosynthetic performance within leaf cells.

P9.19 BUD TO BLOOM:DECODING TRANSCRIPTIONAL NETWORK UNDERLYING FLOWERING REGULATION IN SAFFRON (CROCUS SATIVUSL.)

Diksha Kalia (Council of Scientific Industrial ResearchInstitute of Himalayan Bioresource Technology (CSIR-IH, India), Rajesh Kumar Singh (CSIR- Institute of Himalayan Bioresource Technology (CSIR-IHBT), India)

dikshakalia47@gmail.com

Saffron is a high-value spice renowned for its stigma, yet the genetic and molecular mechanisms governing its flowering remain poorly understood. This study investigates the role of key flowering regulators in saffron, focusing on the Florigen Activation Complex (FAC) componentsFLOWERING LOCUS T(FT) and the bZIP transcription factorFD. WhereTFL1serves a contrasting role by repressing flowering. Floral induction is modulated by the balance between two floweringrelated proteins,FLOWERING LOCUS T (FT)andTERMINAL FLOWERING LIKE 1(TFL1).

We identified sixFThomologs (CsatFT1-6), threeFDhomologs (CsatFD1-3) and threeTFL1(TFL1-1-TFL1-3) in saffron. Spatiotemporal expression profiling showed thatCsatFT3andCsatFD2are specifically expressed in the floral meristem and coincide with floral induction. In contrast,CsatTFL1-3downregulates in apices during flower induction, suggesting thatCsatTFL1-3has a role in floral repression. Using BiFC and Y2H assay techniques, we confirmed the interaction betweenCsatFT3/CsatFD2andCsatFD2/TFL1-3.

Functional characterization through Arabidopsis and ViGS in saffron demonstrated thatCsatFT3andCsatFD2positively whereasCsatTFL13negatively regulates floral induction.

Short vegetative phase(SVP) is particularly responsive to temperature changes, as the saffron flowering is highly temperature sensitive, we have identified twoCsatSVPgenes. Notably,CsatFT3is regulated by the transcription factorCsatSVP2. Binding and activation studies indicate thatCsatSVP2negatively regulatesCsatFT3. Additionally, interactions

betweenCsatFT3andCsatSVP2were confirmed using the luciferase assay, and Y1H technique. Overall, the study uncovers components of the floral induction in saffron, offering the potential for genetic improvements to address sterility and enhance yield through targeted manipulation.

P9.20 NOVEL ANTIMICROBIAL PEPTIDES FROM SPINACH CONFER TOLERANCE TO CITRUS GREENING AND POTATO ZEBRA CHIP DISEASES.

Kranthi K Mandadi (Texas AM AgriLife Research, United States), Carmen S Padilla (Texas AM AgriLife Research, United States), Sonia C Irigoyen (Texas AM AgriLife Research, United States)

kkmandadi@tamu.edu

Citrus greening or Huanglongbing, and potato zebra chip are devastating diseases affecting worldwide citrus and potato production. The diseases are associated with the fastidious (unculturable), phloem-limited bacteria, ‘Ca. Liberibacter spp.’ and are transmitted by insect vectors. Defensins are short (~40 to 50 amino acids) basic, cysteine-rich peptides integral to the innate immune system in plants, animals, and insects and possess broad-spectrum inhibitory activity against bacterial and fungal pathogens. Here, we evaluated whether expressing defensins from spinach in citrus and potato can confer tolerance to ‘Ca. Liberibacter spp.’ diseases. Given the unculturable nature of ‘Ca. Liberibacter spp.’, efficacy evaluation of two spinach defensins (SoAMP1 and SoAMP2), was first performed using the ex vivo microbial hairy root system. Both SoAMP1 and SoAMP2 demonstrated significant antimicrobial activity against ‘Ca. Liberibacter spp.’ in citrus and potato hairy roots compared to controls. The spinach defensins disrupted bacterial cell membranes and permeability, leading to mortality, as demonstrated by in vitro cytotoxicity assays using a culturable surrogate bacteria, Liberibacter crescens. Furthermore, heterologous expression of SoAMP1 and SoAMP2 in potatoes and citrus using genetic engineering or viral vector-mediated expression conferred plant tolerance to ‘Ca. Liberibacter spp.’ and significantly improved crop yield of infected plants. In conclusion, one or more spinach defensin peptides could be used as crop protection products for managing citrus greening, potato zebra chip, and/or other diseases.

P9.21 MULTIPLE KNOCKOUT GENES ENCODING PROTEASES TO INCREASE THE RECOMBINANT PROTEIN CONTENT IN NICOTIANA BENTHAMIANA

Kyeong-Ryeol Lee (National Institute of Agricultural Sciences, Korea (South)), Nan-Sun Kim (National Institute of Agricultural Sciences, Korea (South)), So-Yun Kim (National Institute of Agricultural Sciences, Korea (South)), Mi Ae Kim (National Institute of Agricultural Sciences, Korea (South)), Jihyea Lee (National Institute of Agricultural Sciences, Korea (South)), Juho Lee (National Institute of Agricultural Sciences, Korea (South)), Seon-Kyeong Lee (National Institute of Agricultural Sciences, Korea (South))

realdanny@korea.kr

Plant-based recombinant protein production has the potential to be used for vaccines and other medical and industrial applications. Compared to other recombinant protein production systems, such as the systems using bacteria, yeast, insect cells, and mammalian cells, plant-based system has advantages such as safety, low production cost, and scalability, but it has limitation such as low protein yield. To overcome this limitation, we planned to reduce the protease activity, which is considered to be one of the causes of low protein production, using the CRISPR/Cas system. We selected two serine proteases and five cysteine proteases whose expression increased the most when agrobacterium was infiltrated into Nicotiana benthamiana Seven guide RNAs covering 11 genes encoding these proteases in N. benthamiana, an allotetraploid plant, were designed. Seven gRNA expression cassettes were also integrated into one binary vector using the MoClo system and N. benthamiana was transformed with the binary vector and Cas9 vector. From more than 100 transformants, three lines with 9-10 knockout genes were selected and their total protease activity was reduced by up to 60% or more. We plan to test the how much content of recombinant protein production is enhanced using them compared to WT.

P9.22 PHYSIOLOGICAL AND BIOCHEMICAL PROFILING OF CHICKPEA GENOTYPES FOR FUSARIUM SUSCEPTIBILITY AND TOLERANCE

Atyia NA Naeem (Government College University Faisalabad, Pakistan), Muhammed S Akram (Govenrnment College University Faisalabad, Pakistan)

atyianaeem856@gmail.com

Chickpea (Cicer arietinumL.) is the third most significant legume crop in the world and an important source of dietary protein.Fusarium oxysporumis a soil-borne disease that may leads to 90% yield losses, annually, in chickpea. A study was conducted to evaluate and compare the biochemical and physiological responses ofFusariumtolerant and sensitive genotypes, with the aim to identify the key traits and mechanisms that lead to resistance toFusariumseverity. Fusarium-tolerant and susceptible genotype has been screened by growing chickpea in healthy and sick soil located in the field of Ayub Agricultural Research Institute Faisalabad (AARI). The study examined the response of 10 chickpea genotypes to Fusarium. Out of 10 genotypes, 7 characterized as moderately tolerant, while 3 exhibited sensitivity. Two tolerant (PCK-23005, PCK-23009) and two sensitive genotypes (PCK-23003, PCK-23004) was subsequently collected after 40 days of sowing at the vegetative stage. The sample will be analyzed to determine growth and a variety of physio-biochemical characteristics, notably chlorophyll, proline, protein, antioxidant enzyme and malondialdehyde. The result indicated that chlorophyll content was15%higher in PCK-23009 genotype as compared to PCK23003 under Fusarium severity. Similarly, proline concentration was significantly increased in PCK-23009 genotype by29%in contrast to PCK-23003 genotype. This study identifies the aspects linked with chickpea wilt and root disease, thereby providing a charter for cohesive disease management. Further, it spotlights the agricultural environment where disease-resistance breeding techniques may have the biggest impact.

P9.23 MOON-RICE: CEREAL CROP PRODUCTION FOR FUTURE PLANETARY BASES

Marta Del Bianco (Marta Del Bianco, Italy), Vittoria Brambilla (University of Milan, Italy), Stefania De Pascale (University of Naples ‘Federico II’, Italy), Raffaele Dello Ioio (University of Rome ‘Sapienza’, Italy)

marta.delbianco@asi.it

The development of growth systems for cultivation in space aims at minimizing the resources required in terms of energy and volume. This technological progress affects also the plant organisms used, where the optimization of the plant architecture and productivity in a controlled environment will be fundamental to maximize space efficiency and reduce waste. In this context, for example, the generation and selection of crop dwarf varieties, which makes crops compatible with efficient vertical farming systems, is a rapidly expanding field for the first space settlements. An ideal space crop, however, should also be highly productive, optimised for growth in a closed environment and resistant to space stressors.

Most calories in the human diet come from complex carbohydrates, obtained mainly from the cultivation of cereals. Among cereals, rice is currently the main source of energy for the world population. Rice has interesting nutraceutical characteristics: it contains small and readily digestible starch, does not contain gluten and, depending on the variety, can provide fibre, proteins, vitamin B, iron and manganese. Rice is also one of the highest yielding cereals and can be easily grown with soilless methodologies (e.g., hydroponics), which are currently considered the most adapted technologies and potentially applicable to space exploration scenarios.

Starting from the identification of the ideal ideotype, the project Moon-Rice aims at developing new varieties of rice, selected specifically for future space applications.

P10: OPEN PLANT

ORGANISED BY: GEORGE LITTLEJOHN (UNIVERSITY OF PLYMOUTH)

P10.11 WHY DO HYPOMETHYLATED PLANTS DISPLAY TRANSGENERATIONAL INFERTILITY?

Friday 11th July 2025 09:30

Robyn Emmerson (University of Birmingham, United Kingdom), Marco Catoni (University of Birmingham, United Kingdom)

r.emmerson@bham.ac.uk

Hypomethylation in plants is associated with improved stress responses and is therefore a favourable trait. However, when methylation mutants are produced there is often a transgenerational decrease in fitness, meaning this is not a viable avenue to explore in crops. Previously this has been associated with ectopic methylation ( ibm1 ) and alternative splicing of the IBM1 transcript due to changes in intron methylation (met1-3). We aimed to determine the responsibility of IBM1 in this phenotype, and investigate whether other genes are involved.

Utilising a set of epigenetics recombinant inbred lines (epiRILs), where met1-3 was crossed with Col-0 to produce a ‘mosaic pattern’ in DNA methylation, a ditch in chromosome 3 where inheritance was solely Col-0 was identified in the F8 generation. Within this region, genes were mined from the F1, selected based on hemimethlyation. One other gene, VHA, was identified to have a similar methylation profile to IBM1 and has a complementary expression within the flower. We hypothesized that the interaction of IBM1 and VHA could explain the transgenerational decrease in fitness observed inmet13plants. We generated RNA-seq and methylomic data in the pollen and carpels to assess the impacts of this interaction, and a range of genetic approaches were applied including crossing of IBM1 and VHA knockout mutants and CRISPR-Cas9 to generate double mutants. We propose there is incompatibility between the pollen and carpels of these methylation mutants, ultimately resulting in decreased fitness and viability.

P10.26 EXPLORING ABA-MEDIATED

TOMATO: INSIGHTS FROM INTROGRESSION LINES

Friday 11th July 2025 09:45

Hermann PRODJINOTO (Institute of Plant Sciences and Genetics in Agriculture The Hebrew University of Jerusalem, Israel), Dana Menkes (Institute of Environmental Sciences The Hebrew University of Jerusalem, Israel), Moshe Shenker (Institute of Environmental Sciences The Hebrew University of Jerusalem, Israel), Menachem Moshelion (Institute of Plant Sciences and Genetics in Agriculture The Hebrew University of Jerusalem, Israel)

hermann.prodjinoto@mail.huji.ac.il

Global warming intensifies flooding, causing US$7.8 billion in annual agricultural damages, making it the second most destructive disaster after drought. Plant flood tolerance depends on structural and physiological traits like adventitious roots and hypocotyl hypertrophy, but tomato plants are particularly sensitive to flooding. Current tomato varieties lack sufficient flooding tolerance, leading to significant crop losses. Introgression lines (ILs) provide genetic diversity, precise trait mapping, and improved flood resilience, enabling stable production under changing conditions. We hypothesized that tomato ILs IL81 and IL11-4, with distinct drought responses, exhibit significantly different physiological and morphological reactions to flooding compared to the mother plant M82, likely due to differential abscisic acid-mediated stress regulation. Under oxygen deficiency (via nitrogen gas) and flooding for seven and fourteen days, parameters such as oxygen levels, redox potential, nutrient concentration, flood sensitivity index (FSI), transpiration rate, and adventitious root formation were measured. Flooding reduced midday transpiration rates by 9.72% to 67.37%, with M82 showing the least reduction. M82’s shoot dry weight was unaffected, while ILs decreased by 50%. M82 developed 10% stem hypertrophy and had the lowest FSI (27.35%). Despite forming more adventitious roots, ILs were more sensitive to flooding. This research highlights IL potential for breeding flood-resilient tomatoes.

P10.12 EXPLORING THE IMPACT OF BIOCHAR ON GROWTH AND MOLECULAR RESPONSES IN YOUNG BLUEBERRY (VACCINIUM CORYMBOSUM L.), CV. SIERRA, PLANTS

Friday 11th July 2025 10:00

Anna Agosti (University of Parma, Italy), Raul Huertas (The James Hutton Institute, United Kingdom), Kyriakos Varypatakis (The James Hutton Institute, United Kingdom), Raymond Campbell (The James Hutton Institute, United Kingdom), Benedetta Chiancone (University of Parma, Italy), Robert Hancock (The James Hutton Institute, United Kingdom)

anna.agosti@unipr.it

Biochar, a soil amendment known to influence plant growth by modifying soil properties, nutrient availability, and physiological processes, has been extensively studied in field and soilless cultivation systems. However, its molecular effects on plants remain poorly understood. Research on crops, such as tomato, pepper, soybean, lettuce, and wheat, has revealed different gene expression responses to biochar, with growth-related genes generally upregulated, while defense-related genes show more variable trends. This study investigates the molecular effect of biochar on young blueberry (Vaccinium corymbosum L.) plants (cv. Sierra). To evaluate the effect of biochar on plant growth and gene expression, before transplanting, it was added at 0, 5, and 10% v/v in combination with a coir-based substrate, in 10L pots. Key parameters, including plant height, branch number, and chlorophyll content, were measured. Additionally, photosynthetic performance was evaluated through leaf gas exchange analysis and qRT-PCR was conducted to assess the expression of four growth-related and four defense-related genes. The results showed that biochar influenced plant growth and physiology in a concentration-dependent manner. At 10% biochar, plant height significantly decreased, while branch number remained unaffected. Photosynthetic efficiency did not seem to be influenced by the different substrates tested, even if chlorophyll content was lower in biochar-treated plants. Gene expression analysis revealed up-regulation of auxin-responsive and sugar transporter genes, while defense-related genes displayed variable expression patterns based on biochar concentration. These findings suggest biochar modulates physiological and molecular processes in blueberries, making further research necessary to optimize its application strategies and assess long-term effects.

P10.13 FUNCTIONAL TRAITS AND STRATEGIES

THAT DETERMINE ‘WEEDINESS’ OF AN AGRICULTURAL WEED, AVENA

FATUA

Friday 11th July 2025 10:15

Callum Myers (University college cork, Ireland), Vijaya Bhaskar (Oakpark Teagasc, Ireland), Astrid Wingler (University college cork, Ireland) 119342326@umail.ucc.ie

Weeds are, if left unmanaged, the most serious problem faced by farmers around the globe, causing higher crop losses than pests and pathogens. Our work investigates the traits that determine “weediness”, i.e. high competitive ability and high fecundity inAvena fatua(wild common oat), which is closely related toAvena sativa(oat) and reduces crop yields of, e.g. wheat and barley, through competition.A. fatuapopulations from around the Republic of Ireland, gathered from predominantly arable agricultural land, were compared in glasshouse, growth chamber and field experiments. Leaf traits, functional strategies and photosynthetic data were compiled to analyse the differences among populations, based on herbicide tolerance/sensitivity. We found highly significant differences of traits such as height, tiller number, and leaf area among the populations. However, initial analysis did not reveal any link of these traits to herbicide tolerance. Field work compared cereal crops andA. fatuain a

working agricultural setting. Analysis based on the competitive-stress tolerant-ruderal (CSR) system showed that grass weeds are more competitive than cereal crops and exhibit very low stress tolerance scores. Plant stress responses are being investigated to examine the impact of climate change on grass weeds (A. fatuaandLolium multiflorum(Italian ryegrass)) and a commonly used pasture grass (Lolium perenne(perennial ryegrass)). Our research clearly shows a high fecundity inA. fatuawith an abundance of smaller seeds when compared to cereal crops as well as a higher overall competitive ability, which may be associated with lower stress tolerance.

P10.14 IN DEPTH CHARACTERIZATION OF AUTOCHTHONOUS BEAN (PHASEOLUS VULGARISL.) AND LENTIL (LENS CULINARISMEDIK) LANDRACES FROM APENNINE ITALIAN REGIONS

Friday 11th July 2025 10:30

Alessandra Renella (Department of Biosciences and Territory University of Molise, Italy), Martina Falcione (Department of Biosciences and Territory University of Molise, Italy), Massimiliano Corso (Institut Jean-Pierre Bourgin Universite Paris-Saclay, France), Stéphanie Boutet (Institut Jean-Pierre Bourgin Universite Paris-Saclay, France), Gabriella S Scippa (Department of Biosciences and Territory University of Molise, Italy), Dalila Trupiano (Department of Biosciences and Territory University of Molise, Italy) a.renella@studenti.unimol.it

Autochthonous landraces or local varieties are plant genetic resources characterized by high genetic variability, specific adaptation to environmental growth condition, and the presence of healthpromoting specialized metabolites. However, these varieties are at risk of extinction due to their replacement by genetically uniform modern varieties. Untargeted metabolomics, based on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), is a powerful tool to explore metabolite diversity, promote the valorization, and support the conservation of these landraces. This study investigated the metabolite diversity of three autochthonous lentil landraces from Molise region (Italy) — Capracotta (CA), Rionero Sannitico (RS), and Agnone (A) — compared to one landrace from Umbria region (Italy) — Castelluccio di Norcia (CS) — and three bean landraces from Molise (Ciliegino, CI), and Basilicata (San Spanish Ciliegino, CI SP), respectively. Untargeted metabolomics allowed the detection of 662 and 344 differentially accumulated metabolic features (DAMfs) in lentil (Le) and bean (Be) landraces, respectively. Metabolite annotation, supported by molecular network analysis, assigned 53% and 54% of DAMfs to different metabolic categories, with flavonoids, amino acids, and cinnamic acids as the most represented. Multivariate statistical analyses (PCA, PLS-DA, and HCA) highlighted the distinctiveness of each landrace. The antioxidant, and antibacterial activities of legume seed extracts were evaluated, correlating bioactivity with their metabolic profiles. Ongoing enrichment analysis will further define landrace-specific metabolic features, enhancing the understanding of their health-promoting potential and supporting conservation efforts of traditional varieties.

