Overview
Braconids are speciose in most habitats. The majority of species parasitise the larval stage of their hosts; rarely do they oviposit into host eggs, pupae or adults. They develop as either primary endo- or ectoparasitoids on a wide variety of insect hosts, with specific subfamilies parasitising particular insect orders. For example, Microgastrinae, Cardiochilinae and Agathidinae parasitise lepidopteran larvae, Opiinae and Alysiinae attack dipteran larvae, Doryctinae and Helconinae mostly parasitise Coleoptera, and Aphidiinae parasitise aphids. One unusual Australian group are cecidogenic (gall-inducers) on Banksia spp., while the endemic Australian Trachypetinae are thought to be the most primitive extant braconid subfamily. Numerous species are utilised as biological control agents of agricultural pests, and some 40 species have been introduced into Australasia for this purpose.
Keys to the 30+ subfamilies can be found in Wahl and Sharkey (1993) and Wharton et al. (1997).
Description
They vary in size from small (1.5 mm) to very large wasps (80 mm, including the ovipositor) and are morphologically very diverse. They are closely related to Ichneumonidae but can be distinguished from them by the following characters: vein 2m-cu of the fore wing absent, basal cell in hind wing shorter than vein SC + R, and metasomal terga 2 and 3 fused, not free and moveable.
Distribution
This very large family has 575 described species recorded from Australia and about 90 from New Zealand. However, for Australia this probably represents less than 10% of the true size of the fauna.
Further information about the Braconidae can be found in Austin & Dangerfield 1992, Austin & Dangerfied 1998, Austin, Wharton & Dangerfield 1993, Naumann 1991, Shaw & Huddleston 1991, Wahl & Sharkey 1993 and Wharton, Marsh & Sharkey 1997.