Flesh Flies
Sarcophaga spp., Sarcophagidae, DIPTERA

DESCRIPTION

Adult -- Flesh flies usually have gray bodies with three black stripes on the thorax. The abdomen has a light and dark gray checkerboard pattern and is often red at the tip. Though some species may be smaller than house flies, most flesh flies are about 10 to 13 mm long.

Larva -- These near white to yellowish maggots have pointed heads. Depending on the species, they range from 10 to 22 mm in length when fully grown.

BIOLOGY

Distribution -- As a group, flesh flies occur throughout most areas of the world although species distribution varies. Flesh flies are found in urban and rural communities but, fortunately, are relatively uncommon in houses or restaurants. They breed in excrement, decaying vegetable matter and animal flesh or meat.

Feeding Habits -- Adult flies do not bite but feed on a wide range of liquid substances. Most larvae infest wounds, carrion or excrement. The larvae of some species of flesh flies are beneficial in that they prey on eggs, nymphs, or larvae of more harmful insects. Lesser house fly larvae, blow fly larvae, and grasshopper nymphs are common hosts of flesh flies.

Damage -- Though they can carry leprosy bacilli, flesh flies usually are not problems as disease carriers or even as nuisances and pose little threat to human welfare or to livestock. A few cases are known in which flesh fly maggots have burrowed from wounds into the healthy flesh of livestock, and some species can cause intestinal pseudomyiasis (infection by fly larvae) in humans who consume food contaminated with larvae.

Life History -- Flesh fly life histories vary with species and location. They overwinter as pupae in North Carolina and other temperate climates. Rarely very numerous, the flies emerge in spring and mate. Eggs are laid only under very unusual circumstances. As a rule, eggs hatch within the body of the adult. Females of most species deposit 20 to 40 larvae directly onto the host or substrate. As many as 325 larvae have been known to be born by a single female.

Flesh fly maggots feed for 3 or 4 days and develop through 3 instars. Soon afterward, these mature maggots enter the pupal stage. Adult flies emerge in 10 to 14 days and the life cycle is repeated. Several generations are produced each year.

CONTROL

Flesh flies rarely require chemical control. The burial or destruction of carcasses, manure heaps and mounds of decaying organic matter eliminates many favorable breeding sites. Proper treatment of wounds also helps to prevent flesh fly harm to animals.