Mate limitation causes sexes to coevolve towards more similar dispersal kernels

Sex-specific dispersal behavior has been documented in a wide range of different species. Avoidance of inbreeding and kin competition as well as different benefits of philopatry have been invoked as explanations for these patterns. All of these factors have, however, focused on explaining why dispersal behavior differs between the sexes. In this paper, we make the case that dispersal causes an increase in spatial variability in the sex ratio which can reduce the local availability of mates, and thus feed back to influence the evolution of sex-specific dispersal and lead to more, rather than less, similar dispersal behavior in the sexes. We investigate this mechanism in two different models, first in a conceptually simple case showing why the coevolutionary effect arises, second in an individual-based model where we model a population in explicit space with dispersal implemented as dispersal kernels. While our mechanism is not expected to completely remove sex-bias in dispersal, it can act alongside other selection pressures to reduce such biases. Our model thus shows that dispersal of one sex can have an effect on the selective pressures on the opposite sex, without implementing inbreeding avoidance or differential benefits or costs of dispersal.