Flesh-fly


Flies of the Diptera family Sarcophagidae (from the Greek sarco- = flesh, phage = eating; the same roots as the word “sarcophagus”) are commonly known as flesh flies. Most flesh flies breed in carrion, dung, or decaying material, but a few species lay their eggs in the open wounds of mammals; hence their common name. Some flesh fly larvae are internal parasites of other insects. These larvae, commonly known as maggots, live for about 5–10 days, before descending into the soil and maturing into adulthood. At that stage, they live for 5–7 days.

Characteristics

Antennae 3-segmented, with an arista; vein Rs 2-branched, frontal suture present, calypters well developed. Medium-sized flies with black and gray longitudinal stripes on the thorax and checkering on the abdomen. Arista commonly plumose on basal half; bare in a few species. Four notopleural bristles (short, long, short, long, from front to rear). Hindmost posthumeral bristle located even with or toward midline from presutural bristle.

The family contains three subfamilies, the Miltogramminae, the Paramacronychiinae and the Sarcophaginae, containing between them 108 genera. Flesh-flies are quite closely related to the family Calliphoridae, which belongs to the same (large) infraorder, the Muscomorpha, and includes species such as the blowfly that have similar habits to the flesh-flies.

Biology

Flesh-fly maggots occasionally eat other larvae although this is usually because the other larvae are smaller and get in the way. Flesh-flies and their larvae are also known to eat decaying vegetable matter and excrement and they may be found around compost piles and pit latrines.

Flesh-flies, being viviparous, frequently give birth to live young on corpses of human and other animals, at any stage of decomposition from recently dead through to bloated or decaying (though the latter is more common).

The life cycle of flesh-fly larvae has been well researched and is very predictable. Different species prefer bodies in different states of decomposition, and the specific preferences and predictable life cycle timings allows forensic entomologists to understand the progress of decomposition and enables the calculation of the time of death by back extrapolation. This is done by determining the oldest larva of each species present, measuring the ambient temperature and from these values, calculating the earliest possible date and time for deposition of larvae. This yields an approximate time and date of death (d.o.d.) This evidence can be used in forensic entomology investigations and may assist in identification of a corpse by matching the calculated time of death with reports of missing persons. Such evidence has also been used to help identify murderers.

Association with disease

Flesh-flies can carry leprosy bacilli and can transmit intestinal pseudomyiasis to people who eat the flesh-fly larvae. Flesh-flies, particularly Wohlfahrtia magnifica, can also cause myiasis in animals, mostly to sheep, and can give them blood poisoning, or asymptomatic leprosy infections.

 

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