The role of spatial structure in the evolution of parental care and sexual selection

Background/Question/Methods

Parental care is an important life-history trait that impacts individual fitness through offspring survivorship and/or quality. Given sexual selection and parental care’s potential to affect evolutionary dynamics of other traits through offspring survival, honest signaling of good genes, and effective population size, and due to potential trade-offs such as time or energy allocation, parental care is often examined in conjunction with sexual selection. Both parental care and sexual selection can be influenced by dispersal, as local relatedness typically determines whether or not it is beneficial to be choosy during mate selection (sexual selection) and whether it is worth provisioning offspring (parental care). The spatial relationship among patches can gene flow across a landscape. Here, we examine the relationship between sexual selection and parental care in the face of sex-biased offspring dispersal in spatially explicit landscapes. Specifically, we use an individual-based model in which males and females mate and their offspring move between patches, with a focus on the role of patch interconnectivity.

Results/Conclusions

We find that the spatial relationship between patches determines the optimal level of parental care. Specifically, we find that when dispersal is asymmetrical between patches and contains edge patches, patch-specific differences in mean parental care and sexual selection evolve. This suggests that, for species that disperse across along a gradient such as dispersing down a river or down an elevation gradient, the more abundant sex in the population can be expected to provide more parental care or be choosier dependent on where along the gradient it is located. In future studies, it will be interesting to see if the results of patches differing in strength of sexual selection and parental care along a gradient hold true under natural settings.