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© 2017 Text and Illustrations – Sally Luker Photograph credits: Sally Luker Ysella Luker-Green Adam Poledníček Copyright in the photographs remains with the individual photographers. The right of Sally Luker to be identified as author and illustrator of this work has been asserted by them in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this book may be reproduced, transmitted or stored in an information retrieval system in any form or by any means, graphic, electronic or mechanical, including photocopying, taping and recording, without prior written permission from the publisher.

This book has been typeset in Garamond.

ISBN: 978-0-9559036-8-7

Professor Penny Stories are a series of children’s books written by staff and students of the University of Exeter College of Life and Earth Sciences, based in Penryn, Cornwall. Each with a unique style and appropriate for a range of ages, these stories bring scientific research and natural history to life, from conservation and animal behaviour to microbiology.

Look out for our favourite scientist, Professor Penny, in every story. With her faithful four-legged companion Wilson, she’ll help you understand the science behind the characters’ adventures.

Other stories in the Professor Penny series: The Adventures of Flo, the Special Bacterium The Tale of the Turtle and the Plastic Jellyfish Woolly’s Wonderful Wings

Chapter One – new arrivals

Huddling together for safety, they cowered before the giant, their tiny legs shaking, their eyes closed in fear.


Pop! A very tiny (and to be honest, very odd-looking) creature crawled from an equally tiny – almost invisible to the human eye – egg. On a leaf-bud, on a small twig, on a bush, the very tiny creature looked around and attempted to take in her new surroundings.

Pop! Another very tiny (and to be honest, very odd-looking) creature crawled from another equally tiny – almost invisible to the human eye – egg. And another. And another. Before long, there were lots of very tiny (not to mention very oddlooking) creatures, all clinging together on a single leaf-bud, on a small twig, on a green bush, somewhere in the wide, wide world. The first very tiny creature blinked. Lots of pairs of eyes were focussed on her. Were they expecting her to do something? Why were they all staring? It’s not as though she had any clue what was happening, where they were, or even who they were.

Boing! The tiny creatures’ collective attention was suddenly drawn to what seemed to them a giant, winged beast, landing with force on their new leaf-bud home. Huddling together for safety, they cowered before the giant, their tiny legs shaking, their eyes closed in fear. ‘My babies!’ 2

The very first tiny creature slowly opened her eyes, and peered cautiously at the giant. ‘My first-born? I’ll call you Aroha. In our homeland, ‘Aroha’ means ‘love’.’ ‘Mummy?’ Soon, all eyes were open and staring widely in disbelief. Mummy? This was their mummy?! ‘Oh, my beautiful babies – you’re finally here. Now, let me have a good look at you all. Oh, your father will be proud – such fine psyllid nymphs’ ‘Silly nymphs?’ Muttering to one another in confusion, the tiny creatures, sorry, psyllid nymphs, looked at one another. What on Earth was a silly nymph? Their mummy smiled down at her babies.

Boing! Oh my goodness, the leaf-bud bounced and the small twig shook, as, from apparently nowhere, another winged giant appeared in front of the psyllid nymphs. ‘Here you are. Look – you’re a Daddy! Aren’t they beautiful?’ ‘Oh, bless their tiny little cotton socks, all – um, how many are there?’ ‘Twelve. Twelve perfect psyllid nymphs. Six boys and six girls. This is Aroha, our first-born’ 3

