Progress 03/01/14 to 02/28/18

Outputs
Target Audience:We presented this research to the general public at the annual Insectapalooza open house which is attended by several thousand people in Upstate New York annually. The PD presented the research at talks at the University of Montana, Missoula, Montana, the University of Kentucky, Lexington, Kentucky as the Student Invited Speaker, University of Colorado, Boulder, Colorado, at the Gordon Research Conference on Predator-Prey Interactions, the Gordon Research Conference on Plant-Herbivore Interactions, and at the Entomological Society of America Annual meeting in a symposium on Agricultural Applications of non-consumptive effects. One of the postdocs working on the project, Natasha Tigreros, gave a presentation about this research at the Ecological Society of America meeting in August 2015. And a graduate student Nick Afflito presented a poster at the Predator-Prey Gordon Conference: Temporal patterns in predator-prey interactions We present the highlights of our findings in a factsheet for vegetable growers that was published on the New York Integrated Pest Management website. (https://ecommons.cornell.edu/handle/1813/45068) I presented our research to Cornell undergraduates who I teach and they conducted independent research projects building on our findings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The six undergraduates working on the project this period received one on one mentoring from me and the postdoc associated with the project, Natasha Tigreros. Two of the students on the project also conducted independent research and earned authorship on three published manuscripts. The postdoc and one of the undergraduates also attended a two-day professional development retreat run yearly for the lab members. Three of the undergraduate students and the postdoc received constructive feedback on their research at our weekly lab meetings, in the Plant Insect Interactions seminar course, and two of the undergraduates attended the Ecological Society of America Annual meeting. How have the results been disseminated to communities of interest?We have presented this research to the general public at the annual Insectapalooza open house and it has contributed to undergraduate teaching in Insect Ecology and Chemical Ecology courses at Cornell. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1: Determine how plant resistance influences the strength of non-consumptive effects on pests. The first work on this objective, led by a graduate student, showed that predation risk reduces oviposition and feeding damage by adult beetles in the field (Hermann and Thaler 2014). Next, we evaluated the theoretical expectations for when prey should optimally respond to predators (Orrock et al. 2015). We ended with an experiment showing that plant resistance strongly affects how young larvae respond to predation risk and that in spite of many prey compensatory processes, early predator exposure affects life-time fitness measured as oviposition and offspring quality. These results are important because they show long-term consequences of predator exposure on fitness and magnification of the costs for prey on high-resistance plants (Thaler, Nelson, Nelson, and Nyrop, in review). Objective 2: Determine behavioral, physiological, and developmental mechanisms by which prey compensate for responses to predation risk in different environmental conditions. We started this Objective by writing a synthesis paper discussing the behavioral and physiological intersections between prey responses to predation risk and plant resistance (Wetzel and Thaler 2016). Then, a postdoc and undergraduate research student conducted an experiment investigating behavioral and physiological mechanisms of prey responses to predation risk (Tigreros et al., Functional Ecology 2018). These experiments showed that beetles balance behavioral feeding responses and physiological changes in metabolic rate and nutrient storage to reduce the negative effects of predator exposure. There is substantial family-level variation in responses to predation risk and larval nutritional condition, in part mediated by cannibalistic behavior, which underlies these responses. Cannibalistic beetles have stronger feeding responses to predators and compensate for reductions in feeding by reducing their metabolic rate and storing more nutrients as lipids for future use. This research helps us understand under what conditions prey will have strong, potentially costly, responses to predation risk. Objective 3: Determine the trans-generational consequences of predation risk. Our first research showed strong trans-generational effects of adult predator exposure that affected offspring cannibalism, growth and survival when attacked by predators (Tigreros et al, Ecology Letters in 2017). This showed that predator exposure has the potential to have long-lasting effects on prey and prey populations. To see how general the predator-induced increase in cannibalism and prey responsiveness was, we investigated the consequences of predator exposure during the larval stage for investment in offspring. We found that larval exposure also increases parental investment in offspring, but instead of through cannibalism as found when adults were exposed, through increased provisioning of eggs. This manuscript is authored by a postdoc and an undergraduate Honor's student and is currently in review (Tigreros, Norris, and Thaler). In addition, we conducted a quantitative genetics experiment to determine the genetic and environmental contributions to parental effects of exposure to predation risk; this manuscript is currently in review (Tigreros, Agrawal, Thaler). In combination, these experiments are yielding new insights into how prey avoid the negative effects of predation and suggest that using biological control agents that differentially target adults and their offspring may result in more successful control.

