OBSERVATIONS ON THE DETERMINATION OF THE AGE COMPOSITION AND EPIDEMIOLOGICAL IMPORTANCE OF POPULATIONS OF ANOPHELES GAMBIAE GILES AND ANOPHELES FUNESTUS GILES IN TANGANYIKA.

Abstract

Following a request from the World Health Organization an investigation was undertaken to determine whether the method developed by Polovodova in the USSR for determining the physiological age of female anophelines could be applied to the two main vectors of malaria in Africa, Anopheles gambiae and Anopheles funestus.It was demonstrated that Polovodova's method was fully applicable to these African species. The greater difficulties encountered in determining the age of these species, as compared with A. maculipennis, are due to the smaller size of A. gambiae and A. funestus and to the paucity of ovarioles in which follicular degeneration has occurred.Among the mosquitos examined during a short-term investigation were individuals that had completed up to nine ovipositions. Among the mosquitos infected with sporozoites were females that had completed between three and seven ovipositions. Observations on the numbers of eggs developing in gravid females showed that, in these African species, there was no clear-cut fall in fecundity with age, such as occurs in A. maculipennis.