Overview
Many encyrtids are primary parasitoids of various scale insects (Hemiptera: Coccoidea), with the Tetracneminae restricted to this host group. The other subfamily, Encyrtinae, has a very broad host range including hosts in many insect orders, as well as mites, ticks (Acarina) and spiders (Araneae). Encyrtids are all endoparasitoids, and some are polyembryonic (i.e. a single egg divides to form two or more identical embryos and often hundreds) on larvae of Lepidoptera (moths and butterflies). After the aphelinids, the Encyrtidae are the second most important family of Hymenoptera in biological control, and there are many examples of their successful use in controlling insect pests.
Description
The Encyrtidae are a large family of Chalcidoidea with over 500 described species in Australia and 70 in New Zealand. Although small in size (0.5 4 mm) and extremely difficult taxonomically, the family contains a variety of bizarre and unusual forms. They are characterised by the mesopleuron large, convex, longer than high and without a median groove or furrow, the spur of the mid tibia usually enlarged, the mid coxa inserted anterior to the midline of the mesopleuron, and the cerci usually positioned along the metasoma, some distance from the apex of the metasoma. Many small encyrtids might be confused with aphelinids, however, in encyrtids the axillae meet medially, and in aphelinids they are widely separated.
Distribution
Australasian genera are included in the keys to Indo-Pacific genera by Noyes and Hayat (1984) and Dahms and Gordh (1997) provide a review of the Australian genera and species described by A.A. Girault.
Further information on the Encyrtidae can be found in Dahms & Gordh 1997, Naumann 1991, Noyes 2001 and Noyes & Hayat 1984.