11am–12:10pm We found that herbivory differed between low and high elevation plots and between tree species but not between forest gap and interior areas. (Research supported by the Wellesley College Janina A. Longtine Fund for Summer Research in the Natural Sciences.) Behavioral and Physiological Changes in Honey Bee (Apis mellifera) Queens during a Swarming Event
Victoria Ellis ’12, Biological Sciences Advisor: Heather Mattila, Biological Sciences Within a large and growing honey bee colony, overpopulation results in the initiation of a reproductive process known as swarming, which divides one colony into two smaller colonies. When a colony swarms, roughly two-thirds of its population departs with the original queen to found a new nest. Workers are aware of the queen’s presence in the airborne swarm via the pheromones that she emits and our previous work shows that a queen’s pheromone production increases prior to liftoff. To determine how queens prepared for liftoff and how worker-produced signals facilitate this process, swarming was induced in colonies and queens were monitored through the process for pheromone production and changes in body temperature and activity level. These queen metrics were related to simultaneous activities of workers in the swarm. Our study provides insight into the mechanisms that prepare queens for liftoff and for keeping airborne swarms cohesive. Studying the Biology of Wolbachia, the Male-hating Bacteria
Heidi Park ’12, Biological Sciences Advisor: Heather Mattila, Biological Sciences The Wolbachia bacterium is a reproductive parasite of insects that promotes the survival of female offspring to the detriment of male offspring. Wolbachia is extraordinarily widespread (infecting 60–80% of insect species) and also of medical relevance for the potential it holds as an insect vector control agent and drug target for filarial nematodes. However, little is known about how the bacterium interacts with its hosts. In this study, we studied proteins putatively used by Wolbachia for host interaction through three different techniques: 1) expression in yeast, a model eukaryote, to identify the molecular mechanisms used by Wolbachia to manipulate its hosts, 2) elucidating the function of these proteins by using bioinformatics (comparing them to well-characterized proteins) and 3) identifying
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their localization within the yeast cell. We identified 10 candidate Wolbachia effectors. We are currently working on determining their localization in the eukaryotic cell. When and Where: Divergence times and Colonization Tracks of Darwin’s Darkling Beetles in the Galápagos Archipelago
Julia Wucherpfennig ’12, Biological Sciences Advisor: Andrea Sequeira, Biological Sciences Stomion is a genus of endemic flightless tenebrionid beetles first collected by Charles Darwin on his voyage to the Galápagos. Given that the islands are a dynamic conveyor belt of potential colonization platforms, we tried to establish a link between Stomion’s evolutionary history and the geologic history of the islands that they inhabit. Using a multi-gene dataset, we elucidated a potential colonization pattern, explored the timing of the first colonization event, and considered the subsequent generation of diversity within the archipelago. In order to derive a more generalized pattern further explaining the mechanism of colonization and speciation in island archipelagos, we considered the age of diversification of Stomion and its colonization history in comparison to other species in the Galápagos Islands.
Escaping & Expanding, Plants & Fish (short talks) Pendleton Hall West 116 Comparing the Photoprotective Importance of Nonphotochemical Quenching across a Range of Plant Species
Mia Howard ’12, Biological Sciences, and Jennifer Yang ’12, Biological Sciences Advisor: Martina Koniger, Biological Sciences While light is the driving force of photosynthesis, excess light can be harmful. As sessile organisms exposed to often drastically fluctuating light intensities, plants have evolved several mechanisms for maintaining the delicate balance between maximizing photosynthetic yield and minimizing photooxidative damage. The xanthophyll cycle allows plants to quickly transition from a state of high photochemical efficiency to one of cautious photoprotection upon changes in light conditions. The associated photoprotective state, known as nonphotochemical quenching (NPQ), prevents photodamage by innocuously dissipating excess absorbed light energy as heat. We compared the capacity
WELLESLEY COLLEGE RUHLMAN CONFERENCE 2012
of a range of species to perform NPQ and quantified its photoprotective importance by comparing the abilities of leaves treated with dithiothreitol, a xanthophyll cycle inhibitor, and untreated leaves to recover from high light stress. Ultimately, we hope to better understand photoprotection in plants by comparing our results to data describing the importance of chloroplast movement, another prominent photoprotective strategy. Tip Growth: Assessing the Functional Equivalence of COW1 in A. thaliana and P. patens
Jessica Lee ’12, Biological Sciences Advisor: T. Kaye Peterman, Biological Sciences Tip growth, or polarized cell expansion, produces cellular morphologies characterized by an outgrowth extending from a main body. Tip growth processes involve membrane trafficking to a specific growing point during cellular morphogenesis, and the resulting structure frequently allows for specialized cellular function. The model bryophyte Physcomitrella patens is an optimal system for tip growth studies. A previously characterized COW1 mutation in Arabidopsis thaliana individuals manifests a phenotype consistent with a tip growth defect (Grierson et al. 1997). Three putative COW1 homologs were identified in the P. patens genome based on sequence similarity, and a cross-species complementation study is underway to assess the functional similarities of these homologs to COW1. Identification of a functionally equivalent COW1 homolog in P. patens would suggest that its tip growth-specific function arose early in the evolution of land plants, and provide a conveniently simple model for investigating tip growth processes in the laboratory. Catching Nemo: Fish Escape Strategies and Performance
Allison Robbins ’13, Biological Science, and Janet Jeong ’14, Psychology Advisor: David Ellerby, Biological Sciences Successful predator evasion is essential for the survival of many animals. Performance, and therefore escape success and evolutionary fitness, is strongly influenced by both morphological and behavioral factors. Bluegill sunfish (Lepomis macrochirus) found in Lake Waban exhibit morphological differences based upon habitat. Shallow water fish have deeper body shapes, a morphology associated with increased escape performance. We therefore hypoth-