A regulatory mechanism for thermotolerance in kissing bugs, and its consequences for geographical distribution

SCHILMAN, P.E.; ALVAREZ-COSTA, A.

Congreso; XXVI International Congress of Entomology (ICE 2022); 2022

Temperature affects practically all the physiological processes of organisms, and is the most important abiotic factor in the geographic distribution of insects. The thermal tolerance range is given by the minimum critical temperature (CTmin) and the maximum critical temperature (CTmax). I will present results showing how the geographical distribution of seven species of triatomines, vectors of Chagas disease, can be explained, in part, by their thermo-tolerance range. Briefly, we analyzed the relationship between the ecological niche and the limits of the physiological thermal niche in seven species of triatomines. For this, we combined two methodological approaches: species distribution models, and physiological tolerances. In triatomines, thermo-tolerance range increases with increasing latitude mainly due to better cold tolerances, and we also found positive effects of acclimation on thermotolerance, especially on the CTmin. For one of the seven species studied, i.e., Rhodnius prolixus, a model organism in insect physiology, and an important vectorof Chagas disease, we demonstrated, by thermolimit respirometry and video thermo-imaging, a significant decrease of body-temperature and extension of its upper limits of temperature tolerance (CTmax) by evaporative cooling. Studying the relationship between the physiological mechanisms that allow modulating the effects of high temperatures and geographical distribution is of great importance especially when analyzing invasive insects, pests or vectors of diseases such as triatomines.