Abstract

Green Anoles (Anolis carolinensis: Sauria, Polychrotidae) have been reported to alternate the sex of successive offspring, a pattern not known in any other vertebrate. However, no adaptive explanation has been posed for this novel pattern in Anolis, and the extent to which sex alternation is a phylogenetic constraint versus a facultative reproductive strategy in this taxon has not been determined. I examined consecutive offspring produced by A. carolinensis and A. sagrei from four locations in the southeastern United States over three years under a common garden design in order to identify population and species level variation in patterns of offspring sex independent of maternal and incubation environments. These data do not indicate sequential alternation of offspring sex in either species and allow for rejection of even small deviations from the pattern expected under random production of the sexes. I conclude, therefore, that anole reproduction is not universally constrained to a pattern of sequential alternation of offspring sex and speculate that this pattern is conditionally manifest depending on interactions between stress hormones and fluctuations in parental resources in the form of maternally deposited yolk steroids.