Morfologia Comparada das Peças Bucais de Vespas dos Gêneros Agelaia Lepeletier e Angiopolybia Araújo (Hymenoptera: Vespidae, Polistinae)

Abstract

Among the subfamilies of social wasps, Polistinae has a cosmopolitan distribution, being dominant in tropical and subtropical regions of the globe where there are approximately a thousand species. Many studies have been performed on the behavioral biology of some species, but relatively little has been done on the comparative morphology of the various genera. The present study seeks to describe the morphological diversity of the mandibles of polychaetes and to verify correlations or counterparts in the behavior and life history of these vespids. In particular, we intend to verify the relevance of the hypothesis of O'Donnc1 (1995), which states that species of the genera Agelaia andAngiopolybia, which have the habit of necrophagy, would possess morphological adaptations in the mandibles related to the feeding habit. The study was done with nine species: Polistes infuscatus Lepeletier, Mischocyttasus imitator (Ducke), Miscbocyttarus foveatus Richards, Apoica pallens (Fabrícíus), Angiopolybia pallens (Lepelctier), Allgiopo/)'bia paraensis (Spinola), Agelaia testacea (Fabricus), Age/aia futocfasciata (Degeer) and Agelaia pallipes (Olivier). The remaining three genera are used for comparison purposes, Polístes representing the oldest lineage and, as such, allowing the observation of supposedly primitive conditions in the subfamily. The methodology was based on the characterization of the mandible under different aspects such as the shape of the teeth, the ridges, the anterior and posterior margins, by making drawings of the measurement of the mouthparts and comparing the shapes under the stereoscopic magnifying glass. Despite minor differences in the length and shape of the internal ridges, a high degree of similarity was found between the genera studied. According to O'Donnel, the posterior crest of necrophagous groups is very acute and elongated, forming a sharp laminar edge. It was realized that the author's description is inadequate and that the crest has a widespread occurrence in the other non-necrophagous genera. Moreover, within Agelaia, variation in the degree of development of the crest was observed. Therefore, our observations do not support the hypothesis of a close correlation between mandible shape and necrophagic habit.