Reexamination of honey bee Africanization in Mexico and other regions of the New World

Honey bees (Apis mellifera) are not native to the New World. The initial introduction of the species to the Americas occurred from Europe, with subsequent introductions from Africa. The African bees hybridized with European bees and are now referred to as Africanized bees. A large feral population was established and subsequently colonized extensive areas of both the North and South American continents, including Mexico. The aim of this study was to conduct a morphometric analysis of geographic variation among Africanized bees. Recently acquired data from Southeastern Mexico were compared with existing datasets of Africanized bees and evolutionary lineages from the Old World. The forewing venation was described using 19 landmarks. The honey bees originating from southeastern Mexico exhibited significant differences from all other investigated populations. It is necessary to verify if the observed geographic variation within Africanized bees is related to natural selection or other factors, including hybridization or genetic drift. Furthermore, honey bees from populations in the USA and Argentina, which appear to have not been affected by Africanization, differed markedly from honey bees naturally occurring in Europe and can be classified as hybrids between evolutionary lineages.