The phorid fly is similar to a fruit fly, but Wizzie Brown, an insect specialist with the Texas A&M AgriLife Extension Service, says they manage to get into all sorts of things besides food.
A fly with many names
They’re also known as scuttle flies, humpbacked flies or coffin flies. … They have this large, humped back. The scuttle name comes because instead of flying, a lot of times they’ll just kind of run along the surface of something.
What do they eat?
While they can get into rotting vegetation like the fruit flies, they will also get into fecal material; they’ll get into any sort of wet, organic matter, so slime buildup on drains. … I’ve seen phorid flies coming out of mops in commercial kitchens that are kind of funky, and in regular kitchens if you use a sponge.
Sanitize your kitchen sponge!
If not, they will lay eggs on that, and they can actually breed in those areas.
Why ‘coffin’ fly?
They may be an indicator that there is something dead. And usually if you have something dead, you will have something other than just the phorid flies; a lot of times you’ll have flush flies or blow flies as well.
They can sniff out a sewer problem
[They] can be a signifier for … sewer lines breaking or septic systems having cracks in them. They will need to have their source located and dealt with because if you’re just treating for the adults they’re just going to keep coming.