Meeting Abstract
As the intensity of heat waves and the occurrence of extreme weather patterns increases, ectotherms are likely to rely on heat-shock responses to counteract rapidly warming body temperatures and reduce the costs associated with heat stress. While heat shock responses tend to be conserved across taxa, the plasticity of these responses to increasing environmental temperatures is unknown. If warmer environmental temperatures reduce the strength of heat-shock responses, then the reliance on these plastic responses as a short-term mechanism of lethal temperature avoidance could dwindle as the climate warms. Here, we performed an experiment using five populations of common lizards (Zootoca vivipara) distributed along an elevational gradient to test how heat-shock responses (i.e. heat-hardening) change with acclimation to warmer environmental conditions. We measured cold tolerance (CTmin), preferred body temperatures (Tpref), heat tolerance (CTmax) and the heat-hardening response (the change in CTmax with heat shock) before and after acclimation to temperatures 2C above mean environmental conditions. We found that the strength of the hardening response was attenuated for populations at higher elevations, but not for populations at low elevations. Acclimation also shifted baseline heat and cold tolerances as well as preferred temperatures. These finding suggests that consistent and slow increases in environmental temperatures might over time reduce the ability of populations to mount short-term responses to rapid environmental changes.
