The common housefly, also known as the Musca Domestica, is a cosmopolitan pest that propagates in regions where there is human activity. The housefly is thought to have formed as a species about 65 million years ago on the part of the planet now known as the Middle East, and human migration has resulted in the fly’s dispersal around the globe.

A fly’s body consists of three main parts; it’s head, the thorax in the middle, and the back end which is the abdomen. There are two small antennae jutting out from the very front of the head, which help the insect to detect motion (also aided by the tiny hairs covering the fly’s body, which pick up changes in air currents, as well as smell and taste).

But the most recognizable part of a fly are it’s eyes. To actually “see,â€? flies have what are known as “compound eyes.â€? These orb-like structures, which exist on opposite sides of a fly’s head in some species, actually only detect lightness and darkness (and sometimes color) despite their elaborate construction. As is the widely-held perception, a fly’s eye does indeed refract and reflect many multi-faceted repetitions of an image, captured within the many “ommatidiaâ€? which cover the surface of the eye (from 12 to 1,000 depending on the type of fly) and transport them into the fly’s brain. However, contrary to science fiction and horror films, the individual images picked up by the ommatidia are nowhere near as crisp as the single-retina images that humans see. The ommatidia on the eye’s surface point in different directions to get a kind-of “all-aroundâ€? view of things, and are the openings of tiny tunnels which lead inwards. The structure of these cone-like passages, and they way they reflect and refract light, are different with each species. The insides of the multiple tunnels are divided in half – one side designed to detect light and one to detect darkness. The fly’s tiny brain knows how to process the shifting, duplicate images.

The housefly’s reproduction capacity is tremendous, but because of harsh and shifting environmental factors, can fortunately never be realized. The birthing process of a fly is actually rather complex, and takes about 10 days. A female fly is ready to be impregnated 36 hours after hatching from an egg herself. Females can lay eggs 8-12 hours after impregnation, usually up to 500 eggs in several batches dispersed over a period of a few days. These eggs are bright white and about 1.2mm long. The female lays them in moist areas where there is nutrition, like decaying garbage or flesh or excrement. The larva, which become darker as they feed, grow to 3-9mm long and have black, hook-like mouths at one end, and sinuous slits (bleeaacchhh!) When the larva are fully-grown, they become one of the most universally recognized “gross-out� creatures known to man: maggots. Maggots are are creamy white and 8-12mm long. Contrary to popular belief, maggots do not “feed,� but instead are done eating as soon-to-be-flies, and ready to hide away and finish their birthing cycle. Maggots will crawl up to 50 feet away from the feeding area to a cool dry place, to quietly transform to the pupa stage. The pupa changes back to brown, and also red and then a weird ashy-gray during it’s various growth stages. When the fly is fully formed inside the pupa sac, it pounds it’s head like a pulsating hammer (which is actually designed to swell up and down quickly during this stage) to break out. Flies emerge fully-grown, and the appearance of small flies do not mean they are “children� flies, but simply ones smaller as a result of not having enough nutrition during the larva stage. A typical adult housefly is 6-7mm long, with females usually being larger.

As an adult, a housefly’s life-span is about 15-25 days. Males are very territorial and will duel with other males that enter what they perceive as their territory, and will also try to mount and inject with sperm all females who enter the area. Flies usually travel about one mile away from, and back to, the area where initial nutrition and reproduction have occurred in their lives. Flies are not active at night, and hide in cool dry places, like ceiling beams or window sills to rest. Flies have the ability to walk on ceilings and walls because the ends of their legs have tiny secretors which can emit a gooey substance. Flies only suck nutritional liquids, and do not have mouths to process solids. They can ingest solids by regurgitating saliva onto them to dissolve them. Flies are always cleaning their bodies and legs with their mouths because the many hairs on their bodies contain their smell and taste receptors, and need to remain unclogged.

There more than 100 pathogens of varying degrees associated with the house fly, which they pick up from landing on rotting foods and excrement, and then transporting them to surfaces they land on – through their feces, regurgitation and gooey legs. Seeing the odd single housefly land on your food is not a cause for extreme panic, and not necessarily reason to throw the food out (depending on how paranoid you are about germs) but an infestation with very many flies is cause for alarm. Households with infants or older people, or people with compromised immune systems should be more careful. Bug sprays are a bit pointless for flies, as they usually spray lots of poison in the air or on an indoor surface for just a single fly. Sticky pest strips and fly paper actually do work to control fly populations, and control of them is the best strategy – as total elimination is nearly impossible. Window screens are essential to keep them from entering your house and reproducing. Large numbers of indoor flies may be the result of rotting food, garbage or feces hidden somewhere in your home that you may not know about, or possibly a rotting animal hidden in the walls or under the home.

Fly swatters have a mesh design because flies detect the movement of air, and rely on this characteristic for survival. If you want to swat a fly and avoid it detecting you, you may be able to confuse it by swatting it from two directions at once. One clever way to sometimes capture a fly is to rather rapidly clasp your hands a few inches above it, which will usually cause it fly upwards – often into your just-closing hands.

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