Testing reliability of a potential island mating apiary using DNA microsatellites

Abstract

Twenty-four virgin sister queens were kept for 21 days in mating nuclei on the drone-free island Baltrum to test the reliability of a potential mating area. On each of the neighbouring islands Norderney and Langeoog (750 m and 2 km away) 12 sister queens were kept with drones. Workers from colonies with island-mated queens (Baltrum n = 11, Langeoog n = 7 and Norderney n = 6) were genotyped with four DNA microsatellite loci (n = 996) to estimate queen mating frequency. No differences in queen mating frequency were observed between Langeoog and Norderney. However, the level of polyandry on Baltrum was significantly lower than on the neighbouring islands, indicating that mating conditions were much more difficult. The standard genetic distance and differences in allele frequencies between the populations were determined to estimate putative origins of the drones. In this study, 43.7% of the identified drone fathers did not descend from any of the queens on the adjacent islands. They were most likely from mainland colonies at least 5.4 km (3 km across open water) away, showing that the combination of distances over open water and over dry land is important in explaining the mating behaviour of honeybee queens.