The distribution of the eggs of Damalinia equi (Denny) and Haematopinus asini (L) on the Horse.

Abstract

The eggs of Damalinia equi (Denny) and Haematopinus asini (L.) are attached to the hairs close to the skin with the end of attachment nearest to the skin. The oviposition behaviour of D. equi is similar to that of D. ovis (L.). The only observable differences are that the gonopods are not used at the time of egg laying and the fibre is grasped by the claspers. Temperatures between 32 and 38°C are required for the maximum number of lice in a population to oviposit. Skin temperature can determine the lateral distribution of the eggs in the natural environment. A fibre of suitable diameter is also necessary. D. equi cannot attach its eggs to the coarse hairs of the face, mane, tail, and legs whereas H. asini is able to do so. As the coarse hairs of the mane, tail, and legs are not shed with the fine hairs of the coat at the beginning of summer and winter the shedding of the coat effects a more severe reduction of the population of D. equi than of H. asini.