Monday, January 11, 2010


The housefly (also house fly, house-fly or common housefly), Musca domestica, is a Diptera of the Brachycera suborder. It is the most common of all domestic flies, accounting for about 90% of all flies in human habitations, and indeed one of the most widely distributed insects, found all over the world; it is considered a pest that can carry serious diseases.

Physical description
The adults are 8–12 mm long. Their thorax is gray, with four longitudinal dark lines on the back. The underside of their abdomen is yellow, and their whole body is covered with hair-like projections. The females are slightly larger than the males, and have a much larger space between their red compound eyes. The mass of pupae can range from about 8 to 20 mg under different conditions.
Like other Diptera (meaning "two-winged"), houseflies have only one pair of wings; the hind pair is reduced to small halteres that aid in flight stability. caterpillars (M1+2 or fourth long vein of the wing) shows a sharp upward bend.
Species that appear similar to the housefly include:
a) The lesser house fly, Fannia canicularis, is somewhat smaller, more slender, and the media vein is straight.
b) The stable fly, Stomoxys calcitrans, has piercing mouthparts and the media vein is only slightly curved.

Life cycle
Each female fly can lay approximately 500 eggs in several batches of about 75 to 150. The eggs are white and are about 1.2 mm in length. Within a day, larvae (maggots) hatch from the eggs; they live and feed in (usually dead and decaying) organic material, such as garbage or feces. They are pale-whitish, 3–9 mm long, thinner at the mouth end, and have no legs. They live at least one week. At the end of their third instar, the maggots crawl to a dry cool place and transform into pupae, colored reddish or brown and about 8 mm long. The adult flies then emerge from the pupae. (This whole cycle is known as complete metamorphosis.) The adults live from two weeks to a month in the wild, or longer in benign laboratory conditions. After having emerged from the pupae, the flies cease to grow; small flies are not young flies, but are indeed the result of getting insufficient food during the larval stage.
Some 36 hours after having emerged from the pupa, the female is receptive for mating. The male mounts her from behind to inject sperm. Copulation takes between a few seconds to a couple of minutes. Normally the female mates only once, storing the sperm to use it repeatedly for laying several sets of eggs. Males are territorial: they will defend a certain territory against other males and will attempt to mount any females that enter that territory.
The flies depend on warm temperatures; generally, the warmer the temperature the faster the flies will develop. In winter, most of them survive in the larval or the pupa stage in some protected warm location.

Some types of maggots found on corpses have been found to be of great use to forensic scientists; specifically Forensic Entomology. By their stage of development, these maggots (and other insects) can be used to give an indication of the time elapsed since death, as well as the place the organism died. The lack of maggot presence is also telling in an investigation.
Maggot species can be identified using their DNA. The size of the house fly maggot is 10–20 mm (⅜–¾ in). At the height of the summer season, a generation of flies (egg to adult) may be produced in 12–14 days. Some other families of Insecta, such as Histeridae, feed on maggots. Thus, the lack of maggots would increase the estimated time of death.
Other types of maggots are bred commercially, as a popular bait in angling, and a food for carnivorous pets such as reptiles or birds.
Maggots have been used in medicine to clean out necrotic wounds and in food production, particularly of cheeses designed to rot as part of their 'aging' process. (casu marzu).

Houseflies feed on feces, open sores, sputum, and moist decaying organic matter such as spoiled food, eggs and flesh. Houseflies can take in only liquid foods. They spit out saliva on solid foods to predigest it, and then suck it back in. They also regurgitate partly digested matter and pass it again to the abdomen.

Housefly as a vector of disease
Mechanical transmission of organisms on its hairs, mouthparts, vomitus and feces:
a) parasitic diseases: cysts of protozoa e.g. Entamoeba histolytica, Giardia lamblia and eggs of helminths e.g.: Ascaris lumbricoides, Trichuros trichura, Haemenolypes nana, Enterobius vermicularis.
b) bacterial diseases: typhoid, cholera, dysentery, pyogenic cocci...etc. House flies have been demonstrated to be vectors of Campylobacter and E. coli O157:H7 using PCR. House flies can be monitored for bacterial pathogens using filter paper spot cards and PCR
c) Viruses: enteroviruses: poliomyelitis, infective hepatitis (A & E)..etc
House flies feed on liquid or semi-liquid substances beside solid material which has been softened by saliva or vomit. Because of their high intake of food, they deposit feces constantly, one of the factors that makes the insect a dangerous carrier of pathogens. Although they are domestic flies, usually confined to the human habitations, they can fly for several miles from the breeding place. They are active only in daytime and rest at night e.g. at the corners of rooms, ceiling hangings, etc.
Google SEO sponsored by Red Dragon Electric Cigarette Products