Study of dispersal and associated life-history traits in laboratory populations of Drosophila melanogaster

Abstract

Dispersal has long occupied a pivotal position in many ecological and evolutionary studies, but the evolution of dispersal as a trait still remains under-studied. The study reported here empirically demonstrates for the first time, the evolution of dispersal kernel (distribution of dispersed organisms across space). Within 20 generations of selection on laboratory populations of Drosophila melanogaster, a 100% increase in dispersal propensity and an increment of 35% in dispersal ability has been observed. Life-history assays done on desiccation resistance and female fecundity have not shown a significant trade-off in the selected populations, which may hint at the ease and speed with which dispersal can evolve. Additionally, in contrast to some past studies, we could not find any significant association of life-history traits between dispersers and non-dispersers within a given population. The findings can have major implications on a variety of theoretical models and experimental studies involving assumptions about the constancy of kernel in the case of active dispersal. The results of this work also stress the importance of longer selection experiments in order to delineate the relationship between life-history and dispersal traits.