Meeting Abstract
P1.31 Thursday, Jan. 3 Being a mom isn’t always so hot: the effects of reproductive status on thermoregulatory behavior in squamate reptiles LOGAN, Michael*; SEARS, Michael W; ANGILLETTA, Michael J; University of Texas, Arlington; Southern Illinois University; Indiana State University mlogan@uta.edu
Patterns of field body temperatures exhibited by gravid female squamate reptiles often deviate from those temperatures exhibited by nongravid females or males. Typically, oviparous females choose cooler temperatures when gravid, while viviparous females choose warmer temperatures when gravid. Assuming that animals choose body temperatures to maximize fitness, we propose potential explanations for such patterns. For oviparous females, choosing cooler body temperatures could shift activity patterns to earlier times of day, when other ectothermic predators are inactive. For viviparous females, warmer body temperatures might speed the development and gestation time of offspring, minimizing the duration that females carry young. Minimizing this gestational period would reduce the energetic costs of supporting a clutch and potentially enhance survival because females are at risk to predation due to reduced locomotor performance while gravid. Here, we evaluate the hypothesis that oviparous females choose cooler temperatures to minimize mortality by examining the temporal pattern of body temperatures exhibited by gravid female sagebrush lizards. Consistent with our hypothesis, female sagebrush lizards exhibited cooler body temperatures while gravid than when nongravid. Further, cooler temperatures were chosen despite the availability of warmer operative temperatures that could support activity, and the activity of gravid females declined before that of nongravid females and males. To further evaluate the choice of body temperatures when gravid, we suggest that an optimality framework be adopted that quantifies the costs and benefits of temperature selection of females with respect to their survival versus the fitness consequences to offspring given temperature selection.
