The Phorid Fly

Phorid flies or humpbacked flies belong to the family Phoridae. These flies are also known as scuttle flies because of their habit of scampering across a surface instead of flying away.  Phorid flies are often mistaken for fruit flies or gnats and are common across the world.


They are as small as fruit flies and are often mistaken for the same.  Some of their characteristic physical features are –

  • Body length is 0.5mm to 5.5mm
  • Body color can be brown, black or yellow
  • The thorax is arched, given it a humpbacked appearance
  • Rounded head
  • Wings are clear and transparent

Appearance, Behavior, and Signs

Phorid Fly

Phorid Fly

Phorid flies are found across the world, but they are especially common in the tropics. These tiny flies feed on rotting organic matter, including decaying plants and dead animals. They also feed on honeydew and nectar, and several species of Phoridea are predators of earthworms, snails and insect eggs. They also feed on rotting fruits and vegetables, and even leftover food items.

Some phorid flies fly in swarms, although their characteristic movement is the fast scuttling away on foot. They have short, erratic flight sessions.

They are commonly found near drainage systems and garbage bins. The flies breed in stagnant water and organic matter. To look for signs of phorid flies, check your kitchen, dustbins, washrooms and plumbing systems. Phorid flies often expand their area of exploration from the source of food they have found. This means they can spread throughout your house.


Decaying organic matter and damp spaces attract phorid flies. If your house has leaky pipes, food items lying outside and trash that hasn’t been cleared, chances are that you’ll see adult flies flying around or running across surfaces. Phorid flies can even enter your house if there is a dead animal inside – perhaps because of a rat or a squirrel that has died in the AC vents. They are particularly attracted to drains, so a damaged or dirty plumbing system can make your house more vulnerable to the invasion of phorid flies.

Leaving overripe fruits outside can often attract these flies. Phorid flies aren’t very picky about what they will eat, as long as it is organic. Presence of a lot of plant life around our house can also invite these flies, as there will definitely be rotting plants and plan items in there.


Getting rid of phorid flies is no easy job. The source of the infestation must be identified first (it is more often than not the sewage or plumbing system). Organic material must be cleaned regularly from these plumbing pipes using biological drain cleaners. If the infestation has blown out of control, that particular area of the plumbing system might have to be changed. At this point, it is better to contact a professional pest control service.

Maintaining hygienic surroundings and regularly cleaning the drains is a good way to prevent the entry of phorid flies. It is also advisable to put up fly meshes or screens on windows and other openings in the house. Make sure there is no particularly dense vegetation growing right adjacent to your house.

Phorid Fly Facts

  • Some phorid flies lay eggs on the abdomen of bees. The bee acts strangely for a while, leaves the colony and later dies. The phorid larva then emerges from its neck. This has been termed as colony collapse disorder.
  • Around 4000 different species exist under the category of Phoridae
  • Their larva is about 10mm long
  • They have been used to control the fire ant population in the US