P10.15 LOCATION OF FAR-RED LIGHT PERCEPTION AND SIGNALLING MECHANISMS DRIVING FRUIT GROWTH RESPONSES IN TOMATO

Friday 11th July 2025 10:45

Elena Vincenzi (Horticulture and Product Physiology Wageningen University and Research, Netherlands), Mohan Lu (Horticulture and Product Physiology Wageningen University and Research, Netherlands), Lisa Oskam (Laboratory of Molecular Biology Wageningen University and Research, Netherlands), Ronald Pierik (Laboratory of Molecular Biology Wageningen University and Research, Netherlands), Esther De Beer (Signify, Netherlands), Frank Millenaar (BASF – Nunhems, Netherlands), Leo F.M. Marcelis (Horticulture and Product Physiology Wageningen University and Research, Netherlands), Ep Heuvelink (Horticulture and Product Physiology Wageningen University and Research, Netherlands)

elena.vincenzi@wur.nl

The integration of far-red light into lighting regimes in controlledenvironment agriculture has shown great potential for enhancing tomato fruit yield, primarily by increasing individual fruit fresh weight. Fruit sink strength and sugar content at harvest are improved with supplementary far-red, possibly due to enhanced sucrose transport to the fruits and changes in starch and sugar metabolism within them. Plant responses to far-red light are mediated by phytochromes. While fruit-localised phytochromes have been linked to sugar metabolism, their role in regulating fruit growth responses remains unknown. In this study, we investigated whether far-red perception in tomato plants occurs locally in the fruits or via a systemic response from the vegetative organs. We applied far-red light either to the fruits or to the vegetative organs and compared these treatments to wholeplant far-red exposure and a control treatment without far-red. Fruit weight and sugar content increased only when the vegetative organs were exposed to far-red light, pointing to vegetative organs, not the fruits, as the key site of far-red perception that drives fruit growth. To obtain insights into the molecular pathways involved in far-red signalling to the fruits, we conducted RNA sequencing and hormone analyses; these measurements are currently being analysed. Our research provides new insights into the location of far-red perception and the signalling mechanisms that control fruit growth responses, contributing to the optimization of far-red-based strategies for improving tomato production.

P10.27 HEAT STRESS-INDUCED

PHENOTYPIC PLASTICITY IN C3 AND C4 PSEUDOCEREALS: A COMPARATIVE MOLECULAR PERSPECTIVE

Friday 11th July 2025 11:30

KOMAL GOEL (CSIR- Institute of Himalayan Bioresource Technology, India), Nitin Mantri (RMIT University, Australia), Alexis Marshall (RMIT University, Australia), Andy S Ball (RMIT University, Australia), Gaurav Zinta (CSIR-Institute of Himalayan Bioresource Technology, India)

komalgoel223@gmail.com

As global temperatures rise due to climate change, the ability of crops to withstand heat stress has become a critical concern for food security. Ancient crops like quinoa, amaranth, chia, and millet are increasingly recognised for their resilience in harsh environmental conditions and high nutritional value. However, their phenotypic responses to elevated temperatures, particularly regarding stress tolerance, remain underexplored. This study focuses on two pseudocereals, quinoa and amaranth, which, despite belonging to the same botanical family, follow distinct photosynthetic pathways—quinoa is a C3 plant, while amaranth is a C4 plant. These differences make them ideal candidates to study how varying photosynthetic mechanisms affect phenotypic responses to heat stress. We compare their heat stress responses, focusing on key phenotypic traits such as biomass accumulation, leaf area, and photosynthetic efficiency. Our results reveal that quinoa, as a C3 plant, experiences significant growth inhibition and reduced photosynthetic rates under heat stress, while amaranth, a C4 plant, demonstrates greater heat tolerance, maintaining higher biomass and physiological function. To understand the molecular basis of these differences, we performed RNA transcriptome analysis. Findings show that amaranth upregulates heat shock proteins and thermotolerance genes, while quinoa enhances antioxidant and osmotic stress-related pathways. This research provides valuable insights into the heat tolerance mechanisms of ancient crops with different photosynthetic pathways, highlighting their potential for climate-resilient agriculture. It is crucial to develop heat-tolerant varieties to secure global food production in the face of climate change.

P10.17 INTERACTIONS OF ARBUSCULAR MYCORRHIZAL FUNGI WITH NATIVE GRASSLAND SPECIES UNDER COMBINED HEAT AND WATER STRESS

Friday 11th July 2025 11:45

Shae L Jones (University of Wollongong, Australia), Marlien Van der Merwe (Royal Botanic Gardens and Domain Trust, Australia), Andy Leigh (University of Technology Sydney, Australia), Sharon Robinson (University of Wollongong, Australia), Kristine French (University of Wollongong, Australia)

shaej@uow.edu.au

Arbuscular mycorrhizal fungi (AM fungi) may facilitate plants during increasingly prevalent extreme stress events such as heatwaves and drought. Heatwaves are commonly characterised by the presence of extreme temperatures and frequently co-occur with droughts or water deficits. The combination of these stressors is deleterious for plants and the role of AM fungi in ameliorating this compound stress event is not fully understood, particularly within threatened communities such as grasslands. This study has investigated the role of field-collected AM fungi in facilitating plant responses to heat and water stress using a simulated heatwave event in a factorial greenhouse experiment to test how native grassland species respond. We found that the impact of heat stress combined with water stress on plant performance was shown to be greater than the additive effects of heat and water stress in isolation. AM fungi was shown to have variable influences on plant growth, fitness, and physiological responses but these influences were commonly at odds with previous publications on AM fungi with agricultural species. Most notably, AM fungi increased the germination success of seeds of one species grown following exposure to climate

stress. The results of this study highlight the dynamic role of AM fungi and help us understand grassland responses to heatwave events in the face of increasing extreme climate events. Furthermore, this study emphasises the importance of building ecologically relevant ex-situ experiments to study and understand current global pressures facing natural ecological communities.

P10.18 COMPARATIVE HOLOBIONT DYNAMICS IN DROUGHT RESILIENCE: EXPLORING THE ROLE OF FYNBOS MICROBIOTA IN SUTHERLANDIA (L) FRUTESCENS AND GLYCINE MAX

Friday 11th July 2025 12:00

Tebogo I Masetlana (Stellenbosch University, South Africa), Itumeleng P Moroenyane (Stellenbosch University, South Africa), Nokwanda P Makunga (Stellenbosch University, South Africa)

timasetlana@sun.ac.za

The plant holobiont, encompassing a host plant and its associated microbiomes, responds to abiotic stress to aid adaptation. This project aims to compare the adaptive contributions of soil microbiomes with varying microbiota assemblages and communities. Our study species Sutherlandia (L) frutescens (cancer bush), a medicinal plant native to southern Africa, and Glycine max (soybean), a globally cultivated nutrient-rich crop are both leguminous and ideal for comparing holobiont responses to drought. Unlike drought-sensitive Glycine max, Sutherlandia frutescens exhibits drought resilience (observed in fynbos populations) and distinct regional metabolite profiles suggesting soil microbiota may be underpinning metabolomic changes and chemotype. Fynbos soil microbiota will be isolated and applied as inoculum to drought-stressed plants in order to compare physiological and metabolomic responses. Soil sample collection will account for soil microbial legacy based on prior land use and precipitation rates. We hypothesise fynbos soil sampled from a lower rainfall region will exhibit greater functional diversity for drought resilience and improving metabolite production and crop yield. The mitigation of drought stress by microbes will be quantified through eco-physiological measurements, oxidative stress assays and metabolite profiling (LC-MS). Amplicon sequencing will be used to identify active microbial communities and establish a library of plant growth-promoting rhizobacteria (PGPR) useful as a bio-fertilizer. This project has the potential to mitigate climate change impacts, improve crop quality and yield, and standardize the production of medicinal plant metabolites, all while promoting sustainable water use.

Marco Maccaferri (University of Bologna, Italy), Francesco De Sario (University of Bologna, Italy), Rafika Benbernou (INRAE, France), Fabrice Ntakirutimana (INRAE, France), Nicolas Lapalu (INRAE, France), Karim Ammar (International Maize and Wheat Improvement Center, Mexico), Elisabetta Mazzucotelli (CREA, Italy), Muhammad A Farooq (University of Bologna, Italy), Jad B Novi (University of Bologna, Italy), Sandra B Stefanelli (University of Bologna, Italy), Roberto Tuberosa (University of Bologna, Italy), Frédéric Suffert (INRAE, France), Thierry C Marcel (INRAE, France) marco.maccaferri@unibo.it

Zymoseptoria tritici, the causal agent of Septoria Tritici Blotch (STB) disease, is recognized as a major threat to bread and durum wheat worldwide. Due to a long selection track, mainly aimed at increasing yield potential, cultivated wheat, particularly the durum wheat adapted to the Mediterranean area, is depleted of effective resistances. Identification of novel, effective and durable resistances in untapped Genetic Resources, and monitoring of pathogen’s population dynamics and its arsenal of effectors should be combined. On the host side, an exploratory association study was conducted on a panel of 600 durum wheat landraces, representative of eight distinct mainT. turgidumsubpopulations originated from areas where the pathogen co-evolved with its host. The haplotype-based GWAS analysis (Illumina 90K SNP array) revealed considerable variability across all eight subpopulations forStbresponse, and located main QTLs for resistance under field conditions whose alleles were dissected by local haplotype analysis and confirmed in recombinant populations obtained from three resistant Mediterranean landraces (Trinakria, Kyperounda, and Russello SG7) crossed with a susceptible reference. Five major loci for necrosis and sporulation with resistant alleles inherited from the landraces were located on chromosome 1A, 1B, 2A, 3A, 4A, 6A. The international consortium for tetraploid wheat pangenome is leading the long read PACBIO sequencing and RNAseq annotation of a wide range of 40 diverse tetraploid wheat genomes, including the landraces herein considered. Detailed results of haplotype-GWAS in the wide germplasm representation based on a domestication and evolutionary view of tetraploid wheat will be reported and discussed.

P10.20 LEAF BURN

IN

GRAPEVINE UNDER HIGH TEMPERATURE: WHICH PHYSIOLOGICAL DETERMINANTS DRIVE GENETIC VARIABILITY?

Friday 11th July 2025 12:30

Laurine Chir (INRAE Montpellier, France), Romain Boulord (INRAE Montpellier, France), Eva Coindre (Université de Montpellier Montpellier, France), Vincent Segura (INRAE Montpellier, France), Nicolas Saurin (INRAE Montpellier, France), Agnès Doligez (INRAE Montpellier, France), Benoît Pallas (Institut Agro Montpellier, France), Stéphane Berthézène (INRAE Montpellier, France), Thierry Simonneau (INRAE Montpellier, France), Aude Coupel-Ledru (INRAE Montpellier, France)

laurine.chir@inrae.fr

Friday 11th July 2025 12:15

Extreme heatwaves increasingly threaten viticulture, leading to irreversible leaf and fruit burns. In 2019, we capitalized on an unprecedented heatwave in south France and demonstrated a

genetic basis for leaf burn susceptibility on a large panel of 279 potted cultivars representing the diversity ofVitis viniferaL.. Genetic variation in leaf temperature was further explored within this panel under irrigated field conditions, and the influences of key morphophysiological traits affecting the leaf energy balance, including stomatal conductance, leaf inclination, area, folding, reflectance, and transmittance were investigated. Substantial genetic variation was observed for all these morpho-physiological traits in a range that could theoretically contribute to change in leaf temperature. Among the factors influencing leaf temperature, stomatal conductance emerged as the most influential, followed by transmittance. Genome-wide association studies also identified genomic regions linked to genetic variation in leaf temperature, stomatal conductance, inclination and transmittance. However, no colocalization was detected among these traits, suggesting distinct genetic controls. Cultivars ranking for heat tolerance may vary with the water regime. Notably, when air temperature reached 60°C in a greenhouse experiment, we observed that exacerbation of leaf burn under drought as compared to wellwatered conditions was genotype-dependent. These findings provide valuable insights for breeding programs aiming to mitigate heat stress effects by enhancing heat tolerance.

P10.21 HOW

DRIVING FORCES

Friday 11th July 2025 12:45

Théo M Degand (Earth and Life Institute Université catholique de Louvain, Belgium), Lei Ding (Earth and Life Institute Université catholique de Louvain, Belgium), Marco D’agostino (Earth and Life Institute Université catholique de Louvain, Belgium), Noémie Thiébaut (Department of Plant and Environmental Sciences Faculty of Science University of Copenhagen, Denmark), Thomas Dagbert (Earth and Life Institute Université catholique de Louvain, Belgium), Daniel Persson (Department of Plant and Environmental Sciences Faculty of Science University of Copenhagen, Denmark), Adrien Heymans (Umeå Plant Science Center Dept of Forest Genetics and Plant Physiology, Sweden), Monica Rothwell (Earth and Life Institute Université catholique de Louvain, Belgium), Valentin Couvreur (Earth and Life Institute Université catholique de Louvain, Belgium)

theo.degand@uclouvain.be

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

P10.2 PHENOTYPIC EVALUATION OF GARLIC (ALLIUM SATIVUM L.) GENOTYPES UNDER OPEN-FIELD CONDITIONS

Elena Barcanu Tudor (Vegetable Research and Development Station Buzau, Romania), Ovidia Loredana Agapie (Vegetable Research and Development Station Buzau, Romania), Ion Gherase (Vegetable Research and Development Station Buzau, Romania), Eliza Teodorescu (Vegetable Research and Development Station Buzau, Romania) barcanuelena@gmail.com

This study examines the impact of climate variability on garlic (Allium sativum L.) cultivation in Buzau, Romania, focusing on agricultural drought and breeding strategies for stress resilience. Between October 2023 and September 2024, precipitation remained below the multiannual average, with severe drought conditions affecting the southern and eastern regions. The Combined Drought Indicator (CDI) and Aridity Index confirmed increased drought severity, while heatwaves in July–August further stressed crops. Phenological observations indicated an earlier onset of developmental stages by 7–10 days due to rising temperatures, negatively affecting vegetable yields. A total of 26 garlic genotypes were evaluated against the registered cultivars ‘Benone’ and ‘Ramniceanu’ for productivity, stress tolerance, and morphological traits. Using Agglomerative Hierarchical Clustering (AHC), three distinct genotype groups were identified based on leaf morphology, bulb weight, and dry matter content. Preliminary results highlight significant phenotypic variability and potential for selecting drought-tolerant lines. The findings emphasize the importance of breeding programs in developing climate-resilient cultivars. Future research will refine genotype selection and enhance adaptation strategies for sustainable garlic production in Romania.

P10.3 AEGILOPS UMBELLULATA: A WHEAT WILD RELATIVE GIVING HEAT TOLERANCE TO HEXAPLOID WHEAT

Jake Hill (The University of Nottingham, United Kingdom), Surbhi Grewal (The University of Nottingham, United Kingdom), Julie King (The University of Nottingham, United Kingdom), Stella Edwards (The University of Nottingham, United Kingdom)

jake.hill@nottingham.ac.uk

Global temperatures are rising, putting pressure on our wheat production systems. Predictions indicate that for every 1°C increase in temperature, wheat yields have the potential to decrease by 6%. This represents an approximate one million metric tonne loss in the UK yearly. Furthermore, regions experiencing the largest temperature shifts align with some of the world’s most food-insecure communities. Wild relatives of wheat offer a solution for enhancing

yields under elevated temperatures. One such wild relative is Aegilops umbellulata, which can be found in Iran, Iraq, Turkey, and Syria— areas that frequently experience temperatures exceeding 40°C. Consequently, these conditions have influenced the development of Ae. umbellulata to withstand high temperatures compared to bread wheat. We measured chlorophyll fluorescence to determine Tcrit (the temperature at which Fv/Fm shifts from a steady decline in efficiency to a rapid decline, indicating severe damage to photosynthetic apparatus due to high temperatures) in a collection of Ae. umbellulata accessions and Ae. umbellulata/hexaploid wheat addition and substitution lines. Furthermore, we recorded plant yields and assessed seed morphology and elemental composition through imaging, ICP-MS, and carbonnitrogen analysis. Our findings suggest that chromosome 7U of Ae. umbellulata may possess the ability to enhance the thermotolerance of bread wheat, therefore protecting yields under high-temperature stress.

P10.4 CELLULAR IMPACT OF BACTERIA-MEDIATED MAIZE DROUGHT RESISTANCE: INSIGHTS FROM KINEMATIC ANALYSIS

Miao Jiang (Antwerp University, Belgium)

Miao.Jiang@student.uantwerpen.be

Drought is a major factor contributing to yield losses in crops such as maize. Microbial communities play a crucial role in enhancing drought tolerance by promoting plant growth. However, the mechanisms by which bacteria facilitate plant adaptation to drought stress and the corresponding plant responses remain poorly understood.In this study, we investigated the effects of two bacterial strains on maize under drought conditions. Comparative genome analysis was performed to identify functional genes associated with metabolic pathways, while cellular kinetic parameters in maize leaves were examined on the 3rd day after the emergence of the fifth leaf. The two strains exhibited distinct profiles of functional genes related to secondary metabolism, particularly those involved in antioxidant synthesis and drought stress resistance. Flavonoid degradation and synthesis by bacteria may enhance plant drought resilience by fostering a beneficial plant-microbe interaction.Notably, the two bacterial strains employed distinct growth-promoting strategies. Strain 327 enhanced leaf elongation by increasing both meristematic cell number and division rate, thereby elevating overall cell production. In contrast, strain BR5 primarily influenced growth by modulating cell division dynamics. These findings demonstrate that bacterial inoculation can enhance maize drought tolerance through distinct cellular mechanisms, offering valuable insights into plant-microbe interactions and potential applications in sustainable agriculture.

P10.5 NEW INSIGHT IN PLANT-MICROBE INTERACTION UNDER ORGANOCHLORINE PESTICIDES SOIL CONTAMINATION

Dalila Trupiano (Department of Biosciences and Territory - University of Molise, Italy), Anna Gillini (Department of Biosciences and Territory - University of Molise, Italy), Maria Tartaglia (Department of Science and Technology - University of Sannio, Italy), Antonello Prigioniero (Department of Science and Technology - University of Sannio, Italy), Daniela Zuzolo (Department of Science and Technology - University of Sannio, Italy)

dalila.trupiano@unimol.it

The rhizosphere is one of the most dynamic terrestrial ecosystems, functioning as a hotspot for plant-soil-microbe interactions, that can significantly influence nutrient cycles and, thus, the spatio-temporal dynamics occurring in soil system. The presence of such organic and inorganic contaminants in the environment poses a threat to various populations of plants and microorganisms affecting biocenoses and putting the integrity of ecosystems at risk. Recently, a comprehensive view of plant-microbe interactions and dynamics occurring under soil metal(loid)s contamination has been obtained by integrating spatial mapping of enzyme activities (2D-zymography) with the analysis of main root traits and structural/functional diversity of microbial communities. Conversely, the impact of soil organic contamination on rhizosphere interactions has remained a significant challenge. With this in mind, the Rhizo_Tongue project [funded by the European Union - Next-GenerationEU - National Recovery and Resilience Plan – PRIN 2022 MISSION 4, COMPONENT 2, INVESTIMENT N. 1.1, CUP: H53D23005300006] aims to observe the rhizospheric environment as a single dynamic entity, analyzing plant-bacteria-fungi interaction divergence under soil contamination with organochlorine pesticides. Specifically, the effect of a candidate microbial consortium inoculation on a dichloro-diphenyl-trichloroethane contaminated soil will be examined by analyzing the rhizosphere as metaphenomenon: changes in (plant-microbe) meta-transcriptome data together with plant specific root trait and exudation spectrum. It represents a clear opportunity to understand mechanisms regulating rhizosphere dynamics and to guide next-generation biotechnologies for soil ecosystem resilience.

