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Life Cycle of Blowflies

Blowflies are a group of insects that inhabit the contiguous United States and other temperate climates. They typically feed and lay their eggs on decaying cadavers and other organic matter, but are not adverse to infesting the open wounds of live animals. According to Stephen W. Bullington, Ph.D., blowflies have become "the most important insects on corpses" for forensic entomologists in determining time of death in cases of suspicious death.

Laying Eggs
- Within moments of death, female blowflies will descend upon a corpse and begin laying eggs. Each female will typically lay about 250 white, oval-shaped eggs in open wounds and in the nose, mouth, ears and other mucus membrane-lined areas.
First Stage Larva
- Within 24 hours, the eggs hatch into first-stage larva, or maggots. The white, cone-shaped maggots use the "hooks" in their mouths to attach themselves to decaying flesh and begin feeding.
Second-Stage Larva
- Within 27 hours, the first-stage larva molt (shed their outer skin) into second-stage larva. Larger than the first-stage larva, these maggots continue to feed, but will expand their feeding area as they begin to move about the corpse.
Third-Stage Larva
- In fewer than 24 hours, the second-stage larva molt for the final time into third-stage larva. Third-stage maggots continue to grow, feeding voraciously and producing enough heat to raise their environmental temperature by more than 10 degrees F.
Puparium Stage
- After a few days, third-stage larva move away from the corpse. Amazingly, their soft white skin hardens into a rigid shell (puparium) that contains the pupa, which is a motionless, rudimentary insect.
Adult Stage
- Within a few days, the tops of the puparia pop off and pale, soft, but fully-formed adult blowflies emerge. In one to two days, their soft bodies harden, they begin to fly and mate, and the life cycle starts all over again.

Insects & Science