Abstract: | A field experiment was carried on with the view of compulsory change of the frequency of chromosomal inversion (2R1) in the population of Anopheles messeae from the centre of the area. Quick return of the population to the original structure was observed. This confirmed that the local differentiation of chromosomal polymorphism is supported by natural selection. The fertility of the females was shown to be connected with the inversion polymorphism. The females with inversion complexes of genes of the "northern" type (with homozygotes 2R1) had higher fertility and lower dispersion of the fertility, in comparison with those having gene complexes which prevailed in the south part of the area. |