moscow común or doméstica (Domestic musca) is a aerial animal belonging to insects, being one of the most common and known throughout the world. It can be found on all continents except the Arctic Circle and Antarctica.

House fly in profile

House fly in profile


The common fly belongs to the more than 240.000 different species distributed throughout the world, but only about half of them have been studied and documented. The study of all species is a pending challenge for the scientific community.

The fly is also the common name of the Diptera order, which includes families such as Calliphoridae or Sarcophagidae, better known as blowflies. Mosquitoes and horseflies also belong to the same order. They all have in common that they have two membranous wings instead of four like almost all insects.


The adult housefly can grow to 6 to 7 mm in length with a wingspan of 13 - 15 mm. The females are usually larger than the males, although the legs of the males are usually more elongated. Among females the size is very uneven and there are geographical variations between individuals of different latitudes.

There is a myth that flies live 24 hours, but it is totally untrue. Although they do not have a very long life, they usually live between 15 to 25 days but in ideal conditions they can exceed 60 days.

The head is highly convex in front and flat and slightly conical behind. The pair of eyes they possess almost touch each other in males, being further apart in females. Flies have the ability to process visual information seven times faster than humans, that is, they can see human movements in slow motion at a higher blink fusion rate so they can identify and avoid attempts by flies. humans from being crushed or trapped.

The thorax is gray in color that may turn black, with four longitudinally dark bands of similar width on the dorsal surface. The entire body is covered with hairs that are invisible to the naked eye.

They have only one pair of wings, what would be the rear pair is reduced to small halters that help the stability of the flight. They are transparent with a small yellowish tinge at their base. The middle vein (M1 + 2 or fourth long vein) shows a strong upward flexion. On each wing it has a lobe on the back, called a calipter, that covers the halter.

Common fly enlarged

Common fly enlarged

The abdomen is gray or yellowish in color with a dark streak and uneven dark spots on the sides. It has 10 segments that carry spiracles to breathe. In males, the ninth segment carries a pair of classifiers for copulation, and the tenth has the anus in both sexes.

The mouthparts are specially designed for a liquid diet; the jaws and jaws are reduced and not functional. The other parts of the mouth form a flexible, retractable proboscis with an enlarged, fleshy tip, the lip. It is a spongy structure characterized by numerous grooves, called pseudotracheos, which suck in fluids by capillary action. It is also used to distribute saliva to soften solid foods or collect loose particles.

House flies have taste organs on their legs, called chemoreceptors, with which they can obtain information about food by walking on them. When we see a fly rubbing its feet, it is actually cleaning its chemoreceptors in order to detect a new flavor.

At the end of the legs it has a pair of claws, and under them it has two sticky pads, called pulvilli, which allow the fly to climb smooth walls and ceilings using the forces of Van der waals. The claws help to detach the legs to take the next step.

To walk, as with the horses, they do it with a common step on both horizontal and vertical surfaces with their three legs making contact and three moving. If the surface is inverted, the fly alternates gait keeping all four legs glued to the surface. When they land on a roof, they do so by flying directly towards it and when they approach they turn around just before landing and point their six legs towards the surface to absorb the impact and later hitting with the other four.


Houseflies are diurnal and sleep through the night. If they are inside a building when it gets dark, they tend to concentrate on roofs, beams, and overhead cables, while the outdoors they move onto foliage or long grass, or rest in bushes and trees or on cables.


The fly has been strongly associated with humans and has accompanied them around the world since the beginning of time. It is believed that it does so due to the organic waste that humans produce, as it is the perfect place for flies to inhabit.


The fly is distributed throughout most of the world, in fact it is clearly the insect with the largest presence in the world. It is present in all populated parts of Europe, Asia, Australasia (the union of Asia and Australia) and America. They can also be found in the Arctic Circle, as well as in the tropics, where it is especially abundant.


Flies are omnivorous animals, feeding on virtually anything from plant nectar to sap and even the blood of animals. To feed, the fly uncoils its long, pointed tongue and then sucks the liquid.

When they are larvae they feed on decomposing matter such as excrement and meat.


The fly has a wide variety of predators, due to its small size and abundance. The most common predators are amphibians such as frogs, toads, and newts, some fish that feed on flies that land on the surface of the water, reptiles such as lizards, and small mammals.

The fly's unnatural enemy is humans, who find them especially annoying. For this reason, they have developed numerous utensils or chemical products to kill them with great ease.


The female fly inserts her eggs into decaying matter, be it plants or animals. The eggs hatch very quickly, giving rise to tiny fly larvae known as maggots. The worms go through a metamorphosis until they become flies. The process from egg to adult fly takes about two weeks.

State of conservation

The fly is in good health and is therefore not classified as endangered and is a 'Least Concern'.

Relationship with humans

Both flies and mosquitoes are known pests throughout the world, generally related to dirt, decay and disease, as many species of flies are known to carry disease due to their ingestion of animal feces and their connection to decomposing bodies.


  • Eye irritation: Flies cause eye irritation if the presence of it is constant in the area where we move. Even in the most severe cases it can lead to conjunctivitis.
  • Anger: Bacterial intestinal disease that causes watery diarrhea, vomiting, muscle cramps, and fluid loss. It is transmitted by African flies.
  • Typhoid fever: Caused by a bacterium of the salmonella genus, it causes general malaise, weakness, loss of appetite, headache or constipation.
  • Dysentery: A disease that causes bloody diarrhea, along with abdominal cramps, fever and rectal pain. You can have complications that affect the kidney.
  • Worms: Mild infection that causes vomiting and nervous changes.
  • Sallmonelosis: It is transmitted from contaminated food with the appearance of being completely healthy. It is advisable to keep flies away from food to avoid contagion. Its symptoms are severe diarrhea, fever and abdominal pain.
  • Trachoma: Infection caused by a fly bite in the eye. It is the leading cause of blindness in the world.

Popular culture

Flies were used in art and artifacts in many cultures. In European vanitas paintings of the 1496th and XNUMXth centuries, flies sometimes appear as mori souvenirs. They can also be used for other purposes such as in Flemish painting, The Master of Frankfurt (XNUMX). Fly amulets were popular in ancient Egypt.

They have appeared in documentaries, films such as "La mosca", literature, theater and is very present in dozens of Hispanic sayings such as:

¿qué mosca te ha picado?

Andar con la mosca detrás de la oreja

En boca con mella, si entra una mosca, allá ella.

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