BOTTLE FLY

Identification, Facts, & Control

Latin Name

Calliphora spp.

Appearance

Green or Blue Metallic Sheen

Green and blue bottle flies get their name from the fact that they have a metallic blue or green sheen. This characteristic makes them easy to see and identify despite the fact that they look like house flies in most other respects.

Green and blue bottle flies are also commonly referred to as "blow flies". There are several different species of these flies but their life cycles and habits are very similar. For this reason, we will discuss them as a group.

Green and blue bottle flies are among the common domestic flies found in urban areas. When an infestation of adult blue or green bottle flies occurs, one of two larval sources may be suspected: 1) garbage and/or 2) dead animals (especially rodents). The sources, if they are on the customer’s property, can usually be pinpointed and eliminated. Thus, the PCO can usually attain success in supplying successful fly control services when this fly is involved if he is willing to participate in mechanical reduction of larval sites. Garbage cans that are in poor physical condition and are not washed out routinely can serve as a larval source for myriads of adult flies. Even what we call "good" garbage cans (cans in good physical condition) can harbor many fly larvae. You will notice a small vent hole in the lid of metal garbage cans just under the lid handle. This vent hold is large enough to admit adult flies to the interior of the can ——— one female loaded with eggs is all it takes.

Homes situated near slaughter houses, meat processing plants and garbage dumps can also have severe problems with these flies. The preferred larval food sources of green and blue bottle flies are meats such as the carcasses of dead animals.

Green and blue bottle flies are very active and fly about in a noisy fashion. For these reasons, they are considered to be more annoying than house flies when found indoors. A large indoor population of adults is sometimes an indication that there is a dead rat, cat, large bird or other animal somewhere in the wall void, the attic or sub area (crawl space underneath the house) or in the yard outdoors.

A dead animal in the attic can result in fly larvae dropping down between double walls of closets and marching out into the bedroom looking for a place to pupate. A garbage can by the back door of an apartment - not emptied on a weekly basis — can result in larvae migrating over the side of the can, under the door and into the kitchen area looking for a place to pupate. The larvae can be recognized by the fleshy protuberances surrounding the spiracular plates. Blow flies are the flies most commonly associated with dead animals. However, the larvae of the Humpback fly is most commonly found in mausoleums, decaying organic matter, or dirty, moist mop heads made of long cotton fibers.

If no dead animal is seen, smelled or suspected in the house, green and blue bottle flies may still be getting in because they are attracted to certain odors (gasses). One gas which attracts female green and blue bottle flies is methane. Methane is given off by decaying animals and is also the same gas used as a fuel source for natural gas furnaces, stoves and water heaters. If there is a leak in the gas pipe in the between wall areas, green bottle flies will come to rest on the wall just over the spot where the leak is occurring.

Female green and blue bottle flies lay up to 600 eggs during their short two or three weeks’ lifetime. Although they "prefer" to lay their eggs on a dead animal or other meat source, they may alternatively deposit their eggs in manure or decaying vegetable matter (garbage). The larvae first feed on the surface of the material they are infesting, and then burrow down deeper into less decayed areas. When fully grown, the larvae leave their food sources and burrow into the ground where they change into the pupa stage. If the food source has been a rat or other small animal trapped between the wails or a room, when the adults hatch from their pupa cases, the homeowner may notice them coming out from around the edges of plumbing pipes, heater ducts, light fixtures, light sockets and other areas where there are openings in finished wails. The adults have a heavy, almost laborious flight characteristic and produce an annoying "buzzing" sound when in flight. An excellent way to monitor blow flies (e. g. in a meat processing plant) is to use a light trap.

Click on a species of flies below to learn further information.