Intra-specific Nest Form Variation in Some Neotropical Swarm-founding Wasps of the Genus Parachartergus (Hymenoptera: Vespidae: Epiponini)

Abstract

Previous authors have called attention to nest form variation between and within species of the Neotropical swarm-founding polistine wasp genus Parachartergus. One author characterized nests oriented horizontally and having the nest comb petiole central and in-line with nest cells as anomalous, and he suggested that anomalous nests constrain colonies from successful reproduction. We report two distinct nest forms of Parachartergus amazonensis (Ducke), one of which was oriented primarily horizontally and one only vertically, from a single locality in Peru. Horizontal and vertical nests, with corresponding difference in orientation of nest comb petioles, have additionally been observed in P. fulgidipennis (de Saussure) in Peru and Brazil and P. griseus (Fox) in Brazil and French Guiana. Nest orientation and comb petiole placement in these Parachartergus species may reflect a labile trait that is variably expressed as a function of availability of suitable nest sites. “Anomalous” nests may not constrain colonies from successful reproduction.