Parasite Taxonomy

Although parasitism is found in at least five orders, the primary orders of parasites are the Hymenoptera and Diptera. Within the Diptera, several families have members that are parasitic, but are less amenable to biological control. These families include the Acroceridae, Bombylidae, Cecidomyiidae, Cryptochetidae, Phoridae, Pipincluidae, and Sarcophagidae; several of these families contain non-parasitic taxa. One of the more famous (and successful) uses of flies for biological control was the importation from Australia of the fly Cryptocaetum iceryae, which was used against cottony cushion scale. The family Tachinidae, which is exclusively parasitic, has many species that have been manipulated for biological control of a range of pest taxa. Examples include Lydella thompsoni imported and used against European corn borer (Ostrinia nubilalis); Lixophaga diatraeae used in the Caribbean against sugarcane borer (Diatraea saccharalis); or Cyzenis albicans introduced to Canada against winter moth (Operophtera brumata). As might be expected with parasitism spottily represented in the Diptera, the parasitic lifestyle has been thought to have evolved several times within this order. Readers interested in tachinids are directed to Arnaud (1978), Clausen (1940) or McAlpine (1981).

The order Hymenoptera is divided into the suborders Symphyta and Apocrita. The suborder Apocrita is further subdivided into the Aculeata (primarily bees, social wasps, although three families of Aculeata are parasitic -- the Dryinidae, Bethylidae and Chrysididae) and Parasitica, of which nearly all the taxa are parasitic. These hymenopteran suborders and subdivisions do not represent true phylogenetic taxa, even though parasitism is thought to have evolved only once in the Hymenoptera. For a discussion of the evolution of parasitism, see Godfray (1994). Parasitic Hymenoptera are a very diverse and speciose group.

Further discussion of the Diptera and Hymenoptera, especially details about superfamilies and families and a key to the parasitic Hymenoptera, is found in subsequent windows.