Selection for dispersal leads to evolution of kernel and increased locomotor activity in Drosophila melanogaster

Dispersal enables organisms to respond to climate change and habitat degradation and hence it is important to understand dispersal evolution and its consequences. Studies on dispersal evolution often investigate isolated components of dispersal like propensity or ability, thus neglecting how these components and their related costs interact with each other to shape the dispersal kernel. We investigated these issues by evolving replicate populations of Drosophila melanogaster using a setup analogous to increasing habitat-fragmentation over generations. The selected populations showed significantly higher dispersal propensity, ability and rate, which translated into an evolved kernel with a lower skew and kurtosis and a 67% increase in spatial extent. The enhanced dispersal was attributable to significantly greater locomotor activity. The flies paid a cost in terms of reduced desiccation resistance, but showed no reduction in fecundity. Thus, under the right conditions, multiple aspects of dispersal can evolve simultaneously, with potentially serious ecological consequences.