Life Cycle of Calliphora

The calliphora, commonly known as the blue bottle fly or blowfly, has a special affinity for decaying meat, although it is not so particular about whether the meat is dead or alive. Blue bottle flies are as likely to infest a wound on a live animal as they are to feast upon raw steak. Like all other insects, they have a four-stage life cycle consisting of egg, larva, pupa and adult. Because the life cycle of Calliphora is relatively short, as many as eight generations can be born in a single season.

  1. Egg

    • The eggs of the blue bottle fly are laid in exposed flesh of live animals, decaying flesh of dead animals or in meat. The eggs are laid in clusters of 20 or more and will hatch within a day as long as enough humidity is present.

    Larva

    • The larva is blunt-ended at the rear and tapers to a point at the head, which features hooked mouth parts for tearing at flesh. The saliva of the calliphora maggot can also dissolve flesh. The maggot feeds aggressively and grows rapidly, nearly quadrupling in size in five to eight days. Once full-grown, the larva abandons the flesh and burrows into the ground before becoming a pupa.

    Pupa

    • In the ground, the larva forms a thick brown case around itself as it pupates. In the summer, the adult fly will emerge from the pupa after one to three weeks, but a pupa formed in late fall can overwinter underground, emerging in the spring.

    Adult

    • The adult bottle fly is about 1/2 inch long and has red eyes, a grey thorax, a metallic blue abdomen and black, bristly legs. After the adult female fly emerges from the ground, it will once again seek out a source of meat or decaying flesh, mating and then feeding upon the flesh before laying her eggs in it. The female blue bottle fly can lay up to 500 eggs.

    Relevance

    • Calliphora infesting the wounds of livestock can cause extreme irritation and, if the flies spread bacteria, even death. Scientists involved in the relatively young field of forensic entymology use the presence of calliphora on or a near a dead body to assist detectives in solving homicides. By observing the number of calliphora eggs, larvae, pupae and adults on or near the victim, along with other information (such as ambient temperature and humidity), entymologists can determine the time of person's death.