Aroha smiled shyly at her father. ‘Um, very pleased to meet you, sir. Could you please tell me, what’s a ‘silly nymph’?’ Daddy Psyllid smiled. ‘No need for all this politeness – we’re family! And it’s not a ‘silly’ nymph, it’s a ‘psyllid’ nymph. We’re psyllids, also known as jumping plant lice, and sometimes as ‘suckers’. Our closest relations are aphids – I expect you’ll meet some of them before too long, whiteflies – which aren’t flies at all, and scale insects. Now scale insects are very, very odd but perfectly friendly if you make an effort to get to know them.’ Mummy Psyllid joined in. ‘And we’re all Hemipterans, which includes leafhoppers, planthoppers, groundhoppers, froghoppers, and all manner of bugs – shield bugs, ground bugs, you name it, there’s a bug for that. And all Hemipterans are insects – generally animals with three body parts, three pairs of legs, and one or two pairs of wings, and most are small like us.’ ‘And nymph means ‘youngster’. You’ll grow through several nymphal stages before eventually emerging as grown-up psyllids, like us.’ Daddy Psyllid continued. ‘Will it hurt?’ ventured one of the nymphs. ‘Not at all. You might feel a bit funny at times but it doesn’t hurt.’ ‘So’, Aroha was feeling more confident. ‘Are there lots of types of psyllids? Are we special?’ ‘Of course you’re special’, cooed Mummy Psyllid. ‘You’re our babies!’ ‘Yes, of course you’re very special to your Mummy and me but to answer your question, yes, there are lots of psyllids, at least 3000 species in the world, and yes, we’re special psyllids because we 4

come from New Zealand, and live and feed on Pittosporum plants.’ ‘So, is this New Zealand then?’ ‘Well, no…’


Chapter Two – early days

‘What are they?’ a small voice whispered, making Aroha jump. She turned to see one of her six brothers hanging over the edge of a nearby leaf, straining to see what it was that was making such a loud noise.


After a long meal of sweet plant juices, Aroha took some time out and looked around her. It was a lovely, sunny day. Birds were singing (she knew they were birds because Daddy Psyllid had told her so), and although Aroha couldn’t quite put any of her sensory leg hairs on it, today there was something of a buzz of excitement in the air. Not like the buzzing of the enormous furry bees Aroha sometimes observed from a safe distance – something else – as though something important were about to happen. ‘How about this one, Sue?’ All of a sudden, a loud voice boomed through the leaves. ‘Nah, I’m not keen – I would prefer something with yellow flowers’ ‘This one then? September’.’

It says, ‘shade-loving, flowers May to

‘Hmm, maybe Jo. How big does it get?’ ‘Height 1-2 metres…’ ‘OK, make sure you choose a nice-looking one then’ ‘What are they?’ a small voice whispered, making Aroha jump. She turned to see one of her six brothers hanging over the edge of a nearby leaf, straining to see what it was that was making such a loud noise. ‘Why are you always so nosy?’ ‘You’re one to talk! I’ve seen you, watching everything that goes on, listening in on conversations, always asking questions of Mummy Psyllid and Daddy Psyllid.’


‘Yeah but… Anyway, to answer your question, I don’t know what they are. Can you see them?’ ‘I think so. They’re ENORMOUS – proper giants! They’re long and funny coloured, with only four legs, and I definitely can’t see any wings or wing-buds’ ‘Do you think they’re going to hurt us?’ ‘Mummy Psyllid! Daddy Psyllid! Where are you? Are we safe? Do we need to hide?’

Boing! ‘Hello my lovelies. Your mother and I were just having a slurp of plant juices with some friends who live at the top of the bush. Are you OK?’ ‘What are they, Daddy Psyllid? Are we safe? Do we need to hide?’ ‘Come now, much as I enjoy a cuddle as much as the next psyllid, there’s no need to cower under my wings! They’re humans. We’ve never met any that have given us any cause for alarm, in fact some are very friendly but it is always best to exercise a little caution around them, just in case one of them ‘turns’.’ ‘Um, OK.’ Aroha slowly crawled out from under Daddy Psyllid’s wings, and strained in the direction of the human voices. ‘Jo, look at this one! Look at those funny, crinkly leaves!’ ‘Oh yes, a Pittosporum. My mum’s got one of those.’ Aroha recoiled in fear, as a large pair of blue eyes peered into the foliage. There were definite advantages to being very tiny, and


being able to disguise yourself as a little bump on a leaf was one of them. ‘Maybe next time, Sue, don’t you think? Although it definitely has potential.’ ‘Phew, that was a close call!’ Aroha’s brother had been playing ‘I’m a leaf bump’ too. ‘Nice eyes though.’ ‘Oh, you two’, Daddy Psyllid’s calming (and rather amused) voice reassured them. ‘You’ll get used to the humans. I’m going back to find your mother. If you need us, shout.’ As the day went on, Aroha’s fears lessened, and she found herself beginning to look forward to seeing, or sometimes only hearing, the human passers-by. That night, she settled down to sleep, her mind buzzing with new-found knowledge of shade-loving plants, what would be good for the pond area, and who was going to win ‘the rugby’. However, she still wasn’t sure about a lot of things. In particular, what was this New Zealand place about which Daddy Psyllid had spoken?


