# Transcriptional profile and differential fitness across a cardenolide gradient in a specialist milkweed insect reveal the costs of response.

Stephanie Birnbaum¹, David Rinker¹, Nicole Gerardo², Patrick Abbot *1

¹ Vanderbilt University – United States

² Emory University – United States

Interactions between plants and herbivorous insects have been models for theories of specialization and coevolution for over at century, and it is well-established that phytochemistry governs many aspects of these interactions. Despite this, the mechanisms insect specialists employ to sequester or otherwise tolerate plant secondary metabolites, and the costs of these responses, remain poorly characterized. Using a milkweed-specialist aphid model, the *Aphis nerii* system, we test the effects of increased plant secondary metabolites on aphid life history traits and whole transcriptome gene expression. We show that increased secondary metabolites have a negative effect on aphid development and lifetime fecundity. When feeding on host plants with higher levels of secondary metabolites, aphids differentially express a narrow, targeted set of genes including those involved in canonical detoxification processes including P450s, esterases, hydrolases, and UDP-glucuronosyltransferases. These results indicate that *A. nerii* marshal a variety of metabolic detoxification mechanisms in host plant specialization and circumvention of milkweed secondary compounds, but not without deleterious effects on fitness.

Keywords: specialist, insect, secondary metabolite, sequestration, tolerance

*Speaker: patrick.abbot@vanderbilt.edu
# Evolutionary analyses of a new quantitative catalogue of candidate secreted salivary effectors in *Acyrthosiphon pisum*

Hélène Boulain*<fnref n="1" />, Fabrice Legeai<fnref n="1" />, Endrick Guy<fnref n="1" />, Jean-Christophe Simon<fnref n="1" />, Akiko Sugio<fnref n="1" />

The pea aphid, *Acyrthosiphon pisum*, is a sap-feeding phytophagous insect that forms a complex of 15 biotypes, each of which is specialized to one or a few species of Fabaceae. Successful establishment of aphid phloem feeding depends on the functions of salivary proteins injected into the host plant. Most of the proteins secreted with aphid saliva are thought to be produced in salivary glands (SG) of the aphid, and some are shown to suppress or trigger plant defence reactions like effectors of microbial pathogens. Transcriptomics and proteomics studies of SG or isolated saliva have created catalogues of candidate salivary proteins in the past; however, those catalogues often lack quantitative data of expression and tissue specificity. To create more informative catalogue of salivary proteins with quantitative expression data, and to analyse their evolutionary histories in *A. pisum*, we conducted SG and guts transcriptome by RNAseq. The data revealed around 2000 genes that were up-regulated in SG compared to gut. Among these SG induced genes, more than 600 genes are predicted to encode secreted proteins. Orthologous gene search conducted with 16 arthropod whole genomes (1 arachnid, and 15 insects including 5 aphid species) revealed that more than 50 % of our salivary gene candidates were aphid or *A. pisum* specific. By analysing the evolutionary rates of well-characterized salivary genes and their orthologues, we observed contrasting evolutionary patterns possibly influenced by their different roles in aphid feeding. The orthology analysis also revealed expansions of some gene families in *A. pisum* compared to other aphid species. Moreover, the positive selection acting on some salivary gene copies among these families suggests an important role of gene duplication in the evolution of *A. pisum* and may indicate the involvement of these genes in host adaptation.

Keywords: Salivary genes, evolutionary patterns, pea aphid

*Speaker: helene.boulain@inra.fr

<footnote n="1">¹ Institut de Génétique, Environnement et Protection des Plantes (IGEPP) – Institut national de la recherche agronomique (INRA) : UMR1349 – AGROCAMPUS OUEST, UMR1349 IGEPP, F-35042 Rennes, France</footnote>
Olfactory specialization contributes in the making
of the fruit pest *Drosophila suzukii*

Marianthi Karageorgi*<fnref n="1" />, Sebastien Lebreton<fnref n="1" />, Mathilde Paris<fnref n="1" />, Caroline Minervino<fnref n="1" />,
Matthieu Cavey<fnref n="1" />, Kunhi Purayil Siju<fnref n="2" />, Ilona Grunwald Kadow<fnref n="2" />, Nicolas Gompel†<fnref n="3" />,
Benjamin Prud'homme‡<fnref n="1" />

Behavioral innovations can facilitate animal invasions into new ecological niches, with the potential of turning species into pests. However, currently little is known about the underlying genetic basis of such events. Here, we study how the agricultural fruit pest *Drosophila suzukii* has evolved its egg-laying preference for ripening fruit. Most closely related Drosophila species, including *D.melanogaster*, lay their eggs in decaying plant substrates. In our study, we combined behavioral experiments in multiple species with neurogenetics and mutant analysis using the CrispR/Cas9 technology in *D. suzukii*. Our results establish that *D. suzukii* has evolved a specific egg-laying preference for ripening fruit, but most likely it has retained the ancestral feeding preference for decaying fruit. Our results also show that changes in the olfactory system of *D. suzukii* have contributed to the evolution of its novel egg-laying behavior. In particular, we show that the odorant receptor subsystem is involved in its olfactory attraction to fresh fruit as well as the detection of odorant egg-laying stimulants present in fresh fruit. Interestingly, though a comparative transcriptomic analysis, we find that the several orthologs of odorant receptors that detect odors of fresh fruit in *D. melanogaster* are upregulated in the antennae of *D. suzukii*. In overall, our study shows that olfactory specialization, likely through remodelling of the odorant receptor repertoire, has contributed in the novel egg-laying preference of *D. suzukii*.

Keywords: *D. suzukii*, agricultural pest, egg, laying, evolution, olfaction, CrispR/Cas9, neurogenetics

<footnote n="1">¹ Institut de Biologie du Développement de Marseille (IBDM) – Aix Marseille Université : UMR7288, Institut National de la Santé et de la Recherche Médicale, CNRS UMR7288 - Parc Scientifique de Luminy 13288 Marseille Cedex 9, France</footnote>

<footnote n="2">² Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Planegg-Martinsried – Germany</footnote>

<footnote n="3">³ Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried – Germany</footnote>

<footnote>* Speaker: marianthi.karageorgi@univ-amu.fr</footnote>

<footnote>† Corresponding author: gompel@bio.lmu.de</footnote>

<footnote>‡ Corresponding author: benjamin.prudhomme@univ-amu.fr</footnote>
# Ecogenomics analysis of *Solanum dulcamara* reveals chemical diversity in glycoalkaloids related to slug resistance

Onno Calf<fnref n="1" />, Alexander Weinhold<fnref n="2" />, Jules Beekwilder<fnref n="3" />, Nicole Van Dam*<fnref n="1" />,<fnref n="2" />

Chemical diversity among individuals within a single plant species is commonly found in natural populations. This diversity is thought to originate from and maintained by (local) co-evolution between plants and herbivores. Metabolomic analyses are extremely valuable to study such natural polymorphisms. Because of their untargeted nature, they provide a comprehensive overview of the plant's metabolome. These individual metabolomic profiles can be correlated to measures of herbivore resistance. Here we present an example of how resistance to slugs in natural populations of *Solanum dulcamara* (Bittersweet nightshade) concurs with metabolomic differences. A high throughput resistance screening performed on a total of 96 accessions from eight natural populations in the Netherlands identified a sub-set of accessions covering a consistent range of resistance to slug feeding, ranging from highly preferred to fully rejected. Metabolomic analyses on Liquid Chromatography-Time of Flight-Mass Spectrometry (LC-qToF-MS) revealed a high diversity in glycoalkaloid (GA) concentrations and profiles among the selected accessions. Whereas slugs overall preferred plants with low GA concentrations, it was also found that most susceptible accession showed a completely different GA profile than the more resistant accessions. Molecular studies showed that plant chemical diversity may readily arise from mutations, gene-duplications and neo-functionalization of specific enzymes within a biosynthetic pathway. Because of their toxicity to humans and presence in closely related crops, such as tomato (*S. lycopersicum*) and potato (*S. tuberosum*) many of the genes and enzymes involved in GA biosynthesis are known. Therefore, we combined our metabolomic studies with a comprehensive RNAseq analysis of five of the genotypes with the most divergent GA profiles and slug resistance scores. Combined with additional data on natural herbivore damage in a common garden experiment, these ecogenomics analyses will show the ecological consequences of this natural chemical and genetic diversity.

Keywords: chemical ecology, chemodiversity, glycoalkaloids, Liquid Chromatography, Time of Flight, Mass Spectrometry, metabolomics, slugs, Solanum, transcriptomics

<footnote n="1">¹ Radboud University, Institute of Water and Wetland Research (IWWR) – PO Box 9010 6500 GL Nijmegen, Netherlands</footnote>

<footnote n="2">² German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig/FSU Jena – Deutscher Platz 5e 04103 Leipzig, Germany</footnote>

<footnote n="3">³ Wageningen Plant Research, Bioscience – Droevendaalsesteeg 1 6708 PB Wageningen, Netherlands</footnote>

<footnote>* Speaker: nicole.vandam@idiv.de</footnote>
Keynote

Novel insights into symbiotic paths to sustainable agriculture

Michael Thomas-Poulsen * 1

¹ University of Copenhagen, Department of Biology, Section for Ecology and Evolution (UCPH) – Universitetsparken 15, 2100 Copenhagen East, Denmark

Thirty million years ago, the ancestors of the termite sub-family Macrotermitinae and the basidiomycete Termitomyces joined forces in what became one of the most sophisticated plant biomass decomposition symbioses on Earth. Through an intricate and efficient decomposition process that involves plant biomass passing termite guts before decomposition in external fungal gardens, these termites fully utilize a range of plant substrates and have become major decomposers in the Old World, while having no apparent problems with infectious diseases. Here I review how recent applications of state-of-the-art sequencing and chemical analyses tools have provided novel insights to our understanding of complementary symbiont biomass decomposition, division of labour in termite hosts, and how obligate gut passage of the plant substrate may be key to efficient suppression of antagonists of the symbiosis.

Keywords: Macrotermitinae, symbiosis, gut microbiota, 16S rRNA, metagenomics, CAZymes, LC, MS

*Speaker: mpoulsen@bio.ku.dk
Session 1 Monday evening

<table><thead><tr><th colspan="3">Insect-plant-microbe interactions in forests and agrosystems - *COST action Poster Session 1</th></tr></thead><tbody><tr><td>P1</td><td>Fatma Acheuk</td><td>Insecticidal and developmental inhibitory properties of extracts of the saharian plant <i>Haplophyllum tuberculatum</i> (Rutaceae) on <i>Locusta migratoria</i> five instar larvae (Acrididae: Oedipodinae)</td></tr><tr><td>P2</td><td>Niccolò Bassetti</td><td>Towards the genetic basis of the hypersensitive response induced by <i>Pieris</i> spp. eggs in <i>Brassica rapa</i></td></tr><tr><td>P3</td><td>Moe Bakhtiari</td><td>Root Induced Defense specificity in Above & Belowground tri-trophic Interaction in <i>Cardamine</i> Spp.</td></tr><tr><td>P4</td><td>Emilie Bosquée</td><td><i>Myzus persicae</i> dispersion and Potato virus Y transmission under elevated CO2 atmosphere</td></tr><tr><td>P5</td><td>Agnès Brosset</td><td>Belowground and aboveground damage can impact the conifer growth and feeding behavior of the weevil <i>Hylobius abietis</i> (Coleoptera: Curculionidae)</td></tr><tr><td>P6</td><td>Yayuan Chen</td><td>Variation in induced resistance among tree genotypes: how does it influence the interaction between bark-feeding insects and conifer seedlings?</td></tr><tr><td>P7</td><td>Xavier Chiriboga</td><td>Root-colonizing bacteria enhance the levels of (E)-β-caryophyllene produced by maize roots in response to rootworm feeding</td></tr><tr><td>P8</td><td>Michael Eisenring</td><td>Reduced Caterpillar Damage Benefits <i>Lygus hesperus</i> on Bt Cotton</td></tr><tr><td>P9</td><td>Maria Faticov</td><td>Geographical variation of endosymbionts in the insect food web on oak</td></tr><tr><td>P10</td><td>Ludovico Formenti</td><td>Interactive effects of mycorrhizal inoculation and jasmonic acid endogenous production on plant resistance against herbivores</td></tr><tr><td>P11</td><td>Tae Woong Jang</td><td>Effect of ground-fogging of thiacloprid on target and non-target insects in Korean pine forests</td></tr><tr><td>P12</td><td>Giacomo Santoiemma</td><td>Distribution and development of <i>Drosophila suzukii</i> along elevation gradients</td></tr><tr><td>P13</td><td>Jeltje Stam</td><td>Herbivory and florivory at different strawberry plant resistance levels</td></tr><tr><td>P14</td><td>Meng Ye</td><td>A conserved priming signal: Volatile indole activates early defense signaling in Rice</td></tr><tr><td>P15</td><td>Wei Huang</td><td>Neighborhood effects determine plant-herbivore interactions below ground</td></tr><tr><td>P16</td><td>Sihem Ziouche</td><td>Interactions plant-insectes dans un écosystème forestier : le cas de la chenille processionnaire du pin <i>Thaumetopoea pityocampa</i> en région de l'Est Algérien</td></tr></tbody></table>
<table><thead><tr><th></th><th>Community ecology and phylogenetics</th><th>Poster Session 1</th></tr></thead><tbody><tr><td>P17</td><td>Ayman Elsayed</td><td>Life history of two leaf bud gallers associated with the deciduous tree <i>Schoepfia jasminodora</i> (Schoepfiaceae) in Japan</td></tr><tr><td>P18</td><td>Rieta Gols</td><td>Herbivore-mediated fitness effects of increasing chemical variation among neighbouring Plants</td></tr><tr><td>P19</td><td>Kotaro Konno</td><td>Why are terrestrial ecosystems generally green with small herbivores biomass? Why are anti-nutritive and inducible defenses effective? The realities that a novel fully-parameterized food web model tells</td></tr><tr><td>P20</td><td>Antonino Cusumano</td><td>Canola/cabbage aphid food web – underestimated top-down pressure in invaded range</td></tr><tr><td>P21</td><td>Veronika Mayer</td><td>Evolutionary and functional ecology of ant-plant-fungus symbioses</td></tr><tr><td>P22</td><td>Daan Mertens</td><td>Plastic plant defence strategies as an optimal response to unpredictable multiherbivore Communities</td></tr><tr><td>P23</td><td>Yu Okamura</td><td>Pieris butterflies regulate two genes differently for adapting to wide range of Brassicaceae host plants</td></tr><tr><td>P24</td><td>Daniel Potter</td><td>Teaching Insect-Plant Relationships - Template for a Successful Graduate Course</td></tr><tr><td>P25</td><td>Lora Richards</td><td>Diverse phytochemical profiles and ecological interactions</td></tr><tr><td>P26</td><td>Diego Santos-Garcia</td><td>Portiera as a phylogenetic tool on whiteflies</td></tr><tr><td>P27</td><td>Bernardus Schimmel</td><td>Overcompensation of herbivore reproduction through hyper-suppression of plant defenses in response to competition</td></tr><tr><td>P28</td><td>Jiri Skuhrovec</td><td>Morphological adaptations of coccinellid species determined by host-plant architecture</td></tr><tr><td>P29</td><td>Johan Stenberg</td><td>Plant resistance ecology: what happens to insect communities when host plants evolve more resistant?</td></tr><tr><td>P30</td><td>Klaas Vrieling</td><td>Paralell evolutionary changes in resource allocation to anti-herbivore traits in an invasive plant species.</td></tr></tbody></table>
<table><thead><tr><th colspan="3">Plant-insect-microorganisms interactions - *COST action Poster Session 1</th></tr></thead><tbody><tr><td>P31</td><td>Sandra Baksay</td><td>Pollination network analysis by environmental metagenomics</td></tr><tr><td>P32</td><td>Junior Corneille Fingu Mabola</td><td>Impact of endophytic entomopathogenic fungus on plant attractiveness in aphid virus-plant interaction</td></tr><tr><td>P33</td><td>Gabriella Caballero Vidal</td><td>Are aphid vectors manipulated by plant virus?</td></tr><tr><td>P34</td><td>Fryni Drizou</td><td>Insect-pathogen interaction in oilseed rape (OSR): <i>Myzus persicae</i> increases susceptibility of <i>Brassica napus</i> to <i>Rhizoctonia solani</i> AG 2-1.</td></tr><tr><td>P35</td><td>Galit Eakteiman</td><td>Using dsRNA of the BtGST2 Detoxification Gene to Develop <i>Bemisia tabaci</i> Resistant Plants</td></tr><tr><td>P36</td><td>Luis R Paniagua Voirol</td><td>Antibiotic treatment of <i>Pieris brassicae</i> attenuates egg-mediated anti-herbivore defenses in two brassicaceous species</td></tr><tr><td>P37</td><td>Hyeok Jun Kwon</td><td>Dispersal capacity of <i>Monochmus saltuarius</i> (Gebler) (Coleoptera: Cerambycidae) on fight mills</td></tr><tr><td>P38</td><td>Ian Kaplan</td><td>Phylogenetic farming: Can evolutionary history inform crop and insect management?</td></tr><tr><td>P39</td><td>Miika Laihonen</td><td>Fungal grass endophytes can influence host plant preference and fitness of a satyrine butterfly</td></tr><tr><td>P40</td><td>Kirsten Leiss</td><td>Induced resistance to thrips by bacterial infection</td></tr><tr><td>P41</td><td>Valeria Mereghetti</td><td>Strength in cooperation: bacterial symbionts help the insect host overcome plant defences</td></tr><tr><td>P42</td><td>Luis R Paniagua Voirol</td><td>The role of the <i>Pieris brassicae</i> microbiome during a host-plant shift</td></tr><tr><td>P43</td><td>Bruna De Càssia Ramos</td><td>Learning in two butterfly species when using flowers of the tropical milkweed <i>Asclepias curassavica</i>: no benefits for pollination</td></tr><tr><td>P44</td><td>Sandeep Sarde</td><td>Sweet Pepper-Thrips Interaction: Uncovering dynamics of the plant defense-signaling network to identify novel leads for maximizing crop protection</td></tr><tr><td>P45</td><td>Osariyekemwen Uyi</td><td>Developmental and reproductive performance of a specialist herbivore depend on seasonality of, and light conditions experienced by, the host plant</td></tr><tr><td>P46</td><td>Zhenggao Xiao</td><td>Earthworms indirectly mediate plant-herbivore interaction via changes in soil nutrient composition and plant chemical traits</td></tr></tbody></table>
Session 2 Tuesday evening

Multitrophic interactions and ecological networks Poster Session 2

<table><tr><td>P47</td><td>Christine Becker</td><td>Herbivore-induced plant volatile blends are influenced by plant nutrition</td></tr><tr><td>P48</td><td>Mascha Bischoff</td><td>Disease in bloom - exploring the link between pollination and phytopathology</td></tr><tr><td>P49</td><td>Zoe Bont</td><td>A herbivore tag-and-trace system reveals contact and density-dependent repellence of a root toxin</td></tr><tr><td>P50</td><td>Sandrine Mariella Bayendi Loudit</td><td>Can we use semiochemicals to control <i>Aphis craccivora</i> Koch?</td></tr><tr><td>P51</td><td>Diana La Forgia</td><td>Soil wars: biological alternatives to pesticides to control wireworms</td></tr><tr><td>P52</td><td>Andre Busch</td><td>Cellulases in phytophagous beetles: Characterization and molecular evolution of family 45 glycoside hydrolases in leaf beetles and weevils</td></tr><tr><td>P53</td><td>Carlos Bustos Segura</td><td>Terpene chemotypes and interactions with insect herbivores</td></tr><tr><td>P54</td><td>Ibtihel Ghrissi</td><td>Ecological study of pistachio bark beetle, <i>Chaetoptelius vestitus</i> Muls &amp; Rey (Coleoptera: Curculionidae)</td></tr><tr><td>P55</td><td>Mickal Houadria</td><td>The relationship between ant abundance and leaf biomass in ant-inhabited <i>Macaranga pearsonii</i> in human-modified landscapes in SE Asia</td></tr><tr><td>P56</td><td>Charlyne Jaccard</td><td>The consequence of plant domestication for resistance against insects: testing the role of the plant-breeding target</td></tr><tr><td>P57</td><td>Tuuli-Marjaana Koski</td><td>Insect herbivory may cause changes in the visual properties of leaves and affect the camouflage of herbivores to avian predators</td></tr><tr><td>P58</td><td>Issei Ohshima</td><td>Interspecific competition between dominant and infrequent parasitoid wasps of a leaf miner</td></tr><tr><td>P59</td><td>Foteini Pashalidou</td><td>The role of butterfly eggs on plant-plant communication</td></tr><tr><td>P60</td><td>Christelle Robert</td><td>Transfer of stabilized and reactivated plant toxin derivatives to the third and fourth tropic level protects the western corn rootworm from its natural enemies</td></tr><tr><td>P61</td><td>Michel Renou</td><td>Plants as sources for insect odorscapes</td></tr><tr><td>P62</td><td>Ai Sato</td><td>Adaptation of Japanese Swallowtail butterfly to host plant</td></tr><tr><td>P63</td><td>Gaetan Seimandi Corda</td><td>Linking genotypic susceptibility to insects pests with plant chemistry: an example from the oilseed rape - pollen beetle interaction</td></tr><tr><td>P64</td><td>Gaetan Seimandi Corda</td><td>Is quantity or quality of food the issue in feeding site choice in oilseed rape by the pollen beetle?</td></tr><tr><td>P65</td><td>Daniela Sepulveda</td><td>The ecology and evolution of host preference in an aphid parasitoid</td></tr><tr><td>P66</td><td>Diabate Seydou</td><td>Role of volatiles from cowpea varieties on the behavior of <i>Megalurothrips sjostedti</i></td></tr><tr><td>P67</td><td>Juan Traine</td><td>Early-flowering induced by herbivory in wild Lima bean plants affects late-season seed predators but not their parasitoids</td></tr><tr><td>P68</td><td>Joop Van Loon</td><td>Whitefly fitness on tomato plants is reduced by spider mite colonization through jasmonic acid and salicylic acid signaling pathways</td></tr></table>
<table><tr><td>P69</td><td>Ilka Vosteen</td><td>Parasitoid foraging behaviour in complex situations: Influence of weather, surrounding vegetation and learning</td></tr><tr><td>P70</td><td>Zhang Xi</td><td>The wolf in sheep's clothing: Entomopathogenic nematodes attract their insect herbivore hosts by manipulating plant and cadaver odors</td></tr><tr><td>P71</td><td>Hao Xu</td><td>Combined use of herbivore-induced plant volatiles and sex pheromones for mate location in braconid parasitoids</td></tr></table>

