The term Horse fly is applied to large species of tabanid flies that attack wildlife and occasionally humans. Their size ranging from 10 to 30 cm. They belonging to the subfamily Tabaninae within the family Tabanidae . They have fairly large body size in appearance and are known mostly to people who possess livestock or those who camp outdoor. Tabanid flies can be distinguish from other flies by their brilliantly patterning of their eyes with shade of green, yellow orange and violet. Some species of tabanid flies have completely green eyes, reason for calling them greenheads. Horse flies are more of nuisance to livestock. Horse flies are different from deer flies which are smaller (96-10 cm in length) and have public health importance.
Taxonomy and Geographical Distribution
Horse flies are biting flies in the genus Tabanus of the Tabanidae. Horse flies and deer flies are all tabanid flies that have medical and veterinary importance. Both group of flies are classified in the family Tabanidae (Diptera). There are approximately 4300 described species and subspecies of tabanid flies classified in 133 genera in the world. The familiy Tabanidae comprises three subfamilies including Pangoniinae,Chrysopinae and Tabaninae. The Pangoniinae include the species Goniops and stonemyia which are heamatophagous. Tabaninae comprise the horse flies. and is considered the most advanced group within the Tabanidae family. Tabanid flies can virtually be found in all continents except in Antarctica.
Bio-ecology of Horse Flies
Life cycle of Horse Flies
Most species of tabanid flies are anautogenous and they require a blood meal before they develop their eggs.
Ecology and behavior of Horse Flies
Problem associated with Horse flies
Horse flies are serious source of nuisance for livestock and great potential for mechanical transmission of disease. Horse flies are involved in the transmission of diseases like surra, anaplasmosis and equine infectious anemia to livestock. Some horse flies species like the greenheads (Tabanus nigrovittatus and T. simulans) which occur in the coastal marsh of the Eastern United States are known to bite human beings.
Medical and Veterinary Importance of Horse Flies
Medically important horse flies species belong to the genus Tabanus, Chrysops and Haematopoda. Species of Crysops, especially Chrosps silaceus and Chrysops dimidiatusare important vector of of the filarial worm Loa loa which cause Loasis in West and Central Africa.