Meeting Abstract
91.4 Wednesday, Jan. 7 Testing models of behavioral thermoregulation in a spatially-explicit context: a large-scale field experiment ANGILLETTA, M.J.*; SEARS, M.W.; SCHULER, M.S.; RUSCH, T.W.; MITCHELL, W.A.; Indiana State Univ., Terre Haute; Southern Illinois Univ., Carbondale; Indiana State Univ., Terre Haute; Univ. of Wisconsin, Stevens Point ; Indiana State Univ., Terre Haute mangilletta@indstate.edu
More than three decades after the birth of a quantitative theory of thermoregulation, we still cannot predict the body temperatures of animals in natural environments. For example, a recent comparative analysis indicated that lizards thermoregulated less accurately when the energetic costs of thermoregulation seemed low. Yet theory predicts the exact opposite! This discrepancy likely results from models and experiments that do not account for the spatial distribution of temperatures. We used computer simulations to predict the effect of spatial structure on the costs and benefits of thermoregulatory behavior. All else being equal, thermoregulation confers a greater net benefit in a patchy environment than it does in a clumped environment. We tested this model in replicated arenas (400 m2) at Sevilleta National Wildlife Refuge, New Mexico. We manipulated the temperature and patchiness of each arena by attaching shade cloth to a wire scaffold. We recorded the body temperatures of 27 spiny lizards (Sceloporus jarrovi), each of which experienced the environments of three arenas. In general, lizards thermoregulated more accurately as their environments heated throughout the morning. However, lizards thermoregulated more accurately in patchy environments than they did in clumped environments. This observation accords with the predictions of our spatially explicit model of optimal thermoregulation.
