Geographic variation in Tetragonisca angustula (Hymenoptera, Apidae, Meliponinae)
Eliana Barroso Castanheira and Eucleia Primo Betioli Contel
Tetragonisca angustula is a small stingless bee occurring throughout Brazil as two subspecies. Tetragonisca angustula fiebrigi has a ferruginous coloured thoracic region (mesepisternum) and is found in south-western Brazil. In most parts of Latin America T. a. angustula, which has a black mesepisternum, is the common subspecies. A sample of T. a. angustula collected in south-east Brazil presented only the hexokinase Hk100 allele, while a sample of T. a. fiebrigi displayed a high frequency of the Hk88 allele. Samples from locations between these two regions had a ferruginous-and-black stained mesepisternum and intermediary Hk88 allele frequencies suggesting a clinal distribution or racial admixture between the two subspecies. There was a highly significant correlation between the amount of ferruginous colour displayed in the mesepisternum and the Hk88 allele frequency. Morphometric analysis of worker wings also suggests clinal distribution or racial admixture because the wings in the hybrid sample were of intermediate size.