The diurnal feeding activity of Glossina pallidipes Aust. in relation to trypanosome challenge.

Abstract

The limitations of the use of apparent density in estimating trypanosomechallenge are discussed, and it is concluded that such estimates should be based on the feeding portion of the tsetse population, its activity in relation to a given host, the total period of feeding activity (or parts thereof) as the unit of time, and the trypanosome infection rate.A method of investigating the diurnal feeding activity of Glossina pallidipes Aust. in the late dry season at Eekomitjie, in the Zambezi Valley in Southern Rhodesia, is described. A black ox was tethered daily under a large tree from before dawn until after dusk. Only flies that engorged on the ox were caught; the time of capture and sex of each fly was recorded, and the fly then marked and released. Catches were made on 15 separate but not consecutive days between 21 October and 30 November, 1959.Diurnal activity extended from 0445 to 1845 hr., there being a small earlymorning peak, reduced activity over the midday period, and a comparatively large evening peak. Climatic factors were recorded but no conclusions could be drawn about their separate effects on activity.