Microsatellites for the inference of population structures in the Red Mason bee Osmia rufa (Hymenoptera, Megachilidae)

Microsatellite loci were isolated from the solitary Red Mason bee (Osmia rufa) by an enrichment protocol for partial genomic libraries. Six polymorphic microsatellite loci were used for a first population structure survey including 9 continental European and one island population. Observed levels of genetic variability and heterozygosity proved to be moderate. There was no significant differentiation among continental O. rufa populations. Only the island population from Cyprus was clearly separated. A correlation between geographical and genetic distance indicates gene flow among continental bees. The relatively high homogeneity in O. rufa is probably caused by low effective population size rather than an imprint of past population events. All microsatellites amplified in three further Osmia species.