Insect effectors and plant responses Poster Session 2

<table><tr><td>P72</td><td>Franziska Beran</td><td>Multiple adaptations allow the cabbage stem flea beetle to tolerate plant defense compounds</td></tr><tr><td>P73</td><td>Merijn R. Kant</td><td>Salivary proteins of spider mites that manipulate plant defenses and promote mite reproduction</td></tr><tr><td>P74</td><td>Melanie Body</td><td>Correlation between phytohormone patterns and gall induction by Phylloxera on grape leaves</td></tr><tr><td>P75</td><td>Luis Portillo</td><td>Early cell responses of poplars to salivary extracts of a gall-inducing aphid, <i>Phloeomyzus passerinii</i></td></tr><tr><td>P76</td><td>Kun-Yu Tu</td><td>Responses of <i>Cnaphalocrocis medinalis</i> resistant varieties in rice</td></tr><tr><td>P77</td><td>Wannes Dermauw</td><td>The salivary protein repertoire of the polyphagous spider mite <i>Tetranychus urticae</i>: a quest for effectors</td></tr><tr><td>P78</td><td>Maria Cristina Digilio</td><td>Interactions between the courgette <i>Cucurbita pepo</i> L. and the cotton aphid <i>Aphis gossypii</i> Glover</td></tr><tr><td>P79</td><td>Sylvia Drok</td><td><i>Nicotiana attenuata</i> distinguishes between different herbivorous insect species by their eggs</td></tr><tr><td>P80</td><td>Ali Güncan</td><td>Within-plant distribution and susceptibility of hazelnut cultivars to Hazelnut Gall Midge, <i>Mikomya coryli</i> (Diptera: Cecidomyiidae)</td></tr><tr><td>P81</td><td>Jucelaine Haas</td><td>Does cabbage seeds treated with jasmonic acid and chitosan affect diamondback moth performance?</td></tr><tr><td>P82</td><td>Wiebke Häger</td><td>Interaction of beetle polygalacturonases with plant cell wall proteins</td></tr><tr><td>P83</td><td>Ruth Jakobs</td><td>What is driving aphid abundance? Effects of intraspecific and intraindividual variation of plants on aphid preference and performance in relation to phloem chemistry</td></tr><tr><td>P84</td><td>Carlos Sanchez-Arcos</td><td>Modulation of legume defense signaling pathways by native and non-native pea aphid clones</td></tr><tr><td>P85</td><td>Daniel Geuss</td><td><i>Solanum dulcamara</i>'s response to insect eggs comprises ovicidal hydrogen peroxide production</td></tr><tr><td>P86</td><td>Tobias Lortzing</td><td>Transcriptomic responses of <i>Solanum dulcamara</i> to natural and simulated herbivory</td></tr><tr><td>P87</td><td>Osnat Malka</td><td>EdenShield products: A new class of ecological substances for insect pests control</td></tr><tr><td>P88</td><td>Osnat Malka</td><td>Plant utilization by phloem feeder insects: secondary metabolites interacts in primary metabolism</td></tr></table>
<table><tr><td>P89</td><td>Chad Nihranz</td><td>Transgenerational consequences of inbreeding and herbivory in <i>Solanum carolinense</i></td></tr><tr><td>P90</td><td>Sergio Ramos</td><td>Evolutionary Changes in Floral Traits Mediated by Pollinators and Herbivores in Experimental Evolution</td></tr><tr><td>P91</td><td>Theresa Sporer</td><td><i>Phyllotreta armoraciae</i> flea beetles combine two strategies to sequester intact glucosinolates from crucifer plants: A rapid uptake and the inhibition of plant myrosinase activity</td></tr><tr><td>P92</td><td>Colin Turnbull</td><td>Genetics of virulence in pea aphid on <i>Medicago truncatula</i> hosts differing in R gene complement</td></tr><tr><td>P93</td><td>Isabella Visschers</td><td>Identifying natural resistance factors conferring resistance to thrips in Capsicum</td></tr><tr><td>P94</td><td>Ming-Shun Chen</td><td>Expansion, Diversity, and Function of Putative Effectors in Gall Midges (Mayetiola)</td></tr></table>

Global change and thermal ecology Poster Session 2

<table><tr><td>P95</td><td>James Blande</td><td>Muting, distorting and deafening: How ozone pollution affects plant communication</td></tr><tr><td>P96</td><td>Solène Blanchard</td><td>Climate change: impact on plant-aphid-ant interactions</td></tr><tr><td>P97</td><td>Antoine Boullis</td><td>Elevated CO2 concentration reduces alarm signaling in aphids</td></tr><tr><td>P98</td><td>Antoine Boullis</td><td>Plant-aphid-hover fly interaction under elevated CO2 concentration: oviposition behavior and larval development</td></tr><tr><td>P99</td><td>James Buckley</td><td>Testing the Preference-Performance hypothesis on natural populations of <i>Arabidopsis halleri</i> distributed along an elevation gradient</td></tr><tr><td>P100</td><td>Rocio Escobar-Bravo</td><td>Light intensity-mediated induction of trichome-associated defenses increases resistance against thrips in tomato</td></tr><tr><td>P101</td><td>Ibtihel Ghrissi</td><td>Effect of temperature on development of <i>Chaetoptelius vestitus</i> (Muls &amp; Rey) (Coleoptera: Curculionidae) on <i>Pistacia vera</i> L.</td></tr><tr><td>P102</td><td>Anouk Guyer</td><td>Impact of climate change on below ground tritrophic interactions in maize</td></tr><tr><td>P103</td><td>Po-An Lin</td><td>Impacts of drought stress on caterpillars and defensive responses of tomato</td></tr></table>

Evolutionary genomics Poster Session 2

<table><tr><td>P104</td><td>Apostolos Kapranas</td><td>Root-derived attractants for larvae of the cabbage root fly <i>Delia radicum</i> to be used in novel control strategies</td></tr><tr><td>P105</td><td>Shai Morin</td><td>Unravelling the role of <i>Bemisia tabaci</i> - plant associations in the species diversification</td></tr><tr><td>P106</td><td>Caroline Müller</td><td>Distinct shaping of gene expression profiles in an oligophagous beetle by longterm versus short-term experiences with different host plants</td></tr></table>
Poster abstracts
## Poster 1

# Insecticidal and developmental inhibitory properties of extracts of the saharian plant *Haplophyllum tuberculatum* (Rutaceae) on *Locusta migratoria* five instar larvae (Acrididae : Oedipodinae)

Fatma Acheuk *<fnref n="1" />, Michel Cusson *<fnref n="2" />, Khemais Abdellaoui *<fnref n="3" />, Bahia Doumandji-Mitiche *<fnref n="4" />

Many plant bio-synthesized compounds with toxic and defensive action of the plant against phytophagous insects have been identified. These compounds from the secondary metabolism of plants belong to different chemical groups: phenols, terpenoids, alkaloids, steroids and others. To assess the bioinsecticidal effects of compounds produced by *Haplophyllum tuberculatum* (Rutaceae) on *Locusta migratoria migratoria*, a crude ethanolic extract and alkaloids were obtained by maceration of leaves and stems of the plant. Newly emerged fifth instar larvae were treated by forced ingestion. The test extracts (ethanolic extract and alkaloids extract) exhibited a potent larvicidal effect, with dose-dependent mortality. At higher concentrations (≥ 1000 g/larvae), the two extracts induced a strong neurobehavioral toxicity and a significant inhibition of acetylcholinesterase activity for alkaloids. At a sub-lethal dose of 300 g/larvae, the extract had anti-feedant effects and caused severe developmental disruption, manifested by a delay in adult emergence and a high level of morphological deformities in larvae. In addition, protease activity was strongly reduced in treated larvae. In contrast, we observed an induction of glutathione S-transferase and esterase activities. Phytochemical analysis of the test extract revealed the presence of several active compounds, which may act as larvicides.

Keywords: *Haplophyllum tuberculatum*, *Locusta migratoria*, alkaloids, methanolic extract, toxicity, sublethal effect

Speaker * Corresponding author: fatma.acheuk@yahoo.fr

## Poster 2

# Towards the genetic basis of the hypersensitive response induced by *Pieris* spp. eggs in *Brassica rapa*

Niccolò Bassetti<fnref n="1" />, Lotte Caarls<fnref n="1" />, Gabriella Bukovinszkiné Kiss¹³, Guusje Bonnema <fnref n="2" />, Bas Zwaan<fnref n="3" />, Eric Schranz<fnref n="1" />, Nina Fatouros<fnref n="1" />

Pests and pathogens are responsible on average for about a third of yearly crop losses. Identification of resistance (R) genes in crops has been successful for pathogens and partly for phloem-feeding insects such as aphids, whiteflies and planthoppers. However, R-gene-mediated resistance mechanisms against caterpillars (butterflies and moths) are less explored. An alternative may be preventing the caterpillar attack by investigating plant defence mechanisms that target the insect egg-laying phase. Eggs of *Pieris spp.* (cabbage white butterflies) induce a necrotic lesion in different brassicaceous plant species, including crops like *Brassica rapa*. This lesion resembles the hypersensitive response (HR) usually triggered by pathogens. It determines egg mortality through egg desiccation and dropping off. In a preliminary screening, different *B. rapa* accessions showed phenotypic variation for egg-induced lesions. This opens the possibility to study plant direct response against insect eggs through genetic approaches.

This project aims at unravelling the genetic and molecular mechanisms of the HR-like necrosis induced by *Pieris* spp. eggs in *B. rapa* through a combination of genetic mapping, transcriptomics and phenotyping of TILLING populations. This research will result in improved knowledge on egg-targeting plant defences as first line of resistance against lepidopteran pest insects.

<footnote n="1">¹ Laboratoire de Valorisation et Conservation des ressources Biologiques, Département de Biologie, Faculté des Sciences, Université de Boumerdes, Algeria</footnote>

<footnote n="2">² Centre de Foresterie des Laurentides, Service canadien des forêts, Ressources naturelles Canada, Canada</footnote>

<footnote n="3">³ Departement des Sciences Biologiques et de la Protection des Végétaux, Institut Superieur Agronomique de Chott-Mariem, Université de Sousse, Tunisia</footnote>

<footnote n="4">⁴ Département de Zoologie Agricole et Forestière, Ecole Nationale Supérieure d'Agronomie, Algeria</footnote>

<footnote n="1">¹Biosystematics Group, Wageningen University & Research, Wageningen</footnote>

<footnote n="2">²Laboratory of Plant Breeding, Wageningen University & Research, Wageningen</footnote>

<footnote n="3">³Laboratory of Genetics, Wageningen University & Research, Wageningen</footnote>
# Poster 3

## Root Induced Defense specificity in Above and Belowground tri-trophic Interaction in *Cardamine* Spp.

Moe Bakhtiari

Laboratory of Functional Ecology, Institute of Biology, University of Neuchatel, Switzerland
Institute of Biology, University of Neuchatel, Rue Emil-Argand 11, 2000, Neuchatel, Switzerland

Herbivore induced plant volatiles (HIPVs) are part of indirect defensive arsenal of many plant species against herbivores and have been shown to aid plants against herbivores by attracting natural enemies of herbivores. However, the extent in which such defensive strategies are employed by plants against belowground herbivores, and how the presence of different aboveground herbivores modifies the nature of these interactions remains largely untested. We examined the effect of AG herbivory by *Pieris brassicae* and *Brevicoryne brassicae* on BG herbivory by *Delia radicum* and its natural enemy's recruitment, nematode *Heterorhabditis megidis* to test for the specificity of root indirect defense among five different *Cardamine* plant species, originating from different elevation gradients. We used a custom-made four-arms BG olfactometer to test the attraction of entomopathogenic nematodes toward 4 different odour sources: 1) control plants without herbivory, 2) plants infested with the specialist root-chewers *D. radicum*, 3) plants co-infested with *D. radicum* and *P. brassicae*, and 4) plant co-infested with *D. radicum* and *B. brassicae*. Overall, we observed consistent patterns in the BG attraction of natural enemies toward each treatment among the species originating from low elevation habitats. Although the presence of root herbivores strongly enhanced the attraction of natural enemies, this pattern was negatively affected by AG herbivores, indicating that AG herbivores, independent of their feeding guilds, reduce the ability of roots to signal distress when damaged by root herbivores. On the other hand, mid-elevation plant species attracted more nematodes when co-infested by phloem-feeding *B. brassicae* and *D. radicum*. Our results indicate the specificity in induction of root defenses by different AG herbivores in different *Cardamine* species belonging to different elevation gradients which can be explained by variation in emission of HIPVs from damaged roots and root biomass

# Poster 4

## *Myzus persicae* dispersion and Potato virus Y transmission under elevated CO2 atmosphere

Emilie Bosquee *¹, Antoine Boullis¹, Morgane Bertaux ¹, Frédéric Francis ¹, François Verheggen ¹

¹ Entomologie fonctionnelle et évolutives - Université de Liège, Gembloux Agro-Bio Tech, Passage des Déportés, 2 B-5030 Gembloux, Belgium

Most phytophviruses are dependent on insect vectors to spread and infect the surrounding crop plants. To increase their chances of dissemination, viruses are able to indirectly modify the behavior of insects through changes in plant physiology. However, changes in abiotic factors such as atmospheric gas concentrations could also alter plant physiology and metabolism, influence vector's biology and therefore, modify virus spread strategy. The present study compared the impact of two carbon dioxide (CO2) concentrations (aCO2 and eCO2) on the ability of a phytovirus (Potato Virus Y, PVY) to spread from a central infected tobacco plant to surrounding healthy ones, thank to the dispersion of aphid vectors (*Myzus persicae* (Sulzer)). We found that aphid dispersal, as well as the associated spread of viruses, were not affected by an increased CO2 concentration. In addition, the ability for aphids to transmit efficiently the virus was also determined. Here we highlighted the better capacity of aphids grown under eCO2 to transmit viruses to healthy plants, compared to aphids reared under aCO2 conditions. The results of the experimental trials undertook herein indicate that CO2 level could significantly modify the feeding behaviour of insect herbivores and thus alter the viral transmission ability, but not sufficiently to increase PVY spread.

Keywords: Green peach aphid, PVY, carbon dioxide, dispersal, transmission, non persistent virus

Speaker*
## Poster 5

# Belowground and aboveground damage can impact the conifer growth and feeding behavior of the weevil *Hylobius abietis* (Coleoptera: Curculionidae).

Agnes Brosset*<fnref n="1" />, Yayuan Chen<fnref n="2" />, Adriana Puentes<fnref n="2" />, Helena Bylund<fnref n="2" />, Christer Björkman<fnref n="2" />

Regeneration plantations of conifer seedlings are subject to feeding by bark beetles (Hylastes sp.) and pine weevils (*Hylobius abietis*). Both species are severe pests of young conifers and limit the forest regeneration at clear-cuttings in Europe. To protect seedlings from damage, a novel method utilizing the plant hormone Methyl Jasmonate (MeJA) has shown promising results by inducing resistance and decreasing the amount of damage received. However, the efficacy of MeJA has not been compared to other methods that can also be used to induce defences in plants (e.g. mechanical damage). In this study, we investigated how equal amount of mechanical damage either on stem or roots and previous feeding damage by the pine weevil on Scots pine seedlings can: 1) affect successive pine weevil feeding behavior, measured in terms of area debarked and 2) impact the plant growth measured by comparing the size of damaged and undamaged seedlings each week during two months. The experiment showed that previous herbivore and mechanical damage on stem and root altered the pine weevil feeding by limiting the area debarked on seedlings with a tendency for less feeding found for the root damage treatment. These results may suggest that the root damage disturbed seedling physiology by inducing defenses in responses to the damage and could impact the aboveground feeding behavior of pine weevils. It was also indicated that the root damage treatment reduced the seedling growth, suggesting that damage to belowground part, essential for the extraction and transport of the nutrients, may have a strong cost for the plant. To develop plant protection methods to reduce damage caused by the bark beetles and pine weevils, the sensitivity of the root should be taken into account.

Keywords: *Pinus sylvestris*, *Hylobius abietis*, feeding behavior, seedling damage, above, below-ground interaction, plant growth.

Speaker*: agnes.brosset@etu.univ-tours.fr

## Poster 6

# Variation in induced resistance among tree genotypes: how does it influence the interaction between bark-feeding insects and conifer seedlings?

Yayuan Chen<fnref n="1" />, Agnes Brosset<fnref n="2" />, Helena Bylund<fnref n="1" />, Adriana Puentes<fnref n="1" />, Niklas Björklund<fnref n="1" />, Christer Björkman*<fnref n="1" />

Plants are food resources to many organisms and to fight attacks from herbivores they possess constitutive and induced defences. Constitutive defences are continuously expressed regardless of herbivore attack, while induced defences are activated when plants receive signals that they are being damaged. Methyl jasmonate (MeJA), a plant signalling hormone, has been proven to trigger induced defences when exogenously applied to plants. In Swedish managed conifer forests, feeding damage by the pine weevil *Hylobius abietis* and the black spruce beetle *Hylastes cunicularius* constitutes a severe threat to newly-planted seedlings in regeneration areas, causing high levels of seedling mortality and growth loss. Efforts to reduce damage have recently generated studies investigating if MeJA-induced defence can protect seedlings, and so far results are promising. However, responses to MeJA have been examined in only a few families/genotypes and we lack knowledge on genetic variation in induced responses to MeJA treatment and their effectiveness in deterring herbivores. To investigate variation in induced defence among genotypes, different families/genotypes of Norway spruce *Picea abies* and Scots pine *Pinus sylvestris* will be treated with MeJA. After MeJA treatment, the feeding extent and behaviour of bark-feeding insects, the defence traits induced and the growth of seedlings will be investigated. This will provide insight on how induced defences can influence the interaction between bark-feeding insects and conifer seedlings.

Keywords: methyl jasmonate, Norway spruce, Scots pine, induced defence

Speaker*: Corresponding author: Christer.Bjorkman@slu.se

<footnote n="1">¹ Université Francois Rabelais, UFR Sciences et Techniques, Parc Grandmont 37200 TOURS, France</footnote>

<footnote n="2">² Swedish University of Agricultural Sciences (SLU), S-750 07 Uppsala, Sweden</footnote>

<footnote n="1">¹ Swedish University of Agricultural Sciences (SLU), S-750 07 Uppsala, Sweden</footnote>

<footnote n="2">² University of Tours, UFR Sciences and Techniques, Parc Grandmont 37200 TOURS, France</footnote>
## Poster 7

# Root-colonizing bacteria enhance the levels of (E) - β-caryophyllene produced by maize roots in response to rootworm feeding

Xavier Chiriboga<fnref n="1" />, Huijuan Guo <fnref n="2" />, Raquel Campos-Herrera <fnref n="3" />, Gregory Röder <fnref n="1" />,
Nicola Imperiali <fnref n="4" />, Ted Turlings*<fnref n="1" />

When larvae of rootworms feed on maize roots they induce the emission of the sesquiterpene (E)-β-caryophyllene (Eβc) in most maize genotypes. Eβc is attractive to entomopathogenic nematodes, which parasitize and rapidly kill WCR larvae, thereby protecting roots from further damage. Certain root-colonizing bacteria of the genus Pseudomonas benefit plants, by promoting growth, suppressing pathogens or inducing systemic resistance (ISR). In addition, some strains also have insecticidal activity. Effects of root-associated bacteria on direct and indirect plant defenses against insect herbivores have been studied aboveground. But, how beneficial soil bacteria may influence the emission of herbivore-induced plant volatiles (HIPV's) below-ground is not yet understood. In this study, we measured production of Eβc in roots colonized by the growth-promoting-insecticidal bacteria *Pseudomonas protegens* CHA0 and *Pseudomonas chloraphis* PCL-1391 upon feeding by larvae of the banded cucumber beetle, *Diabrotica balteata* Le Conte (Coleoptera: Chrysomelidae). We used a combination of chemical analysis and gene expression measurements to evaluate Eβc production and release, and assessed weight gain and mortality of *D. balteata* larvae to determine the effects of Pseudomonas spp. root-colonization. We found that Eβc emission and expression of the Eβc synthase gene-TPS23 was enhanced in Pseudomonas-colonized roots after 72 hours of *D. balteata* feeding. Undamaged roots colonized by Pseudomonas spp. showed no measurable increase in Eβc production, but a slight increase in TPS23 expression. Root biomass was not affected by Pseudomonas colonization. Larvae that fed on roots colonized by *P. protegens* CHA0 tended to gain more weight than larvae that fed on roots colonized by *P. chloraphis* PCL-1391. Larvae mortality on Pseudomonas spp.-colonized roots was slightly, but not significantly higher. Observed enhanced production of Eβc upon Pseudomonas spp. colonization may have consequences for interactions with root herbivores and other soil organisms such as entomopathogenic nematodes.

Keywords: Root, colonizing bacteria, *Diabrotica balteata*, (E)-β-caryophyllene, terpene synthase, maize
Speaker*

## Poster 8

# Reduced Caterpillar Damage Benefits *Lygus hesperus* on Bt Cotton

Michael Eisenring*<fnref n="1" />, Steve Naranjo <fnref n="2" />, Michael Meissle <fnref n="1" />, Sven Bacher <fnref n="3" />, Joe Hull <fnref n="2" />, Jörg Romeis <fnref n="1" />

The wide scale adoption of genetically modified cotton producing insecticidal Cry proteins from *Bacillus thuringiensis* (Bt), has led to area-wide suppression of major lepidopteran pests and a reduction of insecticide application. However, non-target pests not susceptible to the produced Cry proteins, such as the plant bug *Lygus hesperus*, have increased in Bt cotton fields in some parts of the world. In addition to the reduced application of insecticides, *L. hesperus* might also benefit from reduced caterpillar damage on Bt cotton. The latter was found to reduce the induction of insecticidal terpenoids enhancing the crops' susceptibility to other herbivores. The effects of plant induction on *L. hesperus* development was studied by caging nymphs on Bt and non-Bt cotton plants growing in a greenhouse. Plants were either non-damaged, previously damaged by Bt tolerant caterpillars (*Spodoptera exigua*), or treated with jasmonic acid (JA), a plant hormone known to induce cotton defense. Caterpillar induction, and to a lesser extent, JA induction of plant defenses negatively affected *L. hesperus* survival compared to non-damaged plants. This result was consistent for Bt and non-Bt plants. Induced plants showed increased levels of several terpenoids (incl. gossypol) compared to non-induced plants. Artificial diet feeding assays using purified terpenoids and molecular analyses of potential *L. hesperus* stress gene upregulation are being conducted to better understand mechanisms behind the greenhouse results. This study underpins the importance of plant-mediated, indirect interactions between herbivores for explaining agro-ecological processes and indicates how insect-resistance plant traits can indirectly impact herbivore communities.

