Meeting Abstract
The ‘thermal performance curve’ is the conceptual foundation of thermal adaptation theory. It describes the relationship between fitness (or a fitness proxy) and body temperature. Although these curves are typically used to project the effects of climate change on species with an implicit assumption that they are static in time, it is possible that they can evolve at a rate sufficient to significantly reduce extinction probabilities. Recent analyses have shown that shifts in local climates can result in strong selection on thermal performance curves, hinting at the possibility of rapid evolution. Nevertheless, few data are available on the genetic basis of thermal physiology in vertebrates, and we therefore have limited ability to determine the response to selection. To address this issue, we measured the additive genetic basis of thermal preference and thermal sensitivity of sprint speed in the brown anole lizard (Anolis sagrei) reared in a common garden experiment. Our previous work revealed that this species undergoes strong directional selection in nature when exposed to a rapid change in their thermal environment. Nevertheless, using both traditional and function-valued approaches, we show that parameters of the thermal performance curve in the brown anole have low or undetectable narrow-sense heritabilities, suggesting that selection is unlikely to result in rapid evolution. By contrast, aspects of thermal preference are highly heritable, implying that thermoregulatory behavior can evolve quickly. Our results suggest that the most likely avenues of short-term adaptation to climate change in the brown anole are evolutionary change in thermoregulatory efficiency and plastic change in thermal physiology.
