Data from: One step ahead: a parasitoid disperses farther and forms a wider geographic population than its fig wasp host

The structure of populations across landscapes influences the dynamics of their interspecific interactions. Understanding the geographic structure of populations can thus shed light on the potential for coevolution and adaptive responses of interacting species. Parasitism is an important aspect of insect ecology in natural and agricultural settings, and also represents a significant force in the evolution of plant – insect interactions. However, there have been few comparisons of population structure in an insect host and its parasitoid. We used microsatellite markers to analyse the population genetic structure of P. imperialis sp. 1, a pollinating wasp of Ficus rubiginosa, and its main parasitoid, Sycoscapter sp. A, in eastern Australia. Matched sampling was conducted at several sites in two regions separated by approximately 1500 km. We found that pollinators occupying the two regions represent distinct populations, but there was limited genetic structure in the parasitoid across the sampled range. We observed weak patterns of isolation by distance for each species, suggesting that both pollinator and parasitoid are capable of long-distance dispersal. The contrasting geographic structure of host and parasitoid populations could have varying influences on the scale and direction of evolution in each species. Incongruent structure of host and parasitoid populations highlight the potential for geographic mosaics in an ecologically important and evolutionarily significant system, supporting the significance of their role in the coevolution of interspecific interactions. Furthermore, we provide the first report on the population structure of a non-pollinating fig wasp species.