Patch quality and genotype-by-environment interactions shape dispersal and post-settlement survival in a butterfly metapopulation

Active dispersal is driven by extrinsic and intrinsic factors at the three stages of departure, transfer, and settlement. Most empirical studies capture only one stage of this complex process, and knowledge of how much can be generalized from one stage to another remains unknown. Here we use genetic assignment tests to reconstruct dispersal across five years and 232 patches of a butterfly metapopulation. We link individual dispersal events to weather, landscape structure, size and quality of patches, and individual genotype to identify the factors that influence the three stages of dispersal and post-settlement survival. We found that nearly all tested factors strongly affected departure probabilities, but that the same factors explained very little variation in realized dispersal distances. Surprisingly, we found no effect of dispersal distance on post-settlement survival. Rather, survival was influenced by weather conditions, carry-over effects of natal patch quality, and a strong interaction between genotype and occupancy status of the settled patch, with more mobile genotypes having higher survival as colonists rather than as immigrants. Our work highlights the multicausality of dispersal and that some dispersal costs can only be understood by considering extrinsic and intrinsic factors and their interaction across the entire dispersal process.