Data from: Female choosiness leads to the evolution of individually distinctive males

Individual recognition is a taxonomically widespread ability that underlies a diverse suite of behaviors including the identification of individual nest-mates, agonistic opponents, and mating partners. However, as yet relatively little is known about the circumstances under which the requisite signal diversity can evolve. Here we develop a model describing a novel mechanism of individual identity evolution via sexual selection. Females choose among a subset of males, but can select the most attractive male only when he bears a unique identity signal. This mimics a species in which mate assessment and choice are temporally separate, such as when females observe males in direct conflict and must subsequently locate the winner. When females in our model are choosy at least 10% of the time, diversity at individuality signaling loci evolves as a by-product of selection on male attractiveness more rapidly than does diversity at equivalent loci evolving only under neutral processes. Even at lower discrimination rates, drifting signal diversity gives the female choice mechanism sufficient traction to drive up average male attractiveness. The mechanism we describe here can significantly increase signal diversity at even low rates of discrimination by females.

个体识别（individual recognition）是一类在分类学上广泛分布的能力，支撑着一系列多样的行为，包括识别同种巢友、敌对对手与交配伴侣。然而目前学界对该必要信号多样性得以演化的具体情境仍知之甚少。本研究构建了一个模型，用以阐释通过性选择实现个体识别信号演化的全新机制。雌性会在雄性子集内进行选择，但仅当某雄性携带独特的识别信号时，方能选出最具吸引力的雄性个体。该模型模拟了一类交配评估与选择存在时间分离的物种，例如雌性先观察雄性间的直接争斗，后续再寻找获胜雄性的场景。当模型中的雌性至少有10%的时间处于选择状态时，个体识别信号位点的多样性会作为雄性吸引力选择的副产物发生演化，其演化速率快于仅在中性过程下演化的等价位点的多样性。即便在较低的识别率下，随遗传漂变积累的信号多样性也足以让雌性选择机制发挥足够作用，提升雄性的平均吸引力水平。本研究阐释的这一机制，即便在雌性识别率较低的情况下，也能显著提升信号多样性。