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Tigreros, N., E. Wang and J.S. Thaler. 2018. Prey nutritional state drives divergent behavioural and physiological responses to predation risk. Functional Ecology. 10.1111/1365-2435.13046
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Kersch-Becker, M.F., Kessler, A, and J.S. Thaler. 2017. Plant defenses limit herbivore population growth by changing predator-prey interactions. Proceedings of the Royal Society B. DOI: 10.1098/rspb.2017.1120
• Type: Journal Articles Status: Submitted Year Published: 2019 Citation: Tigreros, N, Agrawal, A, J.S. Thaler. Parental genetic effects contribute to variation in anti-predator plasticity
• Type: Journal Articles Status: Submitted Year Published: 2019 Citation: Jennifer S. Thaler, Scott Nelson, Rebecca Loughner, Jan Nyrop. Interactive effects of predation risk and host plant resistance over prey life-time.
• Type: Journal Articles Status: Under Review Year Published: 2019 Citation: Tigreros, N., R. Norris, J.S. Thaler. Prey reproductive allocation decisions in the presence of predators: Do moms always sacrifice offspring quantity for quality

Progress 03/01/16 to 02/28/17

Outputs
Target Audience:Our target audience includes the grower community reached through a factsheet where we present the highlights of our findings in a factsheet for vegetable growers that was published on the New York Integrated Pest Management website. (https://ecommons.cornell.edu/handle/1813/45068) We have presented this research to the general public at the annual Insectapalooza open house which is attended by several thousand people in Upstate New York. I presented results from this research to the scientific community at the Gordon Research Conference on Predator-Prey Interactions. I presented our research to Cornell undergraduates who I teach and they conducted independent research projects building on our findings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two postdoctoral researchers, including one Hispanic women, seven undergraduates including 4 women and 3 men, and one technician received training in the scientific method through working on this project. These students have also attended lab meetings, scientific conferences, and University seminars and attended several professional development workshops to further their training. How have the results been disseminated to communities of interest?Our target audience includes the grower community reached through a factsheet where we present the highlights of our findings in a factsheet for vegetable growers that was published on the New York Integrated Pest Management website. (https://ecommons.cornell.edu/handle/1813/45068) We have presented this research to the general public at the annual Insectapalooza open house which is attended by several thousand people in Upstate New York. I presented results from this research to the scientific community at the Gordon Research Conference on Predator-Prey Interactions. I presented our research to Cornell undergraduates who I teach and they conducted independent research projects building on our findings. What do you plan to do during the next reporting period to accomplish the goals?Objective 1: The part of the study on the interaction between plant resistance and responses to predation risk will be submitted to the journal Ecology and the results on sibling variation in responses will be submitted to Oecologia. Objective 2: We have collected the data for this project and are in the process of writing for publication in Functional Ecology. To complete Objective 3, we need to finish data collection, finish analyzing the data, and write the second manuscript.

