Opposite Latitudinal Clines for First Mating and Second Mating (Remating) in Males of Drosophila melanogaster



Jyoti Chahal, Department of Genetics, Maharshi Dayanand University, Rohtak 124001, Haryana, India.

E-mail: chahaljyoti@yahoo.co.in


Although female remating has been studied extensively in insects, few studies have been carried out for male remating (second mating). In this study, we analyzed Drosophila melanogaster males for their remating potential, using iso-female line culture initiated with wild flies collected from eight Indian geographic localities. We examined the association of latitude and percent melanization with first and second male mating (including mating-related traits). Our results indicated that second male mating has a negative latitudinal cline opposite to that of first mating. Body melanization is negatively correlated with second mating by male and positively with first mating (measured in terms of percent mated pairs). Mating latency during first (ML1) and second (ML2) male mating has a negative latitudinal cline, but slope values differ significantly as ML2 is great at higher latitudes as compared to ML1. The difference between ML1 and ML2 is non-significant at lower latitudes. However, copulation period of second mating (CP2) has a negative latitudinal cline, whereas copulation period of first mating (CP1) has positive latitudinal cline. Next, the latency and copulation period differ significantly between first and second male mating treatments in within-population analyses as well as in melanic strains. Furthermore, male remating ability (number of maximum successful remating attempts continuously by a male in 12 h) also follows negative latitudinal cline. The lower latitudinal lighter males have more remating ability as compared to darker males from higher latitudes.