Abstract Consistent between-individual differences in behaviour, known as personality differences, are heritable and have consequences for individual survival and reproductive success. Therefore, it is likely that personality differences are not just under natural but also under sexual selection. Indeed, the recently developed idea that individuals choose their mate based on its personality finds empirical support. However, most studies on mate choice based on personality traits are correlative pioneering work and there is a paucity of experimental studies that test for causality by disentangling personality measures from other, potentially correlated traits that may be important during mate choice. Here, we tested female preference for the apparent level and consistency of either male aggression (measured as mean distance of approach towards an animated opponent, manipulated by locating males at a fixed distance) or male boldness (measured as activity under a simulated predation threat, manipulated using a gradient in ambient water temperature) in a bi-parental West African cichlid, Pelvicachromis pulcher . Females could observe the apparent behaviour of paired stimulus males and were allowed to choose between the two stimulus males in a subsequent choice test. We found no direct effect of male apparent aggression/boldness on female choice, but an indirect effect such that female preference for the apparently bold male increased with increasing within-male pair contrast in their apparent level of boldness. Our results indicate females consider male boldness per se during mate choice, suggesting male boldness is sexually selected in our study species. Significance statement Ever since Darwin introduced the concept of sexual selection, female choice has been studied extensively. However, the hypothesis that consistent between-individual differences in behaviour (known as personality differences) affect mate choice is relatively new. Correlative studies support this idea but provide only suggestive evidence. Here, we used behavioural manipulations in order to disentangle male behaviour from other, potentially correlated male traits, allowing us to test for causality between female choice and personality differences in male aggression and boldness (both in level and consistency of behaviour) in a bi-parental cichlid. We found no overall female preference for male apparent behaviour, but female preference for the bold-appearing male increased with increasing between-male contrast in apparent boldness. Our results indicate a causal link between female choice and male boldness. In future, behavioural manipulations using a temperature gradient could provide further valuable insights.

中文翻译：

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雌性彩虹小龙虾会根据雄性的明显侵略性和胆量来选择雄性吗？一项非相关的配偶选择研究

摘要 个体间一致的行为差异，称为人格差异，是可遗传的，对个体生存和繁殖成功有影响。因此，性格差异很可能不仅存在于自然选择之下，也存在于性选择之下。事实上，最近提出的个人根据个性选择配偶的观点得到了实证支持。然而，大多数关于基于人格特征的择偶研究都是相关的开创性工作，并且通过将人格测量与其他可能在择偶过程中可能很重要的潜在相关特征分离来检验因果关系的实验研究很少。这里，我们测试了女性对男性攻击性（以接近动画对手的平均距离衡量，通过将男性定位在固定距离来操纵）或男性大胆（以模拟捕食威胁下的活动衡量，操纵使用环境水温的梯度）在双亲西非慈鲷 Pelvicachromis pulcher 中。雌性可以观察配对刺激雄性的明显行为，并允许在随后的选择测试中在两个刺激雄性之间进行选择。我们发现男性明显的攻击性/大胆对女性选择没有直接影响，但有一种间接影响，即女性对明显大胆的男性的偏好随着男性对内对比的增加而增加。我们的结果表明，雌性在选择配偶时会考虑雄性的大胆本身，这表明在我们的研究物种中，雄性的大胆是通过性选择的。意义陈述 自从达尔文提出性选择的概念以来，女性选择就得到了广泛的研究。然而，个体间一致的行为差异（称为人格差异）影响配偶选择的假设相对较新。相关研究支持这一想法，但仅提供提示性证据。在这里，我们使用行为操纵来将男性行为与其他潜在相关的男性特征分开，使我们能够测试女性选择与男性攻击性和大胆（行为的水平和一致性）的个性差异之间的因果关系。父母慈鲷。我们没有发现女性对男性明显行为的总体偏好，但女性对粗体男性的偏好随着男性之间明显粗体对比的增加而增加。我们的结果表明女性选择与男性大胆之间存在因果关系。将来，使用温度梯度的行为操作可以提供进一步有价值的见解。