Drain and Moth Fly
Drain / Moth Fly
Moth flies are very small delicate and “hairy” flies about 1/16 to ¼- inch long. They are yellowish, brownish-gray, or blackish. Their pointed, leaf-shaped, white speckled wings are held roof-like over their backs when at rest. The body and wings are covered with long dense hairs. These flies have long antennae with 13 to 15 bead-like segments. Mature larvae are 1/8 to 3/5-inch long. They are aquatic and are long and cylindrical with the fore end of the body somewhat flattened on the lower side with has eight suckers. They have dark, hardened patches on the back of each segment, and they breathe through a hardened, stalk-like siphon tube at the end of the body.
The females lay 30 to 100 eggs in the jelly-like film that covers the stones in sewage treatment plant trickling filters or that line the water free portions of drain pipes. The eggs hatch in two days, and the larvae complete development in nine to 15 days. The larvae feed on algae, fungi, bacteria, and sludge. The pupal stage lasts about a day and a half. The developmental time (egg to adult) is seven to 28 days. Adults live for up to two weeks.
Moth flies or drain flies become an annoyance within some structures when they breed in the liquids found in drains, dirty garbage containers, and septic tanks. They are a problem when they breed in large numbers in the filter beds of sewage treatment plans. Adult flies are poor fliers and are found in great numbers on walls or flying weakly in the area where they developed. Adults are more active at night and are seen hovering near the breeding site. During the day, they rest on vertical surfaces indoors and in protected areas outside. Adults feed on nectar and polluted water.