Many species exist on isolated habitats connected by dispersal of individuals. The evolutionary dynamics between two interacting species can be strongly influenced by the difference in mobility.
Using highly variable genetic markers, Zhou et al. compare the genetic differentiation between a perennial herb, the starry campion Silene stellata (Caryophyllaceae) and its major pollinator moth, Hadena ectypa. They find that the plant populations are much more genetically differentiated than the moth. This is supported by the additional result that gene dispersal among the moth populations is more uniform and twice as strong as the plant.