MIXING OF INDOOR-RESTING AND OUTDOOR-RESTING ADULTS OF ANOPHELES-GAMBIAE GILES SI AND ANOPHELES-FUNESTUS GILES (DIPTERA, CULICIDAE) IN COASTAL TANZANIA

From previous studies in Garki, Nigeria, it was deduced that the population of Anopheles gambiae Giles s.l. there includes a proportion of individuals which consistently rest out of doors and are therefore not vulnerable to insecticide residues inside houses, but may still be able to maintain malaria transmission. A direct test for the existence of such individuals in A. gambiae s.l. and A. funestus Giles in a village in Tanzania was made by catching resting mosquitoes indoors and in outdoor pits, differentially marking them according to their site of capture and releasing them from a single site. Recaptures indoors and in the pits showed no significant association between the sites of capture and recapture among the females of either species, i.e. no evidence for an invariably outdoor-resting type of female. It is concluded that behavioural polymorphism is unlikely to interfere with the successful use of house spraying for malaria control in this area. From data on the proportion of the captures found to be marked and on the parity rate, estimates were calculated of the total mosquito population available for sampling in the village.