Does recent habitat fragmentation affect the population genetics of a heathland specialist, Andrena fuscipes (Hymenoptera: Andrenidae)?

Habitat fragmentation is believed to be a key threat to biodiversity as it decreases the probability of survival of populations, reduces gene flow among populations and increases the possibility of inbreeding and loss of genetic diversity within populations. Heathlands represent excellent systems to study fragmentation effects as the spatial and temporal course of fragmentation is well documented for these habitats. At the beginning of the nineteenth century, heathlands were widespread in northern Germany, but they became increasingly fragmented at the end of the nineteenth century until only few fragments had been left. As many insect species are strongly specialized on heathland habitats, they represent ideal study systems to test the genetic effects of such recent fragmentation processes. The solitary bee Andrena fuscipes is strongly specialized on heather (Calluna vulgaris) and, therefore, occurs exclusively in heathland habitats. The species is red-listed in Germany and other parts of Europe. Here, we present an analysis of the genetic structure of 12 populations of A. fuscipes using eight microsatellite loci. The populations showed little geographical structure and the degree of genetic differentiation was low. Compared to related bee species, inbreeding coefficients were relatively low and seem to be mainly affected by the bees' solitary nesting behaviour.