Adult dispersal and genetic structure of butterfly populations in a fragmented landscape

Metapopulation theory is a powerful tool to predict the future of populations within a fragmented landscape. By coupling demographic and generic studies on such a set of populations of the butterfly Proclossiana eunomia, we show that adult dispersal was oriented along river basins. The comparison of allelic frequencies of populations from different river basins revealed that the presence of stepping stone habitats allows effective gene flow. This leads to a hierarchical system of populations where stepping stone habitats and topographical barriers are the major factors determining their differentiation. Isolation by distance plays a minor part at the spatial scale considered here