Musca domestica Fly

The housefly (also house fly or house-fly ), Musca domestica , is the most common fly occurring in homes, the most familiar of all flies and indeed one of the most widely distributed animals; it is a pest that can facilitate serious diseases.

Physical description
The adults are 5-8  mm long. Their thorax is grey, with four dark longitudinal lines on the back. The underside of the abdomen is yellow. The whole body is covered with hair. They have red compound eyes . The females are slightly larger than the males and have a much larger space between the eyes.

Like most Diptera (meaning "two-winged"), houseflies have only one pair of wings ; the hind pair is reduced to small halteres that aid in flight stability. Characteristically, the media vein (M1+2 or fourth long vein of the wing) shows a sharp upward bend.

Species that appear similar to the housefly include:

• The lesser house fly , Fannia canicularis , is somewhat smaller, more slender, and the media vein is straight
• The stable fly , Stomoxys calcitrans , has piercing mouthparts and the media vein is only slightly curved

Life cycle
Each female fly can lay up to 8,000 eggs . The eggs are white and are about 1.2 mm in length. Within a day, the 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. 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 half a month 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 the result of 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 . Normally the female mates only once, storing the sperm to use it repeatedly for 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.

Housefly pupae killed by parasitic wasp larvae. Each pupa has one hole through which a single adult wasp emerged; feeding occurs during the wasp's larva stage.

The flies depend on warm temperatures; generally, the warmer the temperature the faster the flies will develop. In the winter, most of them survive in the larval or pupa stage in some protected warm location.

Some species of wasps can parasitize and kill the pupae.

Typical behaviors
Houseflies can take in only liquid foods. They spit out saliva on solid foods to pre-digest it, and then suck it back in. They also vomit partially digested matter and eat it again.

The flies can walk on vertical planes, and can even hang upside down from ceilings. This is accomplished with the surface tension of liquids secreted by glands near their feet.

Flies continually preen themselves, cleaning their eyes with their forelegs and dusting off their legs by rubbing them together. They do this because most of their taste and smell receptors are on the hairs of their legs.

Flies have a very highly-evolved evasion reaction which helps to ensure their survival. It is possible to confuse a fly's evasion system by swatting it with two objects simultaneously from different directions. The holes in a fly swatter minimise the air current which warns the fly of being hit, whilst reducing air resistance and increasing speed of the swat. This evasion reaction can also be used against the fly. Clapping your hands several inches above the fly will cause it to try to escape, usually into your just closing hands. A successful method of removing flies from living spaces is to use a vacuum cleaner equipped with a long (1m/3 feet)straight tube at the end of a flexible hose. Airborne flies can be chased with the tube and will eventually be sucked into it. Standing flies can be approached slowly with the tube (1cm/half-an-inch per second) and often they will not fly away and will be sucked into it.

Flies and humans
In colder climates, houseflies occur only with humans. They have a tendency to aggregate and are difficult to dispel. They are capable of carrying over 100 pathogens , such as typhoid , cholera , Salmonella , bacillary dysentery , tuberculosis , anthrax , ophthalmia , and parasitic worms . The flies in poorer and lower-hygiene areas usually carry more pathogens. Some strains have become immune to common insecticides .

Swatting flies is difficult because of their excellent peripheral vision and fast reaction times. A technique that works is to clap, or bring two books together, about three inches above a resting fly. The fly instinctively jumps when threatened, and is caught in the trap.