SPECIES COMPOSITION AND INVERSION POLYMORPHISM OF THE ANOPHELES-GAMBIAE COMPLEX IN SOME SITES OF GHANA, WEST-AFRICA

Samples of Anopheles gambiae s.l. were collected from eight localities belonging to four of the five main ecological strata of Ghana. Analys is of ovarian polytene chromosomes revealed the presence of A. gambiae s.s. in all the sites studied, while A, arabiensis was detected only in the extreme northern locality of Navrongo and A, melas in some sout hern sites. Anopheles arabiensis showed a degree of inversion polymorp hism comparable to the one observed in other West African countries. T he analysis of the chromosomal polymorphism of A. gambiae s.s. showed the presence of the FOREST form in the rain forest localities and the SAVANNA form in the coastal savanna sites. The MOPTI form occurred sym patrically with the SAVANNA form in the northernmost locality. The pos sible influence of the presence of Various taxa of the A. gambiae comp lex and of their intra-specific Variants on malaria Vectorial system i s discussed.