Flies are the fourth largest order of insects and there are over 100,000 species. Most of them are beneficial to some degree as they serve as a food source to many animals and even a few plants. Many breed in organic material such as animal manure and help recycle its nutrients to the soil. Others contribute to the decomposition of dead animals. Flies can also be serious pests. Mosquitoes and other biting flies can cause human deaths by spreading such diseases as malaria, dengue fever, encephalitis, yellow fever and many others. Flies are different from other insects in that they only have a single pair of wings. Flies have a variety of different life spans ranging from two weeks to one month.
You certainly don’t want any flies around schools, day care centers, hospitals, nursing homes, animal shelters or other areas where they can infect people or animals.
House flies (Muscidae – Musca domestica)
House flies have a gray thorax (part where head is connected and wings are attached) with four dark stripes, and a mottled abdomen (posterior portion). These flies are considered “filth flies??? and will feed on excrement, garbage, carcasses, and even human secretions from wounds and mucous membranes. If you accidentally eat the larvae (maggots) in contaminated food, they can survive in your intestine. They can harbor over 100 different pathogenic organisms and are capable of transmitting more than 65 diseases and bacteria that can cause duodenal and stomach ulcers. House flies are the most common fly in the world that is found around homes and areas with livestock.
Little house flies (Fannidae – Fannia canicularia)
Little house flies are dull gray with yellow on the upper abdomen and 3 dark longitudinal stripes on the top of the thorax.
These flies resemble house flies but they fly in circles in the middle of a room or on a porch and don’t appear to land. They can lay their eggs in any organic material including compost piles, pet feces, dead leaves, etc. They have even been known to enter the urinary tract of naked sleeping persons and causing urinary myiasis.
Blow flies (Calliphoridae -Phormia, Phaenicia, Cynomya & Calliphora)
Blow flies are larger than house flies and are normally shiny green, blue, bronze or black in color. Blow flies feed on decaying animal matter and if you have them in your house it is an indication of a dead animal in the wall or ceiling. Occasionally the only sign of these flies in an early infestation is when the larvae fall from the ceiling void onto the floor.
Common names for the most frequently encountered blow flies are black blow flies, greenbottle flies and bluebottle flies. Greenbottle and bluebottle flies are metallic green or blue in color. Black blow flies have a black sheen. These flies are also used by forensic entomologists to establish the time of death in human fatalities.
Fruit flies (Drosophilidae)
Fruit flies are usually found in the kitchen where they feed and breed on food spilled in out of the way places such as behind or under appliances or similar areas. These small flies have distinctive red eyes, which you can see with a hand lens. They are tan or brown in color and about 1/8??? long. They are also known as pomace flies and vinegar flies. They can be serious pests when found in food handling establishments as they breed in and feed on fruits, vegetables and any moist, decaying organic material. They have been known to cause intestinal problems and diarrhea when fruit containing their larvae are eaten. They will also breed in discarded fruit juice and soft drink cans and in unsecured bottles of wine. They are also very prolific as the female can lay about 500 eggs which will hatch and reach adulthood in as little as eight days.
Hump-backed flies (Phoridae)
These are small flies, about an 1/8??? long and tan to dark brown in color. They have a distinct hump-backed shape thorax, hence their common name. They do not have red eyes as fruit flies do. When these flies are disturbed, they will run along the surface they are on rather than flying away.
These flies breed in any moist organic material including dirty mops, garbage, decaying fruits and vegetables and dead animal matter. They are also known as coffin flies because of their presence where dead bodies are found, including inside of coffins. There are over 220 species of phorid flies in the United States.
Moth flies aka Drain flies (Psychodidae)
Moth flies are small flies with hairy wings that resemble small moths. They are also called filter flies and drain flies. They are usually found in the bathroom. They will breed in the gunk buildup in drains and will often be found in the tub, on shower curtains or the wall. They are poor fliers and seem to just hop around. The larvae live in gelatinous material in sink and floor drain traps, in sewer treatment plants and in septic tanks. They will also breed in damp crawl spaces under a house.
Fungus Gnats (Sciaridae)
Fungus gnats are very small flies with long legs and long antennae and distinctly patterned wings. They are dark brown or black in color. They are generally found in over-watered house plants where the larvae feed on fungus in the potting soil and moist organic material.