Botflies and Warble Flies

a grouping comprising four families of brachycerous dipterous insects. The larval forms of these insects parasitize mammals. Families of this grouping have three features in common. (1) The number of species is small, since these insects predominantly parasitize animals that live in herds or colonies. (2) The larvae are able to accumulate internally large food reserves in structures called fat bodies, and many species thus can spend the winter in the body of the animal host. As early as the pupa stage a significant portion of the food reserves is depleted as a result of the maturation of reproductive products. Consequently, the life-span of both males and females is very short, the mouthparts are reduced, and the insects are aphagic—that is, they do not feed. (3) All species have undergone certain adaptive changes in their behavior in order to effect the most rapid meeting of males and females. Both sexes hatch simultaneously, usually in the morning in good weather, and gather in a specific location; many species gather at the highest point on the landscape.

The Gasterophilidae comprise three genera with 15 species. Included here is the genus Cobboldia with four species. Members of this genus are elephant parasites; one species was described in 1973. In the USSR, the Gasterophilidae are represented by one genus with six species. The ova are usually attached to the animal hosts—horses, rhinoceroses, and elephants; only one species attaches the ova to grass. Larvae enter the mouth of the host and develop in the intestinal tract.

The Oestridae consist of nine genera with 35 species; five genera with 13 species are native to the USSR. The Oestridae are viviparous; the female while in flight sprays the larvae into the nostrils of sheep, goats, horses, camels, deer, and antelopes.

The Hypodermatidae comprise 11 genera with 33 species; nine genera with 20 species inhabit the USSR. Most species of Hypodermatidae parasitize artiodactyls, rodents, and lagomorphs; the insects attach their ova to hairs on the body of the host. The larvae become embedded in the skin, and, in a number of species, migrate during the first larval stage over a long distance within the body of the host.

The Cuterebridae are represented by six genera with 76 species.

The larvae of botflies and warble flies occasionally parasitize humans, especially children. Botflies and warble flies are pests that cause infested bovine cattle to yield less milk and meat and to produce hides of lower quality. Sheep and horses can die as a result of infestation. Organic phosphorus insecticides are effective in destroying botflies and warble flies, although caution must be taken to safeguard domestic animals and humans when this method is used. Biological methods of control are currently being studied.