More than just noise: chance, mating success, and sexual selection

Chance plays a critical but under-appreciated role in determining mating success. In many cases, we tend to think of chance as background noise that can be ignored in studies of mating dynamics. When the influence of chance is consistent across contexts, chance can be thought of as background noise; in other cases, however, the impact of chance on mating success can influence our understanding of how mates are acquired and how sexual selection operates. In particular, when the importance of chance co-varies with biological or ecological factors in a systematic manner— that is when chance becomes consistently more or less important under certain conditions– then chance is important to consider if we want to fully understand the operation of mate acquisition and sexual selection. Here, we present a model that explores how chance co-varies with factors such as sex ratio, adult population size, and mating regime in determining variation in mating success. We find that in some cases, chance ...