Compensation for Altitudinal Changes in the Thermal Environment by Some Anolis Lizards on Hispaniola

Abstract

Populations of the Anolis cybotes species group on Hispaniola behaviorally compen- sate for changes in the thermal environment associated with altitude. Lizards occupy more open habitats, increase basking frequency, and restrict times of activity at high elevation: a result is that the change in mean cloacal temperature with elevation is very small relative to that known for other anoles. In contrast to this large behavioral variation among populations, physiological differences appear to be minor. In this regard, the evbotes group has several parallels with the well-studied cristatellus group of Anolis on Puerto Rico. However, the cybotes group has no equivalent to Anolis gundlcahi, which employs physiological adaptations to compensate for different thermal environ- ments. Kev ivords: altitudinal variation; Anolis lizards; basking; behavioral thermoregulation; body temperature; critical thermal maximum; habitat shift; Hispaniola.