Impacts
What was accomplished under these goals? Objective 1: Determine how plant resistance influences the strength of non-consumptive effects on pests. We have completed the experiments for Objective 1 and are currently writing the results for publication. Our results show that plant resistance strongly affects how young larvae respond to a predator. On low-resistance plants, first instar larvae reduced feeding and had lower mass in the predation risk treatment. However, on high-resistance plants, beetle sibships had divergent responses to predation risk early in life, some increasing and others decreasing feeding. Older larvae consistently reduced feeding and mass in the presence of the predator on both low- and high-resistance plants. In spite of reduced feeding through most of larval development, larvae on both low- and high- resistance plants appeared to compensate for responses to predation risk by the time they reached pupation as life-time feeding and pupal mass did not differ between treatments. This compensation was due to increased assimilation efficiency early in life and compensatory feeding and delayed development later in life. In spite of apparent compensation in terms of pupal mass, larval plant resistance and predation-risk treatments had effects on the adult stage and the offspring. Adult beetles that had been exposed to predation stress as larvae, but not as adults, had lower fecundity. These results demonstrate an effect of predator exposure that lasts over the life-time of the individual prey. These data are collected and are currently being written for publication. The part of the study on the interaction between plant resistance and responses to predation risk will be submitted to the journal Ecology and the results on sibling variation in responses will be submitted to Oecologia. Objective 2: Determine behavioral, physiological, and developmental mechanisms by which prey compensate for responses to predation risk in different environmental conditions. Our experiments show that beetles use behavioral, physiological and developmental mechanisms to reduce the negative effects of predator exposure. There is substantial family-level variation in responses to predation risk and larval nutritional condition seems to underlie these responses. Beetles in good condition and rapidly growing employ more behavioral responses to predators (reduced feeding) and increase their assimilation efficiency to compensate for reductions in feeding. Beetles in poor condition either don't change how much they feed or even increase their feeding in response to predators. Two environmental conditions influence this outcome. First, beetles grow more slowly on highly-resistant plants and this makes them less responsive to predators. Second, if their parents were exposed to predators, beetles are more likely to cannibalize siblings (see Objective 3). Being a cannibal increases larval nutrition which increases their behavioral responses to predators. Cannibalistic beetles compensate for reductions in feeding by reduce their metabolic rate and storing more nutrients as lipids for future use. Nutritional status of the beetle influences how it responds to predators and the physiological compensatory mechanisms that it uses. We have collected the data for this project and are in the process of writing for publication in Functional Ecology. Objective 3: Determine the trans-generational consequences of predation risk. We have shown there are strong trans-generational effects of predator exposure on Colorado Potato Beetles that affect beetle survival when attacked by predators. When female Colorado potato beetles are exposed to predation risk, their offspring are more likely to cannibalize a sibling compared to offspring whose parents were not exposed to predators. This is an active response of the mothers who produce a higher proportion of unviable eggs which are then consumed by their viable offspring. Egg feeding reduces larval vulnerability to predation by shortening larval development time and improving larval anti-predator responses. This study is accepted pending minor revisions to Ecology Letters. In addition, we are completing experiments investigating when in the parental life-cycle predator exposure affects cannibalism in offspring. In combination, these experiments are yielding new insights into how prey avoid the negative effects of predation. Adults exposed to predators lay fewer eggs (Objective 1), but their larvae are more defended against predators. Using biological control agents that differentially target adults and their offspring may result in more successful control. To complete this Objective, we need to finish data collection, finish analyzing the data, and write the second manuscript.

Publications

• Type: Journal Articles Status: Published Year Published: 2017 Citation: Tigreros, N, R. Norris, E. Wang, J. S. Thaler. 2017. Maternally induced intraclutch cannibalism: an adaptive response to predation risk? Ecology Letters, in press.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Wetzel, W. C. and J.S. Thaler. 2016. Does plant trait diversity reduce the ability of herbivores to defend against predators? The plant variability-gut acclimation hypothesis. Current Opinion in Insect Science 14:25-31.

Progress 03/01/15 to 02/29/16

Outputs
Target Audience:We have presented this research to the general public at the annual Insectapalooza open house which is attended by several thousand people in Upstate New York. One of the postdocs, Natasha Tigreros, working on the project gave a presentation about this research at the Ecological Society of America meeting in August 2015. I presented results from this research at the Entomological Society of America Annual meeting in a symposium on Agricultural Applications of non-consumptive effects. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The six undergraduates working on the project received one on one mentoring from and the two postdocs associated with the project, Natasha Tigreros and Will Wetzel. Two of the students on the project also conducted independent research. Both of the postdocs and one of the undergraduates also attended a two-day professional development retreat. Three of the undergraduate students and the two postdocs received constructive feedback on their research at our weekly lab meetings, in the Plant Insect Interactions seminar course, and the postdocs attended the Ecological Society of America Annual meeting. In addition, the two postdocs attended a biweekly writing workshop run by the lab group aimed at improving their writing. How have the results been disseminated to communities of interest?We have presented this research to the general public at the annual Insectapalooza open house, the Ecological Society of America meeting in August 2015 and the Entomological Society of America Annual meeting in a symposium on Agricultural Applications of non-consumptive effects. What do you plan to do during the next reporting period to accomplish the goals?This coming year we will be writing up our results from Objectives 1 and 3, continuing experiments targeted at different aspects of Objectives 1 and 2, and beginning in earnest our efforts on the physiological mechanisms in Objective 2.

