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Spring 2011

Urban Jungle

The changing natural world at our doorsteps | Illustration and text by Patterson Clark      

May 3, 2011

The drain fly: Denizen of the sink


The dead skin, spit, hair, food and any other waste that you send down the drain are gifts from above for the humble drain fly.

In spring the fly emerges from drains and sewers to mate and lay eggs, which in less than two days hatch into tiny maggots that feed on the gelatinous scum lining drains and sewers.

After two weeks of feasting, the maggots develop a hard shell in which they will pupate and from which they will emerge in a day or two as small furry adults, also known as moth flies.

While they may appear sedentary, quietly hanging out in the tub, the adults can react quickly, flying away from any attempt to swat them. They stay alive by drinking waste water — or flower nectar, if they can find it.

Homeowners can curb the drain-fly life cycle by cleaning their pipes with boiling water and a stiff wire brush. Another alternative: natural drain cleaners containing bacteria and enzymes — you can Google them — that consume the scum before the maggot gets its chance.

SOURCES: Ohio State University,
Penn State University

Drain fly, Clogmia albipunctata