Other Common Names
Drain Flies, Sewage Flies, Filth Flies [all refer to subfamily Psychodinae only]
Numbers
113 spp. in 21 genera of 4 subfamilies in our area
(1), >3000 spp. in 144 genera total
(2)Identification
Adult resembles a tiny moth; body hairy, variably yellow through gray to black; wings held roof-like over body (moth flies; subfamily Psychodinae) or together above body (sand flies; subfamily Phlebotominae) when at rest; wing veins numerous, hairy, parallel, with no cross-veins in outer two-thirds of wing; antennae long, 12-16 segments, each segment bulbous with ring of long hairs (
plumose).
Larva: eyeless and legless; head darker and narrower than body; each segment with one or more dark rectangular bands dorsally; terminal segment narrows, forming dark-colored breathing tube
Pupa: resembles minute grain of brown rice
Range
most of the world; more common and diverse in tropical regions
Habitat
Moth flies (Psychodinae): adults often found around sewage installations, in public washrooms, and bathrooms in homes, and are attracted to light; larvae live in organic sludge that forms on inner surfaces of drains and sewage pipes; pupae occur on the surface of the organic film that the larvae have been living in
Sand flies (Phlebotominae): adults occur in a wide range of habitats but often near water in dry semi-arid areas in the Old World, and in tropical forests and savannas in the New World; larvae inhabit areas containing high levels of organic matter such as in animal burrows, termite hills, tree holes, and leaf litter
Season
spring through fall; all year in tropical and subtropical areas
Food
Psychodinae: larvae feed on algae, fungi and bacteria in sewage and organic sludge; adults feed in polluted water and on flower nectar
Phlebotominae: adult females in three genera suck blood from humans or reptiles in subtropical and tropical regions; larvae feed on dead organic matter in habitats mentioned above
Life Cycle
Psychodinae: indoors, females lay masses of 30-200 eggs in the gelatinous film lining drains, particularly in bathtubs/showers; eggs hatch 32-48 hours thereafter and larvae pupate 9-15 days later; pupal stage lasts 20-40 hours; time from egg to adult is 7-28 days, depending on temperature and food availability; adults live for ~2 weeks
Remarks
Psychodinae larvae play an important role in purifying sewage in industrial sewage treatment plants; adults are very weak fliers, covering only a few feet at a time in short erratic flights. Outside, they can be blown considerable distances by the wind.
Phlebotominae are best known as vectors of Leishmania trypanosomes causing leishmaniases.
