Heroic heirs: evidence for sexy and competitive sons.

Abstract

Leks are the quintessential example of female mate choice, yet male-male interactions at leks may predominate. How, and how much, female mate choice versus male-male competition contribute to precopulatory sexual selection, including whether they are aligned or antagonistic, matters to theory and our understanding of how selection acts on both males and females. For example, if male-male competition predominates and selection favours harmful, dominant males, then female and population fitness may be compromised. Here, using Drosophila melanogaster, we performed two artificial selection experiments in parallel where we altered selection to favour male-male competition (selection for winners and losers in multi-male competition trials) or female mate choice (selection for winners and losers in single-male latency trials). After seven generations of artificial selection, males from winner-selected lines were more competitive than males from loser-selected lines, regardless of the competitive context in which they were selected. There was also a trend suggesting that males from winner-selected lines were also more attractive. Our results support the idea that the outcomes of male-male competition and female choice are aligned, and/or that one process overrides the other.