Creature Feature

Blow Flies

Blow or bottle flies are common around most of the world. They serve an important role by quickly consuming organic waste, such as animal remains, feces, and garbage, in the environment. Adults of some species arrive within minutes to the presence of animal remains, where they’ll lay their eggs that hatch into maggots to consume the body. Forensic entomologists are able to use the maggots’ developmental stages to determine a body’s time of death. 

Adult blow or bottle flies are around half an inch long and usually metallic, with green being the most common color. Metallic blue, bronze or black are also possible. Outdoors, they often gather on the sunny sides of structures. Their populations can be managed by reducing the amount of animal feces that may be on the property or by keeping garbage contained as best as possible. If a large amount of adults are suddenly found indoors, it is usually a result of an animal dying within the structure.

Blow or bottle flies must be managed because of their association with animal remains, feces and garbage, and the possibility of mechanically transmitting pathogens to food or to wounds. Outdoor surfaces where they tend to rest in groups can be treated with a liquid residual product. If adults are suddenly found indoors, search for an animal that may have died within the structure as best as possible. Their numbers will dwindle once the carcass is removed. These flies don’t normally want to be indoors without a food source, so they tend to fly to windows for way out. Applying a fly bait to the windows they are most attracted to will speed up the management process.