P10.6 ABA INHIBITS RICE SEED GERMINATION UNDER LOW TEMPERATURE THROUGH ITS INDUCED BIOSYNTHESIS AND ENHANCED TREHALOSE ACCUMULATION

Jianhua Zhang (Hong Kong Baptist University, Hong Kong), Zhonge Qin (Hunan Agricultural University, China), Jiahan Lv (Hunan Agricultural University, China), Zhenning Teng (Hunan Agricultural University, China), Shuang Meng (Hunan Agricultural University, China), Yan Peng (Hunan Agricultural University, China), Dingyang Yuan (Hunan Hybrid Rice Research Center Hunan Academy of Agricultural Sciences, China), Meijuan Duan (Hunan Agricultural University, China), Nenghui Ye (Hunan Agricultural University, China) jzhang@hkbu.edu.hk

Low-temperature (LT) stress poses a serious threat to rice seed germination under direct sowing in rice production. Germination under LT therefore constitutes an important agronomic trait for such rice cultivation system. In this study, we identified a trehalose synthesis pathway gene, trehalose-6-phosphate phosphatase 3 (OsTPP3), involved in the regulation of LT germination in rice, as well as its upstream regulatory factor, the ABA signaling pathway gene OsbZIP23. LT stress induced the accumulation of ABA by upregulating the expression of OsNCED3. Consistently, overexpression of OsNCED3 significantly inhibited seed germination under LT conditions. RT-qPCR experiments found that the expression of OsbZIP23, a key component of ABA signaling pathway, was also significantly induced under LT stress and ABA treatment. Overexpressing OsbZIP23 increased the sensitivity to LT stress, resembling the phenotype of OsNCED3 overexpressing seeds. Furthermore, both LT stress and exogenous ABA treatment increased the trehalose content in WT seeds, by upregulating the expression of OsTPP3. Enhancing the expression of OsTPP3 or application of exogenous trehalose significantly increased the sensitivity to LT stress during seed germination. Transcriptional activation assays demonstrated that OsbZIP23 bound to the promoter of OsTPP3 and activated its expression, which was intensified by LT stress or application of ABA. Our study revealed an ABA-dependent OsbZIP23-OsTPP3 molecular module that responds to LT stress and inhibits seed germination under LT conditions. The regulated trehalose accumulation then balances growth and stress resistance under different temperature conditions.

ITS TARGETIBKTN80 ON THE SYSTEMIC LEAVES OF SWEET POTATO AFTER WOUNDING

Shih-Tong Jeng (Institute of Plant Biology National Taiwan University, Taiwan), Yi-Ching Chiu (Institute of Plant Biology National Taiwan University, Taiwan), Cheng-Chung Huang (Institute of Plant Biology National Taiwan University, Taiwan), Yu-Chi King (Institute of Plant Biology National Taiwan University, Taiwan)

stjeng@ntu.edu.tw

After wounding, plant leaves produce two signals: the local signal affecting the injured leaves and the systemic signal affecting the upper and lower leaves of the wounded leaves to overcome stresses. MicroRNAs (miRNAs) are involved in plant defense responses by repressing the expression of target genes. The functions of miRNA in plants’ local leaves after wounding have been studied well, but its effect on the systemic leaves remains to be investigated. The wounding-induced miR168-3p in the systemic leaves of sweet potato (Ipomoea batatas cv. Tainung 57) upon wounding was selected from the outcome of small RNA sequencing and studied here. Based on the bioinformatics analysis, the IbKTN80, which encodes the katanin p80 subunit, was the target of miR168-3p. The relationship between miR168-3p and IbKTN80 was verified by agroinfiltration with transient expression of primary miR168 and IbKTN80 transcript. Transgenic sweet potatoes overexpressing and silencing miR168-3p further confirmed that IbKTN80 was the target gene of miR168-3p. In addition, IbKTN80 rescued the functional defectiveness of the AtKTN80.2 in Arabidopsis, indicating IbKTN80 had a similar functionality as AtKTN80.2. Furthermore, IbKTN80, like AtKTN80.2, was involved in the signaling and biosynthesis of jasmonate (JA) through the regulation of MYC2. In conclusion, the systemic expression of miR168-3p was induced by wounding, and

further suppressed the expression of IbKTN80, which regulated MYC2 to participate in JA signaling in the systemic leaves of sweet potato to protect plants from environmental stress.

P10.9 ELUCIDATING HOW A FUNGAL ENDOPHYTE PROMOTES MAIZE GROWTH UNDER DROUGHT STRESS

Chiara Meskens (Antwerp University, Belgium), Hamada AbdElgawad (Antwerp University, Belgium), Gerrit T.S. Beemster (Antwerp University, Belgium)

chiara.meskens@uantwerpen.be

Drought is a major yield limiting factor for crops, including maize. Methods to combat drought in agriculture are often labour-intensive and use a lot of resources, if feasible at all in some cases. Due to restrictions regarding GMO-regulation or the great time investment required for breeding, looking into alternative ways towards drought tolerance is key. Here, we aim to characterise how a Trichoderma plant endophyte improves maize growth under severe drought stress, with particular focus on the cellular and molecular basis for this growth stimulation. Following seed inoculation, the leaf elongation rate (LER) showed to be increased under drought conditions. The stimulation of LER by this fungus can be attributed to an effect on the cell production rate, for which the fungus reduced the inhibition typically seen under drought. By mRNA sequencing of the maize leaf meristem, we found several genes related to DNA replication to be upregulated, confirming its positive effect on cell division. Further, we also could observe upregulation of genes related to the TCA cycle, nucleotide biosynthesis, and amino acid biosynthesis, most likely a result of stress relief. Also upregulation of biotin biosynthesis genes was observed. Biotin has been linked to increased drought tolerance in literature, although the exact function in drought tolerance remains elusive.

P10.10 GENOMIC PREDICTION OF VITAMIN C CONTENT IN SPINACH

Carlos A Avila (Texas AM AgriLife, United States), Janna J Rameneni (Texas AM AgriLife, United States), ASM Faridul Islam (Texas AM AgriLife, United States), Ainong Shi (University of Arkansas, United States) carlos.avila@ag.tamu.edu

Vitamin C (VC), also known as ascorbic acid and ascorbate, is a watersoluble antioxidant in plants that promotes skin health and immune function in humans. Spinach (Spinacia oleracea L.), a leafy green vegetable widely valued for its health benefits, has been identified as a target for nutritional enhancement, including increased VC content. However, the complex inheritance of VC necessitates advanced selection methods to accelerate cultivar development. In this study, VC- associated single nucleotide polymorphism (SNP) markers identified through genome-wide association (GWAS) were employed for genomic prediction (GP) to estimate prediction accuracy (PA) for VC content in spinach. A dataset of 147,977 SNPs generated from whole genome resequencing was analyzed in a panel of 347 spinach genotypes using six GWAS models. Sixty-two SNP markers, distributed across six spinach chromosomes, were significantly associated with VC content. PA was assessed using randomly selected SNP sets and GWAS-derived SNP marker sets across various GP models. Results

demonstrated that PA exceeded 40% when using 1,000 or more SNPs. Furthermore, incorporating GWAS-derived SNP markers improved PA, achieving a r-value greater 0.70 through Bayes ridge regression (BRR) model. This study highlights the potential of GWAS-derived SNP markers for marker-assisted selection (MAS) and genomic selection (GS) in spinach breeding programs aimed at enhancing VC content.

P10.16 DISRUPTION OF THE MAGNAPORTHE ORYZAE CIRCADIAN CLOCK COMPROMISES RICE BLAST DISEASE PROGRESSION IN RICE PLANTS.

S George R Littlejohn (University of Plymouth, United Kingdom), Ciaran Griffin (University of Plymouth, United Kingdom), Rehema Mwaipopo (University of Plymouth, United Kingdom), Naofel Aljafer (University of Plymouth, United Kingdom), Sophie J Folkard (University of Plymouth, United Kingdom), Kokila Wickramanayake (University of Plymouth, United Kingdom), Xia Yan (The Sainsbury Laboratory, United Kingdom), Andrew Foster (The Sainsbury Laboratory, United Kingdom), Nicholas J Talbot (The Sainsbury Laboratory, United Kingdom) george.littlejohn@plymouth.ac.uk

Rice blast is a devastating fungal disease of cultivated rice, causing yield losses of 10-30% of the global rice crop, or enough to feed 60 million people annually. We have shown that Magnaporthe oryzae, the causative agent of rice blast disease, displays strongly circadian behaviour in conidiation. In order to study the role of the clock in pathogenicity, we identified core clock genes in M. oryzae and used CRISPR-Cas9 to produce specific white collar 2 (Mowc2) and frequency (Mofrq) mutants. The circadian clock mutants we generated are greatly reduced in conidial production and timing of infection, making the mutants very significantly reduced in ability to cause disease.

P10.22 DYNAMICS OF INTERORGANELLE CARBON METABOLISM IN EGERIA DENSA LEAF CELLS DETERMINED USING PICOLITRE

SPECTROMETRY

Hiroshi Wada (Ehime University, Japan), Keisuke Nakata (Ehime University, Japan), Takumi Muneta (Ehime University, Japan), Rosa Erra-Balsells (University of Buenos Aires, Argentina), Hiroshi Nonami (Ehime University, Japan), Yoko Yamaga-Hatakeyama (Ehime University, Japan) hwada@agr.ehime-u.ac.jp

Recently, single-cell metabolomics has been widely used for studying cellular metabolic flow and heterogeneity in biology. Most analytical methods for studying the metabolic flow require sample preparation including tissue isolation, metabolite extraction and purification,

whereas in some plant sciences on-site cell-specific analysis is needed because of the limited sap volume from the heterogeneous cells in the living plants. In this view, direct cell metabolic flow analysis combined with 13 C tracer would be promising; however, to our knowledge no attempts have been made with 13 C tracer yet. In this work, growing Egeria densa plants were fed with 13 C to continuously trace carbon and photosynthesis metabolisms in the single leaf cells by using as a single-cell metabolomics technique ‘picolitre pressure-probe electrospray-ionisation mass spectrometry’ (picoPPESI-MS). When the same volume of cell fluids containing chloroplast(s) were collected and the metabolites in the fluids were assayed, numerous metabolites involved in carbon metabolism have been detected. When 13 C/12 C isotope ratio of each metabolite was determined with an Orbitrap mass analyser, the kinetics has revealed that 13 C fed as carbon dioxide was preferentially taken into the Calvin-Benson cycle, and subsequently photorespiration, followed by TCA cycles and glycolysis in the order in the same single cells. And hence, we conclude that picoPPESI-MS is capable for directly determining the dynamics of metabolic flow at the inter-organelle resolution in the target cells and this analytical method combined with 13 C tracer might be useful for various research subjects in biology.

P10.23 RESURRECTION PLANTS: THE UNSOLVED MYSTERY OF VOLATILE ORGANIC COMPOUNDS (VOCS) EMISSIONS UNDER EXTREME PHYSIOLOGICAL DESICCATION

FRANCESCA RAPPARINI (Institute of BioEconomy (IBE) National Research Council (CNR), Italy), GABRIELLA VINCI (Department of Agricultural Food Animal and Environmental Sciences University of Udine Italy, Italy), GIANPAOLO BERTAZZA (Institute of BioEconomy (IBE) National Research Council (CNR), Italy), ALESSIO TEI (Institute of BioEconomy (IBE) National Research Council (CNR), Italy), GERGANA MIHAILOVA (Institute of Plant Physiology and Genetics Bulgarian Academy of Sciences Akad. Georgi Bonchev, Bulgaria), KATYA GEORGIEVA (Institute of Plant Physiology and Genetics Bulgarian Academy of Sciences Akad. Georgi Bonchev, Bulgaria) francesca.rapparini@cnr.it

Resurrection or desiccation tolerant plants are characterized by a remarkable ability to survive extreme desiccation, losing more than 90% of the cellular water in their vegetative tissues, and then recover normal physiological activity after only few hours of rehydration. Plants release many different Volatile Organic Compounds (VOCs) to cope with environmental stresses. The VOC emission capacity have been investigated only in few resurrection species and most of these studies has shown the leaf emission of isoprene and other VOCs (C6 green leaf volatiles), and oxygenated compounds (acetone, and methanol). In the present study, the leaf emission of VOCs was assessed in the resurrection angiosperm Haberlea rhodopensis Friv. (Gesneriaceae) that belongs to the homoiochlorophyllous type species that are characterized to retain the photosynthetic apparatus and pigments, which allows a quicker recovery following rehydration. However, the high concentration of chlorophyll during desiccation is a source for the production of harmful reactive oxygen specie. Therefore, H. rhodopensis needs better antioxidant protection against free radical attack experienced either during dehydration or immediately upon rehydration. Our study aims to understand the role of leaf VOCs emission in the desiccation tolerance strategy of H. rhodopensis. The temporal dynamic of VOC emission during

dehdyration and rehydration was monitored continuously by applying proton transfer reaction – time of flight-mass spectrometry (PTR-MS) and gas chromatography-mass spectrometry (GC-MS). Our study on the VOC emission, together with parallel analysis of the photosynthetic activity and photoprotective mechanisms, provides new insights into the potential role of VOCs for the “drying without dying” ability.

P10.24 BIOGENIC VOLATILE ORGANIC COMPOUNDS (BVOCS) FOR PLANT GROWTH PROMOTION: A PRELIMINARY STUDY ON RICE CALLUS AND SEEDLINGS

Costanza Cicchi (Institute for Sustainable Plant Protection (IPSP) - National Research Council (CNR), Italy), Anna De Carlo (Institute of Bio-Economy (IBE) –National Research Council of Italy (CNR), Italy), Maurizio Capuana (Institute of Biosciences and Bioresources (IBBR) – National Research Council of Italy (CNR), Italy), Veronica Gregis (Department of Bioscience University of Milan, Italy), Claudia M Liberatore (Department of Bioscience University of Milan, Italy), Luigia Pazzagli (Department of Experimental and Clinical Biomedical Sciences University of Florence, Italy), Teresa Guaragnone (Department of Chemistry University of Florence - Center for colloid and Surface Science (CSGI), Italy), Alessio Zuliani (Department of Chemistry University of Florence, Italy), Federico Brilli (Institute for Sustainable Plant Protection (IPSP) –National Research Council of Italy (CNR), Italy)

costanzacicchi@cnr.it

The final morphology of a plant is determined by the activity of the shoot apical meristem (SAM), a group of pluripotent cells responsible for the generation of above-ground aerial plants’ organs. The identity and differentiation of SAM cells are under a strict hormonal and transcriptional regulatory network, involving epigenetic modifications and different signalling molecules. Among these, Reactive Oxygen Species (ROS) play an important role in cell cycle regulation, thus contributing to plant growth. Overall, plant hormones and ROS create a complex interplay of connections that can be modulated to boost plant development and productivity. Biogenic Volatile Organic Compounds (BVOCs) are a large variety of molecules produced by different plant tissues. There is increasing evidence that BVOCs participate in the regulation of signalling pathways involving ROS production and hormone synthesis. For this reason, application of BVOCs may represent a novel strategy to enhance plant meristematic activity, with a positive impact on plant productivity. Our project investigates the effects of exposure to BVOCs (i.e. isoprenoids) on rice, with the aim of exploring the possibility to increase rice yield through modulation of hormone signalling, gene activation and plant redox state. Experiments are currently ongoing to evaluate changes in cell redox mechanisms, hormones synthesis and gene expression at different plant levels: (i) on undifferentiated and regenerating rice callus, (ii) on rice seedlings exposed to exogenous isoprene. Preliminary results suggest that isoprene is able to modulate the rice redox machinery and positively affects the expression of auxinresponsive genes, possibly impacting plant growth and development.

P10.25 DOES PFAS POLLUTION RESULT IN SMALLER VEGETABLES? A CASE STUDY ON PFAS ACCUMULATION AND GROWTH HORMONE LEVELS IN DIFFERENT TYPES OF VEGETABLES.

Demi Rotthier (University of Antwerp, Belgium), Sevgi Oden (University of Antwerp, Belgium), Tim Willems (University of Antwerp, Belgium), Kris Vissenberg (University of Antwerp, Belgium), Thimo Groffen (University of Antwerp, Belgium), Els Prinsen (University of Antwerp, Belgium)

demi.rotthier@uantwerpen.be

Per- and polyfluoroalkyl substances (PFAS) are widely used, resulting in substantial accumulation and pollution by these forever chemicals. Terrestrial plants are able to take up PFAS through their roots, and previous research suggested an association between PFAS accumulation in plants and their phytohormone levels.

In this study we compared PFAS bioaccumulation, translocation, and distribution patterns with phytohormone levels in various plant parts. An environmentally relevant PFAS mixture, containing the ten most dominant PFAS present in private gardens near a PFAS hotspot, was used in this study. These compounds with varying chain length and functional groups were chosen to identify potential distribution differences within the plant due to the characteristics of these individual compounds. Individual plants were grown on soil spiked with three different concentrations of this PFAS mixture alongside a control group. The plants were separated in different plant parts which were collected separately and flash frozen in liquid nitrogen.

After solvent extraction and solid phase extraction, PFAS and phytohormones were quantified using UPLC-MS/MS. The results will identify bioaccumulation, translocation and distribution patterns of the 10 PFAS compounds added to the broad bean plant. Comparing the PFAS-related results and size of the different plant parts to the hormone levels in each plant part, will allow us to understand how PFAS affects plant growth and which mechanisms are involved.

In addition, this study will identify PFAS accumulation sites within different species, which is crucial for assessing potential human consumption risks.

SCIENCE ACROSS BOUNDARIES ABSTRACTS (ANIMAL, CELL AND PLANT BIOLOGY)

SAB1: PHYSIOLOGICAL GENOMICS

ORGANISED BY: EMILY BECK (UNIVERSITY OF KANSAS)

SAB1.1 UNRAVELING THE GENETICS OF COMPLEX TRAIT ADAPTATIONS: INSIGHTS FROM THE HOUSE MOUSE

Thursday 10th July 2025 09:00

Katya Mack (University of Kansas, United States)

katya.mack@ku.edu

One of the greatest challenges in biology is understanding the relationship between genetic and phenotypic variation. Despite advances in sequencing technologies and analysis methods, our ability to predict relationships between evolutionary forces, DNA sequence variation, and phenotypes remains limited. In this talk, I will describe how we have leveraged an integration of computational and experimental approaches to understand the role of gene regulatory variation in phenotypic evolution and climate adaptation in house mice. First, we examined the role of gene expression in driving adaptive differences in body size and metabolism in house mice after the colonization of North America. Next, using environmentally relevant treatments in the lab, we examined the role of gene-byenvironment (GxE) interactions in phenotypic variation and gene regulatory evolution across these populations. Finally, using crosses between mice from diverse localities, we identify candidate genes for metabolic adaptations and body size differences across populations. Together, our results underscore the importance of interactions between gene expression, environmental variation, and GxE interactions to adaptive variation in complex traits.

