Family ENCYRTIDAE
Introduction
The Encyrtidae is a large family, and frequently collected. Although small and extremely difficult taxonomically, the family contains a variety of bizarre and unusual forms to attract attention and interest. The majority of encyrtids are primary parasitoids of various scale insects in the superfamily Coccoidea. One of the two subfamilies, the Tetracneminae, is restricted to coccoid hosts. The other subfamily, Encyrtinae, has a very broad host range, including hosts in many insect orders, as well as mites, ticks and spiders. Encyrtids are all internal parasitoids. The egg is characteristically narrow in the middle, broadening towards each end. The larvae may be of various forms and commonly utilise atmospheric oxygen, which they obtain through the remains of the egg which often protrudes through the body wall of the host. Some encyrtids are polyembryonic on larvae of Lepidoptera (e.g. Copidosoma spp.).
Economic Importance. The Encyrtidae are the second most important family in biological control, after the aphelinids, there being many examples of their successful use in biological control programs.
Distribution. Cosmopolitan
Classification. Classification within the Encyrtidae is not easy to understand. Authors currently recognise two subfamilies, Encyrtinae and Tetracneminae, based on the presence (Encyrtinae) or absence (Tetracneminae) of paratergites (which are specialised plates associated with the terminal abdominal tergites). This character is so difficult to assess, that most keys do not even include it.
Important genera: Anagyrus, Cheiloneurus, Copidosoma, Leptomastix, Metaphycus, Microterys, Ooencyrtus, Psyllaephagus, and Syrphophagus. These are only a few of the most important of the genera; because of the large size of this family, and its importance to biological control, this list could easily be doubled or tripled.
Identification of Australian genera: Australian genera are included in Noyes & Hayat (1984) keys to Indo-Pacific genera. Dahms & Gordh (1997) provide a review of the Australian genera and species described by A.A. Girault.
Diagnosis
Mesopleuron large, convex, longer than tall and without a median groove or furrow. Spur of middle tibia usually somewhat enlarged. Insertion of middle coxae anterior to the midline of the mesopleuron. Marginal vein usually short, often punctiform or wider than long and usually shorter than stigmal vein. Cerci usually advanced on the metasoma, separated from some distance from the apex. Antenna generally without anelli, and with 6 or less funicular segments. Notauli usually absent. Many of the small encyrtids might be confused with aphelinids, however in encyrtids the axillae meet medially, and in aphelinids they are widely separated.
General References
Dahms, E.C. & Gordh, G. 1997. A review of the genera of Australian Encyrtidae (Hymenoptera: Chalcidoidea) described from Australia by A.A. Girault with a checklist of included species. Memoirs on Entomology, International 9: 1-518
Noyes, J.S. & Hayat, M. 1984. A review of the genera of Indo-Pacific Encyrtidae (Hymenoptera: Chalcidoidea). Bulletin of the British Museum (Natural History) Entomology 48: 131-395