Thermal stress in insects: a comparative study of low temperature performance of Central European grasshoppers

Bachelor of Science Caio Vitor Sales Lima de Oliveira, BSc

Master's thesis

Abstract:

The study of heat tolerance mechanisms and adaptation strategies in grasshoppers, with particular emphasis on chill-coma recovery time (CCRT), serves as a crucial benchmark for understanding their physiological responses to temperature fluctuations. Field collections carried out in the summer months of August to September 2023 enabled the careful recording of 14 grasshopper species at different geographical locations in the Czech Republic. Contrary to prevailing assumptions, our results refute that habitat type, including xerothermophily, significantly influences CCRT. Instead, we provide compelling evidence for intrinsic physiological adaptations that allow locusts to mitigate temperature stress in different habitats. In particular, we observe significant sex-specific differences in recovery times, with females exhibiting a faster recovery rate. This observation highlights sex-specific physiological strategies to optimize survival and reproductive capacity amid fluctuating environmental temperatures. Furthermore, our analysis reveals a compelling correlation between body mass and recovery durations, emphasizing the pivotal role of physical and metabolic characteristics in grasshopper thermal tolerance. This correlation further investigates the intricate interplay between body size and thermoregulation strategies among ectothermic organisms. Although our study was temporally constrained to a specific seasonal window, it underscores the critical significance of considering phenological and environmental diversity in evaluating ectotherm adaptation to climate dynamics. By amalgamating ecological, physiological, and evolutionary insights, our research enriches the discourse on grasshopper thermal biology and adaptability in changing climates. Moreover, our findings carry broader implications, contributing to refining conservation tactics and enhancing predictions regarding biological responses to global climate shifts. This underscores the urgent imperative of integrating species-specific traits and environmental adaptations in assessing thermal tolerance and physiological resilience among grasshoppers, thereby informing more productive strategies for biodiversity conservation in an era of rapid ecological change.

Keywords

Climate change, chill‐coma recovery, stress resistance, lower thermal limits

Language used: English

Date on which the thesis was submitted / produced: 29. 3. 2024

Thesis defence

• Date of defence: 23. 5. 2024
• Supervisor: doc. Ing. Michal Knapp, Ph.D.
• Reader: Pavel Jakubec, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme:
Nature Conservation