Flesh flies look like house flies, but are generally larger. They are gray, have a checkerboard pattern on the top of their abdomen, three black stripes running along the top surface of their thorax just behind the head (house flies have four) and sometimes a reddish-brown tip at the end of the abdomen.
Behavior, Diet & Habit
Flesh flies are sometimes among the first insects to arrive at a dead animal carcass and are similar to blow flies in biology and habits. Areas around the home with rotting matter, such as garbage cans, compost piles, animal droppings, and animal carcasses, can attract flesh flies. Not commonly found in the home, flesh flies frequently infest industrial buildings like meat processing and packing facilities. Adult flesh flies don’t bite humans, but they do feed on liquid substances, and may infest wounds, carrion, and excrement. In some instances, flesh flies may be beneficial because their larvae prey on blow fly larvae, lesser house fly larvae, and grasshopper nymphs. Also, forensic investigators may use the development of flesh fly larvae in a carcass or corpse to help determine time of death.
While the life cycle of flesh flies varies by species and location, generally the flies overwinter in their pupal stage within temperate climates and emerge as adults in the spring. Soon after becoming adults, they mate and the female flesh fly may lay eggs. More likely she will deposit from 20-40 larvae that have hatched within her body which she directly lays on the carrion, feces or rotting plant materials. Flesh fly larvae feed for 3 or 4 days and become pupae that burrow into nearby soil and, after about 10 to 15 days, emerge as adults. Flesh flies go through several generations each year.
Some flesh flies prefer to breed in dead rodents, bats and birds found in attics, crevices and wall voids, so if flesh flies become a problem inside a structure, your pest management professional should inspect for a dead animal.
A single female can produce hundreds of eggs during her lifetime. Depending on the species, eggs may hatch within 24 hours and the entire life cycle of the flesh fly may be completed within 1-2 weeks.
Signs Of A Flesh Fly Infestation
Actually seeing adults, pupae or larvae is the most likely sign of a flesh fly infestation. If flies are developing inside, you may see a large number of flies suddenly appear and might find flies in the ceiling light fixtures.
Flesh flies are worldwide in distribution and are found in most regions of the United States.
Flesh flies are rarely problems as disease carriers and pose little threat to human or livestock health. However, flesh fly larvae have been known to burrow from wounds into the healthy flesh of livestock, and some species can cause intestinal infections in humans who consume food contaminated with flesh fly larvae.
Flesh fly prevention and control is comprised of both exterior and, if necessary, interior procedures. The first step in a control program is to contact your pest management professional for assistance. Your pest management professional will positively identify the offending pest, conduct an inspection and then develop an integrated pest management plan (IPM) to resolve the problem. The key components of a flesh fly IPM plan include:
- Identification – since not all flies have the same behavior and habitat, it is important to correctly identify the offending insect so that an effective and efficient IPM program can be put into place.
- Inspection – your pest management professional’s inspection will provide the information and observations needed to develop the proper IPM plan
- Sanitation – keep the property clean and get rid of all sources that provide flesh flies a suitable development habitat.
- Exclusion – seal and repair screens, holes, gaps and any other entryway that flesh flies may use to enter the home.
- Light traps to attract and trap flies.
- Using chemical products to treat fly resting places, using chemical fly baits and using aerosol products.
- Using specific approaches to control flies that are inside a home or business. This occurs when flesh flies have developed in the carcass of a dead rodent, bat, bird or other animal that is located above the ceiling, in a wall void or some other hidden, out-of-the-way place. Your pest management professional may suspect flesh flies are developing in a carcass if he finds a large number of flies inside a building. If the source is found, your pest management professional may use chemical control products in the infested area or may need to use light traps to capture adult flies that have emerged.