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
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
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 )
Flowering Plants Visited by Stomoxys calcitrans in Illinois
(observations are from Robertson, Graenicher, and Reed)
Anacardiaceae: Rhus glabra [pist sn] (Rb); Apiaceae: Cicuta maculata sn (Rb), Sium suave sn (Rb); Asclepiadaceae: Asclepias syriaca dead (Rb); Asteraceae: Ageratina altissima sn/fp (Gr), Anthemis cotula sn/fp (Gr), Arnoglossum muhlenbergii sn/fp (Gr), Aster drummondii sn/fp (Gr), Aster furcatus sn/fp (Gr), Aster laevis sn/fp (Gr), Aster lanceolatus sn/fp (Rb, Gr), Aster lateriflorus sn/fp (Gr), Aster macrophyllus sn/fp (Gr), Aster novae-angliae sn/fp (Gr), Aster pilosus sn fq (Rb), Aster prenanthoides sn/fp (Gr), Aster puniceus sn/fp (Gr), Boltonia asterioides sn (Rb), Cirsium arvense sn/fp (Gr, Re), Conoclinium coelestinum sn (Rb), Coreopsis palmata sn (Rb), Eupatoriadelphus purpureus sn/fp (Gr), Eupatorium perfoliatum sn/fp (Rb, Gr), Euthamia graminifolia sn/fp (Gr), Helenium autumnale sn/fp (Gr), Parthenium integrifolium sn (Rb), Rudbeckia laciniata sn/fp (Gr), Solidago canadensis sn (Rb), Solidago juncea sn/fp (Gr), Solidago nemoralis sn (Rb), Tanacetum vulgare sn/fp (Gr); Bignoniaceae: Campsis radicans [exfl sn] (Rb); Caprifoliaceae: Symphoricarpos occidentalis sn/fp (Gr); Hamamelidaceae: Hamamelis virginiana sn/fp (Gr); Lamiaceae: Blephilia hirsuta sn (Rb), Pycnanthemum pilosum sn (Rb); Liliaceae: Smilacina racemosa fp (Gr)
There is little known predation of this species.
larva of Stomoxys calcitrans inhabits dung of Bos taurus (domestic)
Animal / parasite / ectoparasite / blood sucker
imago of Stomoxys calcitrans sucks the blood of Mammalia
Other: sole host/prey
Life History and Behavior
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)
Molecular Biology and Genetics
Barcode data: Stomoxys calcitrans
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Stomoxys calcitrans
Public Records: 141
Specimens with Barcodes: 165
Species With Barcodes: 1
This species has large populations world-wide, and is in no danger of extinction.
US Federal List: no special status
CITES: no special status
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
Rounded National Status Rank: NNR - Unranked
Relevance to Humans and Ecosystems
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.
Stomoxys calcitrans is commonly called the stable fly, barn fly, biting house fly, dog fly, or power mower fly. Unlike most members of the family Muscidae, Stomoxys calcitrans ('sharp mouth' + 'kicking') and others of its genus suck blood from mammals. Now found worldwide, the species is considered to be of Eurasian origin.
The stable fly resembles the common housefly (Musca domestica), though smaller, and on closer examination has a slightly wider and spotted abdomen. Adults are generally about 6-8mm in length and a lighter color than the housefly. Unlike the housefly, where the mouth part is adapted for sponging, the stable fly mouth parts have biting structures.
As its name suggests, the stable fly is abundant in and around where cattle are kept. Its maggots are often seen in the rotting manure near cattle and poultry.
The earliest and one of the most comprehensive accounts of stable fly biology was presented by F. Bishop in 1913. The adults of both sexes feed on the blood of warm-blooded animals during the daytime. For egg production, the female requires its abdomen to be engorged with blood. The female takes approximately 2–5 minutes to engorge, after which it becomes sluggish for a while. The eggs are laid among putrefying organic materials such as hay, manure, and wood. Males usually die after mating and the females after laying eggs. The life cycle is completed in approximately two weeks at temperatures around 27 °C. The duration is highly dependent on temperature and nutrient quality available for the larvae. Bishop (1913) noted that the larvae can endure for more than 30 days in less nutritious environs.
Cattle heavily infested with stable flies have been noted to become anemic and milking cows have been observed to show lower milk production. The stable fly bites humans at rest in the outdoors; generally the bite is almost painless. In many parts of the world, the species is a carrier of trypanosomid parasites. Some of the reported parasites and diseases of which the stable fly might be a vector of include Trypanosoma evansi (the agent of Surra), Trypanosoma brucei, brucellosis, Equine infectious anemia, African horse sickness (AHS), and fowlpox.  S. calcitrans is also reported to be a vector of Bacillus anthracis, the causative agent of anthrax. 
- Talley, Justin L. (2008). Management and Characterization of Stable Fly Larval Habitats at Round Bale Feeding Sites in Pastures (Thesis). Kansas State University. p. 2. hdl:2097/1072. Retrieved 2009-04-06., citing Hall, R.D.; Smith, J.P. (1986). "Stable fly biology and control in cattle feedlots". Kansas Agricultural Experiment Station. Publication 86–362–D.
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- "Veterinary Entomology | Veterinary Entomology". Entomology.cornell.edu. Retrieved 2013-11-27.
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- Janovy, J.; Roberts, L. (2000). Foundations of Parasitology (6th ed.). USA: The McGraw-Hill Companies, Inc.
- Newberry, Jennifer (2005-02-22). "ADW: Stomoxys calcitrans: INFORMATION". Animaldiversity.ummz.umich.edu. Retrieved 2013-11-27.
- Baldacchino, Frédéric; Muenworn, Vithee; Desquesnes, Marc; Desoli, Florian; Charoenviriyaphap, Theeraphap; Duvallet, Gérard (2013). "Transmission of pathogens by Stomoxys flies (Diptera, Muscidae): A review". Parasite 20: 26. doi:10.1051/parasite/2013026. PMC 3756335. PMID 23985165.
- Mongoh, MN; Dyer, NW; Stoltenow, CL; Khaitsa, ML (2008). "Risk Factors Associated with Anthrax Outbreak in Animals in North Dakota, 2005: A Retrospective Case-Control Study". Public Health Reports 123 (3): 352–359. PMC 2289988. PMID 19006977.
- Turell, MJ; Knudson, GB (1987). "Mechanical transmission of Bacillus anthracis by stable flies (Stomoxys calcitrans) and mosquitoes (Aedes aegypti and Aedes taeniorhynchus)". Infection and Immunity 55 (8): 1859–1861. PMC 260614. PMID 3112013.
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