Meeting Abstract
Two broad (and non-mutually exclusive) hypotheses have been proposed to explain diversity in the plasticity of thermal physiology. The first is adaptive, and proposes that greater plasticity should evolve in more variable thermal environments. The second is based on evolutionary constraints, and says that adaptation to more extreme thermal environments leads to a decrease in plasticity. We tested these hypotheses by calculating acclimation flexibility of the Critical Thermal Maximum (CTmax) and Critical Thermal Minimum (CTmin) for hundreds of ectotherms in five major clades from published studies. For the environmental variability hypothesis, we tested for an association between flexibility and latitude. For the evolutionary constraint hypothesis, we tested for associations between flexibility and species highest thermal tolerance limits. We found little support for either hypothesis. However, we did find that flexibility tends to vary by habitat type and clade, which may have important implications with respect to broad patterns of vulnerability to climate change.
