Fitness consequences of delayed mating on reproductive performance of Chilo partellus (Swinhoe).

We investigated the effects of mating among different-aged males and females on reproductive physiology, progeny production, and longevity of Chilo partellus (Swinhoe) adults under laboratory conditions. Present studies involved virgin males (M) and females (F) of three different ages namely, on the day of emergence (1D), next day (2D), and further next day (3D), thus comprising of a total of nine mating treatments (1DM × 1DF, 1DM × 2DF, 1DM × 3DF, 2DM × 1DF, 2DM × 2DF, 2DM × 3DF, 3DM × 1DF, 3DM × 2DF, and 3DM × 3DF). The observations were recorded on fecundity, fertility, hatchability, and longevity of male and female adults. We found that mating among old aged males and females significantly reduce fecundity, fertility, and egg hatchability. Further, the fecundity, fertility, and egg hatching were significantly higher when newly emerged females mated with either of the ages of males as compared with other mating treatments. Conversely, the 3-day-old females, when mated with either of the ages of males, laid more numbers of unfertilized eggs, thus reduction in egg hatchability. Mating among newly emerged adults significantly reduced the longevity of male and female adults. Kaplan-Meier estimation showed that none of the adults across mating treatments survived more than 6 days. The recovery of spermatophores from the reproductive tract of females from 3DM × 1DF were significantly higher than other mating treatments. However, no association was found between spermatophore recovery and longevity of male and female adults. Findings of present studies will help to devise appropriate techniques to disrupt mating and suppress C. partellus population under field conditions.