Abstract
Charles Darwin introduced the concept of intersexual selection suggesting that apparently costly conspicuous male secondary sexual traits have evolved because they aid individuals in obtaining mates, even at the cost of male survival. Since Darwin’s time, considerable progress has been made in the study of sexual selection. The good genes hypothesis has been one of the major interests of researchers, and a significant amount of empirical research has been conducted in Drosophila melanogaster. The hypothesis states that individuals of one sex (usually female) prefer specific reproductive partners because preferred mates would bring greater genetic quality to offspring than random mates. In this experiment, populations (n=3) of D. melanogaster experiencing sexual selection (promiscuous), or its absence (monogamous), were allowed to evolve against a non-coevolving competing population. If the benefit of sexual selection exceeds the cost under this competitive environment, then we should observe the evolution of higher fitness in promiscuous populations, and it would imply that sexual selection is adaptive with respect to larval competition. Hence, the good genes hypothesis would be supported. After 16 generations of selection under the competitive environment, I did not observe a measurable adaptation with the presence of sexual selection. There was no significant difference in the fitness between promiscuous and monogamous populations. While the promiscuous populations had higher measured fitness due to apparently greater development rate, this result is inconclusive because of the systematic difference in density over the course of the experiment. Repetition of this research would require stricter control on population density.