Chapter Three – making friends, and knowing your enemies…

…as instructed, they raised their abdomens and began to wave. As they did so, they caught sight of a tiny black insect with what looked like a very long tail.


Whoosh! ‘Mummy Psyllid! Mummy Psyllid! Mummy Psyllid!’

Boing! As usual, Mummy Psyllid arrived from seemingly nowhere. ‘Mummy Psyllid, what’s going on?!’

Whoosh! ‘No need to panic my darlings. It’s only rain. It comes from the sky, or sometimes from a hose or watering can. We’re small enough to dodge the drops, so it won’t hurt us. The plants need it to remain healthy, and without it, there would be no plant juice for us to drink.’

Whoosh! Aroha pulled a face. ‘Hmm, I’m still not sure that I like it.’ ‘I do!’ called one of her sisters. ‘Look, it’s fun!’ ‘Hmm…’

Boing! ‘Salut! Allo zere ! Bonjour mes amis’ The psyllid nymphs turned to one another, communicating their confusion via silent facial expressions. ‘Mes amis, bonjour à tous.’ ‘Ah, Marie. Hello my dear – how’s the family?’


‘Très bon, ma chérie. adorables.’

Mes bébés sont arrivés, et ils sont

‘Likewise Marie, likewise. Meet my beautiful babies.’ ‘Ah oui, ils sont adorables aussi. Bravo, felicitations!’ ‘Er, Mummy Psyllid?’ ‘Children, this is Marie. She’s a psyllid too but a different one from us. She lives on the Elaeagnus just over there, and she and her family come from France. Not all Elaeagnus psyllids are from France though, some are from Spain, some are from Italy, some are from Belgium… She has babies too, and soon you’ll be able to meet and hopefully become friends.’ More psyllids? There were more psyllids nearby? So, if they were from New Zealand, and Marie was from France, where were they right now? Did anybody know? ‘Au revoir mes amis. Mes enfants, zey are alone!’ ‘Goodbye Marie – see you again soon. Love to Philippe.’ ‘Mummy Psyllid?’ ‘Yes, Aroha.’ ‘If we’re supposed to live in New Zealand, and Marie’s supposed to live in France, where are we now, and why are we all together here?’ ‘Now, that’s quite some story Aroha. Are you sitting comfortably? Then gather around children, and I’ll begin. Once upon a…’

Boing! 12

‘Ah, Daddy Psyllid. Aroha was just asking about why we’re all living here and not in New Zealand, or France, or wherever else some of our friends would normally live. I was about to…’ ‘No time for that, Mummy Psyllid. A pesky wasp has been spotted. Time to spring into action. And wave!’ ‘Quick, children – copy us!’ The psyllid nymphs weren’t at all sure what was happening but a ‘peskywasp’ didn’t sound good at all, so, as instructed, they raised their abdomens and began to wave. As they did so, they caught sight of a tiny black insect with what looked like a long tail. ‘Keep waving. Don’t stop!’ ‘OK Daddy Psyllid’ The peskywasp approached them, slowly. ‘Wave!’ It stopped and flexed its ‘tail’. ‘WAVE!’ Then it hesitated. ‘WAVE!!’ Once more, the peskywasp flexed its ‘tail’. Then it stopped, turned around and with a quick flutter of wings, flew off. ‘Can we stop waving yet?’ ‘Yes my lovelies, you can stop waving. Well done – you did brilliantly.’