Keywords: *Lygus hesperus*, plant mediated indirect interaction, cotton, terpenoid, defense induction
Speaker * Corresponding author: michael.eisenring@agroscope.admin.ch

<footnote n="1">¹ Fundamental and Applied Research in Chemical Ecology Laboratory, University of Neuchâtel (FARCE Lab. UNINE), Rue Emile-Argand 11, CH2000 Neuchâtel, Switzerland</footnote>

<footnote n="2">² State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijin 100101, China</footnote>

<footnote n="3">³ Centro para os Recursos Biologicos e Alimentos Mediterranicos, Campus Gambelas, Universidade do Algarve (MetBIO), Portugal</footnote>

<footnote n="4">⁴ Department of Fundamental Microbiology, University of Lausanne (DFM-UNIL), Switzerland</footnote>

<footnote n="1">¹ Agroscope, Reckenholzstrasse 191, 8046, Zurich, Switzerland</footnote>

<footnote n="2">² USDA-ARS, Arid-Land Agricultural Research Center, 21881 N. Cardon Lane 8, Maricopa, United States</footnote>

<footnote n="3">³ University of Fribourg, Chemin du Musee 10, 1700 Fribourg, Switzerland</footnote>
## Poster 9

**Geographical variation of endosymbionts in the insect food web on oak**

Maria Faticov*<fnref n="1" />, Anne Duplouy <fnref n="2" />, Ayco Tack <fnref n="1" />

The majority of insects harbor symbiotic bacteria (endosymbionts). Studies show that endosymbionts have diverse effects on their insect host, ranging from protection from natural enemies to manipulating the host's reproduction. Thus, endosymbionts may directly or indirectly affect insect ecology and shape insect food web structure. To elucidate the effect of endosymbionts on the structure and dynamics of insect communities, we need to know their spatial distribution and community structure, which is currently quite limited. The main aim of this project is to investigate the spatial distributions of endosymbionts within the insect food web on the oak tree *Quercus robur*.

For this, we are currently rearing thousands of leaf mining, galling and parasitoid insects from five different geographical locations: Finland (Wattkast), Sweden (Linkoping, Skane), the Netherlands (Loenermark) and France (Bordeaux). We will use molecular tools to identify endosymbiont species, including Wolbachia strains, to answer the following questions: 1) Is there geographical variation in endosymbionts associated with individual species of plant-feeding and parasitoid insects? 2) Do more closely related insect species share more similar endosymbiont communities? 3) Are some insect species simultaneously infected with more than one endosymbiont? 4) Can one plant-feeding insect species be infected with several strains of Wolbachia spp.?

Keywords: herbivore insects, endosymbionts, geographical variation

Speaker*

## Poster 10

**Interactive effects of mycorrhizal inoculation and jasmonic acid endogenous production on plant resistance against herbivores**

Ludovico Formenti *<fnref n="1" />, Sergio Rasmann ²¹

Mycorrhizal fungi, in addition to improve plant performance via increased food acquisition, they have also been shown to increase plant resistance against herbivores, but little is known how endogenous plant defences and mycorrhizal defence enhancement interact with each other in the presence of herbivores. With this study, we asked whether the increased plant resistance conferred by the mycorrhizal symbiosis can synergistically interact with the jasmonic acid (JA) phytohormonal pathway of the plant responsible for orchestrating plant defence strategy against chewing herbivores. To measure the interactive effects of mycorrhizal inoculation and JA-mediated defences, we measured resistance against *S.littoralis* larvae and plant defensive traits of wild-type tomato plants and two mutants lines; a JA-knockout mutant, and a mutant which overexpresses JA, in the presence or absence of mycorrhizal fungi. According to predictions, we observed that plant defensive traits such as the number of trichomes and specific leaf area were higher in WT plants and plants that overexpress JA, compared to plants impaired in JA production. Additionally, both wild-type plants, enhanced JA-producing plants, and mycorrhizal inoculation reduced *S.littoralis* survival and biomass, but their effects were not additive. Instead, the positive effects of mycorrhizal inoculation on plant resistance weakened with increasing JA production. In sum, both JA production and mycorrhizal inoculation increase plant resistance, but do not synergistically interact for multiplying resistance. Instead, we suggest that the magnitude of resistance conferred by mycorrhizal fungi can substitute the lack of defences in plants impaired in the JA phytohormonal pathway.

Keywords: Jasmonic Acid, Tomato, Mutant, Spodoptera littoralis, Arbuscular Mycorrhizal Fungi, Plant resistance

Speaker* : ludovico.formenti@unine.ch <fnref n="2" />*Corresponding author*

<footnote n="1">¹ Stockholm University, Department of Ecology, Environment and Plant Sciences, Svante Arrhenius v 20A, 114 18 Stockholm, Sweden</footnote>

<footnote n="2">² Helsinki University, Department of Biosciences, Viikinkaari 1, 00014 Helsinki, Finland</footnote>

<footnote n="1">¹ Functional Ecology Laboratory (LEF), Institute of Biology, University of Neuchâtel, rue Emile Argand 11, 2000 Neuchâtel, Switzerland</footnote>
Poster 11

# Effect of ground-fogging of thiacloprid on target and non-target insects in Korean pine forests

Tae Woong Jang <fnref n="1" />, Jong-Kook Jung<fnref n="2" />, Mannyeon Kim <fnref n="1" />, Jongkuk Kim<fnref n="1" />, Chansik Jung*<fnref n="2" />, Sanghyun Koh <fnref n="2" />

This study was conducted to assess effect of thiacloprid fogging on mortality of *Monochamus saltuarius* as one of vector insects of pine wood nematodes, and *Apis mellifera* as a non-target species. We compared mortality of two insects among four treatment groups (control and thiacloprid-fogged groups with 3 different doses) in *Pinus koraiensis* forests located in the Kangwon National University Forest. Area of each study plot was about 0.5 ha, and a total of 12 study plots were selected. Before ground-fogging, *M. saltuarius* and *A. mellifera* were put into each meshed cage which installed at 7 m and 15 m heights in center of each study plot. Thiacloprid was sprayed only once (middle May) in each plot using a fogging machine. Overall, thiacloprid fogging was appeared to be low toxicity to the mortality of *A. mellifera*, while it seems effectively impact on the mortality of *M. saltuarius*. However, thiacloprid fogging seems more influenced by microclimates in forests because the mortality of *M. saltuarius* in mesh cages was different according to heights and spatial locations. To control the population density and dispersal of *M. saltuarius* using by fogging techniques, therefore, it may be necessary to minimize the uncertainty about the effectiveness of thiacloprid fogging by improving the fogging techniques.

Keywords: Pine wood nematode, Pine wilt disease, Environmental risk assessment, *Monochamus saltuarius*, *Apis mellifera*
*Speaker* Corresponding author: jk82811@korea.kr

Poster 12

# Distribution and development of *Drosophila suzukii* along elevation gradients

Giacomo Santoiemma *<fnref n="1" />, Damiano Fioretto <fnref n="1" />, Lorenzo Marini <fnref n="1" />

*Drosophila suzukii* (Matsumura, 1931), also known as Spotted Wing Drosophila (SWD), is a polyphagous invasive crop pest native of South-East Asia. The species is widely distributed on the Italian territory due to its large array of host plants and high tolerance to different climatic conditions. The goal of this work was to define the abundance and the distribution of SWD at different elevations in NE Italy. We selected 12 transect covering an overall elevation gradient of 2080 m: 8 transects in the Prealps, ranging between 120 and 1300 m a.s.l. and 4 in the Dolomites, ranging between 1030 and 2200 m a.s.l. Every 100 m ca. elevation gain we identified a sampling site (tot. 115), where we placed a trap lured with selective SWD attractant, monitored every 2 weeks from June to November 2015. Female fertility was determined by checking the development stage of the ovaries. Fruits of elderberry (*Sambucus nigra* L.), largely available in the region and suitable for SWD development, were collected along the Prealps transects to assess the emergence rate of the fly.

The pest shows its highest abundance around 1000 m a.s.l. in the Prealps and a significant positive relationship between
emergence rate and increasing elevation. The most interesting results were found in Dolomites region where, despite a
decrease of abundance with elevation, female ratio and female fertility seem to increase at high altitudes, leaving open the
hypothesis of a summer partial migration towards higher elevations to better exploit food resources.

Keywords: *Drosophila suzukii*, elderberry, elevation gradient, transects, ovary development
*Speaker* Corresponding author: giacomosanto@gmail.com

<footnote n="1">¹ Kangwon National University (KNU), 1 Kangwondaehak-gil, Chuncheon-si, Kangwon-do, 24341, South Korea</footnote>

<footnote n="2">² National Institute of Forest Science (NIFoS), 57 Hoegi-ro, Dongdaemun-gu, Seoul 02455, South Korea</footnote>

<footnote n="1">¹ Universita degli Studi di Padova, Italy</footnote>
## Poster 13

**Herbivory and florivory at different strawberry plant resistance levels**

Jeltje Stam*<fnref n="1" />, Johan Stenberg <fnref n="1" />

Herbivory can cause large damage to plants, leading to both ecological costs for the plant, and economic losses for agriculture. In addition to herbivory on leaves, also flowers can be damaged (florivory). This might reduce pollination and therefore plant fitness. Ideally, plant resistance against herbivory reduces negative effects of both herbivory and florivory, but this is not often studied in combination.

Here we use perennial woodland strawberry plants, *Fragaria vesca*, to address the question whether plants with a higher resistance to herbivory by the strawberry leaf beetle *Galerucella tenella*, have higher flower and fruit production than more susceptible plants. Second, strawberry plants can also reproduce vegetatively via runners. Therefore we investigated whether herbivore resistance poses a trade-off in vegetative versus sexual reproduction.

Wild strawberry plants were collected from Uppsala County, Sweden, and genotypes with either a higher or lower susceptibility to *G. tenella* herbivory were planted in a common garden field experiment. Half of these plots were exposed to *G. tenella* beetles, of which the adults and larvae feed on both leaves and flowers. During the summer, the occurrence of insects and the damage on leaves and flowers was recorded, as well as the sexual (berries) and vegetative (runners) plant fitness.

The results indicate that *G. tenella* caused losses of leaf tissue and strawberries, but this was variable for the resistance levels of the plant genotypes. Importantly, especially susceptible plant genotypes might allocate more to vegetative reproduction when under herbivore pressure. Susceptible plants had heavier runners when beetles were present and a negative runners-versus-berries correlation.

This asexual/sexual reproduction trade-off and the effects of florivory can have important consequences for plant fitness in perennial plants. Moreover, these are important components to take into account when wild plants are used for reverse breeding to increase herbivore resistance in crops.

Keywords: Herbivory, florivory, insect, plant interactions, pollination, resistance, strawberry, wild plants

Speaker* Corresponding author: jeltje.stam@slu.se

## Poster 14

**A conserved priming signal: Volatile indole activates early defense signaling in rice**

Meng Ye*<fnref n="1" />, Lingfei Hu <fnref n="1" />, Matthias Erb² <fnref n="1" />

The capacity of plants to perceive and respond to herbivore-induced plant volatiles is well-known. However, the impact of volatile priming signals on early defense signaling events is not well understood. We studied the impact of indole on early defense signaling in rice (*Oryza sativa*). Indole is induced by herbivory and has been shown to be a strong priming signal in maize in an earlier study (Erb *et al.*, 2015). We found that indole pre-treatment primed rice plants to produce higher levels of the defensive phytohormone jasmonic acid (JA) and the release of monoterpenes upon simulated herbivory. The JA precursor OPDA was directly induced by indole. Furthermore, the expression of the WRKY transcription factor WRKY70, which is involved in early defense signaling, was primed by indole. Our results suggest that indole boosts plant defenses by inducing the biosynthesis of hormonal precursors and priming upstream transcription factors such as WRKY70 (Li *et al.*, 2015). Our results also show that indole can prime both rice and maize, which suggests that it may be a conserved priming signal within the Poaceae.

Keywords: plant volatiles, priming, indole, phytohormone, defense signaling, rice

Speaker* Corresponding author*

<footnote n="1">¹ Swedish University of Agricultural Sciences (SLU), Sweden</footnote>

<footnote n="1">¹ Institute of Plant Sciences, University of Bern, Switzerland</footnote>
## Poster 15

# Neighborhood effects determine plant-herbivore interactions below ground

Wei Huang *<fnref n="1" />, Elias Zwimpfer <fnref n="1" />, Maxime Hervé <fnref n="1" />, Zoe Bont <fnref n="1" />, Matthias Erb²,<fnref n="1" />

Plant neighbors may strongly influence the interactions between below ground herbivores and focal plants, for instance by providing food of different quality (consumptive effects) or by changing the behavior and metabolism of the herbivore and the focal plant without being consumed (non-consumptive effects). Here, we quantified the impact of nine different grassland plant species on the interaction between *Taraxacum officinale* and the root-feeding insect *Melolontha melolontha* and investigated the contribution of consumptive and non-consumptive effects to the observed patterns. *Melolontha melolontha* growth was strongly affected by the presence of different neighboring species. The three grass species increased larval growth when growing with *T. officinale*, with *Poa pratensis* having a synergistic effect in the mixture compared to both monocultures. The forb *Centaurea stoebe* reduced larval growth when growing with *T. officinale* or alone. The other five species had no measurable impact on larval performance. Diet-mixing experiments showed that *P. pratensis* increased *M. melolontha* growth when offered together with *T. officinale*, while *C. stoebe* suppressed it. When feeding was restricted to artificial diet, larval growth was not changed by the presence of *P. pratensis* or *C. stoebe*. However, when feeding was restricted to *T. officinale*, larval growth was increased by both heterospecific neighbors. Together, these results show that consumptive and non-consumptive effects can explain the positive effect of *P. pratensis*. By contrast, the negative effect of *C. stoebe* is likely driven exclusively by intoxication. Our study suggests that different combinations of consumptive and non-consumptive effects are likely to contribute to the diversity of neighborhood effects in nature. Furthermore, the results show that neighborhood effects are important factors in below ground plant-insect interactions.

Keywords: Associational effect, diet mixing, *Melolontha melolontha*, neighboring plant, physiological response, plant, herbivore interactions, plant-plant interactions, root insects, species, specificity, *T. officinale*

Speaker* Corresponding author²

## Poster 16

# Interactions plantes-insectes dans un écosystème forestier : le cas de la chenille processionnaire du pin *Thaumetopoea pityocampa* (Denis & Schiffermüller, 1775) en région de l'Est Algérien

Sihem Ziouche<fnref n="1" />

La chenille processionnaire du pin, *Thaumetopoea pityocampa* est le principal lépidoptère ravageur rencontré chez *Pinus halepensis* croissants dans le sud de l'Europe et en Afrique du Nord. Les interactions pin d'Alep-chenille processionnaire ont une importance écologique, économique, sociétale et scientifique. La combinaison des défenses directes et indirectes des plantes attaquées offre à ces dernières une résistance durable dans l'écosystème. La composition et la dynamique des communautés d'insectes herbivores sont donc largement influencées par les traits des végétaux. Bien que tous les insectes phytophages infligent des dégâts sur les tissus végétaux, la quantité et la qualité des dégâts varient grandement selon les guildes trophiques. Les insectes utilisent des stratégies alimentaires différentes pour obtenir les nutriments nécessaires à leur développement. Les insectes spécialistes sont restreints à une ou quelques plantes de la même famille et utilisent les composés chimiques émis par la plante pour leur propre défense afin de faciliter l'exploitation de leur hôte. Nous avons développé une approche pluridisciplinaire couplant la caractérisation de traits écophysiologiques et dendrométriques impliqués dans la sensibilité/résistance des populations d'arbres aux attaques de scolytes avec la caractérisation de facteurs écologiques clés pour la démographie des scolytes (traits d'histoire de vie des scolytes et stratégies d'exploitation de l'hôte). Les analyses effectuées sur la qualité phytochimique du pin d'Alep des feuilles attaquées et non attaquées. Nous a permis de quantifier les sucres totaux, les polyphénols, les tanins, et les flavonoïdes. Leurs variations temporelles ne présentent pas de différence significative entre les constituants biochimiques chez les deux catégories foliaires. Par besoin d'expliciter nos résultats, nous avons eu recours à la comparaison des pentes des feuilles attaquées par rapport aux feuilles non attaquées. Les résultats obtenus nous ont permis de clarifier les changements des constituants phytochimiques au niveau des arbres attaqués et sains. L'analyse en composantes principales (ACP) nous a permis de résumer la variabilité entre les constituants phytochimiques de l'hôte et l'intensité de l'attaque.

Keywords: arbres attaque, arbres sains, dynamique des populations, écophysiologie, Interaction, *Pinus halepensis*, phytochimie, *Thaumetopoea pityocampa*.

<footnote n="1">¹ Institute of Plant Sciences, University of Bern, Switzerland</footnote>

<footnote n="1">¹Algérie</footnote>
# Poster 17

**Life history of two leaf bud gallers associated with the deciduous tree**
*Schoepfia jasminodora* (Schoepfiaceae) in Japan

Ayman Elsayed*<fnref n="1" />, Makoto Tokuda<fnref n="2" />

The association between a host plant and two different gallers attacking the same plant organ and inducing similar shapes of gall is not a well-studied phenomenon. We report such a case on a deciduous tree *Schoepfia jasminodora* (Schoepfiaceae) on which slightly swollen galls are induced on leaf buds by a gall midge, Asphondylia sp. (Diptera:Cecidomyiidae), and a galling wasp, Ceratoneura (Hymenptera: Eulophidae). In the present study, monthly surveys were conducted in 2015-2016 on Mountains Hinokuma and Koura, Kyushu, Japan, to investigate the life history of both gallers and their relationships.

Both gallers were clarified to have at least three generations per year and similar external gall shape, but they differ in overwintering place and stage as well as in internal structure of galls. Asphondylia sp. overwintered as first instars inside the galls while Ceratoneura sp. was not found in overwintering buds, suggesting that they overwintered as adults outside the galls. Bud galls induced by Asphondylia sp. consisted of a single chamber with white fungal hyphae covering the inner walls, while those induced by Ceratoneura sp. was comprised of 1-7, usually 3, black and hardened chambers.

A previous study divided life history of Asphondylia into several patterns and Asphondylia sp. associated with *S. jasminodora* was revealed to have the life history pattern III, i.e., multivoltine and completing their life cycle on one organ of a single host plant species. This pattern was known only in some species associated with evergreen trees. So this is the first example of Asphondylia adopting pattern III on a deciduous tree species. Life history of Ceratoneura species were unclear and previous studies suspected that Ceratoneura sp. might be gall inducers, inquilines or parasitoids on gall midges. The present study first showed the life history and the species is a true gall inducer.

Keywords: Cecidomyiidae, Eulophidae, gall midges, Schoepfiaceae

Speaker* Corresponding author<fnref n="2" />: ayman.khamis77@gmail.com; Corresponding author<fnref n="2" />: tokudam@cc.saga-u.ac.jp

# Poster 18

**Herbivore-mediated fitness effects of increasing chemical variation**
**among neighbouring plants**

Rieta Gols *<fnref n="1" />, Carlos Bustos-Segura *<fnref n="2" />, Michael Reichelt *<fnref n="3" />, Jonathan Gershenzon *<fnref n="3" />, Erik Poelman *<fnref n="1" />

Intraspecific plant diversity can modify the properties of associated arthropod communities and plant fitness. We explored the effect of intraspecific chemical variation among neighbouring plants on the associated invertebrate community and whether this, in turn, has consequences for plant fitness. In a garden experiment, intraspecific variation among neigboring plants was manipulated using three plant populations of wild cabbage (*Brassica oleracea*) that differ in foliar glucosinolates. The herbivore community was monitored throughout the growing season in the first year. Seeds of individual plants were collected in the second year (*Brassica oleracea* is a perennial plant that does not flower in the first year of growth). Correlation indices were used to reveal relationships among plant chemistry, insect community attributes and plant fitness.

Keywords: *Brassica oleracea*, chemical ecology, community ecology, plant fitness, cabbage
Speaker*

<footnote n="1">¹ The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, 890-0065 Japan,</footnote>

<footnote n="2">² Laboratory of Systems Ecology, Faculty of Agriculture, Saga University, Honjo 1, Saga 840-8502, Japan</footnote>

<footnote n="1">¹ Laboratory of Entomology, Wageningen University (WUR), Netherlands</footnote>

<footnote n="2">² Laboratory of Evolutionary Entomology, University of Neuchâtel, Switzerland</footnote>

<footnote n="3">³ Max Planck Institute for Chemical Ecology, Dept of Biochemistry, Germany</footnote>
## Poster 19

# Why are terrestrial ecosystems generally green with small herbivores biomass? Why are anti-nutritive and inducible defenses effective?: The realities that a novel fully-parameterized food web model tells

Kotaro Konno<fnref n="1" />

Despite perfect adaptations of specialist herbivores to plant defenses, terrestrial ecosystems are generally green with vegetation and annual herbivory is small (< 10%), which means herbivore density is consistently low and stable. This plant-rich pattern called "The Green World" is common around the world where precipitation and temperature are adequate. Nonetheless, the mechanism underlying this pattern has been unclear without suitable food-web models for predicting the absolute density of the herbivore biomass in physical units. I established a fully-parameterized mathematical food-web model based on flux of nutrients among three trophic levels that can predict biomass densities of herbivores h and carnivores c from factors such as nutritive values of plants np, herbivores nh, and carnivores nc, searching efficiency of carnivores S, eating efficiency of herbivores eh and carnivores ec, respiratory decreases in biomasses, dh and dc, absorption efficiencies ah and ac, and probabilities of carnivores preying on herbivores or carnivores, Phc and Pcc. The model predicts a stable convergent equilibrium with biomass densities of herbivore h=ncf{(1-ac)Pcc(ahehnp{nhdh)+2dcPhcg}/2acPhc2nhS (kg/m3) and carnivore c=nc(ahehnp-nhdh)/PhcnhS (kg/m3) with low herbivore biomass h sufficient to keep the world green provided plants are less nutritive than animals (np> eh). These conditions are well-realized in above-ground terrestrial ecosystems where plant-rich "green worlds" are common, versus animal-rich belowground and aquatic ecosystems where both conditions are not realized. The h, c, and annual herbivory calculated from our model fit in the same order of magnitude with those from empirical observations in both forest and savannah ecosystems. The model reasonably explained why anti-nutritive or quantitative defenses (e.g., tannins, protease inhibitors) of plants function as plant defences in the out-door conditions, and why inducible defences are effective.

Reference: Konno K. (2016) Ecological Monographs 86(2), 190-214.