SAB1.2 THE COMPARATIVE AND POPULATION GENOMICS OF AN ICEFISH THAT ESCAPED ANTARCTICA

Thursday 10th July 2025 09:30

Julian Catchen (University of Illinois Urbana-Champaign, United States)

jcatchen@illinois.edu

SAB1.3 RAPID EVOLUTIONARY CHANGE OF HYPOXIA PHYSIOLOGY AND RELATED GENE EXPRESSION PATTERNS IN AN ASEXUAL DAPHNIA POPULATION

Thursday 10th July 2025 09:45

Athina Karapli-Petritsopoulou (Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany), Dörthe Becker (Naturschutzstation Niederrhein (NABU), Germany), Dagmar Frisch (Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany)

athena.karapli@igb-berlin.de

Freshwater ecosystems in the Arctic facing rapid environmental change can serve as important model systems for studying the rapid adaptation potential of their inhabitants. Key members of these Arctic ecosystems often reproduce asexually, raising questions about their capacity to adapt over short time scales, and what are the possible mechanisms. Here, we studied an asexual Daphnia population from a meromictic lake in South-West Greenland using resurrected animals dated to ca. 2012 CE and modern descendants from 2022 forming two temporal subpopulations. The anoxic layer of the lake was previously inhabited by anoxygenic photoautotroph purple sulfur bacteria, a possible food resource for Daphnia. This microbial population, however, seems now to be destabilized, which could be reducing the presence of Daphnia in hypoxic or anoxic waters. In previous work, we found that the two Daphnia temporal subpopulations differ in their genetic structure and physiological traits linked to hypoxia and thermal tolerance. To investigate their physiological and transcriptomic responses to hypoxia in more detail, we exposed three clones from each subpopulation to medium and severe hypoxia. We quantified hemoglobin production, one of the main mechanisms of hypoxia response in Daphnia, and measured two oxidative stress markers: glutathione-S-transferase activity and TBARS, a proxy for lipid peroxidation. Diverging physiological responses and associated gene expression patterns between temporal subpopulations will be discussed in the light of rapid evolutionary change in response to ecosystem changes in an asexual population.

SAB1.4 BEYOND BIOMARKERS: MULTIOMICS AND MULTILAYER NETWORKS AS BREAKTHROUGHS TO PREDICT THE EFFECTS OF GLOBAL CHANGES ON AQUATIC ECTOTHERMS

Thursday 10th July 2025 10:00

Lauric Feugere (MEEP lab Department of Biology Chemistry and Geography University of Quebec at Rimouski, Canada), Fanny Vermandele (MEEP lab Department of Biology Chemistry and Geography University of Quebec at Rimouski, Canada), Ella Guscelli (MEEP lab Department of Biology Chemistry and Geography University of Quebec at Rimouski, Canada), Denis Chabot (Institut Maurice-Lamontagne Fisheries and Oceans Canada, Canada), Bruno Manadas (Center for Neuroscience and Cell Biology University of Coimbra, Portugal), Ricardo Calado (ECOMARE CESAM Department of Biology University of Aveiro, Portugal), Rosário Domingues (Mass Spectrometry Centre LAQVREQUIMTE CESAM Department of Chemistry University of Aveiro, Portugal), Geneviève Parent (Institut MauriceLamontagne Fisheries and Oceans Canada, Canada), Christopher W. McKindsey (Institut Maurice-Lamontagne Fisheries and Oceans Canada, Canada), Kimberly L. Howland (Fisheries and Oceans Canada Arctic and Aquatic Research Division Freshwater Institute Winnipeg, Canada), Carolina Madeira (Department of Life Sciences School of Science and Technology NOVA University of Lisbon, Portugal), Diana Madeira (ECOMARE CESAM Department of Biology University of Aveiro, Portugal), Piero Calosi (MEEP lab Department of Biology Chemistry and Geography University of Quebec at Rimouski, Canada)

feugla01@uqar.ca

Life is complex. The response of marine ectotherms to global changes stems from minute molecular alterations, with consequences scaling up through cellular functions to phenotypes to ecosystems. Another layer of complexity arises from the potential emergence of the interactive effects of multiple stressors. Whilst statistical and methodological developments, such as integrative frameworks and high-throughput omics, marked breakthroughs in clinical sciences, their use is lagging behind in aquatic sciences. Here, we explored a large-scale multilayer dataset on the response of the circumpolar Northern shrimp Pandalus borealis to combined ocean warming, acidification and hypoxia as the ideal opportunity to develop a framework implementing both different levels of the biological hierarchy and multiple stressors. Molecular (metabolomics, lipidomics, proteomics), cellular (enzymatic activity) and physiological (standard metabolic rates, maximum metabolic rates, aerobic scope) phenotypes of Northern shrimp from the Northwest Atlantic were integrated into multiomics and multilayer networks. Multivariate analyses show that the response of Northern shrimp strongly depends on the severity of their multistressor environment. Particularly, when hypoxia is superimposed to ocean acidification and warming, a positive synergistic effect emerges in multiomics profiles. Further analyses will help identify the key cellular functions that underpin the reduction in physiological performance and survival observed under combined ocean change drivers. Implementing integrative multiomics and multilayer approaches in marine and aquatic sciences will facilitate breakthroughs in life sciences, providing a greater understanding of how aquatic ectotherms will respond to ongoing environmental changes. Ultimately this new knowledge will inform more effective conservation measures and management strategies.

SAB1.6 OMICS TOOLS APPLIED TO ANTARCTIC FISH PHYSIOLOGY AND EVOLUTION

Thursday 10th July 2025 11:00

Thomas Desvignes (University of Alabama at Birmingham, United States)

tdesvignes@uab.edu

Antarctic notothenioid fishes form a remarkable marine adaptive radiation that adapted, diversified, and still thrive in the frigid Antarctic environment. Among them are also the white-blooded icefishes, true evolutionary oddities that live without haemoglobin and transport oxygen only by dissolution in the blood plasma. While survival and diversification of Antarctic notothenioids is linked to the innovation of an antifreeze glycoprotein, other molecular mechanisms that contributed to adapting cellular and physiological processes to life in freezing waters remain poorly understood. Recently generated whole-genome sequence assemblies for many notothenioid species helped refine time estimates for Antarctic species initial diversification, enabling us to link molecular and physiological adaptations to past climatic events. Further, high-quality genome assemblies revealed important variations in haemoglobin gene content across the radiation and that the cold Antarctic environment influenced haemoglobin gene evolution. In addition, protein-coding gene transcriptomic analyses uncovered the underlying genetic mechanisms of Antarctic species’ reduced haemoglobin multiplicity, which is the capacity to express multiple haemoglobin isoforms with differing physiochemical properties, a process thought to help adapt to variable environmental and physiological conditions. Finally, small non-coding RNA transcriptomics are shedding new light on the remodelling of the icefish heart that not only pumps a large volume of haemoglobin-less blood but also functions without myoglobin. Together, the combined use of Omics tools develops a comprehensive understanding of the evolution of notothenioid fishes and reveal their physiological adaptations to life in the extreme Antarctic environment.

SAB1.7 GENOMIC COMPENSATION TO MITOCHONDRIAL VARIATION IN THREESPINE STICKLEBACK FISH

Thursday 10th July 2025 11:30

Emily A. Beck (University of Kansas, United States)

emilybeck@ku.edu

SAB1.8

EFFECTS

OF ACUTE HYPOXIA EXPOSURE ON GENE EXPRESSION IN AN EXTREMOPHILE FISH

Thursday 10th July 2025 11:450

Bethany Williams (University of Missouri St. Louis, United States), Ethan Christopher (Kansas State University, United States), Casey Ernest (University of Missouri St. Louis, United States), Isabel Kline (University of California Santa Cruz, United States), Owen Moosman (University of California Santa Cruz, United States), Kegan Morrow (University of Missouri Kansas City, United States), Madison Nobrega (Topeka Zoo, United States), Nathan Surendran (University of California Santa Cruz, United States), Lenin Arias Rodriquez (Universidad Juárez Autónoma de Tabasco, Mexico), Joanna Kelley (University of California Santa Cruz, United States), Michael Tobler (University of Missouri St. Louis, United States)

bwmwb@umsl.edu

It is challenging to isolate the causative effects of single sources of selection in nature, because environments are often complex with different selective pressures covarying along environmental gradients. For instance, sulfidic springs are characterized by high levels of toxic hydrogen sulfide (H2 S) and low levels of oxygen in comparison to nearby non-sulfidic sites, which are normoxic. However, previous studies on fish in these systems have focused primarily on the effect of H2 S on gene expression, while hypoxia is also known to strongly shape gene expression in aquatic organisms. Members of the Poecilia mexicana species complex have repeatedly colonized sulfidic springs in Costa Rica and Mexico. We compared hypoxia tolerance and gene expression after exposure to acute hypoxia in three sulfidic populations and three non-sulfidic populations. We found that fish from sulfidic environments were generally more tolerant of hypoxia. We also found evidence for shared gene expression responses to acute hypoxia across sulfidic and nonsulfidic populations, despite contrasting habitat types and large geographic distances between populations. Our research suggests that acute hypoxia tolerance in both non-sulfidic and sulfidic populations is facilitated by upregulation of genes associated with oxygen sensing, oxygen delivery, and cardiac function. Our studies sheds light on the ancestral responses to hypoxia in this species complex and sets the stage for future studies that consider the simultaneous effects of H2 S and hypoxia on gene expression.

SAB1.9 GENOMIC AND PHENOTYPIC CHANGE WITHIN ONE DECADE IN AN ASEXUAL DAPHNIA POPULATION

Thursday 10th July 2025 12:00

Dagmar Frisch (Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany), N John Anderson (Loughborough University, United Kingdom), Dörthe Becker (NABU Naturschutzstation Niederrhein Kleve, Germany), Athina Karapli-Petritsopoulou (Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany)

dagmar.frisch@igb-berlin.de

Obligate parthenogenesis is a widespread phenomenon in extreme environments both in higher latitudes and high altitudes. This has also been observed in the keystone zooplankton grazer Daphnia, particularly of species belonging to the pulex/pulicaria species complex which have a circumpolar distribution. Arctic lakes are generally nutrient-poor and have low productivity, but in some meromictic lakes, dense photoautotroph bacterial populations in the anoxic zone of the lake can be an important food source for Daphnia. Associated with the recent shift in climatic conditions in the Arctic, this food source may now have diminished considerably, thus relaxing selection pressure on hypoxia tolerance that would have allowed Daphnia to feed in hypoxic or anoxic conditions. For a deeper understanding of their capacity for rapid adaptation to such changes, we studied members of an obligately parthenogenetic Daphnia population resident in a lake in Southwest Greenland at two time points separated by a decade. We compared genotypic and phenotypic properties of the historical population represented by resurrected lineages dating to 2012 CE, to a those of a modern lake population sampled in 2022 CE. We applied whole genome sequencing to study genomic differences at the temporal subpopulation level and combined this data with physiological trait measurements including respiration rate, critical oxygen limit and thermal tolerance. We will discuss the significant differences in functional traits and their potential genomic underpinnings, providing evidence for rapid phenotypic change with potential adaptive value.

SAB1.10 SPATIAL TRANSCRIPTOMICS REVEALS

REGION-SPECIFIC RESPONSES TO ANOXIA IN THE CRUCIAN CARP BRAIN

Sjannie Lefevre (University of Oslo, Norway), Elie Farhat (University of Oslo, Norway), Christian Damsgaard (Aarhus University, Denmark)

s.l.nilsson@ibv.uio.no

The crucian carp (Carassius carassius) is a fish with a remarkable anoxia tolerance, enabling it to survive the Norwegian winters in the wild, where seasonal anoxia is common in small lakes and ponds. While the physiological mechanisms are well documented, there is still a need for better understanding the regulation at the molecular and genetic level. The crucian carp brain overall shows a large transcriptional response to anoxia and reoxygenation but given that the brain is a complex and heterogenous tissue, we wanted to explore if transcriptional anoxia responses differ between brain regions. We prepared brain sections from crucian carp that had been exposed to 5 days normoxia or 5 days anoxia, aiming for a transverse plane that would capture the telencephalon, optic tectum and thalamus. These regions were chosen because previous studies have indicated increased cell death while affecting learning and memory in anoxia in the telencephalon, along with well-known reductions in retinal activity and vision in anoxia. We used the Visium Spatial Gene Expression technology from 10x Genomics to prepare mRNA libraries from the brain sections (four per treatment). Based on the mRNA abundance data, we successfully identified brain regions with distinct gene expression patterns: six in the telencephalon, four in the optic tectum, and two in the thalamus. In response to anoxia, there were more down-regulated than up-regulated genes in the telencephalon, while the optic tectum and thalamus had more up-regulated genes. The study thus confirms the complexity of the crucian carp brain transcriptional response to anoxia.

POSTER SESSIONS

Friday 11th July 2025

18:00-20:00

SAB1.5 METAGENOMIC ANALYSIS OF MICROBIOTA IN SOY SAUCE DURING FERMENTATION

Lai Hsi-Mei (Department of Agricultural Chemistry National Taiwan University, Taiwan), Yi-Ling Huang (Institute of Food Safety and Health National Taiwan University, Taiwan), Yu-Chi King (Institute of Plant Biology National Taiwan University, Taiwan), Hsin-Chang Chen (Institute of Food Safety and Health National Taiwan University, Taiwan), Shih-Tong Jeng (Institute of Plant Biology National Taiwan University, Taiwan)

hmlai@ntu.edu.tw

Soy sauce is a conventional fermented food and soybeans and wheat are used as mainly raw materials. It is an eastern conventional condiment, and made from the koji-inoculated roasted wheat flour and steamed soybeans (called koji fermentation stage), followed by a 4-6 month fermentation of soy sauce mash in brine (called moromi fermentation stage). The complicated interactions of microorganisms during fermentation play an essential role in the metabolites and quality of soy sauce. The biochemical and chemical reactions during fermentation generate various compounds, contributing to the difficulty in controlling soy sauce production. The aim of this study is to investigate the microbiota using metagenomic sequencing of industrial soy sauce production from the 100-ton fermenters. In addition to evaluate the physicochemical characters of moromi, the flavor compounds were analyzed by using GC/MS. The results showed that after one-week fermentation, the primary microorganism in soy sauce mash is fungi, mainly including Aspergillus parasiticus and Aspergillus transmontanensis. While bacteria, containing Bacillus and Staphylococcus became the major microorganism (89%) in 3 to 23-week of mash. The flavor compounds of moromi included aldehydes, esters, alcohols, ketones, and heterocyclics which increased the types and relative concentrations as the fermentation prolonged. The principle component analysis (PCA) showed that the microbiota at the early moromi fermentation significantly impacted the formation of flavor compounds. Conclusively, the quality of soy sauce can be improved and controlled by monitoring the microbiota during fermentation based on this study.

SAB2: SHARED CHALLENGES AND DIVERSE APPROACHES TO PHYSIOLOGY IN CONSERVATION ACROSS TAXONOMIC BOUNDARIES

ORGANISED

BY: BRITNEY FIRTH (UNIVERSITY OF WINDSOR), VERONICA GROVES (MCGILL UNIVERSITY), SEAN TOMLINSON (CURTIN UNIVERSITY), ZJEF PEREBOOM (ANTWERP ZOO)

SAB2.1 UNDERSTANDING SEED LONGEVITY FOR IMPROVED EX SITU PLANT CONSERVATION

Thursday 10th July 2025 11:00

Fiona R. Hay (Aarhus University, Denmark)

fiona.hay@agro.au.dk

A lot of our knowledge about how long orthodox seeds can survive in long-term cold (-20°C) storage in seed (gene) banks comes from studies on crop species. A clear advantage of focusing research on crops is that it is easy to access large, homogenous seed lots. While the general principles behind seed storage broadly apply to wild orthodox species, improving our understanding of seed longevity for wild species has challenges, including the ability to acquire sufficient quantities of seeds, more heterogenous responses, and dormancy. This in turn hampers our ability to optimize conservation protocols, for example in terms of making decisions about when to monitor viability or when to archive an accession and make a new collection. Some of these issues will be discussed in the context of our research on diverse species for improved ex situ plant conservation.

SAB2.2 METABOLIC RATES OF SEEDS: EXPLORING AN EMERGING FUNCTIONAL TRAIT IN SEED BIOLOGY

Thursday 10th July 2025 11:30

Sean Tomlinson (Curtin University, Australia), Emma L Dalziell (University of Western Australia, Australia), Phillip C Withers (University of Western Australia, Australia), Wolfgang Lewandrowski (Kings Park Science Department of Biodiversity Conservation and Attractions, Australia), Fiona R Hay (Aarhus University, Denmark), David J Merritt (Kings Park Science Department of Biodiversity Conservation and Attractions, Australia)

sean.tomlinson@curtin.edu.au

Energetics is fundamental to ecology and evolution, and metabolic rates are broadly considered as insightful functional traits in an ecological and evolutionary context. The study of energetics – how organisms acquire, convert and use energy to sustain life processes – and the measurement of metabolic rates provides key insights into costs of living. Making those measurements, at least for some taxa, has long been considered too difficult to gain these insights and the energetics of plants, and in particular, seeds (i.e. embryonic plants) is less well studied. Through our research, we have demonstrated differences in metabolic rates between batches of seeds with known ratios of live and dead seeds, indicating the potential use of the technique in assessing seed viability. This simple relationship between live and dead seeds and their metabolic rates has been extended to test the metabolic consequences of seed aging, and we have shown that establishing a relationship between seed respiration and longevity is possible, but still complex. Recently, we have investigated interspecific variation in seed metabolic rates, including exploring the relationship between seed mass and metabolic rates. We show that while metabolic rates of seeds scale in the same manner demonstrated in many other taxa, the relationship in seeds is much more variable. We found significant influences of phylogeneticrelatedness and climate on this relationship, and also potential effects of seed dormancy that are yet to be fully understood. We suggest that the measurement of whole-seed metabolic rates has potential as an emerging functional trait in seed biology.

SAB2.3 IMPACTS OF SPERM CRYOPRESERVATION ON EARLY LIFE HISTORY FITNESS OF ENDANGERED INNER BAY OF FUNDY ATLANTIC SALMON (SALMO SALAR)

Thursday 10th July 2025 11:45

Britney L. Firth (University of Windsor, Canada), Trevor E. Pitcher (University of Windsor, Canada), Laura Weir (St. Marys University, Canada), Anna MacDonnell (Fisheries and Oceans Canada, Canada), Nathalie MacPherson (Fisheries and Oceans Canada, Canada), Tyler Wilson (Fisheries and Oceans Canada, Canada), Mike Goguin (Fisheries and Oceans Canada, Canada), Zachary Trefry (Fisheries and Oceans Canada, Canada), Nathalie Brodeur (Fisheries and Oceans Canada, Canada), Darek Moreau (Fisheries and Oceans Canada, Canada), Derek Hogan (Fisheries and Oceans Canada, Canada), Louise De Mestral (Fisheries and Oceans Canada, Canada), Beth Lenetine (Fisheries and Oceans Canada, Canada), Brendan Wringe (Fisheries and Oceans Canada, Canada)

bfirth26@gmail.com

The use ofex situconservation to establish assurance colonies is on the rise as global biodiversity decline. However, assurance colonies need to maintain a high biomass to preserve genetic diversity in captive breeding programs. With technological advancements, gamete cryopreservation can be used to preserve genetic diversity while minimizing maintenance of captive live animals. However, it is still unclear whether gamete cryopreservation impacts fish fitness. Using the established Live Gene Bank for endangered Inner Bay of Fundy Atlantic Salmon (Salmo salar), we assess whether sperm cryopreservation impacts fertilization success, survival, and offspring phenotype over two years. Egg clutches from each female were split in half and fertilized with either fresh or cryopreserved sperm from the same male to reduce parental effects. Cryopreserved sperm significantly reduced fertilization success, as well as embryo and alevin survival. Cryo-derived individuals at 50% hatch were shorter and had smaller yolk-sac area. However, at this timepoint, there was no impact of cryopreservation on global DNA methylation. At first feeding, cryo-derived individuals were significantly larger nevertheless there was no differences in length, mass, or condition factor at later life-stages. This study demonstrates that despite differences in cryo-derived morphometrics at early-life stages, cryopreservation appears to have minimal impact on morphometrics at later life stages, implying individuals could have similar post-release survivorship and reproductive output. Our findings suggest that cryopreservation of sperm can be a useful technique for Inner Bay of Fundy Atlantic Salmon, although further research is needed to assess other fitness metrics and generational impacts.