‘Daddy Psyllid, what’s a peskywasp, and why did we all need to wave?’ ‘Well, not all of the creatures who live around here are friendly. In fact, some are quite the opposite. Peskywasps are actually parasitoid wasps. The thin, tail-like thing is used by the females to lay eggs – it’s called an ovipositor. Unlike us psyllids, they don’t lay eggs on leaves but instead, they lay their eggs inside us. I won’t say anymore, as it’s not particularly pleasant if you become the host to a parasitoid wasp egg but needless to say, we do our best to trick them by confusing and obstructing them with our waving, so that they can’t get to us.’ Aroha ran to the shelter of her father’s wings, and looked at him with wide eyes. ‘Daddy Psyllid, I’m scared.’ ‘Don’t be, Aroha. Just remember to wave, and you’ll be fine.’ ‘Are there any other horrible things out there?’ ‘A few, my darling but a brave girl like you will always make their lives difficult. As well as parasitoid wasps, keep an eye out for predatory bugs. Remember, we’re quite closely related to bugs. A good many live on plants, like us, and feed on plant juices. You’ll probably meet the odd hopper or two, as they have a tendency to drop in every now and again, and when you’re older, you will be able to flutter over to other plants, where you’ll no doubt encounter some aphid colonies. Actually, I’ve seen aphids on other Pittosporum bushes, so you never know – maybe you won’t have to wait until you can fly before meeting some. Aphids are sometimes good fun but often very intent on feeding, plus some are bossed around by ants, 14

which doesn’t help when you’re attempting conversation. But, I digress. Predatory bugs have them, not to mention a look. They have pointed designed to stab and pierce other creatures, so something with a pointed face, hide – or wave!’

to start a a way about mouthparts, if you spot

‘Right, so – aphids good, pointy-faced bugs bad…’ ‘Just remember to wave!’ All this talk of horrible things meant that Aroha had forgotten all about her mother’s story.


Chapter Four – where are we and how did we get here?

The friendly human laughed, and reached up her hand, carefully removing the adult psyllid which had jumped onto her face, and returning it to the Pittosporum


‘Oh, there you are you gorgeous little things.’ Aroha slowly opened an eye to come face-to-face with a human. Somewhat taken aback, she carefully opened her other eye, blinked, and attempted to take in the sight before her. A pair of sparkling, friendly eyes blinked back at her. Again, the human spoke. ‘It’s very good to see you, you know? So, how are you all doing? The garden centre people might not be overly keen on your presence here but I think you’re brilliant! It’s not as though you’re causing any long-term damage to their precious plants, or to the local eco-system, and you have as much right to live as the plants do. Plus, you’re so very entertaining. Hey you – not on my nose!’ The friendly human laughed, and reached up her hand, carefully removing the adult psyllid which had jumped onto her face, and returning it to the Pittosporum bush. ‘So, you gorgeous little nymph – it’s very nice to meet you. I’m Professor Penny. I work at the university, and I love finding out all about you and the other non-native species which live here.’ Aroha smiled back at Professor Penny. Mind you, being so tiny, she wasn’t at all sure if Professor Penny could actually see her smiling but she liked to think she could. ‘Now, I’m not sure how much you know already but did you know that all species have a scientific name, and that yours is Trioza vitreoradiata, which roughly translates as ‘radiating glass’? Have you noticed that when you settle down to feed, you create a little pit, in which you fasten yourself with tiny waxy strands that look like fine glass? I think your scientific name suits you, don’t you? How are you finding it here? As a species, you’ve been here for 17