Keywords: mathematical food web model, prediction of the absolute herbivore and carnivore biomass, forest, savannah, parameterization, green world hypothesis, HSS hypothesis, nutritive value, searching efficiency, eating speed, relative growth rate, plant defense

## Poster 20

# Canola/cabbage aphid food web – underestimated top-down pressure in invaded range

Lefort M.-C.<fnref n="1" />,<fnref n="2" />, Wratten S.D.<fnref n="2" />, Cusumano A. *<fnref n="3" />, Varennes Y.-D. & Boyer S. <fnref n="1" />

The lack of understanding of complex food web interactions has been a major gap in the history of biological control. Technical limitations associated with the deciphering of complex food-webs can now be largely overcome by the use of next generation sequencing technologies. The cabbage aphid, (Brevicoryne brassicae (L.) is a prevalent pest on canola (Brassica napus L. (Brassicaceae)) in New Zealand. The cabbage aphid has been a problem for almost a century in this invaded region, and biological control success tends to remain below 10%. In contrast, in its native range, which includes the UK, B. brassicae is considered only as locally and occasionally damaging. In this study, we used environmental DNA in aphid mummies and Illumina Miseq, to compare the variations in structure and composition of B. brassicae food web in its native range (UK) and in an invaded range (New Zealand). We found an increased top down pressure in the New Zealand (NZ) food web, which coupled to a large ratio of consumer species / prey species and a lack of potential inter-specific competition between primary parasitoids, could cause the NZ food web to be more vulnerable than the UK one. This study also reports for the first time the occurrence of a new hyperparasitoid species in NZ. We conclude that the complexity of aphid food webs in agricultural systems could often been underestimated, particularly at higher trophic levels; and that the use of next generation sequencing tools, could largely help to overcome this impediment and support the implementation of better biological control strategies.

Speaker*

<footnote n="1">¹ Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-8634, Japan</footnote>

<footnote n="1">¹Applied Molecular Solutions Research Group, Environmental and Animal Sciences, Unitec Institute of Technology, Private Bag 92025, Victoria Street West, Auckland 1142, New Zealand</footnote>

<footnote n="2">²Bio-Protection Research Centre, P. O. Box 85084, Lincoln University, Christchurch 7647, New Zealand</footnote>

<footnote n="3">³Departement of Plant Sciences, Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708PB Wageningen, Netherlands.</footnote>
## Poster 21
Evolutionary and functional ecology of ant-plant-fungus symbioses

Veronika Mayer*<fnref n="1" />, Hermann Voglmayr<fnref n="1" />, Rumsais Blatrix²

The frequent occurrence of dense fungal mats of blackish hyphae (fungal patches) within ant-occupied domatia (plant provided nesting space) in myrmecophytes (plants living in symbiosis with ants) was noticed over 100 yr ago but the symbiotic nature of these fungi remained overlooked and was demonstrated only recently. Recent phylogenetic analyses show that most fungi within the ant nests belong to the Chaetothyriales (Ascomycota) and the fungal patches within domatia are mainly constituted of a few strains more or less specific to the ant species. The frequency and extent of associations of these fungi with ants were underestimated for a long time. Fungal patches in ant-occupied domatia are astonishingly abundant in tropical ant-plant symbioses. They occur in Africa, America and Asia, in a wide range of unrelated plant genera associated with a wide range of unrelated ants, including myrmecophytic plants from at least 19 different plant genera and six ant genera from five subfamilies. Female alates of neotropic Azteca ants colonizing Cecropia spp. carry hyphal parts in their infrabuccal pockets. The comparison of fungal patches from foundress queens with patches of established colonies revealed that the hyphal parts stem from the maternal nest. Young foundress queens start a new fungiculture immediately after entering the nesting space provided by the plant and before egg laying. This and the fact that the cultivated fungi are fed to the larvae indicates that the fungal patches may be crucial for establishment and survival of arboreal ant colonies living in symbiosis with ant-plants.

Keywords: Ant plant interactions, fungi, Chaetothyriales

Speaker * Corresponding author: veronika.mayer@univie.ac.at

## Poster 22
Plastic plant defence strategies as an optimal response to unpredictable multi-herbivore communities

Daan Mertens*<fnref n="1" />, Maite Fernandez De Bobadilla ²,<fnref n="1" />, Janneke Bloem<fnref n="1" />, Patrick Verbaarschot<fnref n="1" />, Erik Poelman<fnref n="1" />

Plant defence strategies to single attackers are highly diverse and often tailor made to tol-erate or resist speci c herbivore attackers. Upon initial herbivore attack, plants respond by altering their morphology and chemical composition, thus presenting a new phenotype to the insect community. However, induced responses infer a physiological cost and alter the plant's interactions with the insect community, potentially imposing an ecological cost by increasing its susceptibility to attack by other herbivores. The induced plant phenotype feeds back to the insect community, altering strength and sign of indirect plant-mediated interactions within the attacking community. Reciprocal and dynamic interactions between the plant and its associated insect community shape the plants development, ultimately a cting tness.

Our aim is to improve our understanding of plant defence plasticity in context of the full dy-namic insect community. We argue that an optimal plant response to the current attacker should not outweigh the costs incurred through the sequential herbivore community. It is thus to be expected that plant species have evolved defence strategies in function of their full associated in-sect community, incorporating the physiological and ecological costs of induced responses. This infers that plants integrate a measure of predictability in terms of identity, order, and timing, of the insect community to optimise defence strategies. However, it is unknown which elements of the insect communities are predictable and to what extend plant physiology is adapted to the dynamic insect herbivore community.

By using a comparative approach across 12 Brassicaceae plant species we aim to I) identify a measure and form of predictability in the dynamic herbivore community II) explore the e cts of indirect plant-mediated interactions in this complex insect community on plant tness III) identify plant physiological mechanisms involved in coping with (un)predictable multi-herbivore attack IV) identify di erent physiological solutions to multi-herbivore attack across related plant species.

Keywords: plant defence plasticity, Brassicaceae, multi herbivore, induced responses, plant physiology, community ecology

Speaker * : daan.mertens@wur.nl ²Corresponding author: maite.fernandezdebobadilla@wur.nl

<footnote n="1">¹ University of Vienna, Department of Botany and Biodiversity Research, Rennweg 14, A-1030, Vienna, Austria</footnote>

<footnote n="3">³ Université de Montpellier, EPHE CNRS: UMR5175, 1919 route de Mende, 34293 Montpellier Cedex 5, France</footnote>

<footnote n="1">¹ Laboratory of Entomology, Wageningen University Research Centre (WUR), the Netherlands</footnote>
## Poster 23

# Pieris butterflies regulate two genes differently for adapting to wide range of Brassicaceae host plants

Yu Okamura*¹, Masashi Murakami ¹

¹ Chiba University, Japan

Pieris butterflies use Brassicaceae plants as host plants. Whereas Brassicaceae plants possess strong glucosinolate defense system against general herbivores, Pieris butterflies can overcome this defense system by a gut-expressed protein called nitrile specifier protein (NSP). In NSP gene family, two related genes (MA and SDMA) are included. The functions of MA and SDMA are still unclear. However, NSP and MA gene basically have similar structure and they are known to be found only in Brassicaceae-feeding Pieridae butterflies. This highly suggests that MA also has some functions, which relate to glucosinolate detoxification in Pieris larvae. In this research, we compared the expression levels of NSP gene family in Pieris butterfly larvae (*Pieris napi*). We compared the expression levels of NSP, MA and SDMA in larvae that feed on two different Brassicaceae plant species that have different glucosinolate profiles. We found that the expression level of SDMA showed no difference, however, NSP and MA showed different expression patterns depending on the plant species the larvae feed on. We also let larvae feed on Arabidopsis mutants, that have different glucosinolate profiles and compared expressions of NSP gene family. We observed different expressional patterns of NSP and MA in this experiments, whereas SDMA showed no difference. We found that the expression levels of NSP and MA are differently regulated depending on the profiles of glucosinolates the larvae exposed, whereas SDMA did not show such trend. This indicates NSP and MA are likely to have glucosinolate detoxification functions while SDMA might have a role in general digestion. Moreover, it is likely that the functions of NSP and MA are different each other potentially relating to the glucosinolate type that they can detoxify.

Keywords: Pieris butterflies, glucosinolates, NSP, MA

Speaker*

## Poster 24

# Teaching Insect-Plant Relationships - Template for a Successful Graduate Course

Daniel Potter¹

¹ University of Kentucky (UKy), Dept. of Entomology, S-225 Ag. Science Bldg. N, Lexington, KY 40546-0091, United States

I have taught a 3-credit graduate course in Insect-Plant Relationships (IPR) biannually since 1991. It is capped at 18 students, draws them from as many as six academic departments and receives consistently high ratings. We meet for 75 min, two days per week, alternating between lectures and Socratic-style paper discussions, starting at the historical roots of the field and proceeding through evolution of herbivory, chemical and physical plant defenses, sensory physiology, host-finding behavior and learning, adaptions to plant defense, variability and induced resistance, multi-trophic interactions, polyculture/monoculture theory, community ecology, plant defense and island biogeography theory, climate change, pollination ecology, and ecological aspects of transgenic crops. The reading list includes historical papers (e.g., Verschaffelt 1911, Brues, Dethier, Fraenkel), seminal reviews (e.g., Price/Tritrophic interactions; Root/Resource Concentration; Feeny/Coley/Plant Apparency/Resource Availability, Bernays/Neural Limitations, etc.), as well as interesting and controversial experimental papers. Writing assignments include 1) a critique of Ehrlich and Raven (1965) and three counterpoint papers concerning coevolution, and 2) an original grant proposal, with budget, describing hypothesis-driven research of the students' choice that must be grounded in IPR theory. The course ends with a mini-symposium in which students give short talks on their proposed projects. Class discussion grades are based 50% on peer evaluation. This poster provides examples of class materials and links to all course materials so that persons wishing to develop a similar course can use them as a template or to supplement their own vision for how to teach the topic.

Keywords: Teaching, Graduate Course, Instruction
## Poster 25

# Diverse phytochemical profiles and ecological interactions

Lora Richards *<fnref n="1" />, Celso Oliveira <fnref n="1" />, Lee Dyer <fnref n="1" />, Christopher Jeffrey <fnref n="1" />

Diverse phytochemical mixtures play an important role in plant-herbivore-parasitoid interactions. In the pursuit of understanding these chemically-mediated interactions, we are often faced with the challenge of deciphering the ecologically and biologically important compounds from diverse phytochemical mixtures. Using a network based approach, we analyzed binned 1H-NMR data from 200 artificial mixtures of commonly studied secondary metabolites including, alkaloids, amides, terpenes, iridoid glycosides, saponins, phenylpropene, flanvanoids and phytosterols. Within these mixtures we manipulated multiple dimensions of chemical diversity, including molecular complexity, mixture complexity and differences in the relative concentrations of each compound. This approach was then applied to crude extracts of 20 species in the phytochemically diverse tropical plant genus Piper. Combining a multiple organism bioassays and 1H-NMR data we identified a prenylated benzoic acid from these mixtures that exhibits antifungal properties and identified small structural differences that potentially had a large effect in the bioactivity. In an intraspecific analysis of *Piper kelleyi*, we found ontogenetic differences in chemistry that may relate to changes in natural enemies. In sum, this approach allowed us to combine chemical and ecological datasets and identify potential biologically important compounds from crude extracts.

Keywords: Plant defenses, NMR

Speaker*

## Poster 26

# Portiera as a phylogenetic tool on white flies

Diego Santos-Garcia *<fnref n="1" />, Natividad Mestre-Rjncon <fnref n="1" />, Nir Nqtanel <fnref n="2" />, David Ouvrard <fnref n="3" />, Einat Zchori-Fein <fnref n="2" />, Shai Morin

Whiteflies (Hemiptera: Sternorrhyncha: Aleyrodidae) are small phloem feeding insects that include several agricultural pests. In contrast to other insects, whiteflies taxonomy is based on nymphal stages morphology. However, these stages show phenotypic plasticity, which produces several inconsistencies at the genus level.

All whiteflies have specialized cells (bacteriocytes) that host a bacterial endosymbiont named Candidatus Portiera aleyrodidarum. Portiera is an obligatory mutualistic endosymbiont that complements its host's unbalanced diet, being essential for the whitefly. Portiera has been vertically transmitted since the divergence of whiteflies from their Psyllinae ancestor (circa 160 Mya), and therefore can reflect its host's phylogeny. Also, Portiera from *Bemisia tabaci* lineage has lost the polymerase proofreading subunit (dnaQ) and presents an uncommon genome instability.

Our main goal was to establish a phylogenetic framework based on several Portiera's genes. This framework will be used to improve whiteflies classification and to trace the dnaQ loss and the rise of genomic instability. For these reasons, a PCR screening with specific primers targeting five Portiera genes (16S and 23S rRNA, groEL, dnaK, rpoD and dnaQ), plus some Portiera rearrangements, was performed on 22 whiteflies species (including exsiccata museum specimens). Phylogenetic methods were used for tree inference, divergence dating, species delimitation and ancestral node reconstruction of dnaQ/rearrangements (RaxML, BEAST2, bPTP and ape).

We noticed that teh use of Portiera sequences outperform the universal mitochondrial cytochrome oxidase subunit I (mtCOI) region used so far. In summary, they show low signal saturation, avoid common misclassification of similar insects and can be used on parasitized samples. Therefore, it solves some problems/inconsistencies in current whiteflies phylogeny. The loss of dnaQ and the associated rearrangements are unique to the Bemisia genus.

Keywords: Phylogenetics, Endosymbionts, Molecular dating, Genome instability

Speaker * Corresponding author: diego.santos@mail.huji.ac.il

<footnote n="1">¹ University of Nevada, Reno, United States</footnote>

<footnote n="1">¹ The Hebrew University of Jerusalem (HUJI), Robert H. Smith Faculty, Department of Entomology. Rehovot, Israel</footnote>

<footnote n="2">² Agricultural Research Organisation (ARO), Department of Entomology, Newe-Ya'ar Research Center, Ramat-Yishai, Israel</footnote>

<footnote n="3">³ Natural History Museum (NHM), Department of Life Sciences, Cromwell Road, London SW75BD, United Kingdom</footnote>
# Poster 27

## Overcompensation of herbivore reproduction through hyper-suppression of plant defenses in response to competition

Bernardus Schimmel *<fnref n="1" />, Livia Ataide *<fnref n="1" />;<fnref n="2" />, Rachid Cha *<fnref n="1" />, Carlos Villarroel *<fnref n="3" />, Juan Alba *<fnref n="1" />, Robert Schuurink *<fnref n="3" />, Merijn Kant *<fnref n="1" />

Spider mites are destructive arthropod pests on a variety of crops. The generalist herbivorous mite *Tetranychus urticae* induces defenses in tomato (*Solanum lycopersicum*) when feeding on it and this constrains its fitness. In contrast, the Solanaceae-specialist *T. evansi* upholds a high reproductive performance by suppressing tomato defenses. When present on the same plant, *T. evansi* outcompetes *T. urticae* as was found in natural settings as well as in laboratory experiments, but it is not known to which extent this is facilitated by the defenses of the plant. Here we show that *T. evansi* switches to hyper-suppression of defenses after its tomato host is also invaded by its natural competitor *T. urticae*. Jasmonate (JA) and salicylate (SA) defenses were suppressed stronger, albeit only locally at *T. evansi*'s feeding site, once *T. urticae* was introduced to an adjacent area on the same leaflet. The hyper-suppression of JA and SA defenses coincided with increased expression of *T. evansi* genes coding for salivary defense-suppressing effector proteins and was paralleled by an increased reproductive performance of the mite. Together, these observations suggest that *T. evansi* overcompensates its reproduction through hyper-suppression of plant defenses in response to nearby competitors. We hypothesize that the competitor-induced overcompensation promotes *T. evansi*'s competitive population growth on tomato.

Keywords: competition, defense suppression, effectors, overcompensation, plant, mediated interactions, spider mites, tomato
*Speaker* Corresponding author: B.C.J.Schimmel@uva.nl

# Poster 28

## Morphological adaptations of coccinellid species determined by host-plant architecture

Jiri Skuhrovec*<fnref n="1" />, Alois Honek<fnref n="1" />, Zdenka Martinkova<fnref n="1" />, A. Dixon<fnref n="2" />

Communities of lady-beetles (Coleoptera, Coccinellidae) differ greatly in the plants they colonize. The differences originate because species of coccinellids differ in their tolerance of differences in prey abundance and quality, preference for particular microclimates and for plants of a particular size. The role of host plant in habitat selection is important, however, the correlates of different affinity of coccinellid species in particular hostplants still remain to be demonstrated. We tested two hypotheses predicting association between morphological characters of coccinellid larvae and hostplant stature; (i) Tree architecture is more complicated than herb architecture. Therefore larvae of tree adapted coccinellid species are more mobile than larvae of herb adapted species; and (ii) Coccinellid larvae dropped from trees have greater problems of return to host plant than larvae dropped from herbs. Therefore larvae of tree inhabiting species stick to host plant more firmly than larvae of herb inhabiting species and have greater anal disc. The hypotheses were tested using data on distribution of native and recently arrived invasive species *Harmonia axyridis*.

Keywords: Lady beetles, microclimates, prey abundance, hostplant, morphological adaptation
*Speaker*

<footnote n="1">¹ Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Netherlands</footnote>

<footnote n="2">² Department of Entomology; Federal University of Vicoso, Brazil</footnote>

<footnote n="3">³ Swammerdam Institute for Life Sciences; University of Amsterdam, Netherlands</footnote>

<footnote n="1">¹ Crop Research Institute, Drnovska 507, 16106 Prague 6-Ruzyne, Czech Republic</footnote>

<footnote n="2">² CzechGlobe, Belidla 986/4a, 60300 Brno, Czech Republic</footnote>
## Poster 29

# Plant resistance ecology: what happens to insect communities when host plants evolve more resistant?

Johan Stenberg<sup>*1*</sup>, Daniela Weber<sup>1</sup>, Paul Egan<sup>1</sup>, Anne Muola<sup>1</sup>, Jeltje Stam<sup>1</sup>

Plant resistance is the ability of plants to escape attacking enemies, thus minimizing the amount of damage experienced by the plant. Strong resistance makes it possible for plants to maintain fit in hostile environments. In addition, as plant resistance is pivotal to prevent yield loss in crops, it is important to breed for. However, little is known about how increased resistance affects other ecological players (e.g. parasitoids and pollinators) in natural populations and crop plantations. I will introduce ongoing work dealing plant resistance ecology in The Strawberry Lab at SLU. We use woodland strawberry (*Fragaria vesca*), which show high genetic variation in important traits, as model plant to understand ecological consequences of increased resistance. The lessons we learn can be used to breed for integrated management of pests, and pollinators for strawberry.

Keywords: Plant resistance, Herbivory, Florivory, Pollination, Parasitism, Parasitoid, Diffuse interaction, Integrated Pest Management, IPM

Speaker * Corresponding author: johan.stenberg@slu.se

## Poster 30

# Paralell evolutionary changes in resource allocation to anti-herbivore traits in an invasive plant species

Klaas Vrieling<fnref n="1" />

One of the key factors that affect invasive plant species is the lack of their specialist herbivores in the invasive range. In absence of specialist herbivores it is expected that resources for obsolete defences against specialist herbivores are quickly diverted to other fitness increasing traits. By studying four independent invasive areas and the native area using more than 30 populations we find that the lack of specialist herbivores in the new range is accompanied by a parallel evolutionary change in all traits related to anti-herbivore strategies in invasive common ragwort (*Jacobaea vulgaris*). We find that invasive common ragwort (*Jacobaea vulgaris*) adapted its qualitative defences, quantitative defences, regrowth and growth leading to changes in competitive ability and seed production in this monocarpic plant. Competitive ability of invasive ragworts increased in the absence of herbivores and presence of a generalist herbivore but competitive ability decreased in the presence of a specialist herbivore. The increase in competitive ability and seed production in invasive ragwort are most likely explained by a profound decrease in carbohydrate storage to roots. None of the traits were correlated to climatic differences between the native and invasive populations.

Keywords: paralell evolution, alkaloids, specialists, generalists, tolerance, invasive, competitive ability

<footnote><sup>*1*</sup> Swedish University of Agricultural Sciences (SLU), Sweden</footnote>

<footnote n="1">¹ Institute Biology Leiden (IBL), Faculty of Science, PO Box 9516 2300 RA Leiden, Netherlands</footnote>
# Poster 31
## Pollination network analysis by environmental metagenomics

Sandra Baksay<fnref n="1" />

The plant-pollinator interaction network is a bipartite, mutualistic network between two groups with different interests. For plants, pollinators are essential pollen vectors required for reproduction, for pollinators, plants provide food resources. The study of plant-pollinator interactions is usually based on either field records of pollinator visits to plants, or pollen identification by microscopy. However, both of these methods have inherent limits that preclude an accurate description of pollination networks. For example, they do not take into account individual pollinator behavior and pollen flow. To analyze the pollen loads on pollinators and on plant stigmas, in a quantitative manner, a fine-scale approach is necessary. Recently, new, innovative methods are emerging that combine studies of environmental DNA by metabarcoding, high throughput sequencing and bioinformatics tools to thoroughly identify the taxa in environmental samples. However, the validity and efficiency of these news tools in studying pollination networks remains to be evaluated. The purpose of this work is to explore and analyse the application of environmental genomics in these mutualistic interactions. Our primary results show that, compared to visit observation, metabarcoding allows detection of many more interactions, and causes considerable changes to the properties of the pollination networks. Moreover, by allowing us to build individual pollination networks, metabarcoding adds an essential dimension to our comprehension of plant-pollinator interactions networks at a higher resolution than has previously been investigated.

Keywords: Plant, pollinator networks, metabarcoding, next generation sequencing, eDNA

# Poster 32
## Impact of endophytic entomopathogenic fungus on plant attractiveness in aphid-virus-plant interaction

Junior Corneille Fingu Mabola²¹, Emilie Bosquée<fnref n="1" />, Antoine Boullis*<fnref n="1" />, Francois Verheggen<fnref n="1" />, Frédéric Francis<fnref n="1" />

Endophytic entomopathogenic fungi (EEPF) are biological control agents able to live in their host plants in a symbiotic interaction and secrete secondary metabolites in the host plant tissues interacting with pests and phytopathogenic agents like plants virus. This is the case of Barley yellow dwarf virus (BYDV) transmitted by the Bird cherry oat aphid (Rhopalosiphum padi Linnaeus) and the Grain aphid (Sitobion avenae Fabricius). This virus is one of the most economically important phytoviruses affecting major world cereal crops such as wheat, rice and corn, causing significant yield losses. In this study, we investigated the influence of EEPF presence in the plant tissues on the aphid's orientation behavior by taking into consideration the infectious status of the insect. We performed Olfactometry assays complemented by a choice test in Petri dishes and collection of volatile compounds emitted by plants. The impact of these interactions between plant-fungi-virus is finally discussed.

Keywords: Endophytic entomopathogenic fungi, Aphid, BYDV, Plant attractiveness, multitrophic interaction

<footnote n="1">¹ Evolution et diversité biologique (EDB), Université Paul Sabatier - Toulouse 3, Ecole Nationale Supérieure Agronomique de Toulouse, Centre National de la Recherche Scientifique : UMR5174, Bâtiment 4R1, 118 Route de Narbonne, 31062 TOULOUSE CEDEX 4, France</footnote>

<footnote n="1">¹ Entomologie fonctionnelle et evolutive - Université de Liège, Gembloux Agro-Bio Tech, Passage des Deportes, 2 B-5030 Gembloux, Belgium</footnote>

<footnote>*Corresponding author: jc ngu@student.ulg.ac.be *Speaker</footnote>
## Poster 33
Are aphid vectors manipulated by plant virus?

