Blow-fly
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Blow-flies (also frequently spelled blow flies or blowflies) are members of the family Calliphoridae of flies (Diptera). Flies in this family are often metallic in appearance.
Some members of this family are known as bluebottles, cluster-flies, greenbottles, and in Australia, as blue-arsed flies. The name blow-fly comes from the fact that recently deceased corpses would swell up from bacterial decomposition in the intestinal tract, causing them to become bloated, or "fly-blown". Blow-flies are usually the first insect to come in contact with a dead animal.
The family is divided into two subfamilies, the Calliphorinae, and the Chrysomyiinae, which between them contain about 23 genera.
Adult blow-flies are occasional pollinators, being attracted to flowers with a strong odor resembling rotting meat, such as the American pawpaw.
Prior to laying her eggs the female blow-fly will use her proboscis to consume protein from a corpse's tissues. Her eggs are then deposited in the eyes, nose, mouth, and ears of the corpse. When a female blow-fly is getting ready to lay her eggs, her behaviour changes from frantic to lethargic and persistent.
Blow-fly eggs are approximately 2 mm long, and when they are laid, they look as though they are rice balls. The female blow-fly may lay around 2,000 eggs during the course of her life.
Larvae have three stages of development, molting during the course of each change. The larvae use their hook-like mouths to eat the protein in a corpse. Advancement of a blow-fly from the first stage to the third stage can last anywhere from 12 hours to two days, depending on temperature and climate.
When the third stage is complete the pupa will leave the corpse and burrow into the ground, emerging as an adult 14 days later.
Blow-flies are considered an important indicator in forensic science, as the stage to which blow-fly larvae have developed can help forensic entomologists determine the approximate time of death of a victim when sufficient time has elapsed that other methods, such as the measurement of internal body temperature, are no longer feasible. The specialized discipline related to this practice is known as forensic entomology.da:Spyflue de:Schmeißfliegen