PHOTO CAPTION: Eriothrix rufomaculata (Photo taken by Keith Edkins)
The tachinid flies (family Tachinidae) are by far the largest and most important group of insect parasitic flies, with over 1300 species in North America. It is a diverse group with some resembling drab houseflies and others brilliantly colored.
All species are parasitic in the larval stage, and many are important natural enemies of major pests. Many species of tachinids have been introduced into North America from their native lands and used as biocontrols to suppress populations of alien pests. The female may lay her white oval eggs on the skin of the host insect, or insert the egg into the host’s body, or leave them in the host’s environment, as for example on leaves, where the host will ingest them. The larvae feed on the host tissues, causing death.
Larval tachinids parasitize caterpillars, adult and larval beetles, sawfly larvae, various types of true bugs, grasshoppers, or other types of insects. Many important pests are suppressed by tachinids.
The adult flies typically feed on pollen and can be important pollinators of some plants.