Effect of bottlenecks on incipient sexual isolation, mating activity and fertility in Drosophila malerkotliana.

Effect of bottleneck sizes, on sexual isolation, mating speed and fertility were studied in D. malerkotliana established from natural population. After 10 generations of laboratory breeding, flies showed incipient sexual isolation between control line and some bottleneck lines and also between bottleneck lines. These findings do not fully agree with the general assumption that the establishment of bottlenecks accelerates speciation. The courtship latency and mating speed increases with increasing size of bottlenecks whereas copulation duration and fertility decreases with increasing bottleneck size. There was no sign of rebounding in fitness with in 10 generations as observed by Bryant et al. in house flies.