Gabriella Caballero Vidal<fnref n="1" />, Quentin Fouche<fnref n="1" />, Quentin Chesnais<fnref n="1" />, Vincent Le Roux<fnref n="1" />, Aude Couty<fnref n="1" />, Veronique Ziegler-Gra<fnref n="2" />, Anas Cherqui*<fnref n="1" />, Veronique Brault<fnref n="3" />,<fnref n="4" />, Arnaud Ameline<fnref n="2" />*

Phytoviruses using insects as vectors can manipulate their host-plant or their insect vector for their own benefit. The indirect manipulation induces changes in host-plant phenotypes influencing the nature and the frequency of the host-plant/ vector interactions, promoting virus propagation. Conversely, the direct manipulation, described more recently, may lead to modifications of the vector behaviour, increasing the probability of colonization of non-infected plants by viruses. The purpose of this study was to investigate potential combined indirect and direct effects of a phytovirus on the behaviour of its vector in the pathosystem *Arabidopsis thaliana* / Turnip yellows virus (TuYV) / *Myzus persicae*. Non-viruliferous aphids exhibited no discrimination between odours of healthy or virus-infected plants, but their feeding behaviour was altered on virus-infected plants, showing an indirect effect of infected plant thus precluding any manipulation by the virus. On the other hand, viruliferous aphids exhibited no discrimination between healthy or virus-infected plants, but their feeding behaviour was negatively altered on healthy plants (compared with non-viruliferous aphids), showing a direct effect also precluding any manipulation by the virus. The only element in favour of manipulation was the increased intrinsic velocity of viruliferous aphids. To summarize, our results highlighted both indirect and direct effects of the virus on their host-plant and its vector respectively, but in these two situations virus manipulation was not involved because its dispersion was not promoted.

Keywords: *Arabidopsis thaliana*, Turnip yellows virus (TuYV), *Myzus persicae*, host plant, vector manipulation
*Speaker* Corresponding author: arnaud.ameline@u-picardie.fr

## Poster 34
Insect-pathogen interaction in oilseed rape (OSR): *Myzus persicae* increases susceptibility of *Brassica napus* to *Rhizoctonia solani* AG 2-1.

Fryni Drizou*<fnref n="1" />, Toby Bruce<fnref n="2" />, Neil Graham<fnref n="1" />

Crop plants are constantly exposed to a range of different attackers including plant pathogens and herbivorous insects. Each of them induces specific alterations in the host-plant, which potentially affect other organisms sharing the same host. *Brassica napus*, (oilseed rape, OSR), is the host of the necrotrophic soil-borne pathogen *Rhizoctonia solani* AG 2-1. Currently no resistant cultivar is available for AG 2-1 and it is unclear how the pathogen manipulates plant defences. Furthermore, OSR is one of the secondary hosts of *Myzus persicae*; a notorious aphid species with an impressive ability to adapt to plant-host defence mechanisms. The aim of the present work was to examine if there is an interaction between AG 2-1 and *M. persicae* and determine the role of the main plant-hormones in the interaction. Firstly, we assessed the effect of AG 2-1 inoculation on aphid performance by measuring aphid growth rate and population increase for a period of 7 days. Then we evaluated the effect of aphid infestation on OSR susceptibility to AG 2-1 by assessing disease symptoms in plant stems and quantifying fungal DNA in stems and soil 13 days post inoculation. We studied the expression of WAK1, NPR1, PR2, PR4, MYC2, LOX3 and WRKY38 genes involved in plant defences against *M. persicae* and/or necrotrophic fungi. Our results show that although there is no effect of AG 2-1 on aphid performance, *M. persicae* clearly and significantly alters the response of Canard plants to AG 2-1, making plants more susceptible. Although the amount of fungal DNA was not different between treatments within each cultivar, Canard plants exposed to aphid infestation had an almost two-fold increase in disease symptoms compare to control plants. Our findings suggest that aphids can have an immunosuppressive effect on plants that renders them more susceptible to pathogen attack.

Keywords: plant insect pathogen interaction, *B. napus*, *R. solani*, *M. persicae*
*Speaker* Corresponding author: fryni.drizou@nottingham.ac.uk

<footnote n="1">¹ Ecologie et Dynamique des Systèmes Anthropisés (EDYSAN), Université de Picardie Jules Verne, Amiens, France</footnote>

<footnote n="2">² Institut de Biologie Moléculaire des Plantes, CNRS-UDS, 67084 Strasbourg, France</footnote>

<footnote n="3">³ Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS: UMR7104, Inserm: U964, université de Strasbourg, Parc D'Innovation, 1 Rue Laurent Fries - BP 10142 67404 ILLKIRCH CEDEX, France</footnote>

<footnote n="4">⁴UMR 1131 SVQV INRA-UDS, Institut national de la recherche agronomique (INRA), UMR1131, 28 rue de Herrlisheim, 68021 Colmar, France</footnote>

<footnote n="1">¹ The University of Nottingham (UoN), Division of Plant and Crop Sciences, School of Biosciences, Sutton Bonington Campus, Loughborough, Leicestershire, United Kingdom</footnote>

<footnote n="2">² Keele University, School of Life Sciences, Keele, Staffordshire, United Kingdom</footnote>
## Poster 35
Using dsRNA of the BtGST2 Detoxification Gene to Develop *Bemisia tabaci* Resistant Plants

Galit Eakteiman *<fnref n="1" />*, Pnina Moshitzky *<fnref n="1" />*, Rita Mozes-Koch *<fnref n="1" />*, Osnat Malka *<fnref n="1" />*, Natividad Mestre-Rincon *<fnref n="1" />*, Shai Morin *<fnref n="1" />*

*Bemisia tabaci*, the sweet-potato whitefly, is one of the most devastating pests worldwide, causing enormous economical lost in agriculture. As other phloem-feeding insects, *B. tabaci* is mainly controlled by synthetic insecticides. Insecticide resistance is one of the major problems agriculture faces nowadays and developing alternatives to insecticides is necessary. As a highly polyphagous pest, *B. tabaci* utilizes an induced general detoxification system capable of dealing with a broad range of plant toxins. Our main goal was to develop an RNA interference technology that will allow the production of pest-resistant crops capable of silencing insect detoxification genes.

Artificial feeding assay was performed by exposing *B. tabaci* adults to double-strand (ds) RNA of the BtGST2 (dsBtGST2) gene, a known general detoxifier in *B. tabaci*. In addition, transgenic *Arabidopsis thaliana* plants expressing dsBtGST2 under a phloem specific promoter were produced and feeding and development assays were conducted. Finally, gene expression, in all the experiments, was analyzed by Real Time PCR.

Artificial diet showed significant down-regulation in BtGST2 gene expression in the mid-gut of adults compared to the control group. Individuals developing on transgenic *A. thaliana* plants showed significant developmental delay when compared to those developing on wild type (WT) plants. In parallel, BtGST2 gene expression in the mid-gut showed significant down-regulation in individuals fed on transgenic plants compared to individuals fed on WT plants. Slowing the development of *B. tabaci* on host plants by RNAi can increase the efficiency of its control by natural enemies, which will lead to minimizing the use of synthetic insecticides. Future experiments will assess the influence of combined down-regulation of two detoxification genes (BtGST2 & BtCYP6like5 ) on the ability of *B. tabaci* to utilize plant hosts.

Keywords: *Bemisia tabaci*, RNAi, detoxi cation, BtGST2, transgenic plants

Speaker*

## Poster 36
Antibiotic treatment of *Pieris brassicae* attenuates egg-mediated anti-herbivore defenses in two brassicaceous species

Luis R Paniagua Voirol *<fnref n="1" />*, Vivien Firtzla<fnref n="1" />, Georgios Valsamakis<fnref n="1" />, Arne Weinhold <fnref n="1" />, Reinhard Kunze <fnref n="1" />,
Nina Fatouros <fnref n="2" />, Monika Hilker<fnref n="2" />

Several plant species are known to improve their defense against herbivorous larvae when they have received insect egg depositions prior to larval attack, resulting in stronger detrimental effects on performance of insect larvae compared to egg-free plants (1, 2). Previous studies revealed some similarities of plant responses to insect eggs and phytopathogenic microbes. To test whether bacterial associates of the butterfly *Pieris brassicae* are involved in egg-mediated anti-herbivore defenses of *Arabidopsis thaliana* and *Brassica nigra*, butterflies were treated with antibiotics (AB) to reduce their microbial load. Transcript levels of defense genes and larval performance were determined in plants deposited with eggs of either AB-treated or untreated control females. Plants with eggs from AB-treated females showed lower expression levels of several phytopathogen-responsive genes than plants with control eggs. As expected, control larvae performed worse on plants with control eggs than larvae on egg-free plants. However, performance of control larvae on plants laden with eggs from AB-females was not reduced compared to performance of larvae on egg-free plants. Hence, the AB-treatment of butterfly parents attenuated the egg-mediated plant responses that lead to worse performance of larvae feeding on them. Our study indicates (i) that bacteria associated with *P. brassicae* can affect a plant's anti-herbivore defense and (ii) that the egg-mediated improvement of plant defense against larvae is linked with high transcript levels of plant genes known to respond to phytopathogens.

1. Hilker and Fatouros 2015. Annu. Rev. Entomol. 60: 493-515.

2. Hilker and Fatouros 2016. Curr. Op. Plant Biol. 32: 9-16.

Keywords: egg deposition, antibiotics, insect microbiome, *Pieris brassicae*, *Arabidopsis thaliana*, plant defense

Speaker* Corresponding author*: monika.hilker@fu-berlin.de

<footnote n="1">¹ Hebrew University of Jerusalem (HUJ), Jerusalem 91905, Israel</footnote>

<footnote n="1">¹ Institute of Biology, Dahlem Centre of Plant Sciences, Freie Universität Berlin, Germany</footnote>

<footnote n="2">² Wageningen University, Netherlands</footnote>
## Poster 37

# Dispersal capacity of *Monochmus saltuarius* (Gebler) (Coleoptera: Cerambycidae) on flight mills

Hyeok Jun Kwon <fnref n="1" />, Jong-Kuk Jung ²,<fnref n="1" />, Chansik Jung *<fnref n="1" />, Hye-Rim Han <fnref n="1" />, Sanghyun Koh <fnref n="1" />

The symptoms of pine wilt disease caused by the pine wood nematode (Bursaphelenchus xylophilus), which is recognized as a major forest pest. It was introduced into Korea in 1988, and two insect species, *Monochamus saltuarius* and *M. alternatus*, are known for vector of pine wood nematode. The pine wood nematode is transmitted by *M. saltuarius* to healthy Korean white pine (*Pinus koraiensis*). To understand and predict the spread of pine wilt disease in Korean white pine forests, we examined flight capacity of *M. saltuarius* using computer-linked flight mills in laboratory. Flight capability was individually measured during 30 minutes in each experiment, and repeatedly measured twice a week. In addition, we investigated the effects of age, sex, and biological characteristics (wing and body size) on flight performances of this vector insect. The variation of flight capability of *M. saltuarius* within population was high. And a maximum flight distance was about 4 km over the lifetime of the beetle. Flight performance was more frequently occurred in males than in females, but total distance was higher in females. The mean flight distance in female was highest in 7 days after emergence and decreased with aging, but those in males were not changed until at least 23 days after emergence.

**Keywords:** Flight capability, Pine wilt disease, Pine wood nematode

²*Corresponding author:* jk82811@korea.kr

*Speaker*

## Poster 38

# Phylogenetic farming: Can evolutionary history inform crop and insect management?

Ian Kaplan *<fnref n="1" />, Kathryn Ingerslew <fnref n="1" />

In agriculture, we rotate crops to avoid the buildup of host-specific pathogens that accumulate under single-species cultivation. Scientific guidelines for evaluating which crops are ideal for rotations are lacking, however, except for the common "rule" to avoid successive plantings in the same plant family. Thus, there is an implicit phylogenetic underpinning to rotations, but surprisingly this has never been explicitly tested in an agricultural context. We use a plant-soil feedback framework to test how relatedness affects the strength of soil legacies of one plant on another. Further, we evaluated how this soil-mediated microbial factor impacted insects feeding aboveground. To do so, we conditioned field-collected soil using 36 common crops and agricultural weeds that varied along a phylogenetic spectrum in relatedness to our focal plant, tomato. After a 10 week conditioning period, this soil was used as inoculum to germinate tomato seedlings, on which we assessed plant growth and the performance of hornworm caterpillars (*Manduca sexta*) feeding on leaves. We also used PLFA (phospholipid fatty acid) analysis on conditioned soil to simultaneously track responses in the soil microbial community as a potential explanatory factor. Overall, we found that tomato grows differently in varying soil types (P=0.0023), but this variation was not explained by phylogenetic relatedness among plant pairs (P=0.5762). Rather, plant-soil feedbacks on tomato were species- and family-specific; for example, plants in the Cucurbitaceae and Amaranthaceae had particularly negative impacts on tomato via the soil. Although a PCA of the soil microbial community predicted the strength of this feedback, the explanatory power was relatively weak (R2=0.0336). Caterpillar performance also varied depending on soil types, but as with plant responses was unrelated to phylogeny. As a result, we conclude that plant-soil feedbacks in agriculture should be tailored to specific interactions rather than using broad rules guided by evolutionary history.

**Keywords:** plant, soil feedback, phytobiome, phylodiversity, microbe, plant, insect interaction, crop rotation

*Speaker*

<footnote n="1">¹ National Institute of Forest Science (NIFoS), 57 Hoegi-ro, Dongdaemun-gu, Seoul 02455, South Korea</footnote>

<footnote n="1">¹ Department of Entomology, Purdue University, United States</footnote>
## Poster 39

# Fungal grass endophytes can influence host plant preference and fitness of a satyrine butterfly

Miika Laihonen *<fnref n="1" />, Marjo Helander <fnref n="1" />, Kari Saikkonen <fnref n="2" />, Toomas Tammaru <fnref n="3" />

Fungal endophytes belonging to genus Epichloe are commonly regarded as mutualists of cool-season grasses. The prevailing hypothesis states that such fungi are mutualists contributing to plants' anti-herbivory defenses. Defensive mutualism is attributable to fungal-origin alkaloids such as ergot alkaloids, indolediterpenoids, lolines and peramine. Ergot alkaloids and indolediterpenoids are most well known for their toxicity to vertebrates whereas lolines and peramine are strongly insecticidal. However, the literature testing the hypothesis of defensive mutualism is likely to be biased by the disproportional use of agricultural model systems. To test the hypothesis using a wild Epichloe endophyte-grass-herbivore model system we selected tall fescue (Schedonorus phoenix with E. coenophiala) and red fescue (Festuca rubra with E. festucae) as grass-endophyte models. As the model herbivore, we selected Coenonympha hero butterfly. All the species are native to Europe. Endophyte infection influenced both preference and performance of the herbivore. Ovipositing C. hero females were shown to respond to both chemical and physical cues in host selection. Both these cues appear to be modified by endophyte infection. Neonate larvae were found to be able to select fungus-free grasses, with some indication of better growth performance on such hosts. Nevertheless, the effect of endophyte infection on both preference and performance considerably varied between the host species. Our results thus support the defensive mutualism hypothesis only partly.

Keywords: fungal grass endophyte, host plant preference, symbiosis, fungal alkaloids, anti herbivory defense, insect herbivore

Speaker*

## Poster 40

# Induced resistance to thrips by bacterial infection

Kirsten Leiss*<fnref n="1" />, Gang Chen <fnref n="2" />, Peter Klinkhamer <fnref n="2" />

The pathogenic bacterium *Pseudomonas syringae* activates the jasmonic acid (JA) pathway producing the JA mimic coronatine (COR). In doing so it fools the plant by activating plant defence against insects although being itself a pathogen. We investigated whether infection of tomato with *P. syringae* leads to induced plant defence against herbivores using thrips (*Frankliniella occidentalis*), a key pest in agri- and horticulture worldwide, as a model. Inoculation of tomatoes with low concentrations of *P. syringae* led to a 50% systemically induced reduction of thrips damage 7 days after inoculation. Infected plants did not show bacterial symptoms nor reduced biomass. Likewise tomato plants treated with suspended medium, in which *P. syringae* had been grown but subsequently eliminated, as well as treatments of plants with COR led to substantial reductions in thrips damage. Polyphenol oxidase (PPO), a marker enzyme of the JA pathway was significantly increased in all treated plants. Likewise, metabolomic analysis of inoculated plants with nuclear magnetic resonance spectroscopy (NMR) showed significantly different metabolomes in comparison with the control. The avanoid Rutin substantially contributed to this difference being significantly increased in treated plants. Our results show that infection with low concentrations of *P. syringae* induces plant defence to thrips and thus constitutes a promising tool to reduce herbivore damage in crops.

Keywords: Induced resistance, thrips (*Frankliniella occidentalis*), bacteria (*Pseudomonas syringae*)

Speaker*

<footnote n="1">¹ University of Turku, Finland</footnote>

<footnote n="2">² Natural Resources Institute, Finland</footnote>

<footnote n="3">³ University of Tartu, Estonia</footnote>

<footnote n="1">¹ Plant Ecology and Phytochemistry, Institute of Biology, Leiden University (IBL), Sylviusweg 72, 2333 BE Leiden, Netherlands</footnote>
## Poster 41

# Strength in cooperation: bacterial symbionts help the insect host overcome plant defences

Valeria Mereghetti *<fnref n="1" />, Bessem Chouaia <fnref n="1" />, Alberto Spada <fnref n="1" />, Franco Faoro<fnref n="1" />, Giulia Magoga <fnref n="1" />, Matteo Montagna<fnref n="2" /> <fnref n="1" />

During their evolution, plants have developed a variety of morphological and biochemical traits to fend off herbivores, including insects. Production of secondary metabolites is one of the most important plant biochemical defense mechanisms. In our study system, *Aconitum napellus* (Ranunculales: Ranunculaceae) produces alkaloids, such as aconitine and nepaline, which are extremely toxic to animals. Despite their high toxicity, the leaf beetle *Galeruca laticollis* (Coleoptera: Chrysomelidae) is able to feed and complete its life cycle on this plant. Up to date, the mechanisms by which the insect is able to withstand such high toxicity are not understood. In this study, we investigate the possible involvement of bacterial symbionts in this resistance phenotype. Exploring the gut microbiota of *G. laticollis* using 16S rRNA gene sequencing we identified potential candidates among which bacteria belonging to the genus Pseudomonas. After strain isolation, the ability to degrade this alkaloid was tested *in vitro* with kinetic experiments. This confirmed one Pseudomonas strain as the most efficient degrader among the isolated strains. Furthermore, Pseudomonas sp. activity was tested *in vivo*, using *Drosophila melanogaster* as a model. We were able to confirm that Pseudomonas sp establishes a beneficial symbiosis with their hosts and validate their key role in aconitine-degradation in *D. melanogaster*. We also investigated the genetic determinants of this degradative ability of the bacteria. The obtained results provide further evidence regarding the mechanisms by which insects are able to resist toxic molecules (plant secondary metabolites or insecticides) through the evolution of beneficial symbioses with bacteria.

Keywords: Insect, plant interaction, herbivory, Coleoptera, symbiosis

*Speaker*<fnref n="2" /> *Corresponding author:* matteo.montagna@unimi.it

## Poster 42

# The role of the *Pieris brassicae* microbiome during a host-plant shift

Luis R Paniagua Voirol*<fnref n="1" />, Nina Fatouros <fnref n="2" />, Paul Johnston <fnref n="3" />, Monika Hilker <fnref n="1" />

Insect dietary behavior is well known as one of the most important factors shaping bacterial gut communities. However, it is only until recently that the role of gut bacteria in facilitating diet shifts by insects is being explored. Here, we investigated the impact of the microbiome of *Pieris brassicae* on the performance of larvae feeding on a host plant species that differs from that of their parents. In nature, this multivoltine lepidopteran species often shows a host shift from one generation to the next because of the plant's short life time. In a first experiment, we directly treated larvae with antibiotics and evaluated their performance on either, the parental diet or an alternative one, in comparison to untreated larvae feeding such diets. In a second experiment, and in order to discard antibiotic-related side effects, we treated *P. brassicae* for one generation with antibiotics and then used their (untreated) offspring for the same assessments. For both experiments we found a negative effect of the antibiotic treatment on larval biomass only when larvae were exposed to another diet than their parents. No effect was detected when larvae fed on the parental diet. PCR of the 16S rRNA gene showed a clear inhibition of bacteria present in antibiotic treated individuals, and preliminary sequencing analysis showed a significant disturbance of the bacterial community composition due to the treatment. Our results suggest a beneficial role of the *Pieris brassicae* microbiome only evident when the insect feeds on a host plant not experienced by the parental generation.

Keywords: Plant, insect, microbe interactions, gut microbiome, Brassicaceae, antibiotics, bacteria

Speaker*

<footnote n="1">¹ Department of Agricultural and Environmental Sciences, University of Milan (DISAA), via celoria 2, Milano, Italy</footnote>

<footnote n="1">¹ Institute of Biology, Dahlem Centre of Plant Sciences, Freie Universität Berlin (FU Berlin), Germany</footnote>

<footnote n="2">² Biosystematics group, Wageningen University (WUR), Netherlands</footnote>

<footnote n="3">³ Berlin Center for Genomics in Biodiversity Research (BeGenDiv), Austria</footnote>
## Poster 43

# Learning in two butterfly species when using flowers of the tropical milkweed *Asclepias curassavica*: no benefits for pollination

Bruna De Cassia Ramos <fnref n="1" />, Miguel Rodriguez-Girones <fnref n="2" />, Daniela Rodrigues * <fnref n="1" />

The ability of visitors to learn to manipulate complex flowers has important consequences for foraging efficiency and plant fitness. We investigated learning by two butterfly species, *Danaus erippus* and *Heliconius erato*, as they forage on the complex flowers of *Asclepias curassavica*, as well as consequences for pollination. To examine learning with respect to flower manipulation, butterflies were individually tested during four consecutive days under insectary conditions. At the end of each test we recorded the number of pollinaria attached to the body of each butterfly and scored visited flowers for numbers of removed and inserted pollinia. We also conducted a field study to survey *D. erippus* and *H. erato* visiting flowers of *A. curassavica*, as well as to record numbers of pollinaria attached to the butterflies' body, and surveyed *A. curassavica* plants in the eld to inspect owers for pollinia removal and insertion. Learning improves the ciency of both butter y species in locating and extracting nectar of *A. curassavica* flowers. There were no learning effects for either species on the number of removed and inserted pollinia. *Heliconius erato* removed and inserted more pollinia than *D. erippus*. For both butterfly species, pollinia removal was higher than pollinia insertion. This study is the first to show that Danaus and Heliconius butterflies can learn to manipulate complex flowers, but this learning ability does not confer benefits to pollination in *A. curassavica*.