Impacts
What was accomplished under these goals? We have made substantial progress on Objective 1 and 3. Plant resistance strongly affected how young larvae responded to the predator. On low-resistance plants, first instar larvae reduced feeding and had lower mass in the predation risk treatment. However, on high-resistance plants beetle sibships had divergent responses to predation risk early in life, some increasing and others decreasing feeding. Older larvae consistently reduced feeding and mass in the presence of the predator on both low- and high-resistance plants. In spite of reduced feeding through most of larval development, larvae on both low- and high- resistance plants compensated for predation risk by the time they reached pupation as life-time feeding and pupal mass did not differ between treatments. This compensation was due to increased assimilation efficiency early in life and compensatory feeding and delayed development later in life. In spite of apparent compensation in terms of pupal mass, larval plant resistance and predation-risk treatments had effects on the adult stage and the offspring. Adult beetles that had been exposed to predation stress as larvae, but not as adults, had lower fecundity. There was substantial family-level variation in the behavioral (feeding reduction) and physiological (assimilation efficiency increase) responses to predation risk and these responses were positively correlated with each other. There are both maternal and genetic components to this variation. The offspring of beetles exposed to predators as larvae showed reduced growth and feeding in spite of similarity in egg mass. The variation in feeding responses of the different sibships resulted in different fitness costs; the greater the reduction in feeding in the predation risk treatment the greater the reduction in fitness on high-resistance plants, although they were not correlated on low resistance plants.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Claflin, S., J.S. Thaler, A. Power. 2015. Predators, host abundance, and host spatial distribution affect the movement of wingless non-colonizing vector Rhopalosiphum padi (L.) and PVY prevalence in an oat/potato system. Arthropod-Plant Interactions 9:301-309. 10.1007/s11829-015-9370-3
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Orrock, J.L., A. Sih, M.C.O Ferrari, R. Karban, E.L. Preisser, M.J. Sheriff, and J.S. Thaler. 2015. Error management in plant allocation to herbivore defense. Trends in Ecology and Evolution 8:441-445. http://dx.doi.org/10.1016/j.tree.2015.06.005

Progress 03/01/14 to 02/28/15

Outputs
Target Audience: This year, the results of our research were presented to ecologists at the Ecological Society of America Annual meeting, entomologists at the Entomological Society of America meeting and chemical ecologists at the Symposium for Insect Plant Interactions. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? The four undergraduates received one on one mentoring from the Project Director and the postdoctoral researchers (Natasha Tigreros and Will Wetzel) working on the project. The graduate student, Sara Hermann,got experiencebypresenting her research at several international conferences including the Symposium on Insect Plant Interactions and at the International Society for Chemical Ecology Annual meeting. The postdoc, Natash Tigreros, participated in a two-day professional development retreat. The two postdocs also got experience and constructivefeedback presenting their research findings and future plans at the Plant Insect Interactions seminar course. How have the results been disseminated to communities of interest? We have presented our research for the general public at the annual Insectapalooza Open house which is attended by several thousand people from Upstate New York. A graduate student involved in the project has presented these research concepts to elementary school children in the Ithaca area as part of a program to interest young children in science. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? We made significant progress on Objective 1: Determine how plant resistance influences the strength of non-consumptive effects on pests. We compared the consumptive and non-consumptive effect of the predator on prey and plant damage in three species: tobacco hornworm caterpillars (Manduca sexta), Colorado potato beetle larvae (Leptinotarsa decemlineata) and cabbage looper (Trichoplusia ni) and have found that the non-consumptive effect accounts for at least 50% of the effect of the predator on plant damage in all three species. All three species respond to the presence of the predator by greatly reducing their feeding but varied in how they offset the detrimental effects of reduced food intake. Our research with aphids shows that risk of predation by ladybugs increases aphid wing production, dispersal of wingless aphids and aphid fecundity and that these effects are greater on plants with low levels of resistance compared to high levels of resistance. We have started working on Objective 2: Determine behavioral, physiological, and developmental mechanisms by which prey compensate for responses to predation risk in different environmental conditions. Our results to date show that prey condition, influenced by both plant quality and larval cannibalism greatly influence behavioral responses of prey to predation risk. We find that small prey are less likely to reduce feeding in the presence of the predator and we are currently investigating how physiological and developmental mechanisms change in low and high condition individuals. We are currently developing methods for measuring metablic and hormonal responses to predation risk. We will begin work on Objective 3 in the upcoming year.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Thaler, J.S., E.L. Olsen, I. Kaplan. 2015. Jasmonate-induced plant defenses and prey availability impact the preference and performance of an omnivorous stink bug, Podisus maculiventris. Arthropod-Plant Interactions, in press. DOI: 10.1007/s11829-015-9357-0
• Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: Kersch-Becker, M and J.S. Thaler. 2015. Plant resistance reduces the strength of consumptive and non-consumptive effects of predators on aphids. Journal of Animal Ecology, in press.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Kaplan, I., S.H. McArt, Thaler, J.S. 2014. Plant defenses and predation risk differentially shape patterns of consumption, growth, and digestive efficiency in a guild of leaf-chewing insects. Plos One: 9(4) e93714
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Hermann, S.L. and J.S. Thaler. 2014. Prey Perception of Predation Risk: volatile chemical cues mediate non-consumptive effects of a predator on a herbivorous insect. Oecologia 176:669-676. DOI 10.1007/s00442-014-3069-5