Nesting behaviour and larval stages of some Australian nyssonine sand wasps (Hymenoptera : Sphecidae)

Abstract

Study of the nesting behaviour and larval structure of several nyssonine sand wasps in eastern Australia reveals that these species closely resemble related species in the northern hemisphere. Austrogorytes bellicosus (Smith) makes multicellular nests in coarse sandy soil and provisions them with eurymelid bugs, laying the egg longitudinally on the topmost bug in the cell. Use of the hind legs in digging the nest, as well as certain features of larval structure, suggest that Austvogorytes is properly considered a very generalized nyssonine wasp. Clitemnestva plomleyi (Turner)(= Astaurus hylneoides Rayment, new synonymy), regarded as a structurally primitive sand wasp, preys upon leafhoppers (Cicadellidae) and is believed to utilize pre-existing vertical holes in hard soil. Sphecius pectoralis Smith, on the other hand, digs a long burrow in friable sand and makes up to 12 cells, provisioning them with cicadas. The larva of this species closely resembles that of other members of its genus. Members of the genus Bembecinus also prey on homopterous insects but exhibit two major behavioural specializations: the egg is laid in the empty cell on a pedestal of sand grains and provisioning is progressive. Four members of this genus were studied: egens (Handlirsch), antipodum (Handlirsch), hirtulus (Smith), and an unindentified species.