The diurnal resting sites of Glossina palpalis palpalis were studied from October 1981 to December 1982 in the human trypanosomiasis focus at Bouafle (Ivory Coast). A total of 1382 resting tsetse (970 males and 412 females), were found after 757 hr of search in their natural habitats.
At any season, over 80% of the flies were resting on lianas (Acacia pennata in particular), on coffee trees (Coffea indica) and on Eupatorium odoratum.
Almost all the flies showed a preference for resting on the underside of woody parts of plants selected. The heights of the resting sites ranged from 10 cm to 2.5 m above the ground and their diameters ranged from 0.1 cm to 8 cm. It must be stressed that both in the dry and in the rainy seasons, more than 50% of the flies rested below 50 cm from the ground and over 90% of these favoured stems and branches measuring less than 3 cm in dia.
In the vegetation surrounding villages or along the main access roads and bush pathways, G. p. palpalis were found resting at 1 m to 5 m from the edge of its vegetation habitat.
About 27% of flies were engorged or showed at least red blood meals in their guts. The catching of resting flies therefore, appears to be an excellent way of collecting fresh blood meals for identification of the natural vertebrate hosts of G. p. palpalis in the study area.
The practical interest of the study is discussed and recommendations made for the selective application of residual insecticides in the tsetse habitats to control the vectors of sleeping sickness in the Bouafle focus.