Evolution of interspecific variation in marine larval dispersal kernels: the role of larval navigation ability

Dispersal is an integral part of the life cycle of most organisms, with consequences for individual fitness, population genetic structure, species ranges, community assembly and conservation. Dispersal patterns, and the traits underlying them, have the potential to evolve in response to selection and other evolutionary forces. Here, we investigate two opposing components of selection by quantifying their corresponding costs in a spatially autocorrelated, patchy environment. Kin competition is expected to select for longer dispersal distances, while the risk of being unable to locate suitable habitat should favor shorter dispersal distances. We illustrate the tradeoff between these two components of selection by considering their costs across dispersal distances, among dispersal kernels and through evolutionary time. We then apply this framework to an unsolved empirical problem: explaining the interspecific variation in spatial scale of marine larval dispersal. We propose variation in the ability of larvae to navigate to suitable habitat as a potential source of variation in dispersal distance, and find that species with greater navigation ability evolve dispersal kernels that allocate more offspring to longer distances. Navigation also decreases the impact of both costs, suggesting the potential for coevolution of navigation ability and the dispersal kernel.