Family TRIGONALIDAE

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Family TRIGONALIDAE

Compiler and date details

N.B. Stevens & A.D. Austin, Centre for Evolutionary Biology and Biodiversity and the Department of Applied and Molecular Ecology, Waite Campus, Adelaide University, Adelaide, South Australia, Australia

Introduction

The Trigonalidae comprise about 100 species worldwide (Carmean 1998). Only ten species in two genera are recorded from Australia, where they appear to be associated with sawfly or lepidopteran hosts (Weinstein & Austin 1991).

The adults are moderate sized (4–12 mm) and superficially resemble some Vespidae. The females often have the posterior metasoma modified so they can push eggs into the undersides of leaves with their ovipositor. The eggs are then ingested by the leaf-feeding larval host. They hatch in the gut and burrow into the host's body cavity to develop as endoparasitoids (Naumann 1991; Weinstein & Austin 1991). Trigonalid larvae often develop as hyperparasitoids when the primarily sawfly or lepidopteran host is parasitised by tachinid fly larvae, or when parasitised caterpillars are fed to the larvae of vespid wasps.

Previously, the family was divided into six subfamilies, but after recent phylogenetic analysis this was reduced to two (Carmean & Kimsey 1998): the Orthogonalinae containing only the nominal genus Orthogonalys Schulz (extralimital to Australia) and the Trigonalinae comprising 14 genera, two of which occur in Australia.