Biocentre Grindel, Zoological Institute, Universität Hamburg, Hamburg, Germany.
School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom.
PLoS One. 2018 Apr 10;13(4):e0195766. doi: 10.1371/journal.pone.0195766. eCollection 2018.
Although personality traits can largely affect individual fitness we know little about the evolutionary forces generating and maintaining personality variation. Here, we investigated the hypothesis that personality variation in aggression is sexually selected in the monogamous, bi-parental cichlid Pelvicachromis pulcher. In this species, breeding pairs form territories and they aggressively defend their territory and offspring against con- and heterospecific intruders. In our mate choice study, we followed up two alternative hypotheses. We either expected females to show a directional preference for a high level and high consistency of aggression (potentially indicating mate choice for male parental quality). Alternatively, we expected females to choose males for (dis-)similarity in the level/consistency of aggression (potentially indicating mate choice for compatibility). Individual level and consistency of aggression were assessed for males and females using mirror tests. After eavesdropping on aggressive behaviour of two males (differing in level and consistency of aggression) females were then allowed to choose between the two males. Males, but not females, showed personality variation in aggression. Further, females generally preferred consistent over inconsistent males independent of their level of aggression. We did not detect a general preference for the level of male aggression. However, we found an above average preference for consistent high-aggression males; whereas female preference for inconsistent high-aggression did not deviate from random choice. Our results suggest behavioural consistency of aggression in male rainbow kribs is selected for via female mate choice. Further, our study underlines the importance of considering both the level and the consistency of a behavioural trait in studies of animal behaviour.
虽然个性特征在很大程度上可以影响个体的适应能力，但我们对产生和维持个性差异的进化力量知之甚少。在这里，我们研究了一个假设，即一夫一妻制、双亲抚养的慈鲷 Pelvicachromis pulcher 中的攻击性个性差异是受性选择的。在这个物种中，繁殖对形成领地，并且它们会积极地保护自己的领地和后代免受同种和异种入侵者的侵害。在我们的择偶研究中，我们跟进了两个替代假设。我们要么期望雌性对高水平和高一致性的攻击性表现出定向偏好（可能表明对雄性亲代质量的选择）。或者，我们期望雌性选择雄性在攻击性的水平/一致性上的差异（可能表明对兼容性的选择）。我们使用镜像测试来评估雄性和雌性的攻击性个体水平和一致性。在偷听了两只雄性（攻击性水平和一致性不同）的行为后，雌性被允许在这两只雄性之间做出选择。雄性，但不是雌性，表现出攻击性的个性差异。此外，无论雄性的攻击性水平如何，雌性通常更喜欢一致性而不是不一致性。我们没有发现对雄性攻击性水平的普遍偏好。然而，我们发现雌性对一致性高攻击性雄性的偏好高于平均水平；而对不一致高攻击性雄性的偏好并没有偏离随机选择。我们的结果表明，雄性彩虹鲷的攻击性行为一致性是通过雌性的择偶选择而来的。此外，我们的研究强调了在动物行为研究中同时考虑行为特征的水平和一致性的重要性。
