A source for information on flies
Flesh Fly Family Sarcophagidae
Flesh flies are often
mistaken for houseflies due to their coloration and markings. However, their gray-checkered abdomens are
distinctively larger than those of the housefly. A typical flesh fly also exhibits three dark stripes along the
prothorax and four distinct bristles atop the thorax. An extra row of bristles is found beneath the flesh fly’s
wings and yet another can be found at each side of the thorax. Flesh flies measure approximately 10 to 13
millimeters from end to end. Larvae are yellow in color, with pointed heads. Along with bottle and blowflies, flesh
flies prove useful to forensic entomologists. These fly larvae may assist in pinpointing time of
Flesh flies reproduce on decaying vegetable items,
animal flesh, carcasses, garbage and excrement. Although flesh flies do not bite and are not carriers of disease,
their feeding habits can become a nuisance. However, larvae can also prove beneficial to humans, as they prey on
the eggs and larvae of other pests such as grasshoppers, blowflies, houseflies, spiders and snails. Flesh flies are
rarely found in homes or restaurants. Infestations in these locations are most likely due to a different fly
Flesh flies usually
have gray bodies with black and gray lengthwise stripes on the thorax, and a checkerboard-like pattern on the
abdomen, which is often red-tipped. Their eyes are usually bright red.
Range from 3/8 to 1/2-inch
The life of a flesh fly usually begins in the decaying flesh of a dead animal, regardless of the state of
decomposition. They also lay eggs in dumpsters in various decaying materials as well as manure. Some species even
lay their eggs in the wounds of mammals. The larvae, commonly known as maggots, are cream-colored and have a greasy
texture, live for 5-10 days in these environs before descending into nearby soil where they mature into
A few species of flesh flies can lay so many eggs on an animal carcass that is becomes a squirming mass of maggots
when the eggs hatch. As disgusting as this sight may be, it is also beneficial because these maggots help
accelerate the natural decomposition process and cycle of life by re-depositing nutrients back into the soil. Like
blow flies and bottle flies, flesh flies are important scavengers in nature as they are one of the first insects to
reach a dead animal. These flies are part of the decomposition process that recycles nutrients back into the soil.
The maggots of these flies may be used by forensic entomologists to place the time of death in murder cases. They
also breed in garbage containers and dumpsters.
Adult flesh flies emerge during the summer and are very common outdoors, though they may be attracted to a dead
bird or rodent that may have died in the attic or elsewhere indoors. Flesh flies are usually attracted to buildings
by food odors, and may enter through an open door or window. They are common around farms where they are attracted
to fresh animal dung, and around meat processing plants, dumps and other locations where decaying matter is
abundant. These flies are extremely common and can be found one to a few at a time in homes or businesses during
the warm summer months. They are attracted to buildings by food odors and also warm/cool air currents emitted
through cracks around doors and windows, or through doors propped open for ventilation purposes. The sudden
appearance of dozens of flesh flies within a building signals a potential dead rodent, bird or other animal in the
wall, ceiling, attic or crawlspace.
The life cycle of the flesh fly is very predictable. Because they are the first to arrive on the scene of a dead
mammal, they are often used by forensic entomologists to pinpoint the time of death in homicides in a process
called back extrapolation.
This is done by determining the oldest larvae of each species of present, measuring the specific temperature, and
then calculating the earliest possible date and time for the deposition of larvae. This yields an approximate time
and date of death.
If flesh flies become a nuisance, the first step in eliminating them is sanitation. Keep dumpsters and trash
containers away from buildings and their lids tight. If there is a rodent problem present make sure to dispose of
any rodent carcasses as soon as possible. Since flesh flies feed and breed on dead animals and garbage, it is best
to locate and eliminate all possible breeding sources.
In most cases involving flesh flies around homes, the problem is twofold: (1) flies are being attracted to the
building by trash containers or pet manure and (2) openings (e.g. doors) exist that are permitting flies to enter.
To minimize problems with flies, take the following steps:
- Throw trash away in trash cans in plastic bags. Bags reduce odors associated with garbage and trash thus
attracting fewer flies to the area.
- Locate trash receptacles as far from the building as possible. Those flies that are attracted to the area
will therefore be away from the back door.
- Keep doors and windows closed unless they are equipped with tight-fitting screens.
- Ensure all edges of doors and windows have tight weatherstripping. Flies can squeeze through amazingly
If the presence of these flies is due to a dead animal within the building, finding the location of the carcass
and its removal is necessary, but is not easily accomplished.
Locate and seal any cracks any cracks around doors and windows. Most flies can fit through very small openings and
become an indoor pest. Make sure all screens are fit tightly and are free of holes. All windows and doors should
fit properly. Dispose of discarded food and garbage immediately in tight-fitting containers.