Biography:

Professor Angelletta seeks to understand the ecological and evolutionary processes by which temperature affects the physiological performance and life histories of these organisms. Such an understanding is critical because global climate change has and will continue to pose thermal challenges to ectotherms. Currently, his lab is focused on answering several questions, including which environmental conditions influence the degree of behavioural thermoregulation, how does geographic variation in body temperature affect the evolution of the thermal sensitivity of performance, and how does the thermal sensitivity of performance affect the evolution of the life history. He has widely published on the evolutionary theory.

Abstract:

Adaptive thermoregulation in complex landscapes: bridging the gap between theory and data

The growth, survival, and reproduction of an organism depend strongly on body temperature. This thermal sensitivity presumably causes the evolution of thermoregulation, which ensures a relatively constant body temperature despite variation in environmental temperature. Yet decades after the first evolutionary theory of thermoregulation, we still cannot predict the body temperatures of animals in natural environments. Discrepancies between theory and data likely result from models that ignore three major selective pressures: 1) energetic costs that arise from environmental structure, 2) missed opportunities that arise from social interactions, and 3) mortality that arises from predation. We have modeled the impact of these selective pressures on the optimal strategy of thermoregulation. Because we account for the spatial distributions of temperatures, competitors, and predators, our models make novel predictions about the evolution of thermoregulatory behavior. In particular, a patchy distribution of temperature imposes greater selective pressure for thermoregulation than does a clumped distribution. Moreover, the distribution of temperatures interacts with the presence of competitors or predators. We are testing these models in large thermal arenas, which are located in the Chihuahuan desert of New Mexico, USA. In these arenas, we created various thermal landscapes and recorded the thermoregulatory behaviors of spiny lizards (Sceloporus jarrovi). As predicted from our simulations, lizards thermoregulated more accurately in patchy environments than they did in clumped environments. Future tests of our theory will focus on thermoregulation in landscapes that contain competitors or predators.