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.