SAB2.4 THE CHALLENGES RELATED TO USING THE MINNOW BLACKCHIN SHINER (MINIELLUS HETERODON) AS A SURROGATE FOR THE THREATENED PUGNOSE SHINER (MINIELLUS ANOGENUS)

Thursday 10th July 2025 12:00

Veronica Groves (McGill University, Canada), Marion Morissette (McGill University, Canada), Lauren Chapman (McGill University, Canada)

veronica.groves@mail.mcgill.ca

Freshwater ecosystems are impacted by multiple abiotic and biotic stressors, often in tandem, which may contribute to the imperillement

of freshwater species including species of conservation importance. In Canada, the freshwater minnow, Pugnose Shiner (Miniellus anogenus, formerly of the Notropis genus), is classified as Threatened under the federal Species at Risk Act. In one of the habitats of Pugnose Shiner, the Old Ausable Channel, Ontario, Canada, there are concurrent threats from habitat modification, nutrient loading and increases in turbidity. In addition, an apparent increase in centrarchid (bass, sunfish) species may be affecting both predator risk and competition for the minnows. As such, we conducted a series of studies aiming to understand how warming waters and changing predator/competitor communities affect the behaviour and physiology of Pugnose Shiner, as well as investigate if the non-threatened congener, Blackchin Shiner (Miniellus heterodon, formerly of the Notropis genus) is a suitable surrogate species. In this session, I will share the challenges faced when attempting to use Blackchin Shiner as a surrogate species for Pugnose Shiner in regards to predator risk and thermal tolerance, and share insights into future directions.

SAB2.5 CAPTIVE BREEDING AND THE EFFECT OF TANK COLOUR ON THE BODY COLOUR, SOMATIC GROWTH, SURVIVAL AND BEHAVIOUR OF CHINOOK SALMON

Thursday 10th July 2025 12:15

Trevor E Pitcher (University of Windsor, Canada), Maiza Saqib (University of Windsor, Canada), Britney Firth (University of Windsor, Canada), Dane Roberts (University of Windsor, Canada) tpitcher@uwindsor.ca

Captive breeding often results in the production of animals that exhibit maladaptive phenotypes that result in lower fitness (comapred to their wild congeners) in the context of conservation reintroductions. These maladaptive phenotypes are likely due, in part, to the environmental mismatch (compared to the wild) that occurs during their early ontogeny in captivity. One such potentially environmental mismatch, that may reduce the fitness of captive bred animals for conservation, is the colour of the housing where the animals are reared. We investigated the effects of tank colour on body colour, somatic growth, survival and behaviour in Chinook salmon, which are endangered throughout much of their range. Six different tank colours (that vary in brightness) were used, including grey, red, black, white, blue and green. The body colour was significantly impacted by the brightness of the rearing tanks. We also examined the plasticity of the body colour by experimentally altering the substrate of the rearing tanks halfways through the experiment. The results of the study will be discussed in light of conservation captive breeding efforts for fishes around the globe.

SAB3: CELLULAR METABOLISM AND INDIVIDUAL PERFORMANCE: NAVIGATING FROM ANIMALS TO PLANTS IN A CHANGING WORLD

ORGANISED BY: ELISA THORAL (LA ROCHELLE UNIVERSITY), LOIC TEULIER (CLAUDE BERNARD UNIVERSITY), JULES DEVAUX (UNIVERSITY OF AUCKLAND), ENRIQUE RODRIGUEZ (UNIVERSITY COLLEGE LONDON)

SAB3.1 ACTIVE IN THE COLD: HOW INSECT MITOCHONDRIA POWER WINTER SURVIVAL

Tuesday 8th July 2025 09:00

Nicolas Pichaud (Université de Moncton, Canada), Adèle Léger (Université de Moncton, Canada), Samuel Robichaud (Université de Moncton, Canada), Mélanie Aminot (Université de Moncton, Canada), Hervé Colinet (Université de Rennes, France)

nicolas.pichaud@umoncton.ca

Insects, as ectothermic organisms, display a remarkable ability to thrive in a wide range of thermal conditions, a key factor contributing to their success in colonizing various environments. They are thus ideal models for studying the effects of temperature on metabolic processes. Insects employ diverse strategies to survive cold winters, including entering diapause, migrating, and producing antifreeze compounds. Some insects, however, remain active throughout the winter, relying on specialized adaptations to maintain their metabolic functions. These overwintering insects, such as certain Drosophila species and eusocial honeybees, leverage a variety of physiological and cellular mechanisms to regulate their energy expenditure and sustain their cellular processes despite the challenging cold environments they inhabit. Mitochondria, as the hub of cellular metabolism, play a crucial role in these overwintering strategies. In this presentation, I will examine the mechanistic changes in mitochondrial functions, structure, and regulation that enable these insects to do so. Specifically, I will discuss the adjustments in oxygen consumption with different oxidative subtrates, reactive oxygen species metabolism, and ATP generation, as well as modifications in mitochondrial structure and ultrastructure, observed in the overwintering insects Drosophila suzukii and Apis mellifera during seasonal transitions. The understanding of these cellular and metabolic adjustments are crucial to gain valuable insights into the physiological mechanisms underlying insect cold tolerance and survival strategies.

SAB3.2 PHYSIOLOGICAL CONSEQUENCES OF MITO-NUCLEAR CONFLICT IN CYTOPLASMIC MALE STERILITY IN THE FRESHWATER SNAIL PHYSA ACUTA

Tuesday 8th July 2025 09:30

Sophie Bererd (Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés Université Claude Bernard Lyon 1, France), Damien Roussel (Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés Université Claude Bernard Lyon 1, France), Sandrine Plénet (Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés Université Claude Bernard Lyon 1, France), Loïc Teulier (Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés Université Claude Bernard Lyon 1, France), Antoine Stier (Institut pluridisciplinaire Hubert Curien, France), Emilien Luquet (Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés Université Claude Bernard Lyon 1, France)

sophie.bererd@univ-lyon1.fr

Cytoplasmic male sterility (CMS) originates from a genomic conflict between maternally inherited mitochondrial genes and biparentally transmitted nuclear genes in hermaphrodites, leading to opposing evolutionary interests. Mitochondrial genes induce CMS which can be counteracted by nuclear genes restoring male fertility. CMS is frequent in plants and has recently been discovered in an animal, the freshwater snail Physa acuta, where it is associated with two mitochondrial lineages - D and K - that diverge from the most common one, mitotype N. D snails are male-steriles while male fertility is restored by nuclear genes in K snails. CMS results from an incompatibility between mitochondrial and nuclear genomes, which can disrupt the integrity of mitochondrial function and the relying cellular processes. Dysfunction of mitochondrial complexes has been identified in some CMS plants and appears to be involved in the male sterility. In a previous study, whole-body metabolism was found to be similar among the three P. acuta mitotypes. To investigate the mitochondrial OXPHOS function, we measured the oxygen consumption of the respiratory chain complexes using high-resolution respirometry techniques. The results provide evidence that CMS is associated with an alteration in co-encoded complex I in D male-sterile individuals, although

compensated by a suractivation of complex II, changes that may be involved in the sterilization of the male reproductive function. No differences were found between the mitochondrial functioning of K restored hermaphrodites and N normal hermaphrodites, suggesting that restorer genes are involved in the fertility restoration mechanism.

SAB3.3 TEMPERATURES, TISSUES, AND TRUTHS: ARE UNIVERSAL MITOCHONDRIAL DENSITY BIOMARKERS A MYTH?

Tuesday 8th July 2025 09:45

Mélanie Aminot (Université de Moncton, Canada), Simon G. Lamarre (Université de Moncton, Canada), Nicolas Pichaud (Université de Moncton, Canada)

n ema1027@umoncton.ca

In mitochondria-related research, assessing mitochondrial density (MD) is essential to differentiate between qualitative and quantitative mitochondrial changes. Measuring MD therefore allows researchers to distinguish between mitochondrial functional variations and densitydriven changes within a tissue. Whether MD is measured through stereological analyses or the use of biomarkers, both methods present challenges. Despite there being commonly employed biomarkers of MD, no single biomarker has yet been proven universally effective. This presentation explores the controversies surrounding the use of mitochondrial density markers (MDMs) in ectotherms, emphasizing their context-dependent application across varying temperatures, species, and tissues. Four measures of MD– mitochondrial fractional area, surface density, cristae surface density and number– were evaluated by transmission electron microscopy (TEM) in coldand warm-acclimated Drosophila melanogaster , Leptinotarsa decemlineata and Salvelinus alpinus. Ratios of TEM measures and biomarkers were also compared between temperatures (cold vs. warm within species), species (Drosophila vs. beetles), and tissues (fish muscle vs. liver). All common biomarkers varied with acclimation temperature in at least one of the species tested. Between species, common enzymatic biomarkers, cardiolipin (CL) and mitochondrial DNA copy numbers failed to align with TEM-derived ratios, instead displaying opposite trends. Between tissues, citrate synthase (CS) and complex I activities aligned with TEM directionality, while CLderived ratios exhibited an opposite trend. While some MDMs aligned in directionally with TEM measures, no single biomarker aligned consistently with both the directionality and magnitude of TEM-derived ratios across all conditions, challenging the notion of universal mitochondrial density biomarkers in ectothermic species.

SAB3.4 ECOPHYSIOLOGICAL RESPONSES OF PLANKTON TO SEASONAL VARIATIONS COUPLED WITH SHORT AND LONG-TERM EXPOSURE TO CLIMATE CHANGE SCENARIOS

Tuesday 8th July 2025 10:00

Nelly Tremblay (Université du Québec à Rimouski, Canada), Cédric L. Meunier (Biologische Anstalt Helgoland AlfredWegener-Institut Helmholtz-Zentrum für Polar- und Meeresforsch, Germany), Karen H. Wiltshire (Biologische Anstalt Helgoland Alfred-Wegener-Institut HelmholtzZentrum für Polar- und Meeresforsch, Germany), Maarten Boersma (Biologische Anstalt Helgoland Alfred-WegenerInstitut Helmholtz-Zentrum für Polar- und Meeresforsch, Germany)

nelly_tremblay@uqar.ca

Understanding the factors that drive plankton dynamics and adaptation in shallow coastal seas is increasingly important, especially in global climate change context. The North Sea has experienced rapid warming, extensive shifts in the geographical distribution of species and changes in phenology in the last five decades. In this study, a suite of antioxidant enzymes (superoxide dismutase, catalase, glutathione S-transferase, and glutathione peroxidase) and a lipid oxidative damage indicator (malondialdehyde content) were analysed weekly in micro- and mesoplankton samples covering two years (June 2018 to June 2020). Twice during this time, short- (1 week) and long-term (1 month) experiments were conducted on plankton communities 150-1000 µm to simulate two shared socioeconomic pathways pCO2 scenarios. Oxidative stress was high for plankton < 80 µm all year, compared to larger sizes for which antioxidant enzymes mitigated lipid peroxidation. While plankton was resilient to optimistic scenarios tested, the worst scenarios tested suppressed plankton aerobic metabolism and enhanced oxidative stress. Overall, our findings highlight how plankton communities exhibit plasticity in response to changing ocean temperatures and chemistry, as assessed through biomarkers that link abiotic parameters to physiological fitness over time.

SAB3.5 INTEGRATING METABOLOMICS AND LIPIDOMICS APPROACHES TO INVESTIGATE THE SENSITIVITY OF MARINE ECTOTHERMS FROM DIFFERENT CLIMATIC REGIMES TO MARINE HEATWAVES

Tuesday 8th July 2025 10:15

Piero Calosi (University of Quebec In Rimouski, Canada), Lauric Feugere (University of Quebec In Rimouski, Canada), Nicholas Beaudreau (University of Quebec In Rimouski, Canada), David Drolet (Institut Maurice-LamontagneFisheries and Oceans Canada, Canada), Christopher W. Mckindsey (Institut Maurice-Lamontagne - Fisheries and Oceans Canada, Canada), Kimberly L. Howland (Freshwater Institute - Fisheries and Oceans Canada, Canada)

piero_calosi@uqar.ca

The physiological mechanisms that underpin aquatic ectotherms’ ability to tolerate elevated temperatures have been long studied but remain largely unresolved due to the historical reductionism that has dominated biology for decades. However, recent advances in omics approaches are enabling us to acquire more comprehensive portraits of the way physiological systems function, have evolved and will respond to future environmental challenges. Particularly, integrated multi-omics analyses can provide an in-depth characterisation of the

physiological status of organisms living under different environmental conditions. Polar marine ectotherms face important physiological challenges with the progression of ocean warming. Here we compared (as an ideal study system) the multi-omics response of an Arctic clam species to its more eurythermal temperate counterpart to a gradient of seven temperatures mimicking acute thermal conditions and marine heatwaves exposed under laboratory conditions. We measured survival after 12 days of exposure and sampled three tissues (gills, mantle, posterior adductor muscle), on which we performed targeted metabolomics (focussing particularly on energy metabolism) and untargeted lipidomics. Multivariate analyses combined with breakpoint analyses helped show that the lower tolerance observed under elevated temperatures in the Arctic species is underpinned by a limited ability for metabolomic rewiring, when compared to its temperate counterpart. The latter may rely on the activation of DNA repair and cell-signaling pathways. Further, we present the results for our lipidomic profiling and its multi-omics integration with metabolomics data to acquire a greater mechanistic understanding of the sensitivities of polar and temperate marine species to ocean warming.

SAB3.6 FROM MITOCHONDRIA TO METABOLOME: METABOLIC ADAPTATIONS IN STRESS-TOLERANT MARINE MOLLUSKS

Tuesday 8th July 2025 14:00

Inna Sokolova (Marine Biology University of Rostock, Germany)

inna.sokolova@uni-rostock.de

Metabolism is a fundamental property of life, driven by a complex network of biochemical reactions that extract energy from molecules and generate essential structural components. Energy metabolism—encompassing assimilation, conversion, and utilization—links physiology, behavior, and ecology and is highly sensitive to environmental fluctuations. Dynamic regulation of ATP production ensures organisms maintain homeostasis and adapt to changing conditions, making metabolic flexibility key to resilience. Mitochondria play a central role in ATP production, redox balance, Ca²⁺ homeostasis, and stress responses in aerobic organisms. They are highly sensitive to changes in oxygen, temperature, salinity, and pollution, which can cause energy deficiency, mitochondrial damage, and metabolic disruption. However, stress-tolerant marine organisms, such as intertidal mollusks, exhibit remarkable metabolic flexibility, maintaining homeostasis under stress and rapidly restoring function during recovery. This talk explores the mechanisms underlying adaptive metabolic responses to intermittent hypoxia, temperature shifts, and salinity fluctuations in intertidal mollusks. Emphasis will be placed on mitochondrial functional and proteomic adaptations and their integration with cellular metabolism and stress protection pathways. Finally, I will highlight key knowledge gaps and future research directions to better understand metabolic adaptations in highly variable environments like the intertidal zone.

SAB3.7 CHANGES IN THE LIPIDOME OF KLEPTOPLASTIDIC SEA SLUGS DURING BREAK DOWN OF PHOTOSYNTHETIC CAPACITY: METABOLIC AND ECOLOGICAL IMPLICATIONS

Tuesday 8th July 2025

14:30

Carlos Enrique Paya (University of Aveiro, Portugal), Joao Pereira (University of Aveiro, Portugal), Felisa Rey (University of Aveiro, Portugal), Paulo Cartaxana (University of Aveiro, Portugal), Rosario Domingues (University of Aveiro, Portugal), Sonia Cruz (University of Aveiro, Portugal)

paya@ua.pt

Some sacoglossan sea slugs are able to acquire and retain chloroplasts from their algal prey, enabling them to use light energy for the synthesis of organic compounds, a process known as kleptoplasty. However, the lifespan of these stolen chloroplasts (kleptoplasts) is limited and these sea slugs require regular feeding to maintain high levels of photosynthetic activity. Lipids, essential molecules for cell membrane stability, energy storage, and signaling, are key to chloroplast retention and functionality within the host animal cells. This study used advanced lipidomics techniques (C18-LC-HR-MS & MS/MS) to investigate lipid profile shifts associated with the decline in photosynthetic capacity of kleptoplastidic sea slugs under different feeding and starvation conditions. In the sea slugs Elysia viridis and Elysia crispata, glycolipids – exclusive to chloroplast membranes –declined noticeably in the absence of algal food sources. The rate of decline was different in E. viridis depending on the algal species previously consumed, indicating that the chloroplast donor plays a crucial role in chloroplast retention. Furthermore, sterols from both plant and animal sources increased in sea slugs experiencing reduced photosynthetic capacity, likely due to chloroplast degradation and stress-induced lipid synthesis. These findings revealed how kleptoplastidic sea slugs adapt their lipid metabolism to environmental stress, shedding light on their strategies to cope with fluctuations in algal availability and photosynthetic capacity.

SAB3.8 HIGH TEMPERATURES INCREASE RESPIRATION BUT REDUCE THE EFFICIENCY OF MUSCLE MITOCHONDRIA IN A LITTLE–KNOWN FISH, THE SPIRLIN (ALBURNOIDES BIPUNCTATUS)

Tuesday 8th July 2025 14:45

Julia Watson (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Damien Roussel (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Inès Akoutei (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France), Laëtitia Averty (Plateforme Animalerie Conventionnelle et Sauvage Expérimentale de la Doua (ACSED), France), Angeline Clair-Boisson (Plateforme Animalerie Conventionnelle et Sauvage Expérimentale de la Doua (ACSED), France), Candice Bastianini (Plateforme Animalerie Conventionnelle et Sauvage Expérimentale de la Doua (ACSED), France), Anthony Maire (EDF RD LNHE - Laboratoire National d’Hydraulique et Environnement, France), Martin Daufresne (INRAE AixMarseille University UMR RECOVER, France), Loïc Teulier (Université Claude Bernard Lyon 1 – CNRS ENTPE UMR 5023 LEHNA, France)

julia.watson@univ-lyon1.fr

Aquatic ectotherms are highly vulnerable to climate change, prompting extensive research into the factors that determine their upper thermal limits. A common method to assess thermal tolerance is the critical thermal maximum (CTmax), defined as the temperature at which organisms reach a critical non-lethal endpoint marked by a reversible loss of equilibrium. The physiological mechanisms behind CTmax are still being debated, with a particular focus on mitochondrial dysfunction. Indeed, mitochondria are essential for aerobic metabolism by producing ATP coupled to oxygen consumption through oxidative phosphorylation, which has a highly variable activity and is influenced by temperature. This study aimed to evaluate whether mitochondrial phosphorylation and coupling efficiency are impaired at CTmax temperature in a little-known fish species, the spirlin (Alburnoides bipunctatus), whose long-term persistence in large temperate rivers is questioned under climate change. Wild spirlins were acclimatized at 20°C for two months. Once their CTmax was determined (33.85°C ± 0.12°C), mitochondrial respiration rates and ATP/O ratio (mitochondrial efficiency) were assessed at 20°C and 34°C. Our findings show that mitochondrial complex I respiration is more sensitive to temperature than complex II respiration, and that the ATP/O ratio decreases at CTmax temperature, indicating an increased cost of mitochondrial ATP synthesis at this higher temperature. This observation suggests an increased energy constraint on cellular performance, which may play a role in organismal thermal tolerance. Yet, other organs, such as the heart and brain, are more sensitive to temperature than muscle, underlining the need for further research into mitochondrial efficiency in these organs.

