From Big Medical Encyclopedia

GADFLIES — blood-sicking dipterous insects this. Tabanidae which are actively attacking large mammals and the person; carriers of activators of a number of diseases of the person and animals. Are widespread everywhere, except for the Arctic zone, and also mountains and deserts. In total there is a St. 3 thousand species of gadflies, from to-rykh St. 200 meets in the territory of the USSR. Among them S. of the sorts Tabanus (gadflies), Chry-sops (lacewing), Chrysozona (dozhdevka) are most numerous. Gadflies (fig. 1) differ in rather large sizes (from 6 to 30 mm, on average 10 — 20 mm), precipitancy of flight (speed reaches 60 and more than a km! hour), morbidity of a sting and a large amount of the drunk blood (to 200 mg). Females eat blood, for to-rykh blood is a source of the additional proteinaceous food necessary for maturing of eggs (see. Gonotrofichesky cycle ). For one laying the female lays from 100 to 1000 eggs, to-rye are stuck together among themselves by the substance emitted by adnexal glands of her sexual device in the peculiar small group attached to a lower surface of leaves or on stalks of plants on coast of reservoirs (fig. 2).

Fig. 1. Adult individual of a gadfly of the sort Tabanus.
Fig. 2. A laying of eggs of a gadfly of Tabanus autumnalis on a stalk of a plant (it is specified by an arrow).

The larvae which hatched from eggs (on average on 3 — the 8th day after an otkladka), lead a soil life, eating an organic residues and small soil organisms. Development with full transformation (see. Metamorphoses ). The number of larval stages varies from 5 to 13. Duration of development can reach several years (at the majority of types of S. — one year). S. in a phase of a larva or a doll winter.

Villages warm and photophilous insects, attack in the afternoon and in the evening (before dark). At night, in cold time of day, and also during the period between attacks while blood is digested and eggs ripen, take refuge in crowns, in a bush, more rare in a grass. Accumulations in shelters are not formed.

Page — specific carriers of activators loasis (see), mechanical carriers of activators malignant anthrax (see) and tularemias (see), and also number of diseases of farm animals. Morbidity of a sting of S. is connected both with rather big sizes of the wound, and with action entered into it at a krovososaniye of the saliva containing anticoagulants and toxicants. At a sting there is a development of local and general reactions (a swelling and puffiness around the place of a sting, at numerous stings emergence of allergic reaction is possible). Mass attack of S. on a livestock leads to decrease in a weight gain, reduction of milk yield of milk, decrease in resistance to many diseases because of the general intoxication, etc.

Elimination of places of breeding of S. happens at drainage of the rehumidified lands. It is possible to exterminate S. by means of the baits imitating production (black boards), to-rye cover with glue or insecticides, by means of the traps imitating animals and also by a flood oil or kerosene of pools, from to-rykh they drink water (see. Disinsection ). For individual protection from S.'s attack use repellents (see), light clothes and shadow shelters. It is not required to protect rooms since S. in rooms usually do not attack from S., and, aiming to take off, accumulate at windows.

See also Midges , Flies .

Bibliography: Boshko G. V. of Gedz1, Kshv, 1973; In and about l about in and the p N. A. Slepni of Siberia, Novosibirsk, 1968, bibliogr.; About hp at f e in N. G. Slepni, the Family Tabanidae, L., 1977; P about r h and N - with to and y I. A. Slepni (Tabanidae) and the simplest ways of their destruction, SPb., 1906; With about about Leva R. G. Slepni (Dip-t.era, Tabanidae) the South of Primorsky Krai, Novosibirsk, 1974, bibliogr.

A. N. Alekseev, S. P. Rasnitsyn.