The competitiveness carrying males of three genetic control systems for Aedes aegypti (L.), viz. chemosterilized males, double translocation heterozygote males (TIT3) and distorter double translocation heterozygote males (DT1T3), released into a natural population in the Delhi metropolitanxarea was evaluated using a method based on the principle of release and recapture of marked females. Chemosterilized males and DTIT3 males showed approximately normal competitiveness in the field which is similar to the results obtained from laboratory and field cage experiments. The TIT3 males were found to have reduced competitiveness both in the field and laboratory cage tests, in contrast to previously reported results with unmarked T1T3 males in field cages. The cause of this reduction in competitiveness was not clear.

SUMMARYCycling populations of Aedes aegypti were set up in cages and managed in such a way that the populations had a maximum of threefold recovery potential in response to control measures. Into three such populations daily releases were made of males which had been chemosterilised, or were double translocation heterozygotes (T1T3) or T1T3 with sex ratio distortion (DT1T3). Eradication of the populations was achieved with all cases, but the rate of suppression was markedly slower with T1T3 than the other two systems, with which the rates were similar. T1T3 and DT1T3 releases introduced considerable inherited genetic loads into the target populations. The results were in general agreement with computer predictions.

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