SAB3.9 TOO HOT TO FUNCTION? MITOCHONDRIAL THERMAL PERFORMANCE

Tuesday 8th July 2025 15:00

Ghinter Léopold (LEMAR-DECOD-Ifremer-UBO, France), Lebigre Christophe (DECOD-Ifremer, France), Quémeneur Jean-Baptiste (LEMAR-Ifremer-UBO, France), Roussel Damien (LENHA-University of LYON, France), Blier Pierre (Université du Québec à Rimouski, Canada), Salin Karine (LEMAR-Ifremer, France)

leopold.ghinter@hotmail.fr

Performances in ectothermic animals are tightly linked to temperature, as metabolic processes shape individuals’ energy balance and constrain their performances. Deviations from the optimal temperature therefore reduce bioenergetic efficiency. Mitochondria generate cellular energy (ATP) via oxidative phosphorylation (OXPHOS), but part of the oxygen consumed is dissipated in the proton leakage (LEAK), lowering mitochondrial efficiency. Previous studies have shown that rising temperatures exacerbate both LEAK and enzymatic dysfunctions, impairing mitochondrial function and potentially compromising organismal performance. Juvenile seabass (Dicentrarchus labrax) inhabit coastal nurseries, where temperature fluctuations can be abrupt and unpredictable. Their ability to cope with thermal variability is therefore critical for growth and survival, yet the bioenergetic mechanisms underpinning their thermal tolerance remain unclear. In this study we tested the hypothesis that the mitochondrial thermal performance of juvenile seabass’ reflects their adaptive capacity in these environments. We assessed the mitochondrial function of wild seabass as rates of oxygen consumption (LEAK and OXPHOS respiration), ATP production, and mitochondrial efficiency (ATP/O ratio) in liver and heart mitochondria across a 12–32°C gradient, encompassing natural and extreme temperature ranges. Consistent with our hypothesis, increased temperature in both tissues led to substantially greater increases in LEAK respiration than OXPHOS respiration. ATP/O declined by ~36% in liver from 12 to 32°C. These findings highlight the strong thermal sensitivity of mitochondrial function in wild ectotherms and suggest that fish juveniles may experience bioenergetic limitations under heatwave events, potentially affecting their growth and survival in nursery habitats.

SAB3.10 NADH AND NADPH: THE TWO FACES OF A MITOCHONDRIAL JANUS

Tuesday 8th July 2025 15:15

Damien Roussel (Université Claude Bernard Lyon1, France) damien.roussel@univ-lyon1.fr

Allometric studies have largely reported that interspecific variation in body mass affects nearly all part of mitochondrial bioenergetics processes. The general picture is that mitochondria from small mammals have a high rate of oxygen consumption that is sustain by high activity of oxidative enzymes. However, such high mitochondrial oxidative phenotype carries an oxidative cost that often translate in high release of reactive oxygen species. Studies suggest that there is no strong relationship between mitochondrial electron leak or antioxidant enzyme activities and body mass in mammals. Yet, mitochondrial matrix antioxidant systems also requires the synthesis of NADPH. Here we explore whether the higher mitochondrial H2 O2 release reported in small mammal results from a tradeoff between an oxidative phenotype (the NADH face of Janus), that synthesizes NADH to sustain high oxidative phosphorylation activity, and a reductive phenotype (the NADPH face of Janus), that synthesizes NADPH to remove H2 O2 from the matrix.

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

SAB3.11 AMINO ACID CATABOLISM AND MITOCHONDRIAL SHIFTS SUPPORT INCREASED LONGEVITY IN THE SEED BEETLE

ACANTHOSCELIDES OBTECTUS

Clément J. L. Chevret (Department of Medicine University of Alberta, Canada), Pierre U. Blier (Département de Biologie Université du Québec à Rimouski, Canada), Heather E. Mast (Department of Medicine University of Alberta, Canada), Pauline Bertrand (Département de Biologie Université du Québec à Rimouski, Canada), Mirko Đor’eviĄ (Department of Evolutionary Biology Institute for Biological Research SiniDža StankoviD, Serbia), UroDž SavkoviD (Department of Evolutionary Biology Institute for Biological Research SiniDža StankoviD, Serbia), HǃlɃne Lemieux (Women and ChildrenȢ_s Health Research Institute University of Alberta, Canada) chevret@ualberta.ca

Holometabolous insects often undergo a metabolic shift as adults due to feeding cessation. In the seed beetle Acanthoscelides obtectus, which enters a post-larval starvation phase, metabolic strategies are key to survival and longevity. This study contrasts two experimental evolution lines with divergent life histories: a short-lived, earlyreproducing line (E, ~7 days) and a long-lived, late-reproducing line (L, ~15 days).

Targeted metabolomics revealed significant differences in amino acid metabolism between the two A. obtectus lines. Notably, amino acid concentrations were consistently lower in the long-lived L line than in the E line across all ages, with this distinction evident as early as day 1. This suggests a sustained, higher rate of amino acid catabolism in L beetles, potentially providing an alternative energy source to compensate for reduced complex I activity and the absence of fatty acid oxidation. Furthermore, tricarboxylic acid (TCA) cycle intermediates indicated line-specific mitochondrial adaptations. Higher succinate-to-fumarate ratio observed at day 1 in L beetles suggests increased complex II activity, which could offset the lowered complex I activity. These metabolomic findings strongly corroborate previous respirometry data, supporting metabolic rewiring in L beetles that favours alternative electron entry points into the mitochondrial electron transport system.

Our results highlight that metabolic plasticity, driven by enhanced amino acid catabolism and altered TCA cycle flux, is critical for extending survival in the L line. These adaptations provide insights into bioenergetic mechanisms governing lifespan in insects and highlight how mitochondrial remodelling contributes to the evolution of different ageing patterns.

SAB3.12 MITOCHONDRIAL ENZYME ACTIVITY IN FISH LIVERS IS NOT IMPACTED BY PARASITE PRESENCE

Vincent Mélançon (Université de Montréal, Canada), Tommy Pepin (Université de Montréal, Canada), Sandra A Binning (Université de Montréal, Canada), Sophie Breton (Université de Montréal, Canada)

vincent.melancon01@gmail.com

Parasites can impair host performance through various physiological processes, including alterations to host metabolism. Since mitochondria are responsible for cellular energy production, it is likely that disruptions in host cellular metabolism contribute to changes in metabolism at the organismal level. However, some studies investigating parasite-induced alteration in cellular metabolism have been limited by the presence of parasites in the target tissues. Before analyzing these key tissues, it is critical to confirm that the measured enzyme activities reflect those of the hosts rather than the parasites themselves. Here, we tested a parasite extraction protocol to evaluate the extent to which parasite contamination impacts estimates of cellular enzyme activities in hepatic tissues of wild pumpkinseed sunfish (Lepomis gibbosus) infected with bass tapeworm (Proteocephalus ambloplitis). We tested four treatments: uninfected livers, cleaned infected livers, infected livers (repopulated) and parasites alone. We then compared the activity of key metabolic enzymes among groups. PCR tests were used to assess parasitic contamination after applying the parasite extraction protocol on hepatic tissue. Enzyme activities of cleaned livers and contaminated livers were similar even if PCR tests revealed contamination. The intensity of cestode infection also did not influence enzyme activity, which suggests that parasite presence in the livers does not impact the accuracy of the enzyme activity estimates made. Through this protocol, we show that parasite contamination has no effect on metabolism measurements showing that the study of parasitized organs is possible. We also recommend the use of this protocol to avoid any biases in highly infected individuals.

SAB3.13 EFFECTS OF ENVIRONMENTAL EXPOSURE TO METAL POLLUTION ON MITOCHONDRIAL PLASTICITY AND METABOLISM IN AN INVASIVE CRAB.

Georgina A. Rivera-Ingraham (Griffith University, Australia), Gillian M.C. Renshaw (Griffith University, Australia), Jules Devaux (University of Auckland, New Zealand), Diana Martínez-Alarcón (Centre National de la Recherche Scientifique, France), Mariel Familiar-López (Griffith University, Australia), Jason Van de Merwe (Griffith University, Australia), Jehan-Hervé Lignot (University of Montpellier, France)

g.rivera.ingraham@gmail.com

Pollutants drive adaptive metabolic and evolutionary responses. However, this pollution-driven rapid evolution in invertebrates, particularly its effects on metabolism and mitochondrial oxidative phosphorylation (OXPHOS), remains overlooked. Using the European green crab Carcinus maenas, we investigated: (i) whether historic exposure to cadmium induces adaptive metabolic and mitochondrial responses; and (ii) if pre-exposure to cadmium confers protection

from another source of pollution, copper. Crabs were captured from the wild from one site exposed to cadmium pollution but naïve to copper and a second reference site which had no cadmium or copper. After four months of depuration, animals were exposed to either 8.2 nM cadmium, or 20 nM copper-hydrate, or clean seawater. Mitochondrial respiration in heart homogenates was measured using high performance respirometry (Oroboros). Reactive oxygen species production (ROS) and antioxidant content was measured in hemolymph spectrofluorometrically (C-H2 DFFDA) and electrochemically (BRS system), respectively. While all crabs showed similar mitochondrial routine respiration values, the historically polluted crabs had higher OXPHOS respiration, higher electron transport system capacity, and enhanced capacity of complex II (CII), accompanied by increased ROS formation and higher antioxidant defences. Exposure to cadmium or copper did not affect any of the parameters considered in historically polluted crabs. In contrast, reference animals responded with a decreased complex I (CI) and increased CII contribution. This may reduce CI-associated ROS formation while enabling detoxification and (or) other defence mechanisms. Our findings suggest that long-term metal exposure induces mitochondrial adaptations that enhance resilience to pollution, potentially facilitating the invasion success of C. maenas in contaminated environments.

SAB3.14 DECIPHERING BIVALVE MITOCHONDRIAL CARDIOLIPIN SIGNATURES: A DUAL ROLE IN LONGEVITY AND CLIMATE CHANGE

RESPONSE?

Pauline Bertrand (Université du Québec à Rimouski, Canada), Hélène Lemieux (University of Alberta, Canada), Pierre U. Blier (Université du Québec à Rimouski, Canada) pauline.bertrand@uqar.ca

The mitochondrial membrane lipid composition in ectothermic bivalves plays a crucial role in their ability to adjust fluidity according to the environment. The observed inverse relationship between lifespan and fatty acid unsaturation indicates that increased longevity is associated with the presence of oxidation-resistant membranes. Cardiolipin (CL), a critical mitochondrial lipid, plays a central role in age-related processes such as mitochondrial dynamics and apoptosis, triggered by ROS-mediated CLs oxidation. Moreover, CL’s influence on cristae structure and supercomplex organisation, modulated by fatty acid composition, highlights its essential role in maintaining mitochondrial function. To understand its role in longevity, we examined CL fatty acid composition across seven bivalve species, with lifespan ranging from 4 to over 500 years. We predicted that longlived species would exhibit higher CL content per mitochondrion and distinct polyunsaturated fatty acid profiles within CLs. Our preliminary results confirmed higher CL content in Arctica islandica, the species known for its exceptional longevity. This study explores how CL composition might impact apoptosis and mitochondrial function, potentially revealing climate change resilience mechanisms in longlived bivalves.

5 OUTREACH EDUCATION AND DIVERSITY (OED) ABSTRACTS

OED1: INCLUSIVE DOCTORAL EDUCATION

ORGANISED BY: CLAIRE GARDEN (EDINBURGH NAPIER UNIVERSITY)

OED1.1 FROM FALLING TO THRIVING WITHIN A CHAOTIC SYSTEM: A NEURODIVERGENT PERSPECTIVE OF A LIFE IN EDUCATION WITH DYSLEXIA AND AUTISM.

Tuesday 8th July 2025 09:00

Declan Perry (Royal Holloway University of London, United Kingdom)

declan.perry.2013@live.rhul.ac.uk

The ability to conduct novel research introduces significant difficulties to disabled students, with each individual requiring adjustments to accommodate for their own specific needs. An effective relationship with the supervisory team can provide an encouraging environment, to help confront experimental setbacks and difficulties in mental health. The aim of my talk is to explore from a neurodivergent angle the difficulties disabled students face when pursuing a PhD, to promote discussions on how supervision can be improved to support the students’ experience. I intend to talk about my own personal journey within education, from obtaining my Dyslexia and atypical Autism diagnoses at the age of 10, to my journey navigating doctoral education. I will reveal the difficulties I have experienced from Imposter syndrome, emotional burnout, anxiety and social communication issues. finally I will highlight how I have overcome these difficulties and the key skills I have established with the help of my supervisory team and specialist mentors.

OED1.2 MIND THE GAP: REASONABLE ADJUSTMENT POLICY AND PRACTICE FOR RESEARCH POSTGRADUATE ASSESSMENTS. WHAT ACTION SHOULD YOU TAKE TO SUPPORT DISABLED

STUDENT SUCCESS?

Tuesday 8th July 2025 09:45

Claire LP Garden (Edinburgh Napier University, United Kingdom), Kevin Geddes (Queen Margaret University, United Kingdom), Grainne Barkess (Edinburgh Napier University, United Kingdom)

c.garden@napier.ac.uk

More disabled students than ever are rightfully entering doctoral education, however our systems and practices are not yet equipped to support them. Disabled Students UK produced the ‘Improving the experience of disabled PhD students in STEM’ report in 2023, highlighting important areas of action it is incumbent on all of us to engage in. There is disparity between the experience and provision for taught students and research students, who are ‘falling through the cracks’ because of under developed policy and practice. Understanding student experiences and sharing good supportive practice is essential to addressing this. We will explore the challenges, research and policies related to reasonable adjustments for disabled postgraduate research students in Scotland. We highlight the disparity in support between levels, emphasizing the need for consistent terminology and better implementation of adjustments. We will provide recommendations for improving accessibility and support through the implementation of local policy and share case studies from two Scottish Universities to illustrate good practices. We call for a cohesive approach to research, policy and practice, aiming to enhance the experience and success of disabled postgraduate students within and beyond Scotland.

OED2: CREATIVITY IN HIGHER EDUCATION

ORGANISED BY: SARAH RAYMENT (NOTTINGHAM TRENT UNIVERSITY), NICHOLAS FREESTONE (KINGSTON UNIVERSITY)

OED2.1 FROM BIRMINGHAM TO BLUE SKIES

Tuesday 8th July 2025 14:00

Declan Perry (Royal Holloway University of London, United Kingdom)

m.m.grant@bham.ac.uk

Communicating science and inspiring others in pursuing science at higher levels can take many different forms. The use of art-science partnerships can be a rewarding way in which to explain, visualise and stimulate scientific findings and discussions. Through curating the Open Wide exhibitions space, working with undergraduate students during lock down with outside the box ways to conduct science experiments and by working in partnerships with artists Grant will explore her personal journey in communicating science and inspiring others. The cases presented can provide examples of some of the many ways in which art and science can be used.

OED2.2 TRANSACTIONAL SCAFFOLDING IMPROVES LEARNING ENGAGEMENT WITHIN BLENDED LEARNING ENVIRONMENTS IN SCOTTISH HIGHER EDUCATION

Tuesday 8th July 2025 14:30

David G Smith (David Graham Smith, United Kingdom), George Chambers (Edinburgh Napier University, United Kingdom)

d.smith@napier.ac.uk

Transactional scaffolding (TS) is an innovation that has recently been applied to the pedagogic approach in a first year (SCQF7) module in Comparative Anatomy and Physiology at Edinburgh Napier University. The technique aims to enhance self-actualisation of new HE learners by increasing engagement with virtual learning environments (VLE) and improved self-knowledge of attendance and engagement; with the goal of promoting connections between theory and practice.The idea of TS has grown out of the work of Salmon (2019) and Smith (2023). Salmon (2019) promotes the idea of strongly structured learning within VLE. Whilst the findings of Smith (2023) showed that for most learners the strongest motivational factors to study are transactional. Many learners are slow to engage in self-actuation activities unless

they see how these contribute to their achievement of their intended qualification and graduate destination.Transactional scaffolding harnesses data from VLE engagement and attendance monitoring to allow learners to unlock access to learning material and summative assessments. Crucially, the approach provides opportunities for learners to latterly compensate for earlier poor engagement and is relatively unlaborious for academic staff and requires no dedicated administrative support. It allows learners to confidentially rank themselves within the cohort in terms of attendance, engagement and progress within a single online environment.The initial intervention appears to have significantly improved student evaluation of the investigated module compared with previous cohorts. Overall student satisfaction increased from 89% in 2023 to 98% in 2024. Student attendance at on-line learning events improved from 10% to 95%.

OED2.3

BEYOND THE CLASSROOM: RETHINKING THE ECOLOGY OF LEARNING SPACES IN STEM EDUCATION

Tuesday 8th July 2025 14:45

Luke D McCrone (Imperial College London, United Kingdom)

luke.mccrone12@imperial.ac.uk

There is increasing evidence in STEM education that creativity and innovation occur in spaces at the edge and in-between. This talk presents research, conducted at a STEMMB-focused university, that employed a mixed-methods approach to explore student transitions between formal and informal learning spaces. Applying an ecological lens helped to reveal tensions between timetabled and non-timetabled spaces which students navigate as part of their learning experience. These insights informed the redesign of campus transitional spaces across multiple departments to foster more serendipitous learning experiences and collaboration within the university community. The research highlights the untapped potential of in-between transitional spaces for creativity, innovation, and learning—an area that warrants further exploration.

OED2.4 VIRTUAL TEAMWORK AND CREATIVITY: A JOURNEY IN SCIENCE COMMUNICATION

Tuesday 8th July 2025 15:00

Amanda Rasmussen (University of Nottingham, United Kingdom)

amanda.rasmussen@nottingham.ac.uk

The modern workplace requires teamwork bridging distances, timezones and cultures using virtual collaboration platforms. As such teamwork is a key employability skill for our graduates, and yet we rarely explicitly teach team skills or how to navigate and collaborate in a virtual environment. Here we demonstrate that integrating inperson (synchronous) and online (synchronous and asynchronous) learning environments can prove an extremely resilient teaching method that allowed continuity during the pandemic, while providing students with these essential skills. But this isn’t just a story about using collaborative software – this is also a student journey into the creative side of science communication. The assessment (which we all know is what matters to students!) is a semester long documentary video team assignment supported by regular compulsory team training sessions and using the Microsoft Teams online collaboration platform. Students interview researchers outside the University of Nottingham (our home university) and create animations, film footage and determine stock footage that is legal to use. I would love to share this journey with you, from both my instructor view and the student perspective and introduce new directions we are exploring with virtual reality.

OED2.5 WHEN PIXEL ART MEETS BIOSKILLS

Tuesday 8th July 2025 15:15

Sarah J Rayment (Nottingham Trent University, United Kingdom), Bunmi Omorotionmwan (Nottingham Trent University, United Kingdom), Jody Winter (Nottingham Trent University, United Kingdom), Jess Fountain (Nottingham Trent University, United Kingdom), Karin Garrie (Nottingham Trent University, United Kingdom)

sarah.rayment@ntu.ac.uk

Practical skills development is a core aspect of undergraduate biosciences degrees, creating graduates who can excel in a range of careers, including those that involve laboratory work. However, when we consider the global picture, it is clear that not all students have equality of opportunity to access laboratory spaces to develop these skills and so may not aspire to careers with a practical element. This project describes how we can take lessons learned during the pandemic and apply these to build skills capacity in different areas. In this case, the project described focuses on how learning pipetting and serial dilution skills can be taught outside of the classroom through a “pixel art” competition.

Students at the University of Benin in Nigeria who undertook this skills training were surveyed before and after the training. In addition to increased confidence in pipetting and making serial dilutions, 79% of

students who took the survey after the training said that they would be more likely to consider a career with a practical element to it than before they did beforehand. Not only this but 83% of students strongly agreed that they appreciated the opportunity to be creative: with a third of students including the creativity as the most enjoyable aspect of the training. Whilst this project focussed on one cohort of students, the potential for building skills capacity across courses now that local staff can deliver the training independent has the potential to make a significant impact on the country’s infrastructure.

