Tachinidae

The Tachinidae are a large and variable family of true flies within the insect order Diptera, with more than 8,200 known species and many more to be discovered. Over 1,300 species have been described in North America alone. Insects in this family commonly are called tachinid flies or simply tachinids. As far as is known, they all are protelean parasitoids, or occasionally parasites, of arthropods, usually other insects. The family is known from many habitats in all zoogeographical regions and is especially diverse in South America. Reproductive strategies vary greatly between Tachinid species, largely, but not always clearly, according to their respective life cycles. This means that they tend to be generalists rather than specialists. Comparatively few are restricted to a single host species, so there is little tendency towards the close co-evolution one finds in the adaptations of many specialist species to their hosts, such as are typical of protelean parasitoids among the Hymenoptera. Larvae (maggots) of most members of this family are parasitoids (developing inside a living host, ultimately killing it). In contrast a few are parasitic (not generally killing the host). Tachinid larvae feed on the host tissues, either after having been injected into the host by the parent, or penetrating the host from outside. Various species have different modes of oviposition and of host invasion. Typically, Tachinid larvae are endoparasites (internal parasites) of caterpillars of butterflies and moths, or the eruciform larvae of sawflies. For example, they have been found to lay eggs in African sugarcane borer larva, a species of moth common in sub-Saharan Africa, as well as the more northerly Arctic woolly bear moth. However, some species attack adult beetles and some attack beetle larvae. Others attack various types of true bugs, and others attack grasshoppers; a few even attack centipedes. Also parasitised are bees, wasps and sawflies. Probably the majority of female Tachinids lay white, ovoid eggs with flat undersides onto the skin of the host insect.