The filter fly is the fuzzy little "moth" you find resting on bathroom walls near the drain, but it's actually a fly, not a moth. Its wings are covered in fine hairs and edged with a row of white spots. It's also called a drain fly or moth fly.
Appearance
- Appearance
- Tiny—about 1/12–1/5 in (2–5 mm) long. The broad, hairy wings are brownish to blackish, with a pair of black spots near the middle and several white spots along the edge. The antennae are covered in white hairs, and the legs have white rings.
Look-alikes
Trickle filter flyPsychoda alternata
The trickle filter fly is on the small side (about 1/16 in, 1.5–2 mm) and has small dark spots at the wing tips. This species is usually larger, with white spots along the wing edge.
Why they get mixed upBoth are fuzzy, moth-like drain flies that breed in the same household drains.
Where it lives
- Typical habitats
- Bathrooms
- Kitchen drains
- Sewers
- Sewage treatment plants
- Range
- Found worldwide in tropical and temperate regions, almost always around people. In the US it turns up as a drain fly in bathrooms and other buildings.
- Preferred conditions
- Breeds in shaded, damp places with decaying organic matter. In homes the larvae live in the slimy film inside drains, especially rarely used ones like a guest shower, and also in wet compost, clogged gutters, and standing water in plant pots.
Behavior
- Diet
- Larvae feed on decaying organic matter and soap scum in the drain film.
- Activity
- Adults spend most of their time sitting still on walls and fly weakly in short hops. They are attracted to light.
Life cycle
- Reproduction
- The pupal stage lasts about 5 days, and adults live about 12 days. Because new flies keep coming from the drain, cleaning out the buildup works far better than killing adults.
- Larva
- Larvae live in the wet drain film and feed for about 18 days before they .
Cautions
- Cautions
- Mainly a nuisance—it doesn't bite or sting. In rare cases tied to poor sanitation, larvae have been found in the human body.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
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