ST. MARY, Colette M; SINGLER, Heather; SABASTIZABEL, Maria N; University of Florida; University of Texas Marine Science Institute; University of Florida: Consequences of variation in sexual selection for sex allocation in simultaneous hermaphrodites: effects of population density

Sexual selection typically consists of competition among males for access to mates and female preference for males. In simultaneous hermaphrodites these processes can still have important consequences for mating success via male and female function and hence for the mating system and sex allocation. Sperm competition is one form of male-male competition that has been widely considered in the sex allocation literature. However, other behavioral components of male-male competition and female choice have been less well studied. We consider the effects of these sources of variation in male mating success in a dynamic state variable model of hermaphroditic sex allocation. We then compare the predictions of this model to the sex allocation patterns of the gobies Lythrypnus dalli and Lythrypnus zebra. These species differ in average natural density and mating system and we have sampled populations at high and low density for each species. Thus, by comparison to the predictions of our model, make inferences about the importance of variation in sexual selection for sex allocation between and within these species.