A comparative study of the proventricular structure in corbiculate apinae (Hymenoptera, Apidae)

The present study compares the proventricular structure, analyzed under sca nning electronic microscope (SEM), among tribes of corbiculate Apinae, Fift y-one species of stingless bees (Meliponini), one species of honeybee (Apin i), three species of bumblebees (Bombini) and seven species of orchid bees (Euglossini), were analyzed as in-group, and one species of sphecid wasp (S phecidae) and two species of Halictidae bees, as out-groups. The proventric ular bulb presents a basic morphology pattern similar to that of other Hyme noptera such as ants and wasps, being a symplesiomorphy for bees. The shape of proventricular folds constitutes a synapomorphy for Meliponini and an a utapcsmorphy for Apini. The shape of hair-like projections of the cuticle t hat lines the proventriculus is a synapomorphy for Meliponini and Apini. Th ese proventricular data corroborate the monophyly of the tribe Meliponini a nd the hypothesis that recognizes only one tribe for stingless bets. Zn add ition, Meliponini + Apini constitutes a monophyletic group and Bombini + Eu glossini another monophyletic group. The results confirm that internal morp hology is a character that can be used in studies of the phylogeny in insec ts and the use of SEM as a powerful tool in these analyses. (C) 2001 Elsevi er Science Ltd. All rights reserved.