Measuring behavioral thermal tolerance to address hot topics in ecology, evolution, and conservation

作者：Camacho Agustin^*; Rusch Travis; Ray Graham; Telemeco Rory S; Rodrigues Miguel Trefaut; Angilletta Michael J

来源：Journal of Thermal Biology, 2018, 73: 71-79.

DOI：10.1016/j.jtherbio.2018.01.009

• Behavioral thermal tolerance
• CTMAX
• Preferred body temperature
• Voluntary thermal maximum
• Thermoregulation
• Panting

Understanding the impacts of anthropogenic climate change requires knowing how animals avoid heat stress, and the consequences of failing to do so. Animals primarily use behavior to avoid overheating, but biologists' means for measuring and interpreting behavioral signs of stress require more development. Herein, we develop the measurement of behavioral thermal tolerance using four species of lizards. First, we adapt the voluntary thermal maximum concept (VTM) to facilitate its measurement, interpretation, and comparison across species. Second, we evaluate the sensitivity of the VTM to diverse measurement options (warming rate, time of day, etc) across four species with highly different life histories. Finally, we clarify the interpretation of VTM in two ways. First, we show the effects of exposure to the VIM on panting behavior, mass loss, and locomotor function loss of two species. Second, we compared the VIM with the preferred body temperatures (PBT) and critical thermal maximum (CTMAX) intraspecifically. We found that the VTM can be consistently estimated through different methods and methodological options, only very slow warming rates affected its estimates in one species. Exposure to the VIM caused panting between 5 and 50 min and induced exceptionally high mass loss rates. Loss of locomotion function started after 205 min. Further, the VTM did not show intraspecific correlations with the PBT and CTMAX. Our study suggests the VTM is a robust and flexible measure of thermal tolerance and highlights the need for multispecies evaluations of thermal indices. The lack of correlation between the VIM, the PBT and CTMAX suggests the VIM may evolve relatively free between the other parameters. We make reccommendations for understanding and using the VIM in studies of ecology, evolution, and conservation.

• 出版日期2018-4