Meeting Abstract
Female mate choice is usually implicated in behavioral isolation between species with divergent male ornaments. However, males in many sexually dimorphic species with traditional sex roles also demonstrate mate choice, suggesting they could also play an important role in behavioral isolation between species. Many examples of male choice demonstrate preferences for indicators of female fecundity that often do not vary across species, effectively excluding male mate choice from any role in the maintenance of species boundaries. But, male mate choice for homotypic females has been observed as well, suggesting that at least in some cases, male choice contributes to behavioral isolation. We therefore test the role of male mate choice in the maintenance of species boundaries for two species of darters (Percidae: Etheostoma), sexually dimorphic freshwater fish with visually elaborate males and drab females. Dichotomous choice assays using sympatric darters Etheostoma barrenense and E. zonale tested male preference for size-matched, gravid conspecific and heterospecific females, thus reducing the possibility that males were selecting for general indicators of fecundity. Results show that males of both species strongly prefer conspecific females and that male preference for conspecific females is as strong as female preference for conspecific males in E. barrenense. Calculating the accumulated contribution of male mate choice, female mate choice, and male-male competition to behavioral isolation suggests that male mate choice may have a larger role in the maintenance of species boundaries than generally predicted in this system. Our results suggest that the contribution of male choice to behavioral isolation may be underestimated in sexually dimorphic species with elaborate males.
