Impacts of climate change on the performance of an insect pest and associated consequences for tritrophic interactions

Defended on the 11th December 2019

Funding: French national research agency

Supervisors: Jérôme Moreau, Philippe Louâpre and Denis Thiéry

Started in October 2016

Abstract

Global warming poses a major challenge to living organisms, particularly for ectothermic animals like insects, whose physiology and behaviour are closely related with direct thermal surroundings. This thesis aims at experimentally investigating the impacts of climate change on the overall performance of a major grapevine pest, the European grapevine moth (Lobesia botrana), and the associated consequences for interactions involving this phytophagous insect and adjacent trophic levels, more specifically natural enemies (parasitoids). The experiments conducted focus on three facets of climate change: an increase in mean temperature, an alteration of daily thermal range, and the occurrence of heat waves as extreme thermal events. Results highlight an impact of temperatures on both life-history traits related with larval performance (defensive abilities of caterpillars) and adult reproductive success, with demonstrated repercussions for the interaction between this pest and an oophagous parasitoid. Furthermore, they reveal an important variability of thermal responses occurring among traits and even facets of climate change, thereby suggesting complex consequences of this phenomenon in terms of pest population dynamics. Hence, predicting a species response to climate change requires adopting an integrative perspective of the biology of the focal species while considering the complexity of changes occurring in insect direct thermal environment.

Keywords

multi-trait approach, thermal fluctuations, host-parasitoid interactions, Lobesia botrana, climate change, grapevine

Jury

Patricia Gibert, université Lyon 1 – referee
Philippe Vernon, université Rennes 1 – referee
Joan Van Baaren, université Rennes 1 – examiner
Sylvain Pincebourde, université de Tours – examiner
Jérôme Moreau, université Bourgogne Franche-Comté – supervisor
Philippe Louâpre, université Bourgogne Franche-Comté – cosupervisor

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Impacts of climate change on the performance of an insect pest and associated consequences for tritrophic interactions

Defended on the 11th December 2019

Funding: French national research agency

Supervisors: Jérôme Moreau, Philippe Louâpre and Denis Thiéry

Started in October 2016

 

Abstract

Global warming poses a major challenge to living organisms, particularly for ectothermic animals like insects, whose physiology and behaviour are closely related with direct thermal surroundings. This thesis aims at experimentally investigating the impacts of climate change on the overall performance of a major grapevine pest, the European grapevine moth (Lobesia botrana), and the associated consequences for interactions involving this phytophagous insect and adjacent trophic levels, more specifically natural enemies (parasitoids). The experiments conducted focus on three facets of climate change: an increase in mean temperature, an alteration of daily thermal range, and the occurrence of heat waves as extreme thermal events. Results highlight an impact of temperatures on both life-history traits related with larval performance (defensive abilities of caterpillars) and adult reproductive success, with demonstrated repercussions for the interaction between this pest and an oophagous parasitoid. Furthermore, they reveal an important variability of thermal responses occurring among traits and even facets of climate change, thereby suggesting complex consequences of this phenomenon in terms of pest population dynamics. Hence, predicting a species response to climate change requires adopting an integrative perspective of the biology of the focal species while considering the complexity of changes occurring in insect direct thermal environment.

Keywords

multi-trait approach, thermal fluctuations, host-parasitoid interactions, Lobesia botrana, climate change, grapevine

 

Jury

Patricia Gibert, université Lyon 1 – referee
Philippe Vernon, université Rennes 1 – referee
Joan Van Baaren, université Rennes 1 – examiner
Sylvain Pincebourde, université de Tours – examiner
Jérôme Moreau, université Bourgogne Franche-Comté – supervisor
Philippe Louâpre, université Bourgogne Franche-Comté – cosupervisor