Common Name: Parasitic flies
Scientific Name: Varies
Description: Adult tachinid flies can superficially resemble houseflies, but vary by species in size, coloration and shape. Many are gray or black or have bodies marked with stripes. Many have distinct long bristles on the ends of their abdomens. However, some species are brightly colored (e.g., with a red abdomen and smoky black wings), and they may have prominent fringes of hairs along their hind legs. Larval (maggot) stages are rarely seen, but they may be observed when they emerge from host insects to pupate.
Some species of flesh flies (Diptera: Sarcophagidae) are also parasitic on some species of bees (Hymenoptera), beetles (Coleoptera) and caterpillars (Lepidoptera). Some species of humpbacked flies (Diptera: Phoridae) parasitize species of ants and bees (Hymenoptera), beetles (Coleoptera) and scale insects (Homoptera). Some smaller groups of flies (Sciomyzidae, Pipunculidae, Pyrgotidae, Anthomyiidae) also contain parasitic species.
Life Cycle: Life cycles vary by species. Eggs are sometimes laid on leaves and ingested by a host caterpillar during feeding. Female flies of other species may glue their eggs to the hosts’ body after which the hatching larva tunnels inside. In other species, eggs are inserted directly into the hosts’ body by the female. Once inside the body of the host, one or more larvae can develop through several stages (instars) for 4 to 14 days. They emerge from the host to pupate inside their last larval skin (puparium). Adults emerge 1 to 2 weeks later. Depending on species one or more generations occur per year.
Habitat and Food Source(s): Larvae (maggots) with hook-like mouthparts that tease apart tissues of their hosts. Adults have lapping mouthparts similar to those of houseflies. Individual species are generally host-specific. As a group, most species parasitize caterpillars (Lepidoptera) or beetles (Coleoptera). However, some species develop in sawflies (Hymenoptera), true bugs (Hemiptera), grasshoppers (Orthoptera) or other insects. Adult flies can be found while they visit flowers. Immature stages are only found in parasitized host insects. Stink bugs (Hemiptera) that are easily collected in rice or soybean fields or various caterpillars can be a good source for some tachinid fly parasites.
Pest Status: Larval stages develop inside developmental stages of other insects; beneficial insects; medically harmless.
Common Name: Small flies
Scientific Name: Varies
Description: Adult flies are small, yellowish, tan to dark brown 1/8 inch long flies, normally with red eyes. The antennae are characteristic in having a feathery bristle.
Life Cycle: Adults lay cylindrical eggs near suitable larval habitat. Tiny maggots hatch from eggs and develop though several molts before leaving the food source in search of a drier location to pupate. Pupae are brown and seed-like with two horn-like stalks on the front end. Development from egg to adult can be completed in 8 to 10 days.
Habitat and Food Source(s): Mouthparts are for lapping in adults, while maggots have chewing or “teasing” mouthparts. Immature stages feed on over ripe, fermenting or rotting fruit and vegetables, whole or in part (peels), fermenting liquids (vinegar, beer, wine, cider) and other rotting organic material in garbage and other unsanitary areas. Adults can be attracted to fruit or fermenting liquid especially if placed outdoors in a compost pile or near garbage. They can be allowed to breed on the food source. D. melanogaster is also available through scientific supply catalogs.
Pest Status: Adult flies can be a nuisance in restaurants, wine cellars and near fruit and vegetable fields and food processing areas, anywhere where abundant breeding habitat is available; otherwise medically harmless. Fruit flies, particularly Drosophila melanogaster Meigen sometimes called the “banana fly,” have been used extensively as laboratory animals for experiments in genetics, insect behavior and physiology.
Literature: Ebeling 1978; Metcalf et al. 1962.