Cross-breeding of Aedes (S.) polynesiensis Marks with an autogenous species of the A. scutellaris group.

An autogenous species belonging to the Aedes (Stegomyia) scutellaris subgroup was found on the island of Tafahi, Kingdom of Tonga. A subcolony was established at Johns Hopkins University, Baltimore, Md., USA, where cross-breeding experiments were conducted with the Samoan strain of A. polynesiensis. The cross between Tafahi females and A. polynesiensis males produced viable hybrid progeny, which were inbred through five generations. The reciprocal cross was not successful. F(1) Tafahi x A. polynesiensis hybrid males were backcrossed successfully to Tafahi females, but of the many eggs produced by backcrossing these F(1)TP males to A. polynesiensis females, only 0.7% hatched. Of the eggs produced by the F(2)TP male x A. polynesiensis female backcross, about 7% were viable. The results indicate a close genetic relationship between the Tafahi species and A. polynesiensis. The one-directional compatibility observed suggests the existence of cytoplasmic factors for sterility, which might eventually be useful in the control of members of the A. scutellaris complex.