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Phorid “hump-backed” flies

Phoridae is a family of small flies with a pronounced hump to the thorax. They can be found throughout the world but the greatest variety of species can be found in the tropics. Phorid flies are actually weak fliers, and are often seen walking rapidly across surfaces rather than taking off. They are also known for breeding rapidly in decaying organic matter, fungi, and even corpses. For these reasons, they are also called “scuttle flies” and “coffin flies’. In some places, they may be referred to as “sewer flies” since they also lay eggs in sewers and drain pipes.


Phorid Hump-backed Fly

  • Black, brown, or tan in colour
  • Approximately 0.5 to 5.5 millimeters
  • Arched thorax gives the appearance of a humped back
  • Tendency to walk long distances

image of phorid fly

More Pictures of Phorid “Hump-Backed” Flies

Habitat and Behaviour

A day in the life of a phorid fly

If you like flies (or simply studying them), the Phoridae family has many fascinating species. Researchers are looking for ways in population of fire ants can be controlled by Phorid flies, as over 100 species of Phoridae use ants as hosts for their eggs. They are of interest to forensic entomologists because they are also capable of creating sustainable communities in coffins.

Phorid flies have characteristically short and erratic flights. Adult flies can be seen rapidly running across windows, TV screens, tables, walls, and plant foliage.

The most obvious sign of an infestation are adult flies. The typical life cycle for Phorid flies is 25 days, and a single female can lay as many as 700 eggs in her short life and is ready to reproduce in as little as two days after hatching. That is why killing the adult flies is uphill and often losing battle. Do-it-yourself treatment may work for a few days to a couple weeks until the next wave of eggs has matured.

Contact your local Orkin Canada branch and to have an expert diagnose and treat the infestation properly.

Phorid Fly Life Cycle

Phorid flies typically breed in moist, decaying organic matter. Female Phorid flies lay an average of 40 eggs in a 12 hour period. The eggs hatch in 24 hours into tiny whitish to yellow maggots; where they feed and develop in the medium for 1 to 2 weeks depending on environmental factors, such as temperature. Upon reaching maturity, the larvae leave the breeding medium in search of a dry area to pupate. It typically takes between two weeks and a little over a full month to complete life cycle from egg to adult depending on temperature. However, adult Phorid flies only live for a few days.

Phorid Fly Larvae

Phorid flies reproduce rapidly. Adult females are capable of laying 40 eggs within 12 hours and approximately 500 eggs over the course of their lifetime. The eggs hatch into larvae, also known as maggots. Phorid fly larvae are legless and spindle-shaped, measuring 4 to 10 millimetres in length. Their colour depends on the species but typically varies from whitish to light-yellow.

The adult females of many Phorid fly species in Canada lay their eggs in or on decaying organic materials, such as animal faeces or carcasses, sewage, rotting food and plants, and the layers of film that build up on the sides of drains. When larvae hatch from the eggs, the immature insects feed on the organic matter comprising the surrounding environment. The larvae of some Canadian Phorid flies even parasitize other animals. Depending on the particular species, parasitic types of Phorid flies lay eggs in the nests of ants, bees, termites, and wasps as well as on the bodies of live beetles, caterpillars, and millipedes. After emerging from the eggs, the newly hatched larvae feed on the occupants of the nest or the living animal in which they were deposited. All Phorid flies spend about 8 to 16 days in the larval phase of development, depending on the conditions of the environment.


Why should I be concerned?

Like other flies, Phorid flies have the ability to mechanically transport diseases. Since phorid flies prefer decaying matter as a source of food and place for reproduction, the risk of disease transmission is very high. To make matters worse, the presence of phorid flies in and around the home is usually linked to clogged or damaged drain or sewer pipes. Therefore, the solution requires a thorough and professional inspection of the plumbing in and around the home as well as the removal of any affected soil.

Phorid Fly Infestation

Tips for prevention and control

These tips may help you get rid of Phorid-Humpbacked flies in your home:

  • Clean all drains and sink areas
  • Replace broken windows and screens
  • Reduce the presence of ripe fruits and vegetables; place them in a refrigerator or a paper bag
  • Create an air current to prevent them from landing in their favourite areas
  • Close the lids on all garbage and waste containers

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