A verandah-trap hut for studying the house-frequenting habits of mosquitos and for assessing insecticides. I.—A description of the verandah-trap hut and of studies on the egress of Anopheles gambiae Giles and Mansonia uniformis (Theo.) from an untreated Hut

Abstract

A description is given of a verandah-trap hut designed to assess the egress and survival of mosquitos escaping through the eaves of the type of window-trap hut used in insecticide testing in East Africa.Fifty-one per cent. of females of Anopheles gambiae Giles in all gonotrophic stages and 19 per cent. of those recently fed left the hut each night, with 15 and 30 per cent., respectively, of the egress occurring through the eaves.Ninety per cent of females of Mansonia uniformis (Theo.) in all gonotrophic stages and 91 per cent. of those recently fed left the hut each night, with 69 and 66 per cent., respectively, of the egress occurring through the eaves.It was concluded that, owing to the high proportion of individuals of M. uniformis that leaves by the eaves, the verandah-trap hut was of a more suitable design for studying the house-frequenting habits of this species, and of other species with similar habits, than the simple window-trap hut.

The effects of smoke from mosquito coils on Anopheles gambiae Giles and Mansonia uniformis (Theo.) in verandah-trap huts at Magugu, Tanzania

“…The study area has been described by Smith (1964a) and the verandah-trap hut by Smith (1965a). Six verandah-trap huts were used in the experiments: two with corrugated iron roofs (VI and V2), two with grass-thatched roofs (V6 and V4) and two with grass-thatched roofs lined with a layer of mud (V3 and V5).…”

“…Distribution of unfed, fed, and gravid A. gambiae in treated and control huts during trials of pyrethrins coils Pyl-9• In making the totals and percentages, the numbers in the verandah traps have been doubled, followingSmith (1965a).…”

Experimental hut evaluation of the pyrrole insecticide chlorfenapyr on bed nets for the control of Anopheles arabiensis and Culex quinquefasciatus

“…Experimental hut evaluation was carried out at Mabogini field station, Moshi, Northern Tanzania in three experimental huts constructed according to a design described by Smith (1965) and Smith and Webley (1969). Some slight modifications were made involving reduction of eave space, addition of cardboard and hessian cloth ceiling, concrete floor surrounded by a water filled moat, and improved screening of the veranda.…”

Sampling Adults by Animal Bait Catches and by Animal-Baited Traps

“…Also, when huts are sprayed with certain insecticides a large proportion of the mosquitoes that would normally be caught in window traps may be stimulated to leave before sunrise, and many of these escape via the eaves. To sample such mosquitoes Smith (1965) developed a verandah trap. This is made by extending the thatch roof beyond the four walls of a square or rectangular hut to form a roof over a verandah, which is enclosed on two sides by mesh screening.…”