Family Phoridae - Scuttle Flies

Humpbacked Flies, Coffin Flies

Phoridae Curtis 1833

376 described species in 50 genera in NA (half of the fauna are Megaselia), >4,200 described species in >300 genera total(1), and many times that number undescribed(2)

Adult 0.4‒7 mm (many 2‒4 mm)

flies with a humped back, a low small head, and dark eyes; costa extends only about halfway along wing margin; two strong longitudinal veins in costal area, and 4‒5 weak veins posteriorly, not connected by cross-veins; metafemora enlarged and flattened, and hind legs long; antennae appear 1-segmented

worldwide

A few common, synanthropic species, especially Megaselia scalaris, Dohrniphora cornuta, Megaselia rufipes, and Puliciphora borinquenensis, live in almost any type of decaying organic material. Larvae of D. cornuta often build up to huge populations when sewer pipes break and nutrient-rich water soaks into the soil; adults emerge in swarms through drain pipes in affected houses. The most commonly noticed species of phorid is M. scalaris, which is found in a number of filth-fly situations, and also infests nearly every type of invertebrate and small vertebrate cultures, such as insect zoos, tarantulas, lizards, snakes, hermit crabs, etc.

Most species are probably specialized scavengers, predators, parasitoids, or even true parasites. Many Megaselia species are found in fungi, some feeding on the fungus (including a few commercially important pests), others probably on sciarid larvae. Many species are found in buried carrion, away from competition from blow flies and other agressive species. One such species, the coffin fly, is found commonly on buried human bodies. Small invertebrate carrion, such as snails, slug, and dead insects, are also breeding sites for phorids. Species of the genus Anevrina are found in the burrows of mammals, probably as scavengers.

Many species are associated with ants, as commensals in ant nests or as parasitoids. The largest group of ant-parasitoids, Apocephalus, are known as ant-decapitating flies because they develop inside the ant's head, and some species cause the ant's head to fall off, sometimes before the rest of the body stops moving. Most North American Apocephalus attack ants in the genera Camponotus and Pheidole, but other hosts are used here and elsewhere. Another ant-parasitoid genus is Pseudacteon, whose South American species are being used in attempts to biologically control imported fire ants (since the native Pseudacteon are not doing the job!).

Other parasitoid genera attack millipedes (phorid genus Myriophora), fireflies and cantharid beetles (some Apocephalus), bees (some other Apocephalus), scale insects, beetles, and probably many other hosts we do not know about.

Some phorids have wingless or short-winged females. Some of these are commensals or parasitoids associated with ants, others are scavengers that are apparently not associated with ants. ‒Brian Brown

Year-round indoors

Extremely diverse: there are scavengers (some extraordinarily generalized, others highly specialized), herbivores, fungus-feeders, predators, parasitoids, and true parasites. Adults feed on honeydew, nectar, dead insects, carrion, host hemolymph; a few prey on insects

Some species are wingless

(4)(5)(6)