Keywords: Asclepias, complex flowers, Danaus, flower visiting, Heliconius, learning, pollination
*Corresponding author: ramos.bcm@gmail.com*

*Speaker

## Poster 44

# Sweet Pepper-Thrips Interaction: Uncovering dynamics of the plant defense-signaling network to identify novel leads for maximizing crop protection

Sandeep Sarde *<fnref n="1" />, Merel Steenbergen <fnref n="2" />, Richard Hickman <fnref n="2" />, Saskia Wees <fnref n="2" />, Corne Pieterse <fnref n="2" />, Marcel Dicke <fnref n="2" /> <fnref n="1" />

Insect pest attack can seriously hinder plant development, reducing crop productivity and triggering further agronomic problems. Thrips are minute cell-content-feeding insects that are a major pest in many ornamental and vegetable crops. Additionally, they are also important vectors of viral plant pathogens. The objective of this study is to investigate at high temporal resolution the dynamics of the defense-signaling network of Arabidopsis and sweet pepper plants during their interaction with western flower thrips (*Frankliniella occidentalis*). To answer this, we monitored the early dynamics of the transcriptome of pepper using RNA-sequencing followed by advanced bioinformatical analysis. Advanced bioinformatical analysis includes co-expression analysis, promoter/motif analysis and building detailed gene regulatory network using different tools. Using a greenhouse setup, we collected leaf samples from infested and non-infested plants, and subjected these to RNA sequencing. This approach generates profound knowledge into highly accurate gene regulatory networks with unprecedented details and allows us to make models of plant immune signaling sectors with which we can predict and validate novel key regulators of plant defense against thrips. To elucidate the role of jasmonates in defense of pepper upon thrips feeding, we targeted CaLOX2, known to be involved in biosynthesis of jasmonic acid (JA), for silencing by Viral-Induced Gene Silencing (VIGs). For CaLOX2 -silenced pepper plants we assessed JA accumulation upon thrips feeding, susceptibility to thrips, and thrips host selection behaviour. These experiments were complemented with studies of the effects of exogenous JA application. In conclusion, this work unravels plant-signaling networks underlying defences against western ower thrips and specific pathways involved in such defences. This will be instrumental in finding new ways to combat thrips in pepper crops.

Keywords: Thrips, Sweet pepper, Transcriptome, Signalling network, Plant Defense, Genes
*Speaker <fnref n="2" />* *Corresponding author: marcel.dicke@wur.nl

<footnote n="1">¹ Universidade Federal do Rio de Janeiro (UFRJ), Brazil</footnote>

<footnote n="2">² Estacion Experimental de Zonas Aridas (EEZA/CSIC), Spain</footnote>

<footnote n="1">¹ Wageningen University (WUR), Laboratory of Entomology, P.O. Box 8031, NL-6700 EH Wageningen, Netherlands</footnote>

<footnote n="2">² Utrecht University - UU, Plant-Microbe Interactions, Department of Biology, Utrecht University, P.O Box 800.56 3508 TB, Utrecht, Netherlands</footnote>
Poster 45

# Developmental and reproductive performance of a specialist herbivore depend on seasonality of, and light conditions experienced by, the host plant

Osariyekemwen Uyi *<fnref n="1" />½, Costas Zachariades ¹³, Martin Hill <fnref n="4" />

Seasonal and light-modulated changes in the phenotypic and phytochemical properties of leaves have been hypothesised to equivocally influence insect herbivore performance. Here, we examined the effects of seasonality (autumn versus winter) and light environment (shade vs full-sun habitat) on the leaf characteristics of the invasive alien plant, *Chromolaena odorata* (L.) King and Robinson (Asteraceae). In addition, the performance of a specialist folivore, *Pareuchaetes insulata* (Walker) (Lepidoptera: Erebidae), feeding on leaves obtained from both shaded and full-sun habitats during autumn and winter, was evaluated over two generations. Foliar nitrogen and magnesium contents were higher on shaded plants during winter while leaf toughness was noticeably higher on full-sun plants during winter. Leaf water content was higher on plants in autumn compared to winter. Irrespective of season, shaded leaves had higher nitrogen, magnesium, carbon, potassium, water and lignin contents compared to full-sun ones. Non-structural carbohydrate and phosphorus contents were higher in full-sun leaves in both autumn and winter. *Pareuchaetes insulata* developed faster and had larger pupal mass, increased growth rate and higher fecundity when reared on shaded foliage (relative to full-sun) or when reared on autumn leaves compared to leaves of plants growing in winter. Although egg hatchability and mating success did not differ between seasons and between habitats, Maw's host suitability index (HSI) indicated that shaded leaves during autumn were more suitable for the growth and reproduction of *P. insulata*. This study demonstrates that seasonality and light environment can indirectly affect insect folivore performance in ways that are less straightforward.

Keywords: *Pareuchaetes insulata*, invasive alien weed, *Chromolaena odorata*, sunlight, autumn, winter, leaf characteristics, herbivore performance, insect, plant interactions

*Speaker Corresponding author: osariyekemwen.uyi@uniben.edu*

Poster 46

# Earthworms indirectly mediate plant-herbivore interaction via changes in soil nutrient composition and plant chemical traits

Zhenggao Xiao *<fnref n="1" />½, Linhui Jiang ³¹, Xiaoyun Chen ¹³, Emmanuel Defossez <fnref n="2" />, Manqiang Liu ¹³, Feng Hu ¹³, Sergio Rasmann <fnref n="2" />

How plants cope with herbivore attack is partially dictated by the biotic and abiotic environment where the plant lives. For instance, plants growing in richer soil may grow bigger and produce more nutritious leaves, but at the same time, might allocate more resources to defence production. Soil fauna earthworms, by their borrowing and casting activities, are known to favour soil nutrient availability. Earthworms could thus indirectly modify plant-herbivore interaction by modifying plant growth and chemical composition. We tested this hypothesis using tomato plants attacked by one of the major greenhouse pests, the western ower thrips (*Frankliniella occidentalis*), and which were inoculated with single earthworm species and a mix of two earthworm species that differ in their ecological functions. We found that earthworm presence significantly affected soil biochemical properties, and overall, they enhanced plant growth and the concentration of leaf soluble amino acids and sugars. Nonetheless, we found variation in the results, which was driven by species-specific variation in the earthworm ecological types and functional diversity. Meanwhile, earthworm presence significantly increased the concentration of leaf defence-related hormone jasmonic acid, as well as the concentration of phenolics. Taken together, this resulted in earthworm presence near the roots to decrease thrips abundance. These results were corroborated using structural equation modelling, indicating that, independently of earthworm species, earthworm presence significantly increased plant growth and chemical defences, and in turn suppressed thrips abundance mainly through the increase of plant chemical defences. These results strongly build towards a better understanding of the earthworm functional roles in the ecosystems, and how they could be integrated into ecologically sound pest control programs.

Keywords: Earthworm ecological type, functional diversity, western ower thrips, bottom, up force, soil nutrient, plant defence

Speaker*

<footnote n="1">¹ Agricultural Research Council, Plant Protection Research Institute (ARC-PPRI), Private Bag X6006, Hilton 3245, South Africa</footnote>

<footnote n="2">² Department of Animal and Environmental Biology, University of Benin (UNIBEN), P.M.B. 1154, Benin City, Nigeria</footnote>

<footnote n="3">³ School of Life Sciences, University of KwaZulu-Natal (UKZN), Private Bag X01, Scottsville 3209, South Africa</footnote>

<footnote n="4">⁴ Department of Zoology and Entomology, Rhodes University (RU), P.O. Box 94, Grahamstown 6140, South Africa</footnote>

<footnote n="1">¹ College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China</footnote>

<footnote n="2">² Institute of Biology, University of Neuchâtel, Neuchâtel 2000, Switzerland</footnote>

<footnote n="3">³ Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210014, China</footnote>
## Poster 47

# Herbivore-induced plant volatile blends are influenced by plant nutrition

Christine Becker *<fnref n="1" />, Peng Han <fnref n="1" />, Mateus Ribeiró De Campos <fnref n="1" />, Eva Thomine <fnref n="1" />, Philippe Béarez <fnref n="1" />, Edwige Amiens <fnref n="1" />, Christiane Metay-Merrien <fnref n="1" />, Richard Brun <fnref n="1" />, Stéphane Adamowicz <fnref n="2" />, Nicolas Desneux <fnref n="1" />, Xavier Fernandez <fnref n="3" />, Thomas Michel <fnref n="3" />, Anne-Violette Lavoir <fnref n="1" />,<fnref n="3" />

Due to climate change, dry regions like the Mediterranean face increasing water limitation; nitrogen leaching risks eutrophication. While resource input into agricultural systems has to be optimized, crop production has to stay feasible. In plants, nitrogen and water are involved in basic physiological processes and at the same time linked to defense compound production. Additionally, studies indicate that their availability influences the blend of volatile organic compounds (VOC) emitted by plants. When attacked, plants emit a specific blend of herbivore-induced plant volatiles (HIPV) which can be perceived by natural enemies of the respective herbivores. Constitutively emitted VOC blends can be affected by abiotic factors. If HIPV blends are likewise impacted, this indirect plant defense strategy could be impeded. Using solid-phase micro extraction (SPME) fibers we have collected volatile compounds from tomato plants (*Solanum lycopersicum*) receiving moderately reduced water and/or nitrogen, before and during infestation with one of two sap-feeding (*Macrosiphum euphorbiae* and *Bemisia tabaci*) or one of two leaf-chewing herbivore species (*Tuta absoluta* and *Spodoptera littoralis*). Compounds were analyzed via GC-MS, chromatograms evaluated via XCMS online, and results analyzed via MetaboAnalyst 3.0. We detected significant effects of the plant nutrient solution on HIPV, especially regarding blends emitted by plants infested by sap-feeders, and on constitutive volatile blends emitted before infestation. Additionally, principal component analysis indicates that leaf-chewer HIPV blends differ more from constitutive volatiles than sap-feeder associated HIPV. Our results suggest a bottom-up effect of plant nutrient solution on indirect plant defense, especially against sap-feeders. HIPV blends associated to leaf-chewers appear to be less susceptible to changes caused by abiotic factors. Indirect defense against leaf-chewers might be under higher selective pressure for resilience due to their higher potential to cause massive damage to the plant compared to sap-feeders.

Keywords: herbivore induced plant volatiles, HIPV, VOC, *Macrosiphum euphorbiae*, *Bemisia tabaci*, *Spodoptera littoralis*, abiotic factor, nitrogen, water. Speaker*

## Poster 48

# Disease in bloom - exploring the link between pollination and phytopathology

Mascha Bischoff *<fnref n="1" />, Kerstin Zikeli <fnref n="2" />, Andreas Jürgens <fnref n="3" />, Jürgen Gross <fnref n="2" />

Like all organisms, plants do not exist in isolation but interact with their environment in a multitude of ways. Plant signalling via secondary metabolites, e.g. volatile organic compounds (VOCs), is thus indispensable. Plant VOCs have been well-studied in the context of tri-trophic (plant-herbivore-natural enemy) interactions and as mediators of plant-pollinator interactions. However, the dynamic nature of oral VOC emissions and the potential for VOC bouquet shifts in response to environmental stimuli and stressors have been largely ignored to date. Among the many potential hazards are plant pathogens, often associated with severe consequences for plant survival and fitness. For instance, the two most severe diseases in pome and stone fruit growing areas, apple proliferation (AP) and European stone fruit yellows (ESFY), are caused by phytoplasma pathogens (Candidatus *Phytoplasma mali* and Ca. *P. prunorum*, respectively). Although fruit crop failure and the effects of phytoplasma infection on fruit development are well-documented, impacts on oral phenotype (e.g. flower colour, scent and nectar), and in turn pollinator behaviour, are unknown. Here, we propose the fruit tree - phytoplasma - bee pollinator model to explore tri-trophic interactions at the vital pollination stage. We compared the nectar and oral VOC bouquets of healthy apple flowers with those infected with phytoplasma strains Ca. *P. mali* 3/6 and 12/93. Moreover, we tested flowers of AP- and ESFY-infected trees for phytoplasma presence in oral tissue and nectar. PCR results confirmed phytoplasmas in petals and young shoots. The sucrose concentration in nectar did not differ between treatments. However, there is evidence for shifts in the oral VOC bouquets in response to infection. Thus, changes in oral phenotype may potentially influence pollinator behaviour and pollination success. Our model allows us to explore fundamental questions on ecological interactions under stress as well as pressing matters on plant and pollinator health and food security.

Keywords: pollination, phytopathology, phytoplasma, apple proliferation, European stone fruit yellows, *Malus domestica*, oral VOCs. Speaker*

<footnote n="1">¹ Institut Sophia Agrobiotech [Sophia Antipolis] (ISA) Institut national de la recherche agronomique (INRA) : UMR1355, Université Nice Sophia Antipolis (UNS), CNRS : UMR7254 INRA Centre de recherche Provence-Alpes-Côte d'Azur, 400 route des Chappes, BP 167, 06903 Sophia Antipolis Cedex, France</footnote>

<footnote n="2">² Unité Plantes et Systèmes de Culture Horticoles (PSH) Institut national de la recherche agronomique (INRA) : UR1115 Domaine St-Paul, site Agroparc 84914 Avignon cedex 9, France</footnote>

<footnote n="3">³ Université Côte d'Azur CNRS : UMR7272 Institut de Chimie de Nice, Parc Valrose, 06108 Nice Cedex 2, France</footnote>

<footnote n="1">¹ TU Darmstadt, Plant Chemical Ecology Schnittspahnstrasse 10 64287 Darmstadt, Germany</footnote>

<footnote n="2">² Julius Kühn-Institut (JKI), Bundesforschungsinstitut für Kulturpflanzen, Germany</footnote>

<footnote n="3">³ TU Darmstadt, Germany</footnote>
## Poster 49

# A herbivore tag-and-trace system reveals contact and density-dependent repellence of a root toxin

Zoe Bont*<fnref n="1" />, Carla Arce<fnref n="1" />, Meret Huber<fnref n="2" />, Wei Huang<fnref n="1" />, Adrien Mestrot<fnref n="3" />, Craig Sturrock<fnref n="4" />, Matthias Erb²¹

Foraging behaviour of root feeding organisms strongly affects plant-environment-interactions and ecosystem processes. However, the impact of plant chemistry on root herbivore movement in the soil is poorly understood. Here, we apply a simple technique to trace the movement of soil-dwelling insects in their habitat without disturbing or restricting their interaction with host plants: We tagged the root feeding larvae of *Melolontha melolontha* with a copper ring and repeatedly located their position in relation to their preferred host plant, *Taraxacum officinale*, using a commercial metal detector. This method was validated and used to study the influence of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) on the foraging of *M. melolontha*. TA-G is stored in the latex of *T. officinale* and protects the roots from herbivory. Using behavioural arenas with TA-G deficient and control plants, we tested the impact of physical root access and plant distance on the effect of TA-G on *M. melolontha*. *M. melolontha* larvae preferred TA-G deficient plants over control plants, but only when physical root contact was possible and the plants were grown at a distance of 5 cm. *M. melolontha* showed no preference for TA-G deficient plants when the plants were grown 15 cm apart, which may indicate a trade-off between the cost of movement and the benefit of consuming less toxic food. We demonstrate that *M. melolontha* integrates host plant quality and distance into its foraging patterns and suggest that plant chemistry affects root herbivore behaviour in a plant-density dependent manner.

Keywords: Root herbivore, foraging, imaging, *Melolontha melolontha*, *Taraxacum officinale*

*Speaker* <fnref n="2" />*Corresponding author:* matthias.erb@ips.unibe.ch

## Poster 50

# Can we use semiochemicals to control *Aphis craccivora* Koch?

Sandrine Mariella Bayendi Loudit ²¹:<fnref n="2" />, Boni Barthelemy Yarou<fnref n="2" />, <fnref n="1" />, Antoine Boullis <fnref n="1" />, <fnref n="2" />, Francois J. Verheggen <fnref n="1" />, Frédéric Francis <fnref n="1" />

*Amaranthus hybridus* L. (Amaranthaceae) is among the most important vegetable crop in several sub-Saharan countries. *Aphis craccivora* Koch (Homoptera: Aphididae) is an aphid species that cause significant losses in absence of chemical control. In this laboratory research, we evaluate the efficiency of informative substances (E-β-farnesene, methyl salicylate, essential oil of *Ocimum gratissimum* L. and *Ocimum basilicum* L.) to repel aphids from their host plant. Our assays were carried out in plastic trays containing twenty-five amaranth plants. In each tray, twenty apterous *A. craccivora* adults were placed on the central plant (release plant) associated with a semiochemical releaser containing 100 µl of the substance to be tested diluted in paraffin oil. The number of aphids was then counted on each plant surrounding plants every three-days for twelve days.

We observed a significant repulsive effect of *O. gratissimum* and *O. basilicum* essential oils, that considerably reduced the aphid population on the treated plant, compared to control. However, no repulsive effect of E-β-farnesene and methyl salicylate on aphids was observed. Bioactivities of these substances and their using as alternative aphicidal in integrated pest management are discussed.

Keywords: Amaranth, Natural substances, Cowpea aphid, Pest control

²*Corresponding author:* entomologie.gembloux@ulg.ac.be *Speaker

<footnote n="1">¹ Institute of Plant Sciences, University of Bern (IPS), Switzerland</footnote>

<footnote n="2">² Department of Biochemistry, Max-Planck Institute for Chemical Ecology, Germany</footnote>

<footnote n="3">³ Institute of Geography, University of Bern (GIUB), Switzerland</footnote>

<footnote n="4">⁴ Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, United Kingdom</footnote>

<footnote n="1">¹ Entomologie fonctionnelle et évolutive - Université de Liège, Gembloux Agro-Bio Tech, Passage des Déportes, 2 B-5030 Gembloux, Belgium</footnote>

<footnote n="2">² Institut de recherches agronomiques et forestières, BP 13260, Libreville, Gabon</footnote>
# Poster 51
## Soil wars: biological alternatives to pesticides to control wireworms

Diana La Forgia¹, Antoine Boullis *¹, Francois Verheggen¹

¹ Entomologie fonctionnelle et évolutives - Université de Liège, Gembloux Agro-Bio Tech, Passage des Déportés, 2 B-5030 Gembloux, Belgium

Most of the studies on plant-insect interactions focus on the aboveground parts of the plant while belowground interactions are less explored. Yet, soil pests are equally dangerous for plant fitness and can interact with the aboveground pests and plant defenses. Amongst them, wire-worms (Coleoptera: Elateridae) are common polyphagous soil pests of various crops, including maize and potatoes, inflicting severe economic damage. Their management with pesticides is often not successful or sustainable, and more research on biological alternatives is required. One of them is to use traps baited with attractive volatile organic compounds (VOCs) and a microbial control agent. To achieve this general objective we defined four specific directions to follow: 1) developing a behavioral assay suitable for the study of wireworm orientation behavior; 2) profiling VOCs released in the rhizosphere of potato; 3) evaluating the role of the identified VOCs on wireworms foraging behavior; 4) developing a monitoring trap based on the previously identified VOCs, and associated with the entomopathogenic fungi *Metarhizium anisopliae* Sorokin (Hypocreales: Clavicipitaceae) to be tested in the laboratory and in the field. We will also evaluate the impact of larval development on the perception and orientation behavior toward host plant and specific VOCs released in the rhizosphere.

Keywords: Soil insect pests, indirect defense, biological control, semiochemicals, integrated pest management, microbial control.

Corresponding author: diana.laforgia@doct.ulg.ac.be

*Speaker

# Poster 52
## Cellulases in phytophagous beetles: Characterization and molecular evolution of family 45 glycoside hydrolases in leaf beetles and weevils

Andre Busch*¹, David Heckel¹, Yannick Pauchet²¹

¹ Max Planck Institute for Chemical Ecology, Germany

Cellulose is a polysaccharide made of glucose units. It could provide a potentially rich source of energy for plant feeding organisms except for the fact that it is recalcitrant to enzymatic breakdown. For a long time, it had been believed that only cellulolytic microorganisms were able to digest cellulose. Recent studies have revealed that genes encoding putative cellulases of several glycoside hydrolase (GH) families were present in genomes of various metazoans, such as nematodes and arthropods. Our previous work indicated that putative cellulases belonging to the GH45 family were present in beetles of the Chrysomeloidea (leaf beetles and longhorned beetles) and Curculionoidea (weevils and bark beetles).

My work aims to address whether GH45s are indeed true cellulases or whether they have evolved other functions. I also investigate their evolutionary history and their biological relevance. My current hypothesis is that these cellulases have been originally acquired by beetles through horizontal gene transfer (HGT).

Heterologous expression in cultured insect cells and several enzymatic assays allowed me to identify 13 cellulases and, interestingly 10 xyloglucanases (active on xyloglucan, the most abundant hemicellulose polysaccharide in primary plant cell wall) out of a total of 34 GH45s. The remaining 11 GH45s showed no activity on any substrate I tested. RNAi experiments suggested that in these beetles, the breakdown of cellulose is rather accessory and facilitates the access to the nitrogen-rich cell content.

According to our phylogenetic analyses, we hypothesize that this gene family has evolved from originally two genes present in the last common ancestor of the Chrysomeloidea and the Curculionoidea followed by gene duplication events which lead to a differing number of GH45 genes in each species. Interestingly, a cluster of orthologs in the Chrysomelidae shows single activity towards xyloglucan. Still under investigation is whether GH45s in beetles were acquired by HGT.

Keywords: Chrysomelidae, Curculionoidea, Glycoside hydrolase, Cellulase, Endoglucanase, Xyloglucanase, Plant cell wall degrading enzymes

Speaker* Corresponding author: ypauchet@ice.mpg.de
## Poster 53
Terpene chemotypes and interactions with insect herbivores

Carlos Bustos Segura<fnref n="1" />

Chemical polymorphisms or chemotypes are found across several plant families, in particular related to terpene composition. The Australian tea tree (*Melaleuca alternifolia*) presents terpene chemotypes based on its foliar composition, however there is little knowledge on the relevance of this intraspecific variation for ecological interactions that can be useful for pest management or genetic conservation efforts. I investigated how these chemotypes affect interactions with specialized herbivore beetles in laboratory and field conditions, and the intraspecific variation in volatile emissions. I found that the most common beetle (*Paropsisterna tigrina*) shows a preference for local chemoyp types at the adult stage, but larvae are not affected by chemotypic variation. A rarer species (Faex sp.) shows different oviposition preference to chemotypes that depends on the larval diet. Terpene emissions also show intraspecific variation based on the foliar composition, while herbivory increases the emissions. Overall, I found that chemotypes influence specialized herbivores to some degree and that chemical variation in leaves extend to other plant traits.