quite a while now, since 1993, if I remember correctly, and seem to have settled in quite nicely. I often wonder how our little part of the world compares to New Zealand. Did you know that there are over 2800 known non-native species in Great Britain, and that roughly two-thirds of these are established here? Around 300 of Britain’s non-native species are insects. Most live here without causing any problems. Others don’t. Those that do cause problems do so, mainly, because they cause problems in our native ecosystems. Garden centres like this are something of a hotspot for non-native insects, as many arrive as eggs on plants brought into our country for people’s gardens. Not all survive but a fair few do.’ Penny paused briefly, seemingly lost in thought. Aroha was transfixed by her sparkling green eyes! ‘Like you, my pretties. Now, I know you’re considered something of a ‘pest’ by some because of the damage you do to Pittosporum foliage and possibly to the overall health of the plant but I even know some people who enjoy having you on their plants but then, perhaps they’re a minority! Actually, it’s a little psyllid like you, which goes by the rather long name of Aphalara itadori, that has been brought over from Japan, in the hope that it will help to control another non-native species, a plant called Japanese Knotweed. Now, Japanese Knotweed is a right pain in the bum. It’s not fussy where it grows, has an enormously strong root system which can damage buildings and the like, and basically, it seems to be nigh on impossible to get rid of. It’ll be a while before we’ll be able to properly tell whether or not your Japanese friends are helping but fingers crossed.’ Aroha liked Professor Penny, although she did do an awful lot of talking! 18

Chapter Five – close encounters of the shiny kind

It gradually dawned on Aroha that the black, shiny leaf appeared to be moving, and she reached out to grab one of her sister’s legs.


‘Saboda haka, za a ko'ina kyau a kan holidays? Wat het jy gedoen laaste nag? Qhov no yuav saj ntau nicer nrog ib co txiv lws suav uas ketchup’ ‘Aroha, what’s that funny noise?’ One of Aroha’s sisters had crept forward in an attempt to find out the source of a very unfamiliar sound. ‘Don’t ask me! What do you think it could be?’’ ‘Come on, let’s find out!’ ‘Bạn có xem trận đấu ngày hôm qua?’ The noise was becoming louder. ‘Oh no, why is that leaf all black and shiny?’ ‘I’m scared, Aroha’ The youngsters crept nearer. The funny noise was getting louder and louder. It gradually dawned on Aroha that the black, shiny leaf appeared to be moving, and she reached out to grab one of her sister’s legs. ‘I think the black is actually lots of little animals – insects like us, I believe.’ ‘I’m still scared, Aroha.’ ‘Do you think we need to wave?’ ‘Well, I’m sure it wouldn’t hurt!’ ‘Unsa matahum nga panahon kita may.’ ‘Oh no, we’ve attracted their attention – what do we do now?’ 20

‘Punya gosip?’

Boing! ‘Phew, it’s Mummy Psyllid’ Aroha relaxed a little. ‘Hello you two, and hello you, um, however many there are of you today. It’s been a while since you dropped by? Did you fancy a change from Camellia juice? I guess there’s plenty of Pittosporum juice to go around, so make yourselves at home. Oh, I guess you already have!’ ‘Mummy? Do you know these ‘things’?’ Yes Aroha’, Mummy Psyllid smiled in amusement. ‘Do you remember Daddy Psyllid telling you about being related to something called an ‘aphid’? Well, these are aphids – to be precise, Black Citrus Aphids. They’re not overly fussy about what they feed on but here, they’re usually to be found hanging out on Camellia. Like us – and like Marie and her family – they too come from another part of the world. ‘Is that why they’re making such a funny noise? Did they end up coming here on plants from other countries too?’ ‘Yes, my little clever clogs! You must have met Professor Penny – she’s rather nice, isn’t she? Although, she does do an awful lot of talking! Did she have her dog Wilson with her? As a species, they come from parts of Africa, Asia and the Pacific Islands. Apparently, they like to practise speaking in all sorts of different languages – mainly because it makes them feel exotic and rather special – although New Zealand is a Pacific island too! Actually, there is something that makes them special – they’re the only


aphid that makes a noise that humans can hear. Professor Penny told me that.’ ‘I think I’ll just leave them to it – they’re a little loud for my liking!’ ‘Oh, they’re OK – if you don’t take them too seriously, you might find them to be rather amusing.’ ‘Perhaps another day. place…’

Mummy Psyllid – this New Zealand


Chapter Six – New Zealand

Alerted by the welcoming sound of a very familiar voice, Aroha peeked out from behind her leafbud to observe Gerty and Mummy Psyllid clinging tightly to each other in a warm embrace.


