Meeting Abstract

P1.99  Jan. 4  Thermal Microhabitat Selection in Hatchling Anoles WALGUARNERY, J.W.; University of Tennessee jwalguar@utk.edu

The Caribbean lizards of the genus Anolis serve as a model taxon in the study of interspecific competition and comprise the basis for one of the most well-developed conceptualizations of multidimensional niche partitioning. Lizards, as ectothermic vertebrates, depend on variation in the thermal environment to maintain body temperature near species-specific physiological optima, and thermal microhabitat has been regarded as a major axis along which sympatric anoles partition resources. Typically, assessment of interspecific partitioning of thermal microhabitat is inferred based on measurement of body temperature in adult lizards, despite theoretical and empirical reasons to assume a variable relationship between body temperature and thermal resources. In particular, body size is expected to influence thermal exchange with the environment and therefore the pattern of thermal microhabitat utilization. In the present study, I directly determine thermal microhabitat preference in hatchlings of the purported competitors, A. carolinensis and A. sagrei through laboratory observation of movement over fine-scale substrate temperature gradients and describe empirically derived rates of heating and cooling via conduction. Despite high variance in selected temperatures, hatchlings of these species exhibited a significant difference in mean thermal microhabitat preference. Results of this investigation contrast those for adult anoles and suggest important effects of scale and ontogeny in resource partitioning.