Skink Reproduction and Sexual Dimorphism: Eumeces fasciatus in the Southeastern United States, with Notes on Eumeces inexpectatus

Abstract

The morphology and reproductive biology of Eumeces fasciatus and E. inexpectatus were studied in the southeastern United States. Eumeces inexpectatus are slightly larger in body size than E fasciatus. Males are larger than females in E. inexpectatus but not in E. fasciatus. In both species there is sexual dimorphism in head size (males larger) independent of body size among sexually mature adults, apparently as a consequence of sexual selection. Individuals of both species reach sexual maturity in their second spring at an age of 21 months. Females of E. fasciatus lay eggs in nests constructed in hardwood logs, trees, and stumps, often in proximity to nests of other females. Eggs deposited in late May and early June are brooded by females and hatch in late July or early August. Clutches brooded in the laboratory revealed that eggs increase in mass considerably during development, but offspring hatch at a size much smaller than eggs at deposition. In addition, significant differences were found in hatchling size among clutches. Brooding behavior and the potential significance of variable offspring size are discussed.