Surely somebody knew about New Zealand. Just when she thought her mother was going to tell her about their homeland, one of Aroha’s other sisters had nearly fallen from a leaf, and Mummy Psyllid had gone rushing to the rescue. Aroha sighed. ‘How about Pittosporum? Evergreen, so good colour all year. Delicately fragranced. And from New Zealand, so absolutely perfect for your New Zealand garden.’ New Zealand garden? A New Zealand garden? Aroha tried to contain her excitement but it was very nearly she who now needed to be rescued. She quickly pulled herself back up and onto her leaf! ‘We have Manukas and Hebes too...’ Aroha was no longer paying attention to what was being said. She was trying her hardest to have a good, long look at the human with the New Zealand garden. ‘I tell you what. You work out how many of each species or variety you need, and we’ll come up with a good price for you. Then we’ll pick out the best specimens and go from there. Give us a call as soon as you know what you’d like.’

Boing! ‘Hey, what’s been going on here? Everything OK?’ ‘Yes Daddy Psyllid. Yes Mummy Psyllid’ Aroha struggled to catch her breath.


‘I’ve just heard some humans talking about a New Zealand garden. How exciting is that? We can go home!’ ‘Just hold on, my darling. New Zealand’s a long way from here – are you sure you heard correctly?’ ‘Yes Daddy Psyllid, there’s a human with a New Zealand garden!’ ‘Hmm…’ ‘Let’s go home, oh do let’s go home!’ ‘Calm down Aroha. Even if we could go home, we’d have to think long and hard about whether it would be the right thing to do. We’ve been here quite some time now, and have become used to our way of life. What about our friends? What about Marie and Philippe? What about Professor Penny?’ ‘But I really want to see what our homeland is like!’ ‘We’ll talk about it later – now try to get some rest.’ ‘OK, Mummy Psyllid.’ Reluctantly, Aroha did as instructed. Soon she was daydreaming. She was on a big boat, crossing oceans, journeying to far-off lands. Strange voices accompanied her wherever she went, and her eyes met with rich, vibrant colours. ‘Those go over there, mate. That’s it, next to the Phormiums.’ Aroha was suddenly wide awake. The big boat was nowhere to be seen. This wasn’t right. This wasn’t where she lived. Everything looked different. Where was Mummy Psyllid? Where was Daddy Psyllid? Where were her brothers and sisters? She looked down at her feet – at least this was her Pittosporum bush – thankfully that hadn’t changed. 25

‘They look good there, don’t they? The garden centre did us a great deal. Our New Zealand garden’s going to look fantastic!’ New Zealand garden? The New Zealand garden? Surely she’d only been daydreaming for a few minutes. ‘Daddy Psyllid! We’re here! This is it! Mummy Psyllid!’

Boing! ‘You’re not my mummy! Where’s my mummy! I want my mummy.’ Aroha began to quietly sob. If this is what going home meant, she didn’t like it, not one little bit. ‘Sshh now, sweetheart. When did you last see your parents?’ ‘I [sob] don’t [sniff] know. One moment I was [sob] talking with them about going home [sniffle], then the next thing I [sob] remember is dreaming [snort] about being on a [sniff] boat, and now I’m [sob] here, and they’re [wail] not’ ‘Well, my name’s Gerty, I usually live on that big purple Pittosporum over there. Try not to panic – I’m sure your parents can’t be far away. Now, let’s have a think. Oh, and what’s your name?’ ‘Mate, I think we’re going to need more pittosporums. Could you give the garden centre a call and see if they’ve got a few more we could have, and if so, could you pop back today to collect them?’ Soothed by Gerty’s kindly manner, Aroha did as advised, and tried not to panic. It was hard though – being all alone in a strange place, especially when you’re only tiny (and not to mention, really quite odd-looking). 26