Keywords: chemical ecology, terpenes, chrysomelidae, chemical variation, plant volatiles

## Poster 54
Ecological study of pistachio bark beetle, *Chaetoptelius vestitus* Muls & Rey
(Coleoptera: Curculionidae)

Ibtihel Ghrissi *<fnref n="1" />, Mohamed Braham <fnref n="1" />, Imen Said <fnref n="2" />

The pistachio bark beetle, *Chaetoptelius vestitus* (Muls & Rey) (Coleoptera, Curculionidae, Scolytinae) is a serious pest of pistachio trees in Tunisia. Despite its phytosanitary importance, some aspects of its population dynamic are still unclear. In this study, we investigated the population fluctuations of *C. vestitus* between 2013 and 2016. The distribution of *C. vestitus* was also investigated both in the center and south of Tunisia. We recorded the direct damage caused by beetle on pistachio branches and buds. The highest pistachio bark beetle population density (for all developmental stages) was detected in Elguettar (*Gafsa goveronarate*). This bark beetle overwinters in larval stage on pistachio trees. The adults emerge to attack new suitable trees at mid-February. We found that the sex ratio of beetles recovered from pistachio buds and branches was approximately 1:1 at all experimental sites, and this trend did not vary seasonally. Reproduction starts in autumn, and the copulation takes place at the entrance hole. It was found that females initiated egg tunnel construction copulation takes place either on the bark in the initial phase of egg tunnel construction or inside the tunnel system. Mean achieved fecundity was 50.95 (+/- 9.68 SD) eggs/ female. The colonization process occurs in two phases; during the first phase, the construction of feeding galleries drilled through the buds, in the second phase reproduction galleries are constructed in the thickened branches of the tree. The results obtained in this work are considered essential for developing optimal control of the pest.

Keywords: *Pistacia vera* L., population dynamic, fecundity, colonisation, Tunisia.
*Speaker*

<footnote n="1">¹ Université de Neuchâtel, Switzerland</footnote>

<footnote n="1">¹ Entomological Laboratory, Regional Center of Research in Horticulture and Organic Agriculture, Chott-Mariem Sousse, Tunisia</footnote>

<footnote n="2">² Faculty of Science, City Zarroug, Gafsa, Tunisia</footnote>
Poster 55

# The relationship between ant abundance and leaf biomass in ant-inhabited *Macaranga pearsonii* in human-modified landscapes in SE Asia

Mickal Houadria*<fnref n="1" />, Tom Fayle <fnref n="1" />

One of the most diverse mutualistic interactions occurring in SE Asia is between Macaranga trees and Crematogaster ants. These early succession trees, often comprising the majority of individuals in disturbed habitats, are ecologically important because they potentially provide shade for late-succession trees. However, little is known about how plant fitness is affected by the identity of their ant mutualists and how this varies across anthropogenically modified landscapes. *Macaranga pearsonii* is a frequently encountered species in both oil palm plantations and logged forest, which could potentially play an important role in the future restoration of these sites. This role might be altered by changes in the mutualistic relationship between ants and plants during habitat degradation. Here we analyse the relationship between ant occupation and herbivory damage of these plants, and compare a degraded habitat where severe logging has occurred but where *Macaranga pearsonii* density is very high with oil palm plantation, where densities are lower. Over 40 trees (0.5m to over 6.5m) were collected and dissected in each habitat. We quantified ant and coccid abundance in each branch as well as leaf biomass. We controlled for environmental factors including soil phosphate, nitrate, pH, soil density and canopy cover that may also influence plant fitness. Additionally we considered specific aspects of the mutualism relating to plant fitness such as ant patrolling and herbivory damage. We demonstrate that depending on the habitat the relation between ant abundance and herbivory is not always positively correlated. Other factors such as ant species identity, the number of colonising queens and how many different species simultaneously occupy the same tree influence the herbivory damage of plants, which may differ in relation to the habitat.

Keywords: herbivory damage, ants, oil palm, logged forest, mutualism, Macaranga, south east Asia
*Speaker*

Poster 56

# The consequence of plant domestication for resistance against insects: testing the role of the plant-breeding target

Charlyne Jaccard *<fnref n="1" />, Maximilien Cuny <fnref n="1" />, Betty Benrey² <fnref n="1" />

Plant domestication has generally resulted in decreased chemical and physical defense in crop plants compared to their wild ancestors. A reduction in plant defensive traits is often expected to result in increased insect performance. However recent studies have shown that this pattern is not ubiquitous.

The reason for this may lie in the purpose or the organ targeted by domestication. Such that, a positive relationship between reduction in plant defense and increased insect performance will be only, or more evident for cultivars and plant organs that have been selected for consumption.

To test this hypothesis we used wild accessions and cultivated varieties of squash (genus Cucurbita) and larvae of three generalist herbivores: *Spodoptera frugiperda*, *Spodoptera eridania* (leaf-feeding herbivores) and *Diabrotica balteata* (root-feeding herbivore). We chose cultivated varieties that have been selected for different purposes (fruit and seed consumption, and ornamentals). Plants were analyzed and characterized for leaf trichome density and their concentration of cucurbitacins that are known to be toxic to generalist herbivores. In parallel, we conducted laboratory assays to determine insect performance. We found partial support for our hypothesis. Trichome densities were lower on leaves of cultivated varieties, but this did not correlate with insect performance. As predicted, only cultivars selected for fruit consumption had lower concentrations of cucurbitacins than seed varieties and ornamentals, and wild accessions had the highest concentrations. Insect performance was higher on fruit-selected varieties but only for *S. frugiperda*. The performance of *S. eridania* and *D. balteata* was not correlated with cucurbitacin concentration or domestication purpose, which suggests that these species are adapted to feed on plants containing high levels of these toxic compounds.

These results highlight the importance of incorporating plant traits and insect adaptations in studies on crop domestication and insect interactions.

Keywords: Domestication/Squash/Insect performance/Cucurbitacins/Plant resistance
*Speaker*² Corresponding author:

<footnote n="1">¹ Institute of Entomology, Biology Centre of Academy of Sciences and Faculty of Science, University of South Bohemia, Branisovska, Ceske Budjovice, Czech Republic</footnote>

<footnote n="1">¹ Institute of Biology, Laboratory of Evolutionary Entomology, University of Neuchâtel, Neuchâtel, Switzerland</footnote>
## Poster 57

# Insect herbivory may cause changes in the visual properties of leaves and affect the camouflage of herbivores to avian predators

Tuuli-Marjaana Koski *<fnref n="1" />, Carita Lindstedt <fnref n="2" />, Tero Klemola <fnref n="1" />, Jolyon Troscianko <fnref n="3" />, Eija Mäntylä <fnref n="1" />, Esa Tyystjärvi <fnref n="1" />, Martin Stevens <fnref n="3" />, Marjo Helander <fnref n="1" />, Toni Laaksonen

'Cry for help' hypothesis predicts that attraction of predators with chemical or visual cues can decrease insect damage of plants. Visual cues involve changes in photosynthetic activity and the reflectance of leaves, and there is some evidence that birds may use these changes as foraging cues. However, changes in the visual properties of leaves have not been quantified and it is not known how birds see these changes. We also presented and tested a new 'reduction in camouflage' hypothesis (not mutually exclusive with 'cry for help') stating that herbivore-mediated changes in leaf colour can increase the conspicuousness of herbivore against leaves. To define changes in the visual properties of leaves, their detectability to birds, and whether these changes affect the conspicuousness of herbivore, we manipulated the level of herbivory in silver birch trees (Betula pendula) with autumnal moth (Epirrita autumnata) larvae, and used blue tit (Cyanistes caeruleus) vision models to images of leaves and larvae. Hue, luminance (lightness), contrast, transparency, chlorophyll content, photosynthetic activity and water content of the leaves were compared between herbivore-damaged and control trees. The leaves of herbivore-damaged trees had a decreased chlorophyll a concentration, increased contrast and they reflected more longer wavelengths. However, these changes are likely not obvious to birds. In contrast to our expectation, there were only minor differences in conspicuousness of larvae against the leaves of damaged trees, which may be very subtle to predator vision. Nevertheless, according to visual models, larvae should be easily detectable to birds from both herbivore-damaged and control trees.

Keywords: trophic interactions, avian vision model, background matching, herbivory, camouflage

*Speaker* Corresponding author: tmhkos@utu.

## Poster 58

# Interspecific competition between dominant and infrequent parasitoid wasps of a leaf miner

Issei Ohshima*<fnref n="1" />, Keiko Ariyoshi <fnref n="1" />

Parasitoid wasps are one major enemy of phytophagous insects and play important roles in ecosystem stability. Although each phytophagous insect species is generally attacked by several parasitoid wasps, the majority of individuals are often killed by respective specific dominant parasitoid species. This implies that asymmetric interspecific competition between dominant and infrequent parasitoid species. However, we know little about whether dominant parasitoid species in the wild win in the competition with other infrequent parasitoid species in the laboratory condition. Leaf-mining insects are generally small in their body size, so that majorities of their parasitoid wasps are solitary. In this study, we conduct the laboratory competition experiments between dominant and infrequent braconid parasitoid species of a leaf-mining moth, *Acrocercops transecta* (Lepidoptera: Gracillariidae). Previous study shows that *Aneurobracon philippinensis* (Hymenoptera: Braconidae: Agathidinae) is a single predominant enemy for *Ac. transecta*, and Choeras sp. (Hymenoptera: Braconidae: Microgastinae) is a second predominant enemy among braconid parasitoids. As a result, *An. philippinensis* were always dominant irrespective of the order of oviposition and the length of time intervals between ovipositions. These results suggest that the dominant parasitoid species in the field are also dominant in the experimental competition in the laboratory, suggesting that superiority in the competition is an important factor determining the parasitoid communities of leaf miners and host ranges of parasitoids.

Keywords: Braconidae, Gracillariidae, host range, leaf miner, parasitoid community, solitary

Speaker*

<footnote n="1">¹ University of Turku, Finland</footnote>

<footnote n="2">² University of Jyväskylä, P.O. Box 35 (YFL), FIN-40014, Finland</footnote>

<footnote n="3">³ University of Exeter, United Kingdom</footnote>

<footnote n="1">¹ Department of Life and Environmental Sciences, Kyoto Prefectural University, Sakyo, Kyoto, Japan</footnote>
Poster 59

The role of butterfly eggs on plant-plant communication

Foteini Pashalidou *<fnref n="1" />, Lisa Eyman <fnref n="1" />, Nina Fatouros <fnref n="2" />, Mark Mescher <fnref n="1" />, Consuelo De Moraes <fnref n="1" />

Plants are able to recognize eggs of specific herbivores and enhance their defences upon subsequent caterpillar feeding. In a field experiment, we found that egg deposition by a Pieridae butter y on black mustard, induced plant responses that negatively affect the performance of feeding caterpillars. Effects were cascaded up to higher trophic levels and increased attraction of natural enemies. Overall plants use egg-deposition as an "herbivore warning cue" and enhance their direct and indirect responses against subsequent herbivores. This resulted in increased plant fitness (i.e. seed production) compared with plants that did not receive eggs. Black mustard plants grow in patches therefore volatiles from egg-infested plants may be used as another predictable cue of herbivory from neighbouring non-infested plants. It remains unclear whether neighbouring plants can use cues from plants infested with eggs to enhance their defence responses against upcoming herbivory. The first objective was to test whether plants can use volatiles cues from neighbouring plants infested with butterfly eggs to mount enhanced responses upon subsequent herbivory. The second objective is to test whether there are any differences on plant volatiles and phytohormones that suggest an underlying mechanism for the plant response to egg deposition and plant-plant interaction. To investigate our objectives, we used a domestic plant, the white cabbage, which is resistant to herbivory (Brassica oleracea) and the wild plant black mustard, (Brassica nigra). Our first results suggest that plants, which growing next to egg-infested plants are able to use volatiles from the egg-infested plants and mount their defences against subsequent feeding herbivores. This results emphasize the importance of egg deposition as a warning cue within and between plants to anticipate future herbivory, and adds another dimension to understand phenotypic plasticity of induced plant defences. This may impact the structure of plant mediated communities up to higher trophic levels.

Keywords: plant defences, egg deposition, natural enemies, fitness, plant communication

*Speaker* Corresponding author: foteini.paschalidou@usys.ethz.ch

Poster 60

Transfer of stabilized and reactivated plant toxin derivatives to the third and fourth tropic
level protects the western corn rootworm from its natural enemies

Christelle Robert*<fnref n="1" />, Xi Zhang <fnref n="1" />, Ricardo Machado <fnref n="1" />, Michael Reichelt <fnref n="2" />,
Jonathan Gershenzon <fnref n="2" />, Matthias Erb <fnref n="1" />

Herbivore fitness is constrained by plant quality and predation by higher trophic levels. Numerous insect herbivores can redirect plant defenses against their own natural enemies. Yet, plant toxin stabilization and reactivation mechanisms by herbivores, as well as the extent to which they avert predation, remain poorly understood. Here we report that the soil dwelling maize pest herbivore, *Diabrotica virgifera*, tolerates plant benzoxazinoids and accumulates high amounts of the benzoxazinoids glucosides HDMBOA-Glc and MBOA-Glc in its hemolymph and skin. Larvae fed on benzoxazinoid mutant plants were more susceptible to infection by the nematode *Heterorhabditis bacteriophora* which injects and feeds on the entomopathogenic symbiont bacterium *Photorhabdus luminescens*. We found that MBOA-Glc is a strong repellent to the nematode. Furthermore, upon tissue disruption, *D. virgifera* larvae hydrolyze the stored benzoxazinoid glucosides to produce MBOA. We demonstrate that MBOA reduces development and infectivity of both the nematode and its bacterial symbiont. Our results highlight that both stabilized and re-activated plant toxins can be used by herbivores to defend themselves against natural enemies. The presented findings also provide an explanation for the low success rate of certain biological control programs aiming at controlling *D. virgifera*.

Keywords: Tritrophic interactions, belowground herbivory, benzoxazinoids, *Diabrotica virgifera*, entomopathogenic nematodes

Speaker*

<footnote n="1">¹ ETH, Zürich, Switzerland</footnote>

<footnote n="2">² Wageningen University, Netherlands</footnote>

<footnote n="1">¹ Institute of Plant Sciences (IPS), Switzerland</footnote>

<footnote n="2">² Max Planck Institute for Chemical Ecology, Department of Biochemistry (MPI CE), Germany</footnote>
## Poster 61

### Plants as sources for insect odorscapes

Michel Renou<fnref n="1" />

Insects recognize and localize their vital resources such as food or a mating partner by extracting specific odor signals from a complex and changing odor environment. Not only sources of cues to herbivores, terrestrial plants are the main sources for the huge diversity of volatile organic compounds forming odorscapes among which insects must obtain ecologically relevant information. Female moths for instance release a pheromone blend that attracts male from a distance. Plant volatiles may facilitate or decrease perception of the sex pheromone by males, depending on their chemical nature and concentration. However, emissions of VOCs are modified by plant metabolism and their mixing rates in the atmosphere are constantly changing due to aerial turbulence. We will describe some of the characteristics of the spatio-temporal structure of odorscapes and present results of our behavioral and physiological experiments aiming to understand how odor background affects perception of odor signal and behavior in moths.

Keywords: pheromone, olfaction, sensory ecology, neural coding, plant volatiles

## Poster 62

### Adaptation of Japanese Swallowtail butterfly to host plant

Ai Sato*<fnref n="1" />, Masashi Murakami <fnref n="1" />

Recent studies indicated that various plant secondary metabolisms have driven diversity of herbivores. In order to investigate the evolutionary process of adaptation on defense compounds, we focused on the interactions between Japanese swallowtail butterfly, genus Papilio, and its host plants, Rutaceae and Apiaceae.

First, we quantified "furanocoumarin" that is one of the defense compounds included in Rutaceae and Apiaceae. Second, we conducted feeding experiment utilizing *Papilio xuthus* and 8 Rutaceae plants to see how the furanocoumarin profiles affect larval performance. Finally, we analyzed sequences of CYP6B1 that is a detoxification related gene to investigate the evolution of the detoxification mechanism of Papilio species.

The result of furanocoumarin quantification revealed the species-specific profile of the compounds. In addition, it was revealed that some furanocoumarins were common among plant species, whereas isoimperatorin was found only from one species, *Skimmia japonica*. The comparison the result of feeding experiment and furanocoumarin quantification showed the difference in growth rates of larvae feed on different species. We found that the total amount of furanocoumarin negatively affected the host preference of Papilio larvae shown by existing literature. It is notable that the larvae feed on *Zanthoxylum ailanthoides*, which contained relatively large amount of xanthotoxin, also showed high growth. These results suggest that furanocoumarins might affect the host use of Papilio butterflies. However, it is also showed that not all the furanocoumarins are effective defenses against Papilio butterflies.

In addition, as the result of sequence analysis of CYP6B1, we found a large mutation in amino acid sequence at *P. machaon*. It is known that *P. machaon* is a phylogenetically derivative species that was originated from Rutaceae-feeding species. These suggested that the relatively large host jump from the Rutaceae to the Apiaceae of *P. machaon* might necessarily be accompanied by a large change in the detoxification related gene.

Keywords: chemical defense, detoxification, host adaptation

*Speaker

<footnote n="1">¹ Institut d'Ecologie et des Sciences de l'Environnement de Paris (IEES), Institut National de la Recherche Agronomique – INRA, France</footnote>

<footnote n="1">¹ The open University of Japan, Chiba, Japan</footnote>
## Poster 63

# Linking genotypic susceptibility to insects pests with plant chemistry: an example from the oilseed rape - pollen beetle interaction

Gaetan Seimandi Corda *<fnref n="1" />;<fnref n="2" />, David Renaud <fnref n="1" />, Sébastien Faure <fnref n="2" />,<fnref n="2" />,
Anne Marie Cortesero ²¹

Pollen beetle (*Meligethes aeneus*) is one of the main insect pests affecting oilseed rape crops. Efficiency of insecticide use to control this pest is decreasing due to its adaptation to phytosanitary products such as pyrethroids. In this context, alternatives to this kind of control need to be found. Breeding oilseed rape for resistance to insect attacks could be an interesting way to deal with this issue. Actually, the primary benefit of this approach is the ease of its use by farmers. However, it remains complicated to breed plants for insect resistance, especially using field tests on large genotype collections. Our knowledge of the chemical ecology of interactions between oilseed rape and pollen beetles could allow to find biochemical markers of this resistance. In this way an indirect breeding approach based on makers of resistance could be adopted rather than direct confrontation of plants to insects. Laboratory tests have already shown that variation in resistance between oilseed genotypes could be explained by the biochemistry of bud tissues. These observations now need to be validated under field conditions. To test this, we conducted a multi-site experiment in France to observe resistance of different genotypes to pollen beetles. We phenotyped pollen beetle damage and sampled buds in the field to analyse their chemistry and, based on these results, discuss the potential use of identified compounds as markers of resistance to pollen beetle for breeding purposes.

Keywords: Plant resistance, *Meligethes aeneus*, *Brassica napus*, Chemical markers

*Speaker

²Corresponding author: sebastien.faure@biogemma.com

²Corresponding author: anne-marie.cortesero@univ-rennes1.fr

## Poster 64

# Is quantity or quality of food the issue in feeding site choice in oilseed rape by the pollen beetle?

Gaetan Seimandi Corda * <fnref n="1" />;<fnref n="2" />, Kathleen Menacer <fnref n="1" />, David Renaud <fnref n="1" />, Maxime Hervé <fnref n="1" />, Marie Trabalon <fnref n="3" />,
Sebastien Faure <fnref n="2" />,<fnref n="2" />, Anne Marie Cortesero ²¹

According to the optimal foraging theory, diet selection by herbivorous insects should result from a trade-off between food quality and food quantity. Indeed, these insects are expected to optimize their food choice by balancing nutrient intake on the one hand, while minimizing toxicity from specific secondary metabolites in their host plants on the other. While optimal foraging theory has been used to understand food foraging and selection by some generalist herbivore insects, it has seldom been applied to specialist herbivores to understand how they choose among different plant parts or tissues. Yet, within-plant variability of primary compounds such as carbohydrates and proteins can highly influence tissue nutritional quality. The same variability also exists for secondary toxic compounds. Profitability of plant tissues also depends on architecture, organ size and physical defenses. These three factors (nutritional quality, toxicity, morphology) are rarely studied together but all could condition within-plant feeding patterns. We tried to explain feeding patterns of the pollen beetle (*Meligethes aeneus*), a pollinivorous insect and a pest of oilseed rape (*Brassica napus*) in Europe. We observed a clear feeding pattern, with insects preferring young buds in the center of the inflorescence. However, this pattern seems rather counterintuitive because of the low quantity of pollen present in these non-mature buds. We used behavioral and performance experiments paired with chemical analyses of plant tissues and insects to understand how constraints such as nutritional quality, organ toxicity and accessibility of the pollen may explain such paradox.

Keywords: Feeding pattern, *Meligethes aeneus*, *Brassica napus*, optimal foraging, biochemistry

*Speaker

²Corresponding author: anne-marie.cortesero@univ-rennes1.fr

²Corresponding author: sebastien.faure@biogemma.com

<footnote n="1">¹ Institut de Genetique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique : UMR1349,
Universite de Rennes 1, Domaine de la Motte au Vicomte BP 3532735653 Le Rheu, France</footnote>

<footnote n="2">² Biogemma, 6 Chemin de Panedautes, 31700 Mondonville, France</footnote>

<footnote n="1">¹ Institut de Genetique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique : UMR1349,
Universite de Rennes 1, Domaine de la Motte au Vicomte BP 3532735653 Le Rheu, France</footnote>

<footnote n="2">² Biogemma, 6 Chemin de Panedautes, 31700 Mondonville, France</footnote>

<footnote n="3">³ Laboratoire d'Ethologie Animale et Humaine (ETHOS), CNRS : UMR6552, Bâtiment 25, Campus de Beaulieu 263 avenue du General Leclerc CS 74205, 35042 Rennes Cedex, France</footnote>
Poster 65

# The ecology and evolution of host preference in an aphid parasitoid

Daniela Sepulveda *<fnref n="1" />;<fnref n="2" />, Guillermo Ramirez-Caceres <fnref n="3" />, Maria Eugenia Rubio-Melendez <fnref n="1" />;<fnref n="2" />,
Christian Figueroa Caro <fnref n="2" />;<fnref n="1" />;<fnref n="4" />

The parasitoid *Aphidius ervi* is widely used in biological control programs of aphids. Its success as biocontrol agent relies upon its ability to efficiently find specific aphids. This behaviour is mediated by learning chemical signals from the aphid-plant in which females developed, preferring to oviposit on the natal aphid-plant host. This preference for the natal host (host fidelity), represents an important trait for this parasitoid searching for a suitable host in complex environments. However, host fidelity can be lost when in endogamy conditions, which may reduce its efficiency controlling aphids. We studied the host preference in parasitoids that come from crosses between inbred-females (i.e., taken from caged lines) and outbred-males (i.e., collected from natural populations), to test whether managing the genetic diversity of caged *A. ervi* populations could restore their host fidelity. Hence, experimental parasitoids were raised in a common natal aphid-plant system (pea aphid-broad bean; APA) and evaluated in terms of their ability to prefer for the natal or non-natal host (grain aphid-wheat; SA). The results indicate that inbred and outbred *A. ervi* females had preferences for the natal host; showing significantly faster oviposition behaviour on APA than on SA. Indeed, the outbred-females rejected more than 50% of the non-natal aphids. The admixed-females, however, did not show preference for any host. Our results suggest a strong genetic effect that could be result from deleterious genes in inbred females, which are negatively affecting host fidelity after a single generation (admixed population). Interestingly, the preference for the natal host displayed by inbred-females gives some insights that a mechanism other than host fidelity could be explaining the pattern of host preference observed on APA. Our findings should help to understand the complexity of host fidelity in aphid parasitoid waps.

