Stomoxys calcitrans is a cosmopolitan insect, meaning that it can be found worldwide as long as suitable food and weather conditions can be met.

Biogeographic Regions: nearctic (Introduced ); palearctic ; oriental ; ethiopian ; neotropical ; australian

Other Geographic Terms: cosmopolitan

The stable fly closely resembles the common housefly (Musca domestica). Unlike the common housefly, Stomoxys calcitrans have a broader abdomen. Adult stable flies average 8 mm in length, have a gray body, and can be identified by four characteristic longitudinal stripes across the thorax as well as several dark spots on top of the abdomen. On the vertex and frons there are three ocelli and two large compound eyes. Sexual dimorphism occurs in this species, and there is more distance between the compound eyes in females. The proboscis of the stable fly is black, long, and thin, protruding from the front of the head. Its other mouthparts are modified, with the labellum having rows of teeth in order to pierce the skin of its host. The palps are one third of the length of the proboscis.

Larvae range in size from 5 to 12 mm long. Mature larvae are yellowish white maggots, and are a cylindrical shape that tapers anteriorly.. The pupae have a reddish-to-dark brown exterior and are 4 to 7 mm long. The posterior spiracles on the puparia are black with three S-shaped yellow slits, and are lightly sclerotized.

Average length: 8 mm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: female larger

The habitat of the stable fly, as suggested by its common name, is almost anywhere that horses, cattle, and other agricultural animals can be found (especially inside barns and stables).

Habitat Regions: temperate ; tropical ; terrestrial

Terrestrial Biomes: savanna or grassland

Other Habitat Features: suburban ; agricultural

Stomoxys calcitrans is a daytime feeder. The adults of both sexes feed on blood. There is low host specificity; although they feed mainly on the blood of cattle and horses. Adults locate a host by sight, and feeding is usually completed in two to five minutes. After feeding the stable fly is sluggish, and remains motionless near the host. The stable fly will generally feed from many hosts before it is replete. Studies show that there is a rise in feeding during warm wether, whereas there is a decrease in feeding rates during rain. After hatching, the larvae begin feeding on local microbial flora and fauna.

Animal Foods: mammals; blood

Primary Diet: carnivore (Sanguivore )

There is little known predation of this species.

These flies have good eyesight and communicate visually.

Communication Channels: visual

Perception Channels: visual

Stomoxys calcitrans eggs take one to four days to develop. The length of this period is affected by temperature, humidity, and how long the egg was retained by the female. The larval stage lasts from 11 to 30 (and sometimes more) days, based upon habitat suitability and availability of food. After the third instar (growth stage) the maggot will pupate for 6 to 20 days. As with larval maturation, length of pupation is based upon food abundance and quality during larval growth.

Development - Life Cycle: metamorphosis

Soon after mating males die. Females die soon after laying their eggs.

The stable fly breeds in a number of habitats commonly found in agricultural areas such as decaying straw, oats, rice, barley, wheat, silage, horse manure, lot manure (manure from pig farms), and cow manure.

The female must be engorged for reproduction. The female never oviposits before the third feeding and, on average; four engorgements are necessary before eggs can be laid. The female has a greatly extended pseudovipositor with which she deposits eggs into decaying straw where there is moisture. Eggs are laid singly, or in bunches of 25 or 30. This activity usually lasts for about half an hour.

Key Reproductive Features: sexual ; fertilization (Internal ); oviparous

Eggs are laid in a habitat that will provide food suitable for larval growth and development. After eggs are laid, there is no further parental investment.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female)

This species has large populations world-wide, and is in no danger of extinction.

US Federal List: no special status

CITES: no special status

Stomoxys calcitrans economically affects humans in two ways: livestock reduction and disease. The accumulation of stable fly bites leads to a certain degree of anemia, weight loss in cattle, reduced milk production in dairy cattle. In this way, S. calcitrans costs the US millions of dollars. It also affects the cattle industry by destroying the hides of cattle due to the holes created by the piercing of the skin for feeding.

Studies have shown that as few as 20 flies per animal can reduce the rate of milk production. The effect on the hosts increases proportionally with an increase in the number of bites. This trend eventually reaches a plateau, due to the fact that the stable fly is only a daytime feeder.

For ox, horses, and sheep, S. calcitrans is a vector of Trypansoma cazalboui. This parasite causes the disease known as souma. For ox, it is a vector of T. pecaudia. For domestic animals and humans it is a vector of anthrax. This disease can cause a number of different symptoms, inculding lesions in the lungs and brain. It is also a vector for T. evansi (the agent of Surra), T. brucei, ERF, brucellosis, swine erysipelcs, equine swamp fever, African horse sickness, and fowl pox.

Negative Impacts: injures humans (bites or stings, causes disease in humans , carries human disease); causes or carries domestic animal disease

There is no obvious human benefit provided by these flies.