Population substructures in the soil invertebrate Orchesella cincta,as revealed by microsatellite and TE-AFLP markers

Microsatellite and three enzyme-amplified fragment length polymorphism (TE-AFLP) DNA markers were used to describe the population genetic structure in the soil dwelling collembolan Orchesella cincta (L.). Two forests were sampled according to a three-level nested hierarchical design, with fixed distances among samples within a parcel and among parcels within a forest. The largest component of variation was found at the smallest scale, within parcels (77-97%), while the smallest component of variation was found between forests. The two different methods to study population structure indicated a similar allocation of variance. Population genetic substructuring was revealed between samples on a scale of 50 m; the degree of substructuring however, varied between parcels and forests. One forest showed a high degree of structure as revealed by microsatellites, while another showed a low degree of structure. A significant deviation from random-mating (average FIS = 0.23) over the two forests was detected. Two of 18 samples showed a difference in population genetic structure between males and females. We discuss the fact that the population genetic structure of O. cincta is significantly affected by long-range dispersal, even though it is a small and wingless insect. This interpretation is supported by observations on tree-climbing behaviour in this species that may facilitate air dispersal. As a consequence, the assumption that migration a priori may be neglected in demographic analysis of O. cincta is incorrect.