Horsefly, Brake

Tabanidae

Insect with chitinous carapace
Flying, biting (stinging), bloodsucking
Parasite

Annoying pest
Hygiene and health pest

Species

Deer fly (Chrysops relictus)
Pale giant horse-fly (Tabanus bovinus)
Band-eyed brown horsefly (Tabanus bromius)
Dark giant horsefly (Tabanus sudeticus)
Common horse fly (Haematopota pluvialis)

Horseflies can harass and worry farm animals on pasture, and thus, poor milk yields of cows can lead to major economic losses.

Transmission of diseases

The horsefly can mechanically transmit Anthrax, Weilsche’s disease, Tularaemia and Lyme disease to humans through its sting.
Surra in horses and camels also spread outside the Tsetse belt, as did Equine Cross Lameness in South America. Transmission is by mechanical means through the horsefly.
Horseflies are also suspected of mechanically transmitting Nagana Disease to animals and sleeping sickness to humans in Africa.
The horsefly (Tabanus sudeticus) can also transmit the EIA virus, a lentivirus, by mechanical means.

MORE DATA

Class: Insects
Size: 19 to 25mm
Weight: variable
Age: 30 to 60 days
Appearance: Greyish brown body colour
Food: Females: Blood of warm-blooded animals; males: Flower carnivores
Distribution: Worldwide temperate climate zones, approx. 4’000 species, 70 species in Central Europe
Original location: Unknown
Sleep-wake rhythm: Diurnal
Habitat: Swamps, forest edges, wet meadows
Natural enemies: Fish, frogs, hedgehogs, toads, dragonfly larvae, birds and water bugs
Egg-laying: 25 to 1’000 eggs on water-related plants
Threatened with extinction: No

Of the approximately 4’000 species, only females are bloodsuckers, while the males mainly visit flowers and suck nectar. To reproduce, one blood meal is enough.
Horseflies are particularly attracted to sweat and sting through clothing. Like many bloodsucking insects, they inject an anticoagulant secretion before sucking blood, which means that relatively large puncture wounds continue to bleed after bloodsucking. Horseflies can suck up to 0.2 ml of blood.
Compared to mosquitoes, horsefly bites are immediately noticeably painful. They are usually so-called pool feeders that tear wounds in the skin with coarse mouthparts. They feed on escaping blood, lymph and cell fluid. The itching occurs at the site of the bite. As with mosquito bites, a swelling of the skin forms there over several hours.
Horsefly bites are usually harmless. However, if the horsefly bite causes excessive swelling or pain, you should see a doctor.
Horse owners have the most frequent problems with horseflies in warm, humid and windless weather.
In pastoral farming, large-scale infestations of cows can lead to panic, which can have an economic impact through less milk production. It is also more likely that diseases will be transmitted here.
25 to 1’000 eggs are laid on plants near water. The larvae normally pass through 6 to 13 developmental stages and live, in part alternately, predatorily and on plant remains near the water and moist soil until they pupate in a dry place. The development cycle varies from several months to several years depending on the climate zone. In Central Europe, for example, tabanids have a one-year cycle. The life span of an adult is 2 to 4 weeks.