As defined by entomologists, a fly (plural flies) is any species of insect of the order Diptera. These typically have one pair of true wings, with the hind wings modified into halteres. Flies are common amongst humans and some can cause the spread of serious diseases. The housefly (Musca domestica) and mosquito are particularly common amongst humans. Other flies, such as the horse fly (Family Tabanidae), can inflict painful bites. The larva of a fly is commonly called a maggot.
Flies rely heavily on sight for survival. The compound eyes of flies are composed of thousands of individual lenses and are very sensitive to movement. Some flies have very accurate 3D vision. A few, like Ormia ochracea, have very advanced hearing organs.
The diet of flies varies heavily between species. The horse-fly and mosquitoes feed on blood and nectar, and the house fly eats a semi-digested liquid created by mixing enzyme-rich saliva with its food.
In addition to being an essential part of the food chain, some species of flies spread pollen, hasten the decomposition of plants, animals, and dung, and, in the case of about 5000 species of Tachina flies, eat other insects.
Some types of maggots found on corpses can be of great use to forensic scientists. By their stage of development, these maggots can be used to give an indication of the time elapsed since death, as well as the place the organism died. The size of the house fly maggot is 9.5-19.1mm (3/8 to 3/4 inch). At the height of the summer season, a generation of flies (egg to adult) may be produced in 12-14 days.
Maggot identification uses a classification called "Instar" stages. An instar I is about 2-5 mm long; instar II 6-14 mm; instar III 15-20 mm. These measure about 2-3 days, 3-4 days, and 4-6 days (for average house flies or bottle flies) since the eggs were laid. By use of this data, plus other signs, the approximate time since death can be estimated by forensic scientists.
Various maggots cause damage in agricultural crop production, including root maggots in rapeseed and midge maggots in wheat. Some maggots are leaf miners.
Maggots are bred commercially, as a popular bait in angling, and a food for carnivourous pets such as reptiles or birds. Due to the increasing popularity of maggots, a maggot vending machine has been installed in the English county town of Northampton.
Examples
Flies | Insects | ذبابة | Mosca | Flue | Fliegen | Kärbes | Mosca | مگس | Mouche | Musho | Lalat | זבוב | Musė | Lalitra | Lalat | Tweevleugeligen | ハエ | Fluer | Mosca | Муха | Мува | Fluga | פליג