Allozyme polymorphisms in Spanish honeybees (Apis mellifera iberica)

Earlier studies have shown two types of mitochondrial DNA in Spanish honeybees (Apis mellifera iberica): a western European or A. m. mellifera type, which predominates in northern Spain, and a north African or A. m. intermissa type, which predominates in southern Spain. Adult workers from 28 colonies sampled in northern and southern Spain were surveyed for polymorphisms at eight allozyme loci. Polymorphisms were found in Mdh1 (two alleles) and Pgm (five alleles). Three of the Pgm alleles have not been described previously. The frequencies of Mdh1 alleles in northern and southern samples are significantly different: Mdh1(80) = 0.94 in the north and 0.75 in the south. The frequencies of Pgm alleles in northern and southern samples do not differ significantly. The Hk allele (Hk100) found in all Spanish samples is the same as that found in other European populations. The results are consistent with the presence of a hybrid zone between African and west European honeybee subspecies in the Iberian peninsula or north Africa. The high number and frequency of novel Pgm alleles in the Spanish bees resembles the "rare allele" phenomenon observed in other hybrid populations.