A multiplex set for microsatellite typing and sexing of the European bee-eater (Merops apiaster)

Microsatellite loci are widely used in ecological and evolutionary studies to assess inbreeding, genetic parentage and population structure. Such loci are often optimised in multiplexes to allow for economical and efficient use. Here, we tested 11 microsatellite loci designed for use in European bee-eaters (Merops apiaster), along with 31 loci isolated in other species, for their utility in European bee-eaters sampled on Susak Island, Croatia. Of these 42 loci, 20 were polymorphic in 38 individuals. These polymorphic loci were further assessed in a sub-set of 23 adults, excluding close relatives, and exhibited between three and 13 alleles each. All loci were autosomal, as indicated by the presence of heterozygotes in both males and females. One of the polymorphic loci exhibited low heterozygosity, three loci deviated from Hardy-Weinberg equilibrium and three pairs of loci displayed linkage disequilibrium. The remaining selected eight cross-species loci and seven loci isolated in European bee-eaters were combined with two sex-typing markers and optimised in five multiplexes. A combination of 15 autosomal loci of varying degrees of polymorphism makes this multiplex set particularly suitable for both parentage and spatial genetic analyses. This multiplex set therefore provides a useful toolkit for studying kin selection and population genetics in the cooperatively breeding European bee-eater and, potentially, in other closely related species.