Sex-biased dispersal, kin selection and the evolution of sexual conflict.

There is growing interest in resolving the curious disconnect between the fields of kin selection and sexual selection. Rankin’s (2011, J Evol Biol 24, 71-81) theoretical study of the impact of kin selection on the evolution of sexual conflict in viscous populations has been particularly valuable in stimulating empirical research in this area. An important goal of that study was to understand the impact of sex-specific rates of dispersal upon the coevolution of male-harm and female-resistance behaviours. But the fitness functions derived in Rankin’s study do not flow from his model’s assumptions and, in particular, are not consistent with sex-biased dispersal. Here, we develop new fitness functions that do logically flow from the model’s assumptions, to determine the impact of sex-specific patterns of dispersal on the evolution of sexual conflict. Whilst Rankin’s study suggested that increasing male dispersal always promotes the evolution of male harm and that increasing female dispersal always inhibits the evolution of male harm, we find that the opposite can also be true, depending upon parameter values.