Time went by. Soon it would be dark, and there was still no sign of Mummy Psyllid, Daddy Psyllid or Aroha’s brothers and sisters. Once again, a sob arose in the youngster’s throat. Never had she felt so alone. ‘Aroha, did you hear that? The gardeners’ van has just driven up. I’m sure I heard mention of more pittosporums. Whilst you were sitting there, looking sad, the old cogs did a spot of whirring, and I got to wondering if somehow, you’d ended up being on a different bush from your parents. You’ve just arrived from the garden centre, haven’t you?’ ‘I don’t know. I don’t really know anything. I feel terribly homesick though. I want my mummy and my daddy. What’s a garden centre?’ Gerty smiled at her young friend. ‘A garden centre is a place which grows and sells plants and sometimes other garden stuff, such as tools, decorations, pots and so on. People usually go to garden centres to buy things to make their gardens look nice. And some people just like to go to garden centres to look at what’s there. I once met a lovely human called Professor Penny, who used to turn up with her notebook and camera, and tell us all about what she was doing at the university. You see, my plant used to be at a garden centre too, until Jim the Gardener turned up and bought us. And now I live here. Eva?’ ‘Eva? Is that the name of where we are now? What a funny…’ ‘Gerty? Gerty? Is that really you, Gerty?’ ‘Eva!’


Alerted by the welcoming sound of a very familiar voice, Aroha peeked out from behind her leafbud to observe Gerty and Mummy Psyllid clinging tightly to each other in a warm embrace. With an uncharacteristically gentle boing, Daddy Psyllid arrived next to her. ‘You gave us quite a shock, little one!’ Aroha sidled into one of her most favourite spots – under her father’s wings. ‘I’m confused, Daddy Psyllid. What’s happening? Who or what is Eva, and how do Mummy Psyllid and Gerty know each other? Where are we? Where have you all been? Is this New Zealand?’ ‘Well, no…’


Chapter Seven - home

Aroha snuggled up to her father and smiled sleepily at her mother and siblings. ‘I don’t really mind where we live as long as [yawn] we’re all [yawn] together.’


‘Questions, questions, questions – always so many questions, Aroha!’ A very proud (and also a little amused) Daddy Psyllid looked kindly at his daughter. ‘Let’s leave Eva, I mean your mother, and Gerty to chat. Come and join me and your brothers and sisters for a story…’ ‘So, you all went to see Marie’s new babies? Why didn’t you take me?’ ‘Oh, Aroha, you looked so peaceful, fast asleep in your little feeding pit, we thought it best not to disturb you, especially as this lot were all so full of energy and in need of something organised to do.’ ‘And the gardeners were too quick for you? By the time you realised what was happening, it was too late? Our Pittosporum bush had gone, and you weren’t on it? What did you do?’ ‘Oh it was horrible, Aroha. Knowing that you’d soon awake to find yourself all alone, not knowing what had happened or if we’d ever see each other again was almost unbearable. Then your mother happened to overhear a human talking about how there were only a couple of pittosporums left, now that the local botanical gardens had taken a load for their new New Zealand garden exhibit. We did the only thing we could do, and got ourselves all back onto one of those remaining bushes, and hoped and hoped that we’d somehow end up in the same place as you. Imagine our relief when we heard the gardeners’ van pull up nearby.’ ‘And here we all are. I don’t want to even think about what might have happened if they hadn’t needed more pittosporums. So, my beautiful daughter, I trust my dear sister has been looking after you well…’ 30

‘Your sister? Mummy Psyllid – you and Gerty are sisters? Well, fancy that!’ ‘Fancy that indeed! We used to all live together at the garden centre – I understand your Aunt Gerty has been telling you all about garden centres – until Aunt Gerty met your Uncle Hanu, and made the decision to move to his Pittosporum bush. See that rather nice purple one over there? We never knew what happened to Gerty and Hanu but now we do.’ Mummy Psyllid paused for a moment, before softly repeating, very thoughtfully, as if only for her own ears, ‘But now we do.’ Daddy Psyllid put his six legs around as many of his family members as possible. ‘Mummy Psyllid, Daddy Psyllid, my sick, achy feeling has turned into a warm, fuzzy feeling. I don’t mind that this isn’t New Zealand. It isn’t New Zealand, is it?! And do you know? It turns out that although I thought I wanted to go there, I never actually felt homesick for the place. But I was homesick for my family and friends.’ Daddy Psyllid smiled. ‘No, this isn’t New Zealand, Aroha, although it does look quite a bit like it! This is Cornwall, a rather nice place in the far southwest of Great Britain, a little island a long, long way from New Zealand. New Zealand is actually a country on the other side of the world where our great, great, great, great grandparents lived. Cornwall may not be our homeland but it’s definitely our home.’ Aroha snuggled up to her father and smiled sleepily at her mother and siblings. ‘I don’t really mind where we live as long as [yawn] we’re all [yawn] together.’ 31

