Bottle flies, also called blow flies, are common, large flies known for their metallic blue or green color.
Behavior, Diet & Habits
These flies create a buzzing sound while flying and are scavengers that feed on decaying meat or organic substances. They are transmitters of diseases and are considered to be pests.
Bottles flies are typically found outdoors. If a large number of bottle flies is found inside, an indoor breeding site may have been established. To eliminate bottle flies, it is important to implement stringent sanitation measures, which include cleaning garbage containers and making sure that the lids are seated tightly.
A female bottle fly can lay in excess of 2,000 eggs in a lifetime. The eggs are pale yellow or gray in color. Resulting larvae measure 9 to 22 mm in length and may hatch within two to three days, depending on temperature. Within two to 10 days, larvae seek pupation sites, from which they eventually emerge as adult flies. Bottle flies breed in damp, organic matter such as dead animals.
Bottle flies are also good pollinators. They often pollinate flowers with strong odors, such as pawpaws and goldenrod. When food sources are diminished, bottle flies feed upon the nectar of these flowers in order to produce healthy eggs.
Signs of a Bottle Fly Infestation
The most common signs of bottle flies are either the adults themselves or their larvae. The adults may be seen resting on surfaces or buzzing around potential food or odor sources. The larvae may be observed when they crawl out of the breeding material to pupate.
Blue bottle flies superficially resemble the house fly but are shiny blue in color. They are commonly found on windows and produce loud, buzzing sounds. Because blue bottle flies deposit their eggs in decomposing organic matter, their appearance indoors indicates that decomposing matter is present nearby.
First, examine sewer pipes for breaks or fissures. If no breaks are found, rubbish areas should be inspected. Flies may lay their eggs in trash scraps. Dead animal carcasses may also be the source of a sudden appearance of blue bottle flies. A forgotten mousetrap or a dead animal inside a wall or attic may lead to a blue bottle fly infestation.
Small numbers of blue bottle flies may enter homes in pursuit of light or accidentally through an open door or window. Using fly strips is a method of capturing individual flies. Aerosol insecticide may also be of use. However, these methods kill only exposed flies and do not treat infestations. Contact your local pest control professional to discuss eradication options.