Comparative morphology of the skeletal parts of the sting apparatus of bees (Hymenoptera: Apoidea)

Details of the variation in sting morphology for all subfamilies of bees are presented for the first time. A considerable amount of variation, potentially of great utility for phylogenetic studies, has been discovered in every part of this complex structure. Additional probable synapomorphies of bees were found; these include loss of the specialized sensilla-bearing area at the apex of the gonostyli and the reduction and reorientation of the processi mediani at the base of the sting shaft. Synapomorphies for particular subtaxa of bees were found. These include a long, ventral emargination to the second valvifer in Nomiinae and a blister-like protrusion of the lamina spiracularis of the 7th hemitergite in the Megachilinae. Sting reduction and some details of sting morphology would seem to support a relationship between the Stenotritidae and Oxaeinae. Loss of sting function has occurred in four families of bees and repeatedly within the Andrenidae. In some instances loss of function as a sting is associated with increased development of certain structures indicating a change in function for the sting sclerites. It is suggested that all future studies of bee systematics above the species level should include assessment of variation of the sting apparatus and that sting preparations, made and stored in the same manner as preparations of male genitalia, become routine. © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society , 2003, 138 , 1–38.