Life Cycle of Flesh Flies
Life Cycle Stages
Like their name implies, these flies depend on live or dead tissue to complete the entire flesh fly life cycle. These species and other carrion eating flies are used to help solve crimes since the presence of adults and larvae at a crime scene can help forensic specialists determine how long a body has been at that location. Flesh flies develop by complete metamorphosis – meaning they go through 4 distinct life cycle stages:
The genus Sarcophaga fly eggs incubate, develop, and hatch inside the adult female’s body rather than on or near carcasses and other external food sources. This is a behavior known as being larviparous.
After eggs hatch, the female deposits live larvae into piles of manure, decomposing flesh, or other suitable larval stage developmental sites. Each flesh fly species generally prefers various sources and decomposition stages in which to deposit the larvae. Regardless, the female carefully selects the laying site to ensure an abundance of food for the larvae in this stage of the flesh fly life cycle.
Larvae feed for approximately four days, depending on environmental conditions and the species. One female can produce hundreds of eggs during her lifetime, and more than 25 larvae may hatch at one time. Some of their more preferred larval developmental sites are:
- Decaying meat
- Inside animal carcasses
After completing the larval stage of the life cycle, flesh flies pupate, which is a dormant stage of little or no movement. While some pupae might remain dormant for several weeks, most species emerge as adults within 12 to 15 days.
When the larvae are ready to pupate, they leave the host and wander until they find a suitable location, sometimes even below the soil surface. Some flesh fly pupae are able to enter into a facultative diapause, which means they go into a hibernation-like state until appropriate environmental conditions such as temperature, humidity, and available light become normal once again.
By the time adults reach this point in the flesh fly life cycle, they are about the size of the typical house fly. They can have a red body portion located at the end of their abdomen, clear wings, and red eyes. Of the 2,000 known species in the family Sarcophagidae, about 327 are found in the United States.
Flesh fly mating occurs typically in spring.
The lifespan of flesh flies varies and may be as little as 15 to 21 days, depending upon species and conditions.