Evolution of the Multifunctional Mouthparts of Adult Vespidae

Abstract

The morphology of mouthparts and their use in context with nutrition, nesting behaviour and brood provisioning are compared across various lineages of Vespidae. In the plesiomorphic state, adult wasps take up nectar and pollen with a short labiomaxillary complex; females construct subterranean nests with the mandi- bles, moisten hard soil with water collected using the glossa, and larvae are mass- provisioned with paralysed insect larvae which are gathered and transported by the mandibles. The evolution of nectar-feeding proboscises occurred multiple times in the Vespidae. The Masarinae evolved a bee-like life form and collect pollen to supply their larvae. Two lineages have evolved a proboscis composed of the glossa and paraglossa, or only the elongated glossa forms a food canal to imbibe nectar or water. The females of the taxon [Eumeninae + Raphiglossinae + Zethinae + Polistinae + Vespinae] feed on malaxated prey in addition to sugary fluids. Few representatives of the Eumeninae, the Raphiglossinae and some Zethinae evolved a proboscis com- posed of the elongated galeae, glossa and paraglossae. Tusk-like mandibles evolved in some male Eumeninae in the context of male-male competition. In the represen- tatives of the [Raphiglossinae + Zethinae + Polistinae + Vespinae] the mandibles have adapted to processing plant material for nest construction. The short mouthparts of the social [Polistinae + Vespinae] also build paper nests and are used for trophallaxis.