The Mosquitos of the funestus Series in East Africa

Abstract

The paper deals with Anopheles funestus and its allies as they occur in East Africa. The species dealt with are A. funestus type form, A. rivulorum, A. rivulorum var. garnhamellus and A. leesoni.1. Differences between adults are so slight that they have until recently all been regarded as A. funestus. They may, however, be separated from one another by the points given in the Key (above). Differences between larvae of the species are much more pronounced.2. It is also shown that, in this part of Africa at least, A. funestus, though reared from identical larvae and pupae, has four main forms of wing pattern. One of the forms of A. funestus appears to be absent from Uganda, while another form is much more prevalent in coastal regions than inland. A. rivulorum occurs in Uganda, but only two specimens were taken in Tanganyika. A. rivulorum var. garnhamellus is widely distributed throughout E. Africa. A. leesoni was found only in Uganda.3. A. funestus, A. rivulorum and A. leesoni breed in similar situations, i.e., clear, shaded water with growing vegetation. The larvae are more frequently found among grass than among other types of vegetation. Such breeding-places occur in rivers, streams, pools and swamps. Light readings taken at breeding-places corrobate the many reports that these larvae prefer shaded situations and are absent from exposed waters. Larvae of A. rivulorum var. garnhamellus are found most frequently associated with Pistia stratiotes, though on at least two occasions they were found in water where this plant was absent.4. All the adults were taken inside buildings and none outside, in spite of continuous searching. Almost all were A. funestus, the remaining few were A. rivulorum and A. rivulorum var. garnhamellus; adults of A. leesoni were not taken at all. At several places, though adults of A. funestus were common in houses, very few or no larvae of this species were found; but larvae of the other forms were present. It is concluded that A. funestus is therefore an habitual house-frequenter and the others are not. Human blood was found in roughly half of the female A. funestus examined (239 out of 456); a very few contained ox blood and the remainder (204) were negative for ox and human blood. They were not tested for other bloods. Of 122 female A. funestus examined for malaria parasites 15 were found infected.