ABSTRACT
Female remating with more than one male leads to coexistence of sperm from different males in the same female, thus creating a selection pressure on sperm. To understand the extent of divergence in the reproductive behaviour among closely related species, in the present study, the influence of first mating histories like mating latency, duration of copulation and age of flies have been analysed on female remating behaviour in closely related Drosophila nasuta subgroup species with varying levels of reproductive isolation. The time taken for the once mated females to remate varied from 7 days in D. s. sulfurigaster to 19 days in D. s. neonasuta after first mating. The female remating frequency varied from a minimum of 29% in D. s. neonasuta to a maximum of 95% in D. s. sulfurigaster. The younger flies, which had remating latency of three times less than aged flies, show 100% remating frequency. In addition, it was observed that the duration of copulation in the first mating influences the remating behaviour among the nasuta subgroup members. The results revealed that D. nasuta subgroup members despite being closely related differ in their reproductive behaviour.