Flesh flies skip the egg stage and deliver live maggots
Most flies lay eggs, but flesh flies are ovoviviparous: the female deposits larvae that have already hatched or are hatching. Their family name, Sarcophagidae, joins Greek words for flesh and eating, yet adults mostly sip nectar, sweet foods and other fluids, leaving the protein-hungry young to do the scavenging.
Around 2,500 species belong to the family, spread across three subfamilies and 108 genera. Members of the Sarcophaginae range from about 4 to 23 millimetres long and are recognisable by black and grey stripes running down the thorax, a checkered abdomen covered in bristles, and red eyes. Specialists sort them by the precise placement of bristles on the thorax, such as four notopleural bristles arranged short, long, short, long.
Their larvae take many routes to a meal. Most species in the large genus Sarcophaga scavenge small remains, such as dead insects and snails, and the family also turns up around compost heaps where vegetable matter rots and beside pit latrines, feeding on excrement. Some larvae live as internal parasites of grasshoppers and their relatives. The Miltogramminae are kleptoparasites, stealing provisions from solitary bees and wasps, and other genera hunt caterpillars or raid bumblebee nests for developing young.
Maggots of this family sometimes eat other larvae, though usually only because smaller ones get in the way. That opportunism has consequences for people and livestock. Flesh flies can carry leprosy bacilli, and one species, Wohlfahrtia magnifica, can infest animals, especially sheep, sometimes causing blood poisoning.
Telling species apart is famously hard. Generally only males can be identified with confidence, and even then usually by dissecting and examining their reproductive structures under magnification. Reference literature is incomplete or scattered for every region, so taxonomists rely on a patchwork of regional keys and catalogues produced in English, French, German, Russian and other languages over more than a century.
Source: Flesh fly
