The effect of B chromosome on the reproduction of Drosophila albomicans

By using three strains with different number of B chromosome (1-2Bs, 0B, > 2Bs) on the same genetic background, the effect of B chromosome on the reproduction of Drosophila albomicans was studied. Comparison of net reproduction and sex ratio among three strains showed that Bs has significantly effect on flies' net reproduction. The net reproduction of flies with 1-2Bs, 0B, > 2Bs is 196, 157, 147, respectively. Significant difference among three strains exists in the early stage of reproduction. The sex ratios of three strains are all close to 1:1, no significant difference was observed. The results indicated that lower dose of Bs enhances the flies' reproduction and fitness, while higher dose of Bs slightly reduces flies reproduction and fitness. These results lend the first strong support to the heterotic model.