Sex Ratio in Drosophila melanogaster Populations Effect Male Mating Success

Pavkovic-Lucic, S., Kekic, V., & Cvoro, A. 2009. Larger male mating advantage depends on the sex ratio in Drosophila melanogaster. Ethology Ecology & Evolution, 21(2), 155-160.

In this study the mating success of large and small males was examined under specific sex ratios. The mating status of females and males were held constant. Larger males were more successful than smaller males in conditions where the sex ratio was equal, and when there were more males present than females. When more females were present in the population there was no significant difference in mating success of large and small males. In all cases larger males mated earlier, while there was no significant size difference of mated females across the conditions. This is most likely due to the high tracking speeds and increased courtship of larger males. Larger males may have greater mating success than smaller males in male dominated sex ratios because of increased male-male competition. These findings support male-male competition as being an important factor in determining the mating success of larger males rather than a female preference for larger males.