Two physiological regulatory mechanisms for thermotolerance in insects

ALVAREZ-COSTA, A.; COLECCHIA-CORSO, M.L.; PONTES, G.; SCHILMAN P.E.

Simposio; International Symposium on the Environmental Physiology of Ectotherms and Plants (ISEPEP2022); 2022

Temperature is an important abiotic factor aecting many physiological processes in insects, which influence their geographical distribution. The thermal tolerance range is given by the minimum (CTmin) and maximum critical temperature (CTmax) with extreme temperatures having deleterious eects. So, there are many behavioral and physiological mechanisms to avoid extreme temperatures. We analyzed two physiological mechanisms, i.e., the role of HSPs and the evaporative cooling in Rhodnius prolixus, a model organism in insect physiology, and an important vector of Chagas disease. Results showed that exposure to moderate heat (1h at 37C) or cold (1h at 10C) increase thermotolerance by aecting both, CTmax and CTmin, and HSP70/HSP90 RNAi knockdown insects showed lower resistance to low and high temperatures compared with their controls. In addition, we demonstrated, by thermolimit respirometry and video thermo-imaging, a signicant decrease of body-temperature and extension of its upper limits of temperature resistance (CTmax) by evaporative cooling. These results provide further insight into the physiological adaptations of insects to harsh environmental conditions aecting their geographical distribution, which is of great importance especially when analyzing invasive insects, pests or vectors of diseases such as triatomines.