Bulletin of Entomological Research

Research Paper

The effect of a residual house-spraying campaign in East Africa on species balance in the Anopheles funestus group. The replacement of A. funestus Giles by A. rivulorum Leeson.

M. T. Gilliesa1 and A. Smitha1

a1 East African Institute of Malaria and Vector-borne Diseases, Amani, Tanganyika.

In the course of an experiment in malaria control in an inland region of Kenya and Tanganyika, by the use of house spraying with dieldrin, routine catches were maintained of mosquitos resting in artificial outdoor shelters. During the 18 months of the pre-spraying period, catches in the South Pare district of Tanganyika mainly consisted of the principal vectors, Anopheles gambiae Giles and A. funestus Giles, together with small numbers of A. rivulorum Leeson.

During the three years following the spraying, A. funestus disappeared almost completely from the catches, while A. rivulorum showed an increase of about seven times above its former level.