*** As Aroha’s tired, contented eyes closed, she thought she heard a familiar voice. ‘Aw, what a beautiful sight, Wilson – lots of lovely Pittosporum psyllids. You don’t mind if I take a picture, do you? Say ‘plant juice’!’ Wilson wagged his tail and wandered off to investigate a nearby tree. ‘Come on Wilson, all this walking and poking about in botanical gardens has made me sleepy too’. Professor Penny turned and walked away with a contented smile on her face. She was something of a sucker (pun unintended) for a happy ending.

~ The End ~


Scientific background: Aroha, her family, her friends and her enemies

Psyllids are a member of the insect Order: Hemiptera, the bugs – insects which all have piercing, sucking mouthparts, such as shield bugs, assassin bugs, leafhoppers and cicadas. Psyllids are most closely related to aphids, scale insects and whiteflies (these are bugs too – not flies, despite their name!). Most psyllids are host-specific, meaning that they live and feed on one particular plant or group of closely-related plants. Some psyllids live freely on plants, while other form galls, which help to protect the psyllids from predators and from unfavourable weather conditions, such as excessive heat. There are nearly 4,000 known psyllid species in the world, with nearly 100 known to occur in Britain, 16 of which are considered non-native. A non-native species is one that is outside of the species’ natural past or present distribution. Some nonnative species have arrived via human activity, such as with plants that have been brought in from other countries, and some non-native species have arrived naturally, such as by expanding their range. Non-native species can be problematic for native species and habitats – Japanese Knotweed is a well-known plant example of this but for most, their presence is not considered to be too troublesome. Many scientists carry out research into the impact of non-native species.

Psyllids and aphids

Pittosporum Psyllid Trioza vitreoradiata (syn. Powellia vitreoradiata) nymph (above) and adult (below) © Adam Poledníček, Sally Luker

Elaeagnus Psyllid Cacopsylla fulguralis nymph (above) and adult (below) © Sally Luker


Black Citrus Aphid Toxoptera aurantii © Sally Luker

Psyllids have a number of natural enemies, including parasitoid wasps, which most commonly lay eggs within the body of nymphs, inside which the adult wasps develop. Predatory bugs and beetles feed on all life stages of psyllids (eggs, nymphs and adults). Psyllids can also be affected by entomophagous (‘insect-eating’) fungi.

Parasitoid wasps

Parasitoid wasp exit holes on Trioza vitreoradiata nymphs

Unidentified parasitoid wasps © Sally Luker

© Sally Luker

Predatory bugs and beetles

2-spot Ladybird Adalia bipunctata larva (above) and adult (below) © Sally Luker

Harlequin Ladybird Harmonia axyridis larva (above) and adult (below) © Sally Luker


Flower bugs Anthocoris sp. nymph (above) and Anthocoris nemorum adult (below) © Ysella Luker-Green, Sally Luker

Acknowledgments This book was originally produced as part of a Researcher-Led Initiative, organised by Jenni Sanderson and funded by the University of Exeter Researcher Development Team. With heartfelt thanks to Caitlin Kight for all her valuable support and wisdom.


The Psyllid Who Wanted to Go Home, Sally Luker  
The Psyllid Who Wanted to Go Home, Sally Luker  

Pop! A very tiny (and, to be honest, very odd-looking) creature crawled from an equally tiny – almost invisible to the human eye – egg. On a...