OED4: COLLABORATIVE CURRICULUM DESIGN FOR EXPERIMENTAL BIOLOGY PRACTICAL CLASSES

ORGANISED BY: PETE MOULT (UNIVERSITY OF GLASGOW), SARUNE SAVICKAITE (UNIVERSITY OF GLASGOW)

OED4.1 A SCALABLE AND SUSTAINABLE MODEL FOR CO-CREATING LABORATORY CLASSES AND IMPROVING EMPLOYABILITY SKILLS IN THE LIFE SCIENCES SECTOR.

Wednesday 9th July 2025 09:00

Peter Moult (University of Glasgow, United Kingdom), Hanne Krogsaeter (Imperial College London, United Kingdom) peter.moult@glasgow.ac.uk

Co-creation of the curriculum with student partners fosters a greater sense of ownership and belonging to a course and has been widely linked to positive outcomes in terms of professional development and employability skills. With expanding student numbers across the sector and a demand for modern laboratory skills and techniques from employers, it’s important that we are able to keep pace with developing authentic, contemporary lab classes, providing our students with the up-to-date skills required by employers. To be effective, these classes need to evolve year on year, placing increasing demands on staff. With expanding numbers of students, it is also becoming harder to provide enough wet, final year projects due to limitations of lab capacity and available staff supervisors. Here we present a scalable solution which incorporates co-creation of the curriculum with final year student partners as part of our final year project provision. We will present the results of the first pilot study which has successfully designed and embedded a new laboratory class into level 3 of the neuroscience degree here at Glasgow. The contemporary lab is then linked to a summative assessment, which also evolves with the lab provision year on year, providing a connectedness to real world challenges and employer demands. We intend to scale the approach to meet the increased capacity and supervision demands for final year wet projects. We will show how we can offer multiple group projects, co-creating multiple different laboratory classes with no increased demand on supervision.

OED4.2

EMPOWERING STUDENTS IN CURRICULUM DESIGN: FOSTERING OWNERSHIP, SKILL DEVELOPMENT, AND CAREER READINESS IN THE LIFE SCIENCES

Wednesday 9th July 2025 09:30

Hanne Krogsaeter (Independent, United Kingdom) hannekrog@hotmail.com

Empowering students to assist in curriculum co-design fosters ownership and development of employability skills. At a time where student numbers are increasing, and the job market is becoming increasingly competitive, it is crucial that student education places emphasis on the development of skills increasing employability, such as critical thinking, self advocacy, and resilience. Furthermore, rising student numbers and saturated lectures and practical laboratory classes means less resources per student, and risks students becoming disengaged and falling behind in their own development and learning journey. Empowering students to assist in co-curriculum design addresses both of these challenges. Providing the students’ with autonomy and the support required to assist in designing their own honours projects encourages critical thinking and gives students a sense of ownership over their own work and studies, while also developing key skills. Here I will discuss my experiences as a student co-creator on the University of Glasgow project and my perspectives on the curriculum design project.

OED4.3 LESSON PLANNING FOR IMMERSIVE EDUCATION: COLLABORATION, COGNITIVE LOAD, AND CONTEXTUAL FIT

Wednesday 9th July 2025 10:00

Saruna Savickaite (University of Exeter, United Kingdom)

S.Savickaite@exeter.ac.uk

As immersive technologies become more accessible in education, traditional lesson planning strategies require thoughtful adaptation. This short presentation explores how standard approaches can be reimagined to support immersive learning, with a focus on reducing cognitive load for both students and educators. Drawing on early findings and conceptual frameworks from our work at Advanced Research Centre XR facilities,

Academic Peer Review

First steps, best practices & future challenges

Why should I spend time on reviewing? Is anyone going to thank me for my review? How do I find reviewing opportunities? What is triple anonymisation? What is open Peer Review? I've agreed to review - what next? Is Peer Review fair? Is Peer Review functioning? Is Peer Review superfluous?

If thoughts like this have crossed your mind, you're in good company!

Join our workshop on Thursday, 10th July, 14.30-16.00pm to

o make your first steps as a peer reviewer

o learn about best scientific practice and ethical norms of reviewing

o discuss pros and cons of different peer review models

o debate future challenges that the peer review system has to master

OED5: BIOLOGY AS AN EXPERIMENTALLY TAUGHT SCIENCE

ORGANISED BY: ENRIQUE LÓPEZ-JUEZ (ROYAL HOLLOWAY, UNIVERSITY OF LONDON)

OED5.1 “SHARK TALE” AN ALLPRACTICAL MODULE: NO LECTURES, NO EXAMS. OR, WHAT COULD POSSIBLY GO WRONG?

Wednesday 9th July 2025 11:00

Pietro D Spanu (Imperial College London, United Kingdom) p.spanu@imperial.ac.uk

I was asked to design a module for the undergraduate (BSc) degree course in Biological Sciences at Imperial College London (UK). The steer was unconventional: emphasise “hands-on” work, no formal lectures, no recipes, no assessment by examination. The aim of the new modules was to train “skills” in the biological sciences; given my academic research background we called my offering “Molecular and Cell Biology Skills”. The development was first aided by studentled workshops, and then supported by two additional members of academic staff, a small team of teaching technicians, and graduate teaching assistants. The teaching and learning sessions are over 6 weeks, full-time and based on online sessions (introductions, assessments) and executed in laboratories equipped with standard molecular biology materials for undergraduate practicals. The fundamental objectives of the course are for the students to reflect on their learning and training so far (2 years), formulate a question to be addressed using basic molecular biology they have learnt previously, prepare and execute the experiments, evaluate the results and present them to the class for assessment orally, as a poster and as a “manuscript” in a standard IMRD format. Three cycles of experimentation take place: learning a technique, testing the hypothesis and replicating/troubleshooting. What Could Possibly Go Wrong? Try adding SARS CoV-2 into the mix.

OED5.2

ENHANCING STUDENT COMPETENCY, CONFIDENCE,

UNDERSTANDING AND ATTENDANCE THROUGH EMBEDDING A PRACTICAL SKILLS TRACKING PROGRAMME INTO ALREADY ESTABLISHED LIFE SCIENCE LABORATORY SESSIONS

Wednesday 9th July 2025 11:30

Laura McCaughey (University of Glasgow, United Kingdom), Anna McGregor (University of Glasgow, United Kingdom), Lesley Hamilton (University of Glasgow, United Kingdom) laura.mccaughey@glasgow.ac.uk

For Life Science students, practical laboratory sessions offer a way to ignite passion, deepen understanding, and develop hands-on skills in ways that traditional lectures cannot. For courses with large enrolments (300-600+ students), ensuring that students fully engage with laboratory sessions and build confidence in their abilities is challenging.

This talk will cover the development and implementation of a practical skills tracking programme across twenty-one 2nd /3rd year Life Science courses at the University of Glasgow, and will encourage educators to consider how structured, reflective practical experiences can maximise the benefits of practical sessions, especially for large student cohorts. The programme integrates structured, formative feedback into existing practical sessions: trained Graduate Teaching Assistants and/or staff observe students demonstrating key skills, provide immediate verbal feedback, and reassess as needed in the same lab session or a later one. Once students demonstrate competency, their progress is logged via a simple checklist (Moodle). Unlike high-stakes practical assessments in professional degrees, such as OSCEs, this lowstakes formative approach prioritises continuous learning through a reiterative approach and personalised feedback.

By embedding practical skills development within established lab sessions, this model creates an inclusive and supportive learning environment. Although there were some challenges, such as selecting suitable key skills, this model has very positive outcomes for both students and staff, showing enhanced student learning and confidence: 77% of students reported increased competency in practical skills, and 73% noted a deeper understanding of the underlying theory. Additionally, staff reported increased attendance and student engagement.

OED5.3 USING NARRATIVE INQUIRY TO UNDERSTAND STUDENTS’ SENSE OF BELONGING FOLLOWING A RESIDENTIAL FIELD TRIP AT THE START OF THEIR UNIVERSITY JOURNEY – A LONGITUDINAL STUDY

Wednesday 9th July 2025 11:45

Rose R Murray (University of Bristol, United Kingdom), Callie Rice (University of Bristol, United Kingdom), Dominique Baptiste (University of Bristol, United Kingdom), Emily F Bell (University of Bristol, United Kingdom) rose.murray@bristol.ac.uk

As educators, we are aware of the transition periods our students experience throughout their university journey. It is clear that a successful transition into higher education can be fundamental to a student’s ultimate success at university. Moving from secondary education to university can be a challenging time where students experience multiple stressors including the need to create new social groups. During this transition developing a sense of belonging with peers, staff and the institution is crucial and, if successful, can provide academic benefits, increased retention, and support to student wellbeing. In October 2022 we introduced a residential field course into our degree programme, this not only included key biological skills training but a strong focus on community building. Since the field course, we have been following the same student cohort for three years throughout their academic journey to explore whether attending a residential field trip at the start of a degree programme influences their sense of belonging at university. We are analysing the data (comprised of interviews and focus groups) from this longitudinal study using narrative inquiry which aims to explore the students’ experiences throughout their time at university. Preliminary findings from this longitudinal study will be shared, alongside our reflections of using narrative inquiry. Our experiences of implementing the field trip will also be presented alongside advice to any individuals who wish to implement such a trip in their own programmes.

OED5.4 INQUIRY-BASED INTRODUCTORY BIOCHEMISTRY LABORATORY COURSE

Wednesday 9th July 2025 12:00

Erica X Shu (University of Wisconsin-Madison, United States), Srivatsan Raman (University of Wisconsin-Madison, United States)

xshu32@wisc.edu

This poster outlines the design and implementation of Engineering Bacteriophage Laboratory, an inquiry-based lab course for freshmen and sophomores. The course aims to teach students to think like scientists and motivate STEM-oriented students by fostering handson, engaging learning experiences. Developed in collaboration with institutional partners, including a faculty research lab and the molecular visualization facility, the course integrates cutting-edge technologies such as VR protein structure visualization to enhance student engagement. This innovative approach connects students to real-world applications, supporting both their learning and success in the biochemistry field.

OED5.5 PRACTICALS MAKE UNDERGRADUATE PLANT SCIENCE INTERESTING, EVEN FUN

Wednesday 9th July 2025 12:15

Enrique Lopez-Juez (Dept. Biological Sci. Royal Holloway University of London, United Kingdom)

e.lopez@rhul.ac.uk

Higher education was born in discussion classrooms, but also in dissection rooms and “physic gardens” (today botanic gardens). At their roots, biological higher education and experimental biology were very tightly intertwined.

These links may be experiencing greater challenges than they have for a long time, owing to their labour intensity and increasing financial constraints. Maintaining them, however, may be more important than ever given a widely-experienced reduced level of engagement of students in in-person lectures since the Covid pandemic.

Plants lend themselves very well to laboratory practicals, in plant science but also in cell biology, genetics and other disciplines. A current undergraduate module, “Green Planet”, compulsory for year 1 Biology students at our university, is using laboratory practicals developed and perfected over a number of years. They are focused on (1) flower evolution, using also floral homeotic mutants, (2) plant regeneration and hormone biology and (3) flowering time control, including the assessment and molecular genotyping (as problemsolving) of distinct photoreceptor mutants. The module also includes a photosynthetic CO2 capture demonstration, and a guided trip to the World-heritage Kew Gardens focusing on subjects of several lectures. Student participation in practicals approaches 100%, well above the lectures, and feedback is highly positive.

A practical in an advanced cell biology module involves interorganellar communication, using chloroplast-nucleus interaction as a study case, with similarly positive outcomes.

Engaging practicals have hardly ever been of greater value in biological education than they are today.

Labs can be found in this higher education-focused repository:https:// www.sebiology.org/outreach/biology-practicals-for-higher-education. html.

OED6: QUICK WINS: CELEBRATING IMPLEMENTABLE INNOVATIONS IN HE TEACHING AND SCHOLARSHIP

ORGANISED BY: ELLEN BELL (UNIVERSITY OF EAST ANGLIA), COLIN MCCLURE (QUEENS UNIVERSITY BELFAST)

OED6.1 QUICK WINS TO ENHANCE THE STUDENT EXPERIENCE

Wednesday 9th July 2025 15:00

Kelly Edmunds (University of East Anglia, United Kingdom)

K.Edmunds@uea.ac.uk

The Higher Education (HE) sector is undergoing a period of significant and rapid change as we grapple to respond to the post-pandemic landscape, political and economic uncertainty and significant technological developments. HE staff are facing increasing pressure to do more with less; to innovate and be exceptional and meet the needs of a rapidly changing student cohort. Teaching practices that may have been effective as little as 5 or 6 years ago, no longer necessarily reflect best practice. Finding the time and headspace to reflect on our practice, to innovate, adapt and evolve our pedagogical ideas is a sector-wide challenge. And the constant pursuit of teaching excellence is impacting the experiences of both staff and students. We are living to the words of Alice in Wonderland’s Red Queen “It takes all the running you can do to keep in the same place”

In this session, I will share examples of some of the strategies that I have developed within my own practice to enhance the student experience. The strategies are all grounded in relational pedagogy and include evaluating practical skills competency at the start of a course as well as changes to assessments and multiple ‘quick wins’ embedded within teaching that also serve to support student wellbeing. The strategies that I will share can be used by anyone teaching within HE across any level of study.

OED6.2 EMPOWERING STUDENT AGENCY IN ASSESSMENT AND FEEDBACK IN BIOLOGICAL SCIENCES

Wednesday 9th July 2025 15:30

Rose R Murray (University of Bristol, United Kingdom), Reinart Jensema (University of Bristol, United Kingdom), Rebecca K Pike (University of Bristol, United Kingdom) rose.murray@bristol.ac.uk

Engaging our students and supporting them to develop agency in assessment and feedback is important for driving effective selfregulation. It is well documented that assessment is one of the key drivers of student learning. However, assessment and feedback continue to burden the HE sector with low opinion from the student body. We will showcase novel initiatives we have introduced in the School of Biological Sciences at the University of Bristol to improve student assessment literacy and engagement with feedback. We will introduce our ‘Assessment and Feedback Portfolio’ (AFP), an online set of tools including assessment landscapes and an interactive feedback engagement tool, to support student understanding and engagement with assessment and feedback. The AFP is supported by the ‘Feedback Café’, a regular drop-in stall run by lecturers and student partners. The Feedback Café provides students with an opportunity to discuss their feedback which enables better insight and understanding. Students can also discuss upcoming assessments with signposting to existing resources to support their development and allow implementation of lessons learned. Each initiative has been co-designed and evaluated by staff and student partners. We will present how we have embedded these initiatives within our programme and our findings from our evaluation into the student experience of these schemes. We will also share key steps on how you might include such initiatives into your own programmes, and any lessons learned from our own experience.

OED6.3 QUICK WINS IN IMPROVING AUTHENTICITY, ROBUSTNESS AND CHOICE IN ASSESSMENTS

Wednesday 9th July 2025 15:45

Ellen Bell (University of East Anglia, United Kingdom)

ellen.bell@uea.ac.uk

The time when all taught content in higher education could be assessed with an essay or exam is long since passed. Good assessment practice currently requires authenticity in the assignment, robustness against AI and allowance for students to have some level of choice and autonomy. Meeting all of these criteria is a daunting and challenging task. Here I show how a few tweaks to assessment practice can help a move towards meeting some of these criteria, either by incorporating local businesses to improve authenticity, by moving away from written assessments to adopt a more AI robust framework using modified Vivas or by simply creating options for students to tailor their assessments to better meet their interests.

OED6.4 AI-POWERED ENGAGEMENT: 5-MINUTE HACKS FOR YOUR NEXT LECTURE

Thursday 10th July 2025 11:00

Elizabeth Alvey (University of Sheffield, United Kingdom)

e.alvey@sheffield.ac.uk

I will share strategies for busy academics to efficiently adopt GenAI tools by prioritising applications where assessment of the output quality is straightforward and benefits are immediate. The core of this talk presents three case studies from my genetics teaching practice where GenAI has successfully enhanced student engagement and provided timely feedback, thereby boosting student confidence and learning outcomes.

Through these practical examples, this presentation aims to inspire and equip delegates with actionable ideas they can immediately implement in their own teaching contexts. Attendees will leave with a clearer understanding of how GenAI can serve as a powerful tool to address key pedagogical challenges in bioscience education without requiring extensive time investment.

OED6.5 SCIENCE FRIDAYS (SCIFRI): SUPPORTING RESEARCH EXPECTATIONS AND INSIGHTS THROUGH STUDENTDRIVEN DISCUSSIONS

Thursday 10th July 2025 11:30

Colin D McClure (Queen’s University Belfast, United Kingdom)

c.mcclure@qub.ac.uk

PhD research is the backbone of disciplinary innovation within the higher education sector of the UK and beyond. With planned economic growth, and increased research funding expected in the UK, more PhD students are required to meet this demand and deliver these projections. The perception of the research student experience, particularly within the social media sphere, is often negative, and with the ongoing mental health challenge experienced by PhD students, honest discussions around the reality, benefits and commitments are required to ensure better preparedness for prospective students. Here I present a Science Friday (SciFri) initiative whereby PhD research students are given an opportunity to discuss their projects to small groups of interested undergraduate students within the School of Biological Sciences at Queen’s University Belfast. These sessions were delivered weekly during term-time over a series of four weeks across two semesters. All participants stated the benefits of the sessions which provided undergraduates with a unique opportunity to develop a rapport with research students, enabling them to identify day-today information on the research student experience. Interestingly, participants mentioned the importance these sessions were to develop novel connections with other students and researchers, developing their sense of belonging within the school, and even fostering new research collaborations. This study demonstrates how universities can leverage on the expertise already available to them to encourage student preparedness and success, as well as to foster an improved sense of belonging.

OED7: ENABLING LEARNING IN A DIGITAL WORLD

ORGANISED BY: AMANDA RASMUSSEN (UNIVERSITY OF NOTTINGHAM), JORDAN MILLWARD (IMPERIAL COLLEGE LONDON)

OED7.2 THE CHOREOGRAPHY OF HYBRID TEACHING

Thursday 10th July 2025 10:00

James Lamb (University of Edinburgh, United Kingdom) james.lamb@ed.ac.uk

The critical and practical interest in hybrid teaching can be traced as least as far back as the early 2000s, however it has only recently come to the fore as way of reimagining the spatial and pedagogical dynamics of university education. This has been driven by, among things, a desire among some students and teachers for more flexible working patterns, advances in online education, anxiety around the environmental impact of travelling to (as well as constructing and maintaining) physical campuses, and the lived experiences of the Covid-19 pandemic.

In essence, hybrid pedagogy can be understood as teaching that simultaneously happens both online and within a physical classroom or comparable setting. It reduces the conventional dependence on designated teaching spaces, even though physical campuses continue to hold considerable practical and symbolic importance.

What hybrid also involves is a good deal more complexity compared with more traditional classroom-based teaching. Hybrid course design involves configuring spatial, technological, and pedagogical elements in order to provide an equitable learner experience across the two attendance modes. Going further, it involves considering how to build connections between ‘in room’ and ‘online’ students and spaces.

In this presentation, I will argue that we can confront this complexity through the choreography of spatial, technological and pedagogical elements. Combining research literature with examples from practice, I will propose that constraints and rules, patterns of movement, rehearsal, improvisation, and other principles adapted from dance choreography, can support the performance of high quality teaching across modes.

