Impact of body melanization on mating success in Drosophila melanogaster

Abstract

Mating speed and copulation duration respond rapidly to laboratory selection in Drosophila melanogaster Meigen (Diptera: Drosophilidae), but there is a lack of data on the evolutionary response to natural selection in the wild. Further, it is not clear whether body melanization and mating behavior are correlated traits. Accordingly, we tested whether variation in body color impacts on mating latency, copulation duration, and fecundity in latitudinal populations of D. melanogaster. We observed geographical variation (cline) for mating propensity, i.e., mating speed as well as copulation duration increased along latitude. Phenotypic plastic responses for body melanization at 17 and 25 °C also showed significant correlations with mating latency and copulation duration. Within‐population analysis based on assorted dark and light flies of five geographical populations showed significant positive correlations of copulation duration and fecundity with body melanization. To assess the role of males and/or females on mating speed and copulation duration, we used atypical body color strains (i.e., dark and light males of D. melanogaster) for no‐choice mating tests. Our data showed a major influence of males for copulation duration and of females for mating speed. Furthermore, a difference in impact of body melanization on mating speed and copulation duration was demonstrated between species, i.e., low melanization in Drosophila ananassae Doleschall is correlated with lower mating speed and shorter copulation duration than in D. melanogaster. Geographical changes in mating propensity were significantly correlated with body melanization at three levels, i.e., within and between populations and between species. Thus, we have shown that a relationship exists between body melanization and mating success. Further, we found seasonal changes in temperature and humidity to confer selection pressures on mating‐related traits.

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

“…This study reports that D. melanogaster males at lower latitudes have the highest remating potential, which can be explained by low melanization and low first mating copulation duration [based on melanization–mating correlation hypotheses proposed by Parkash et al. ()]. There is a negative latitudinal cline for male remating ability in D. melanogaster .…”

“…Correlated changes in melanization and mating have been shown in a recent study (Parkash et al. ), but there have been no such report for remating in any Drosophila species thus far. Laboratory selection experiments on copulation duration have shown correlated selection responses on fertility (Gromko et al.…”

“…An earlier study (Parkash et al. ) has reported plastic effects (as a result of growth temperatures of 17 and 25°C) for body melanization and mating (mating latency and copulation duration). However, further experiments are needed to determine individual or combined effect of temperature and humidity variations in percent mated pairs during first and second mating by males.…”

“…There is latitudinal cline for mating of D. melanogaster (Parkash et al. ); however, whether latitudinal cline for male remating (second mating)‐related traits exist is still unclear.…”

“…), and body color strains of D. melanogaster (Parkash et al. ). Such correlated traits are important from an evolutionary point of view as natural selection acting on one trait may indirectly affect the other.…”