Ecophysiological and ecotoxicological consequences of global changes in terrestrial insects

• Main Author: Engell Dahl Bjørge, Julie
• Other Authors: Ecosystèmes, biodiversité, évolution Rennes (ECOBIO), Université de Rennes 1 (UR1)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes 1 (UR1)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Université Rennes 1, David Renault, Martin Holmstrup
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2021
• Subjects: Temperature; Tolerance; Distribution; Pesticide; Multi-Stress; Desiccation; Température; Tolérance; [SDV.EE]Life Sciences [q-bio]/Ecology; environment; Antarctic; Antarc*
• Online Access: https://theses.hal.science/tel-03596489; https://theses.hal.science/tel-03596489/document; https://theses.hal.science/tel-03596489/file/ENGELL_DAHL_BJORGE_Julie.pdf

Terrestrial insects are affected by many environmental factors that vary temporally and spatially at micro- and macroscales. Climate change is moreover affecting the variations of these factors in several ways, with potential cascading effects for insect individuals, populations and communities. This thesis addresses how certain environmental abiotic factors can affect the physiological ecology of insects, with beetles as model insects. Firstly, I examined how geographic expansion could affect the thermal tolerance of invasive insects. For that purpose, different populations from the beetle Merizodus soledadinus invading a sub-Antarctic Island were used. This investigation illustrated a general pattern that most populations were best at coping with either cold or heat, and a few did not excel at recovering from either, compared to other populations of the species. This indicates that there are trade-offs between insects having high tolerance to hot or cold temperatures, and other un-investigated traits. Further, researches were conducted to elucidate tolerance levels and responses of insects to temperature and insecticide (cyfluthrin) stress, and investigate how thermal tolerance can be affected by pesticides. Different populations of the invasive pest beetle Alphitobius diaperinus, i.e. one laboratory-reared population and three populations collected from different farms were used. The investigations revelaed that all populations of A. diaperinus had a large thermal tolerance breadth. However, farm collected populations had a wider temperature tolerance than the investigated laboratory reared population. It evidences how variable environments experienced by farm-collected populations can increase tolerance as compared with the individuals reared at constant temperature. In addition, pre-treatment with daily heat spikes decreased the recovery time of the insects to subsequent extreme heat exposure (but not cold), whereas pesticide exposure prior to temperature stress increased recovery times. This provided ...