Meeting Abstract

S8-2.2  Jan. 6  Adaptation, sexual dimorphism, and ecolomorphological diversity in Caribbean Anolis lizards BUTLER, MA; University of Hawaii at Manoa

Sexual dimorphism is widespread and substantial throughout the animal world. It is surprising, then, that such a pervasive source of biological diversity has not been integrated into studies of adaptive radiation, despite extensive and growing attention to both phenomena. Rather, most studies of adaptive radiation either group individuals without regard to sex or focus solely on one sex when studying the relationship between morphology and resource use. However, sexual dimorphism may be constrained by the breadth of ecological variation, or "species packing" may be increased by sexes occupying different regions of available ecological and morphological space. In this study, I show that sexual differences contribute substantially to the ecomorphological diversity produced by the adaptive radiation of Caribbean Anolis lizards: within anole species, males and females occupy mostly non-overlapping parts of morphological space; the overall extent of sexual variation is large relative to interspecific variation; and the degree of variation depends on ecological type. These results have implications for both studies of sexual dimorphism and adaptive radiation: (1) these results cannot be explained exclusively by sexual selection; no matter the proximate mechanism, ecological factors strongly influence the evolution of Anolis sexual dimorphism. (2) when sexual dimorphism in ecologically-relevant traits is substantial, ignoring its contribution may significantly underestimate the adaptive component of evolutionary radiation.