OED7.3 ENHANCING AI LITERACY AND TECHNOLOGICAL INTEGRATION IN EDUCATION: CHALLENGES AND STRATEGIES

Thursday 10th July 2025 10:15

Jordon

JKmillward@askjordon.co.uk

AI literacy and the readiness to apply a range of simple and complex technologies in schools and universities represent significant challenges that our institutions must address as they progress. The uncertainty surrounding when staff and students should employ these technologies perpetuates numerous challenges that disciplines and educationalists must resolve. However, while questions about how these technologies are being adopted arise, it is crucial to consider where their utility can be maximised for both staff and students, as well as the base level of literacy needed to access the various present and emerging tools (Stanković et al., 2024). Nurfidari et al. (2024) argue that overviews and introductions to available technologies and their utilisation in various roles are necessary for both staff and students. Particularly when integrating systems into student and staff roles, it is essential to consider how we can support staff in using these new technologies, whether in teaching-focused roles or other capacities. How do we ensure students can engage with the technology while simultaneously developing their skills and ethical uses? Therefore, we must reflect on how we intend to embed these tools to benefit our communities, rather than merely expanding the user base, while also considering the lifelong learning needs of both students and staff (Simeunović & Ružičić, 2024).

POSTER SESSIONS

Friday 11th July 2025 18:00-20:00

OED7.1 TRAVERSING THE BRIDGE: HOW INTERACTIONS AND FACILITATORS INFLUENCE CAREER TRAJECTORIES AND PROFESSIONAL IDENTITIES

Jordon K Millward (Imperial College London, United Kingdom)

JKmillward@askjordon.co.uk

This project explores how life science students’ career trajectories and professional identities are shaped by their historical perspectives, curriculum experiences, and interactions with facilitators. Conducted at Imperial College London, it highlights the importance of recognising students’ prior experiences and providing support to enhance their engagement with the life sciences discipline.

OED8: GETTING YOUR EDUCATIONAL RESEARCH PUBLISHED

ORGANISED BY: SUSANNE VOELKEL (UNIVERSITY OF LIVERPOOL)

OED8.1 PUBLISHING EDUCATIONAL RESEARCH

Friday 11th July 2025 09:30

Susanne Voelkel (University of Liverpool, United Kingdom) svoelkel@liverpool.ac.uk

Many academics introduce teaching innovations in the classroom and beyond, with the aim of improving student learning and experience. These initiatives can generate a wealth of quantitative and qualitative data which could potentially lead to publications that would benefit the whole sector. What is more, educational publications provide evidence for scholarship which can promote the authors’ career. Despite these obvious advantages, colleagues sometimes struggle to take the step from innovation to publication. This presentation will give an introduction to the processes leading from designing and planning of educational research to its publication. It aims to provide a background and basis for an interactive workshop exploring how publication barriers could be overcome.

SEB Journals Publishing for the Community Peer review workshop

SEB Journals stand

The ‘seb Journals’ stand will be staffed by the society’s editorial team. If you have any questions about the journals, please come and see us.

The seb’s editorial office is running a workshop on peer review after lunch on Thursday 10th July. In this interactive session, participants will learn how to write high-quality peer reviews in line with best scientific practice and ethical norms. We will also discuss different peer review models and future challenges that the peer review system has to master.

Meet the editors

Come and talk to the journal editors at an informal session at lunchtime on Wednesday 9th July. The society’s editorial staff will also be there to answer your questions.

• Impactful applied plant science

• Open access, online publishing

• High Altmetric scores

• Expert editorial board

• Owned by the SEB & the AAB

• Considers short research papers

•Diverse and supportive editorial board

•Fast time to first decision

•OA Research Highlights every issue

•Annual special issue

•TPJ Fellowships to support new group leaders

•Annual Outstanding Paper Prizes

• Serving the plant science community since 1950

• Editorial Internship programme

• Diverse & experienced editorial board

• Society-run editorial office

• 100% of profits reinvested in the community

• Accessible eXtra Botany section

• Ten special issues every year, helping to fund scientific meetings

•Progressive on open data

•Discounted publishing fees for SEB members

•Constructive peer review

•Format-free submission

•Supportive of ECRs

•Committed to a high standard of ethics

•Open access, online publishing

•Considers White Papers

•Rapid and transparent publication

•Owned by the SEB and the ASPB

•Considers Registered Reports

•Transfer relationship with many plant journals

•Discounts for pre-printed manuscripts

•Field-defining editorial board

•Open access, online publishing

•Dedicated editorial staff

•Community-led special issues

•Considers replication studies

The SEB is:

•a signatory of the Declaration on Research Assessment (DORA)

•committed to open access and open data

•dedicated to achieving the highest standards of ethics in publishing

All of the SEB’s income from its journals is used to support the society’s work and charitable activities, including:

•running scientific meetings (SEB Conference, SEB Symposia, supporting smaller meetings)

•training, outreach and engagement work in the community

•the provision of grants for small meetings

John Lunn, Editor-in-Chief, Journal of Experimental Botany

Jonathan Napier, Editor-in-Chief, Plant Biotechnology Journal

Andrea Fuller, Editor-in-Chief, Conservation Physiology

Mike Page

Bridget O’Boyle

Mareike Jezek

The Plant Journal and Plant Direct also represented.

AUTHOR INDEX

Dean, R.A.

Nicola, E.H.D.

Dubiner, S.

BEN, M.A.

Koch, M.M.

Mitchell, M.

Sun, S.

Roberts, K.T.

A10.26

A10.27

A10.29

A10.30

A10.31

A10.32

A10.33

A10.34

Lechner, E.R. A10.35

Furic, C. A10.36

Fernandes, J.F.D.C. A10.38

Huang, S. A10.39

Richard, R. A10.41

Wilkie, M.P. A10.42

Souques, C.

Tamarit, M.E.

A10.43

A10.44

Queiros, Q. A11.1

Kamska, V. A11.2

Clark, T.D.

Garzon, F.

Kuchenmüller, L.L.

C.

Abel, M.G.

Hargiyatno, I.T.

Rudd, J.L. A11.9

Gamperl, A.K.

Cortese, D.

Thambithurai, D.

Goodrich, H.R. A12.9

Huysduynen, A.H.V. A12.10

Abonyi, A.

Tüzün, N.

Gurung, A.

Theys, C.

Almeida, R.A.

A11.10

A11.11

A11.12

Abe, T.K. A11.14

Govaert, L. A12.6

Boukal, D. A12.7

Hasnain, S.S.

A12.11

A12.12

A12.13

A12.14

A12.15

Leite, C.A.C. A12.1

Lamaizi, A. A12.2 Carmo, J.M.S.

Silva, B.S. A12.4

Jamil, F.

Shama, L.N.

Pitt, M.D.

Peters, A.

Malik, T.G.

Tsang, C.T.T.

Hsu, B.

Costa, M.S.

Müller, W.

Crespel, A.

English, S.

Garcia-Co, C.

Langlois, C.

Ruuskanen, S.

Kohlsdorf, T.

Du, W.

Cordero, G.A.

Cowan, Z.

Rummer, J.L.

Pottier, P.

A12.8

Ruthsatz, K.

A12.5

A13.1

A13.2

A13.3

A13.4

A13.5

A13.6

A13.7

A13.8

A13.9

A14.1

A14.2

A14.3

A14.4

A14.5

A14.6

A14.7

A14.8

A14.9

A14.10

A14.11

Green, L.

Gvoždík, L.

Noble, D.

Vámos, M.S.

Schumm, M.

Bettinazzi, S.

Geessinck, Q.F.

Jaspers, V.L.

Marasco, V.

FENNI, N.E.

Wiil, J.

Prokic, M.D.

Petrovic, T.G.

Pottier, P.

Green, L.

Kendall-Bar, J.

Opinion, A.G.R.

Linden, J.F.

Hasegawa, T.

Thaker, M.

Choy, E.

Flávio, H.

Schreck, L.

A14.12

A14.13

A14.15

A14.16

A14.17

A14.18

A14.19

A14.20

A14.21

A14.22

A14.23

A14.24

A14.25

A14.26

A14.27

A16.9

A16.10

A16.11

A16.12

A16.13

A16.14

A16.15

A16.16

Donaldson, A.C. A16.17

Birnie-Gauvin, K. A16.18

Sparkes, M.G.R.

C.J.

Bihun, C.J. A17.62

Hoots, M.E.C. A17.63

Akter, S. A17.65

Blurton, C. A17.66 Lignot, J. A17.67

Berg, M.M.V.D.

Nati, J.J.

Idowu, A.B.

Rato, A.

Howell, B.E.

Pettinau, L.

Uesaka, L.

Urca, T.

Shokri, M.

Last, K.

Cadonic, I.G.

Merza, O.

Allen, G.J.

Toisoul, L.

awan, U.M.

Adeosun, A.

Durnford, F.P.H.

Huang, M.C.

Yang, C.

Hsu, C.

Wilde, M.D.

Hsu, P.

Lignot, J.

Roussel, D.

Murase, I.

Gundiah, N.

Leiva, F.P.

Toit, H.D.D.

Kirsten, T.B.

Rasmussen, A.S.S.

Weihrauch, D.

Nowack, J.

A17.68

A17.69

A17.70

A17.71

A17.72

A17.73

A17.74

A17.75

A17.20

A17.21

A17.22

A17.23

A17.24

A17.25

A17.26

A17.28

A17.29

A17.30

A17.31

A17.32

A17.33

A17.34

A17.35

A17.36

A17.37

A17.38

A17.39

A17.41

A17.42

A17.43

A17.44

A17.45

Baldry, C.J.

Crovetto, L.

Pozzo, C.F.S.D.

Moses, C.A.

Berenbrink, M.

A17.48

A17.49

A17.51

A17.76

Berenbrink, M. A17.80

Souques, C. A17.78 Georgoulis, I.

Fortuny, J.

Wood-Bailey, A.P.

Iken, S. A2.20 Chatar, N. A2.21 Bouda, M.

Montealegre-Z, F.

M.E. A2.24

A.R.M.

Prescott, T.L. A2.10

Wagner, N. A2.11

Garcia-Escolà, L.

Herde, M.

Wilson, M.E.

Schwarz, D.

Giustina, F.D.

Prino, A.

A2.12

A2.13

A2.14

A2.15

A2.16

I.

Schwaner, M.J.

Turner, F.

S.

Forouhar, D.

Davies, Z.T.S.

Koeda, T.

Kornev, K.

Inada, Y.

Posada, G.C.

Kumar, G.

Unterholzner, J.J.

Sathe, E.A.

Wassenbergh, S.V.

Gurka, R.

Koehnsen, A.

Annear, E.

Marcé-Nogué, J.

Modert, M.

Pal, I.

Certini, D.

Harrison, S.L.

Gorp, M.V.

López-Pachón, M.

Thomas, J.

Shimakawa, S.

Montanez-Rivera, I.

Inada, Y.

Watkins, S.

Wölfer, J.

Berndt, M.H.G.

Ridder, T.D.

Mielke, M.

Kuchibhotla, S.

Zhang, B.

Dorsch, M.N.

A5.64

A5.65

A5.25

A5.67

A5.68

A5.69

A5.70

A5.71

A5.72

A5.73

A5.74

A5.75

A5.76

A5.77

A5.78

A5.79

A5.80

A5.81

A5.82

A5.84

A5.85

A5.26

A5.27

A5.28

A5.29

A5.30

A5.32

A5.34

A5.35

A5.36

A5.37

A5.38

Tan, M.M.R. A5.39 Gladman, N.W.

Amador, G.J.

Zullo, L.

Emter, G.

Dethlefs, L.

Scheidt, A.

Berg, O.B.

A5.40

A5.41

A5.42

A5.43

A5.44

A5.45

A5.46 Günther, M.

Wong, J.C.

Mylo, M.D.

Kamalakanthan, Y.

A5.47

A5.48

A5.49

A5.50 Koeber, C.

Brook, C.A.C.

A5.51

A5.54 Eilhardt, R.

Modert, M.

Meer, N.M.V.

Nyakatura, J.A.

Steinkampf--Pellecuer, N.

Yamamoto, Y.

Baars, A.J.

Hormozi, H.

Schaaf, M.

A5.55

A5.56

A5.57

A5.58

A5.59

A5.60

A5.61

A5.66

A6.1

Hubbard, P.C. A6.2

Majelantle, T.L. A6.3

Forin, C. A6.4

Joshi, M. A6.5

Gilmour, K.M. A6.6

Mohanty, N.P. A6.7 Nacarino-Meneses, C. A6.8

Singh, H.R.

C2.2

Meul, Y.

Afonso, S.

Schoenaers, S.

Haas, K.T.

Somoza, S.C.

WANG, H.

Potocký, M.

Denninger, P.

Balcerowicz, D.

Belloli, M.

Feijo, J.

Pejchar, P.

Sadanandom, A.

Menke, F.L.

Sybilska, E.

Benczúr, K. C4.4

Tabler, J. C4.5

Benham, A.

Lignot, J.

Carvalho, M.D.G.S. C4.8

Lucas, M.D. C4.9

Mehra, P. C4.10

Agnessens, J. C4.11

Kashif, S.Z. C4.12

Basu, A. C4.13

Bennett, T. C4.14

Davies, T. C4.15

Tetzlaff, S.L.

Marcia, M.G.

Vocelle, D.

Venn, A. C4.20

An, D.H. C4.21

Perry, D.

Garden, C.L.

Grant, M.

Smith, D.G.

McCrone, L.D.

Rasmussen, A.

Rayment, S.J.

Moult, P.

Krogsaeter, H.

Savickaite, S.

Spanu, P.D.

McCaughey, L.

Murray, R.R.

Shu, E.X. OED5.4

Lopez-Juez, E.

Edmunds, K.

Murray, R.R.

OED6.1

OED6.2

Bell, E. OED6.3

Alvey, E. OED6.4

McClure, C.D.

OED6.5

Lamb, J. OED7.2

Millward, J.K.

OED7.3

Millward, J.K. OED7.1

Voelkel, S.

Mutwil, M.

Mure, S.

OED8.1

P1.1

P1.2

Xu, R. P1.3

Lopez, M.

H.

Hocini, F.I.

Wendering, P.

Jindamol, H.

Cangemi, M.

Allmen, R.V.

Tei, A.

Emmerson, R.

PRODJINOTO, H.

Agosti, A.

Myers, C.

Renella, A.

Vincenzi, E.

Avila, C.A.

GOEL, K.

Jones, S.L.

Masetlana, T.I.

Maccaferri, M.

Chir, L.

Degand, T.M.

Littlejohn, G.R.

Tudor, E.B.

Wada, H.

RAPPARINI, F.

P1.9

P1.10

P1.11

P1.12

P10.11

P10.26

P10.12

P10.13

P10.14

P10.15

P10.10

P10.27

P10.17

P10.18

P10.19

P10.20

P10.21

P10.16

P10.2

P10.22

P10.23

Cicchi, C. P10.24

Rotthier, D. P10.25 Hill, J.

Jiang, M.

Trupiano, D.

J.

Ghannoum, O.

Shrestha, M.S.

Caine, R.S.

Nieves, M.T.

Steppe, K.

Dresch, C.

Soualiou, S.

Wassenaar, M.

Regnier, N.

Alegria, E.V.

Luyckx, A.

Ekele, J.U.

Dupont, K.

Shao, M.B.

Tardieu, F.

Saha, S.

Asayesh, E.J. P3.14

Lawson, T. P3.15

Coindre, E. P3.16

Jayasankar, K.

Strand, D.D.

Fridman, E.

Loiacono, V.F.

Theeuwen, T.

Arimura, S.

Berg, F.V.D.

Štorchová, H. P4.7

Forner, J. P4.8

Barnard-Kubow, K.

Bodenheimer, S.

Gonzalez-Duran, E.

Touzet, P.

Kashkan, I.

Poorter, H.

Bouidghaghen, J.

P4.9

P4.10

P4.11

P4.12

Ferguson, J.N. P5.1

Smet, I.D.

Merilo, E.

Wang, Y.

Pridgeon, A.J. P5.5

McAusland, L. P5.23

Santelia, D. P5.6

Shan, Y. P5.7

Berg, T.E.V.D.

Iamprasertkun, M.N.

Lawson, T.

Miart, F.

Croft, H.

P5.8

P5.9

P5.10

P5.11

P5.12

Fan, M. P5.13

Hõrak, H. P5.14

Al-Salman, Y. P5.15

Ivandi, E. P5.16

Dong, Y. P5.17

Jalakas, P.

P5.19

FORGET, G. P5.20

Papanatsiou, M. P5.21

Tulva, I. P5.22

Ullah, S. P7.1

Baccio, D.D. P7.2

Muller, O.

Johnson, K.

D'Agostino, M.

Parent, B.

Draye, X. P7.10

Lejeune, P.

Dudley, C.E.

Solin, J.

Athanasiadis, I.N.

Rousseau, D.

Liu, S.

Abdelhakim, L.

Enciso, J.

Chapman, S.

Zhu, C.

Cioppo, G.D.

Lemaire, L.

Stevens, F.

Sarkar, A.

Vreken, L.V.D.

Basak, R.

Roychoudhry, S.

Fendrych, M.

Bianco, M.D.

Khan, K.

Sajjad, M.A.

Uzilday, R.O.

Kirschner, G.

P7.11

P7.12

P7.13

P7.14

P7.15

P7.16

P7.17

P7.18

P7.19

P7.20

P7.21

P7.22

P7.23

P8.2

P8.3

P8.4

P8.5

P8.6

P8.7

P8.8

P8.9

P8.10

P8.11

Farooq, M.A.

Truffault, V.

Fagan, S.

Lloyd, J.P.

Raines, C.

Lopez-Juez, E.

Cavanagh, A.P.

Taylor, S.H.

Busch, W.

Patil, S.

Joshi, S.

Arazi, T.

Shameer, S.

Wang, T.

Mason, S.E.

Beauchet, A.

Geurts, R.

Joubert, T.

Lopes, T.S.

Kaste, J.A.

BHAKTA, S.

Gharabaghlou, M.S.E.

Çelik, M.B.

Perry, D.

Kalia, M.D.

Mandadi, K.K.

P8.12

P8.13

P8.14

P8.15

P9.1

P9.2

P9.3

P9.4

P9.5

P9.6

P9.7

P9.8

P9.9

P9.10

P9.11

P9.12

P9.24

P9.25

P9.26

P9.27

P9.13

P9.14

P9.16

P9.18

P9.19

P9.20

Lee, K. P9.21

Bianco, M.D. P9.23

Mack, K.

SAB1.1

Catchen, J. SAB1.2

Karapli-Petritsopoulou, A. SAB1.3

Feugere, L. SAB1.4

Desvignes, T.

Beck, E.A.

Williams, B.

Frisch, D.

Lefevre, S.

Hsi-Mei, L.

Hay, F.R.

Tomlinson, S.

Firth, B.L.

Groves, M.V.

Pitcher, T.E.

Pichaud, N.

Bererd, S.

Aminot, M.

Tremblay, N.

CALOSI, P.

Sokolova, I.

Paya, C.E.

Watson, J.

Léopold, G.

Roussel, D.

Chevret, C.J.L.

Mélançon, V.

Rivera-Ingraham, G.A.

Bertrand, P.

SAB1.6

SAB1.7

SAB1.8

SAB1.9

SAB1.10

SAB1.5

SAB2.1

SAB2.2

SAB2.3

SAB2.4

SAB2.5

SAB3.1

SAB3.2

SAB3.3

SAB3.4

SAB3.5

SAB3.6

SAB3.7

SAB3.8

SAB3.9

SAB3.10

SAB3.11

SAB3.12

SAB3.13

SAB3.14

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