Funded by Fondecyt grant 1170943 to CCF and ICM grant NC120027.

Keywords: Parasitoid, Host preference, Behavior

*Speaker*<fnref n="2" />*Corresponding author: al gueroa@utalca.cl*

Poster 66

# Role of volatiles from cowpea varieties on the behavior of *Megalurothrips sjostedti*

Diabate Seydou *<fnref n="1" />;<fnref n="2" />, Emilie Deletre <fnref n="1" />;<fnref n="3" />, L. Kananu <fnref n="2" />, Ekesi Sunday <fnref n="1" />, Fiaboe Komi <fnref n="1" />, J. Wesonga <fnref n="2" />,
S. Subramanian <fnref n="1" />, Thibaud Martin <fnref n="1" />,<fnref n="3" />*

The bud flower thrips, *Megalurothrips sjostedti* is a major pest of cowpea in sub-Saharan Africa. Main damages are due to the abortion of flowers and their shedding. Chemical sprays generally used by farmers to control thrips have a negative impact on human health and environment. The contribution of semiochemicals in the interactions between cowpea and thrips were investigated to reduce *M. sjostedti* outbreaks in the fields. In order to evaluate the potential effect, a preference host selection, at vegetative and oral stages, was done by observing insect location 24 hours after introduction into a cage with four cowpea varieties. Then, the choice of thrips adults between air control and the vegetative or floral parts of cowpea varieties was observed into Y-tube olfactometer. The chemical analyse of cowpea volatiles was performed by coupled gas chromatography-mass spectrometry (GC/MS) to identify and quantify the compounds emitted by vegetative and floral parts of cowpeas. The preference test showed no significant difference between the four varieties of cowpea at both growth stages. The olfactometer test indicated repellent effect of vegetative and floral parts of the cowpea variety K80 to female thrips. The vegetative parts of varieties EL and M66 were repellent to females but their flowers were repellent to males. In addition, the odour from the vegetative part of cowpea variety KK1 was repellent to males but the flower part was attractive to females. There were no significant differences for most of the variety in pairwise comparisons. Only the variety K80 was significantly attractive to males than the variety KK1. The role of volatiles from different part of cowpea plants was discussed as part of the natural defence mechanism of cowpea against the thrips *M. sjostedti*.

Keywords: *Megalurothrips sjostedti*, cowpea, preference selection, Olfactometer, gas chromatography, mass spectrometry, volatiles, semiochemicals

Speaker*

<footnote n="1">¹ Millennium Nucleus Centre for Molecular Ecology and Evolutionary Applications in Agroecosystems, Universidad de Talca (CEM), Chile</footnote>

<footnote n="2">² Facultad de Ciencias Agrarias, Universidad de Talca, 2 Norte 685, Talca, Chile</footnote>

<footnote n="3">³ Departamento de Ecología, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile</footnote>

<footnote n="4">⁴ Instituto de Ciencias Biologicas, Universidad de Talca, Chile</footnote>

<footnote n="1">¹ International centre of insect physiology and ecology (ICIPE), Duduville Campus P.O. Box 30772-00100 Nairobi, Kenya</footnote>

<footnote n="2">² Jomo Kenyatta University of Technology and Agriculture, Nairobi, Kenya</footnote>

<footnote n="3">³ UR Hortsys CIRAD: UPR103, France</footnote>
Poster 67

Early-flowering induced by herbivory in wild Lima bean plants
affects late-season seed predators but not their parasitoids

Juan Traine*<fnref n="1" />, Carlos Bustos Segura <fnref n="1" />:<fnref n="2" />,
Johnattan Hernandez-Cumplido <fnref n="3" />, Betty Benrey²¹

Early-season herbivory can induce plant responses that affect herbivores later in the season. For wild lima bean, *Phaseolus lunatus*, plant development is well synchronized with that of the associated insects that attack the plant throughout the season. Therefore, any change in plant phenology can alter the interactions with the insect community.

Here, we examined how early-season herbivory affects plant phenology and reproductive traits, and how these changes influence the attack by late-season herbivores and their natural enemies. In a field experiment in Puerto Escondido (Oaxaca, Mexico), plants were either infested with herbivores or kept undamaged and followed throughout the season. We recorded flowering time, pod production and number of seeds per pod. Upon seed maturation, seeds were collected and we recorded the number of seed predators (Bruchinae) and the number of parasitoids that emerged from these seeds. We found that early-season herbivory significantly shortened plant flowering time, and reduced pod and seed production. On the other hand, bruchids were more abundant in herbivore-treated plants. No significant difference was found in the abundance of parasitoids across treatments.

These findings suggest a trade-off between growth and defense whereby, plants subjected to herbivory reproduce early but invest less resources in defensive compounds allocated to the seeds. Overall, these results show how small changes in one trophic level can result in complex cascading effects on higher trophic levels.

Keywords: Tritrophic interactions, Ecology, Plant fitness, Parasitoids, Seed predators, Plant phenology

*Speaker <sup>2</sup>Corresponding author: betty.benrey@unine.ch

Poster 68

Whitefly fitness on tomato plants is reduced by spider mite colonization
through jasmonic acid and salicylic acid signaling pathways

Joop Van Loon *z1*, Yunlin Su <fnref n="2" />, Marcel Dickez<fnref n="1" />

Plants are attacked by herbivorous insects and evolved different defense strategies to prevent or reduce damage. Plants usually upregulate jasmonic acid (JA) based defenses against tissue-damaging arthropods, such as mites, and activate salicylic acid (SA) signaling defenses to prevent further damage by phloem-feeding insects, for example whiteflies. As plant consumers, herbivores have to face not only plant defenses but also interact with other herbivores because plants usually are under attack by multiple herbivores. The white fly *Bemisia tabaci* and the two spotted spider mite *Tetranychus urticae* are important generalist horticultural pests and infestation with both insects on the same plant is common. They represent two different feedings guilds since *B. tabaci* is a phloem feeder and *T. urticae* is a cell-content. Here, we investigated plant-mediated interactions between these two herbivores. We found that the oviposition of *B. tabaci* was negatively affected by the colonization of *T. urticae* above a threshold density. The assessment of expression of marker genes in the SA and JA pathways indicated that both pathways were activated by coinfestation with these two insects. Furthermore, white fly performance assays by using JA deficient mutant Spr-2 and SA deficient mutant NahG tomato plants and by mimicking spider mite infestation with exogenous application of JA and SA demonstrated that JA and SA were important in the plant-mediated interaction between *T. urticae* and *B. tabaci*. Although white flies are able to manipulate plant signaling, this strategy was not found to be used by *B. tabaci* to enhance their fitness on tomato plants infested with *T. urticae*. Instead, *B. tabaci* expressed a higher level of transcripts of detoxification enzymes, such as P-450 monooxygenases, carboxylesterases and glutathione S-transferases, to tolerate the plants defenses triggered by the other herbivore, which may cause a reduction in their fecundity.

Keywords: plant resistance, signal transduction, detoxification

*Speaker <sup>2</sup>Corresponding author: joop.vanloon@wur.nl <sup>2</sup>Corresponding author: marcel.dicke@wur.nl

<footnote n="1">¹ Laboratory of Evolutionary Entomology (E-VOL), Institute of Biology, University of Neuchâtel, Rue Emile Argand 11,
2000 Neuchâtel, Switzerland</footnote>

<footnote n="2">² Université de Neuchâtel, Switzerland</footnote>

<footnote n="3">³ Facultad de Ciencias (UNAM), Mexico</footnote>

<footnote n="1">¹ Wageningen University (WU), Netherlands</footnote>

<footnote n="2">² South China Botanical Garden, Chinese Academy of Sciences, China</footnote>
# Poster 69

## Parasitoid foraging behaviour in complex situations: Influence of weather, surrounding vegetation and learning

Ilka Vosteen *<fnref n="1" />, Nika Van Den Meiracker *<fnref n="1" />, Yavanna Aartsma <fnref n="1" />;<fnref n="2" />,
Felix Bianchi <fnref n="2" />, Erik Poelman <fnref n="1" />

Parasitoid foraging has been intensively studied in simple laboratory set-ups, but less is known about parasitoid host location in more complex natural environments. Herbivore-induced plant volatiles (HIPVs), which are emitted after an herbivore attack are important foraging cues for parasitoids. The ability of parasitoids to follow an odour plume upwind towards its source is likely influenced by weather conditions and surrounding vegetation. Experience with host or non-host related HIPVs may help parasitoids to orient in complex natural environments.

To study parasitoid foraging efficiency in complex situations, we use the parasitoid *Cotesia glomerata*, which attacks caterpillars of the Cabbage white (*Pieris rapae* and *P. brassicae*). Preliminary experiments, in which we released parasitoids in a circle of caterpillar infested plants in the field, suggest that the number of parasitoids that successfully located a caterpillar infested plant strongly depends on humidity, with more parasitoids reaching caterpillar infested plants at higher humidity. This indicates that parasitoid foraging activity or their ability to locate an odor source is reduced at low humidity. Preliminary data further hints that upwind dispersal may only be possible at low wind speed. In a wind tunnel study we showed that non-host infested cabbage plants distract naive parasitoids from the host infested plant, leading to longer foraging until location of the host infested plant. The ability of parasitoids to discriminate between host and non-host infested plants increased after non-host experience, but did not increase foraging efficiency in complex situations. Surprisingly, oviposition experience even decreased parasitoid foraging efficiency in complex situations.

Our experiments suggest that parasitoid foraging in complex (field) environments is less straight forward than in simple laboratory set-ups and that both adverse weather conditions and presence of neighboring plants can decrease foraging efficiency. Our results further show that learning may not always increase foraging efficiency in complex situations.

Keywords: parasitoids, foraging, HIPVs, weather conditions, *Cotesia glomerata*, *Pieris brassicae*

*Speaker

# Poster 70

## The wolf in sheep's clothing: Entomopathogenic nematodes attract their insect herbivore hosts by manipulating plant and cadaver odors

Zhang Xi *<fnref n="1" />, Matthias Erb <fnref n="2" />, Christelle Robert<fnref n="2" />

Plants under herbivore attack are well known to attract natural enemies. Whether natural enemies can attract herbivores by manipulating plants in turn is unknown. We investigated this question using the entomopathogenic nematode (EPN) *Heterorhabditis bacteriophora* and the western corn rootworm (WCR, *Diabrotica virgifera virgifera*), a specialist root herbivore of maize. Belowground olfactometer and Petri dish experiments revealed that WCR larvae are repelled by EPNs alone, but attracted to maize plants that are exposed to EPNs. Surprisingly, WCR larvae are also attracted to EPN-infested WCR cadavers. We are currently in the process of identifying the responsible plant and cadaver volatiles. Our study indicates that EPNs can manipulate the volatile bouquets of plants and herbivores to lure in their prey.

Keywords: Tritrophic interactions, entomopathogenic nematodes, western corn rootworm, below-ground herbivore, natural enemies

*Speaker*<fnref n="2" />*Corresponding author:*

<footnote n="1">¹ Wageningen University Reasearch (WUR), Laboratory of Entomology, Netherlands</footnote>

<footnote n="2">² Wageningen University Reasearch (WUR) Farming Systems Ecology, Netherlands</footnote>

<footnote n="1">¹ Altenbergrain 21, Switzerland</footnote>

<footnote n="2">² Institute of Plant Sciences, University of Bern, Switzerland</footnote>
Poster 71

Combined use of herbivore-induced plant volatiles and sex pheromones
for mate location in braconid parasitoids

Hao Xu<fnref n="1" />

Herbivore-induced plant volatiles (HIPVs) are important cues for female parasitic wasps to find hosts. Here we investigated the possibility that HIPVs may also serve parasitoids as cues to locate mates. To test this, the odour preferences of four braconid wasps, the gregarious parasitoid *Cotesia glomerata* (L.) and the solitary parasitoids *Cotesia marginiventris* (Cresson), *Microplitis rufiventris* Kokujev, and *Microplitis mediator* (Haliday), were studied in olfactometers. Each species showed attraction to pheromones, but in somewhat different ways. Males of the two Cotesia species were attracted to virgin females, whereas females of *M. rufiventris* were attracted to virgin males. Males and females of *M. mediator* exhibited attraction to both sexes. Importantly, females and males of all four species were strongly attracted by HIPVs, independent of mating status. In most cases, males were also attracted to intact plants. The wasps preferred the combination of HIPVs and pheromones over plant odours alone, except *M. mediator*, which appears to mainly use HIPVs for mate location. We discuss the ecological contexts in which the combined use of pheromones and HIPVs by parasitoids can be expected. To our knowledge, this is the first study to show that braconid parasitoids use HIPVs and pheromones in combination to locate mates.

Keywords: Plant, insect interactions, caterpillar, induced plant volatiles, leaf volatiles, mate finding strategy, tritrophic interactions, biocontrol

<footnote n="1">¹ Institute of Biology, University of Neuchâtel, CH-2000 Neuchâtel, Switzerland</footnote>
Poster 72

Multiple adaptations allow the cabbage stem flea beetle to tolerate plant defense
compounds

Franziska Beran *<fnref n="1" />, Franziska Betzin <fnref n="1" />, Christian Paetz <fnref n="1" />, Seung-Joon Ahn <fnref n="1" />, Anton Shekhov <fnref n="1" />,
Daniel Vassao <fnref n="1" />, Michael Reichelt<fnref n="1" />

Herbivores feeding on crucifer plants are confronted with a potent activated defense -the glucosinolate-myrosinase system. Feeding damage triggers enzymatic degradation of glucosino--lates to reactive isothiocyanates which deter non-adapted herbivores. The host plant range of the cabbage stem flea beetle *Psylliodes chrysocephala*, however, is restricted to glucosinolate containing plants. We thus investigated how these specialists overcome this plant defense and avoid isothiocyanate toxicity by analyzing the metabolic fate of ingested glucosinolates. We found isothiocyanates to be only present in traces in samples from beetle bodies and feces; instead, we detected two novel metabolites derived from the isothiocyanate-glutathione-conjugate. The metabolism of isothiocyanates via conjugation with glutathione represents a common detoxification mechanism, and our results suggest that this strategy efficiently enables *P. chrysocephala* to overcome this chemical defense of crucifers. Additionally, we found that *P. chrysocephala* adults also selectively sequester intact glucosinolates into their bodies, and we also detected desulfo-glucosinolates in beetle bodies and feces. The conversion of intact glucosinolates to desulfo-glucosinolates is catalyzed by specific sulfatase enzymes and prevents the activation of glucosinolates to the toxic isothiocyanates. Together, glucosinolate sequestration and detoxification by desulfation accounted for the fate of up to 35% of the total ingested glucosinolate in *P. chrysocephala*. The presence of both general (detoxification of isothiocyanates with glutathione) and highly specific detoxification strategies (sequestration and enzymatic deactivation of intact glucosinolates) in this specialized flea beetle suggests a stepwise adaptation to glucosinolates within the genus *Psylliodes*.

Keywords: adaptation, detoxification, glutathione, isothiocyanate, flea beetle, glucosinolate, plant defense

*Speaker

Poster 73

Salivary proteins of spider mites that manipulate plant defenses
and promote mite reproduction

Charlotte Josephine Blaazer<sup>Z1</sup>, Juan Alba<sup>1</sup>, Robert Schuurink<sup>1</sup>, Carlos Villarroel<sup>1</sup>, Thomas Van Leeuwen<sup>2</sup>, Wannes Dermauw<sup>2</sup>, Merijn R. Kant<sup>*Z1</sup>

Spider mites (Tetranychidae sp.) are widely occurring arthropod pests on cultivated plants. Feeding by the two-spotted spider mite *T. urticae*, a generalist herbivore, induces a defense response in plants that mainly depends on the phytohormones jasmonic acid and salicylic acid (SA). On tomato (*Solanum lycopersicum*), however, certain genotypes of *T. urticae* and the specialist species *T. evansi* were found to suppress these defenses. This phenomenon occurs downstream of phytohormone accumulation via an unknown mechanism. We investigated if spider mites possess effector-like proteins in their saliva that can account for this defense suppression. First we performed an in silico prediction of the *T. urticae* and the *T. evansi* secretomes, and subsequently generated a short list of candidate effectors based on additional selection criteria such as life stage-specific expression and salivary gland expression via whole mount in situ hybridization. We picked candidates from the top 10 most promising protein families and expressed representatives in *Nicotiana benthamiana* using *Agrobacterium tumefaciens* transient expression assays to assess their effect on plant defenses and mite performance. Some of these proteins suppressed defenses downstream of the phytohormone SA. Furthermore, *T. urticae* performance on *N. benthamian* a improved in response to transient expression of three of these proteins. Our results suggest that both generalist and specialist plant-eating mite species secrete proteins via their saliva to reduce the negative effects of these defenses.

Keywords: spider mites, susceptibility, S gene, effector, resistance, plant breeding, protein, interaction, tetranychus

*Speaker * Corresponding author: c.j.h.blaazer@uva.nl *Corresponding author: m.kant@uva.nl

<footnote n="1">¹ Max Planck Institute for Chemical Ecology (MPI CE), Hans-Knöll-Strasse 8, 07745 Jena, Germany</footnote>

<footnote n="1">¹ University of Amsterdam, Netherlands</footnote>

<footnote n="2">² Ghent University, Belgium</footnote>
Poster 74

Correlation between phytohormone patterns and gall induction by Phylloxera on grape leaves

Melanie Body *<fnref n="1" />, Heidi Appel <fnref n="1" />, Jack Schultz <fnref n="1" />

Galls are highly specialized structures arising from atypical development of plant tissue induced by another organism. Many different kinds of organisms can induce galls on plants, including viruses, fungi, bacteria, nematodes, mites and insects. However, gall-inducing insects produce the most diverse galls in nature, ranging from simple stem swellings to complex structures that are ornamented with bright colors and spines. These structures are thought to provide adaptive advantages to gall-inducers by enhancing their nutrition, and protecting them against natural enemies and environmental stresses. Gall formation is a complex and close interaction between the gall-inducing insect and its host-plant resulting from molecular cross-talk between two independent genomes; however, the mechanism underlying the gall induction and maintenance by gall-inducing insects is still unknown. In this study, we characterized phytohormones present (i) in the gall-inducing insect's body (*Daktulosphaira vitifoliae*) and (ii) in the galls they induce on grape leaves (*Vitis riparia*). This will allow us to determine which phytohormones are used as salivary effectors by the insect and how these secretions alter phytohormone profiles within the plant to induce gall initiation and growth. Because galls grow via hypertrophy and hyperplasia, phytohormones that influence cell growth and division, such as auxins and cytokinins, will most likely be involved in host-plant manipulation. These plant growth factors have already been detected in insect saliva in other studies, and these insect-derived plant hormones may be responsible for stimulating gall growth.

Keywords: Gall, Aphid, Phylloxera, Grape, Phytohormones, Cytokinins, Auxins

*Speaker

Poster 75

Early cell responses of poplars to salivary extracts of a gall-inducing aphid,
*Phloeomyzus passerinii*

Luis Portillo <fnref n="1" />, Jessy Tricard <fnref n="1" />, Jerome Duclercq <fnref n="1" />, Elisabeth Huguet <fnref n="2" />, David Giron <fnref n="2" />,
Anas Cherqui * z<fnref n="1" />, Aurelien Salléz<fnref n="3" />

Saliva is considered as the molecular interface between most phytophagous insects and their host plant, and plays a critical role during plant manipulation by gall-inducing insects. We used a multidisciplinary approach to (i) characterize the saliva of *Phloeomyzus passerinii*, an aphid inducing galls in the bark of poplars, and (ii) assess the effects of salivary extracts on host plant cells. We first used the transcriptome obtained from the salivary glands to compare the *P. passerinii* secretome with those of other aphids and gall-inducing insects. In addition, we assessed the early cell responses to salivary extracts transcriptionally using leaves protoplasts from two poplar genotypes, either susceptible (I214) or resistant (Koster) to *P. passerinii*. For this, the expression profile of 45 genes involved in plant response to biotic stress was assessed by qRT-PCR upon short time treatment with salivary extracts from *P. passerinii* and from *Myzus persicae* as control. The secretome comparisons allowed us to unravel the presence of known orthologous effectors in other aphid species, Mp10, ACE, ARMET and an orthologous effector of gall induction, SSGP71, from *Mayetiola destructor*. The transcriptomic approach indicated a classical response to *M. persicae* salivary extracts for both poplar genotypes, activating several plant hormones pathways. The cellular response of the resistant genotype (Koster) also showed an activation of these pathways in response to *P. passerinii* salivary extracts. In contrast, jasmonate and salicylate pathways were repressed in I214 with this salivary extracts as well as genes involved in auxin homeostasis. The potential roles of salivary compounds in plant manipulation are discussed.

Keywords: *Phloeomyzus passerinii*, poplar, gall, inducing aphids, saliva, secretome, gene expression, protoplast, cell response

*Speaker z<fnref n="2" /> Corresponding author: anas.cherqui@u-picardie.fr z<fnref n="2" /> Corresponding author: aurelien.salle@univ-orleans.fr

<footnote n="1">¹ University of Missouri, Division of Plant Sciences, Christopher S. Bond Life Sciences Center, 1201 Rollins Street, Columbia, MO 65201, United States</footnote>

<footnote n="1">¹ Ecologie et Dynamique des Systemes Anthropises (EDYSAN), Université de Picardie Jules Verne, Amiens, France</footnote>

<footnote n="2">² Institut de Recherche sur la Biologie de l'Insecte (IRBI), CNRS UMR7261, Université Francois Rabelais - Tours, Avenue Monge 37200 TOURS, France</footnote>

<footnote n="3">³ LBLGC - EA 1207, Université d'Orleans, Orléans</footnote>