Links between personality, reproductive success and re-pairing patterns in a long-lived seabird

In long-lived monogamous species, the trigger of costly re-pairing is not always clear. Limited research suggests that within-pair behavioural compatibility may be an important driver of partnership success, as cooperation should be enhanced when pair members’ decisions complement one another. Animals’ decision-making processes are influenced by personality traits – defined as individual differences in behaviour that are stable in time. Despite the potential for the personality trait ‘boldness’ to a) directly impact individual willingness to re-pair and b) indirectly impact re-pairing choices via reproductive success, there is currently little work exploring how re-pairing decisions might be impacted by the pair members’ personalities. Using a 13-year dataset, we investigated whether within-pair boldness and its relationship with breeding success explained re-pairing patterns of black-legged kittiwakes (Rissa tridactyla), breeding in two Arctic colonies. We found that pairs with dissimilar boldness levels were more likely to experience breeding failure and that failed pairs were more likely to re-pair the following year. Despite this, only one colony displayed evidence of assortative mating by boldness, and there was no indication that re-pairing impacted reproductive success the following season. Neither individual nor pair boldness directly influenced re-pairing probability, however, in both colonies, re-pairing birds chose partners that were slightly more similar to themselves in boldness than their previous mates. These results imply an indirect pathway by which poorer behavioural compatibility within pairs may lead to breeding failure and ultimately re-pairing. Our findings highlight the importance of behavioural compatibility, and possibly personality, in mitigating sexual conflict and its population-specific drivers.

在长寿单配制物种中，触发高成本重新配对的因素往往并不明确。有限的研究表明，配对双方的行为兼容性或许是伴侣关系成功的重要驱动因素——当配对成员的决策能够彼此互补时，合作关系理应得到强化。动物的决策过程会受到个性特征的影响，个性特征被定义为随时间保持稳定的个体行为差异。尽管“大胆性”这一个性特质可能a）直接影响个体重新配对的意愿，b）通过繁殖成功率间接影响重新配对选择，但目前鲜有研究探讨配对成员的个性会如何影响重新配对决策。我们依托一项为期13年的数据集，针对两个北极繁殖群的黑腿三趾鸥（Rissa tridactyla）展开研究，探究配对双方的大胆性及其与繁殖成功率的关联，能否解释其重新配对模式。我们发现，大胆性水平差异较大的配对组更易出现繁殖失败，而繁殖失败的配对组次年更有可能重新配对。尽管如此，仅在一个繁殖群中观察到了基于大胆性的选型交配迹象，且未发现重新配对会对后续繁殖季的繁殖成功率产生影响的证据。个体或配对整体的大胆性均未直接影响重新配对概率，但在两个繁殖群中，选择重新配对的个体所挑选的新伴侣，其大胆性与自身的相似度均略高于前任伴侣。这些结果暗示了一条间接路径：配对双方较差的行为兼容性可能会引发繁殖失败，最终促成重新配对。我们的研究结果凸显了行为兼容性（乃至个性特征）在缓解性冲突及其种群特异性驱动因素方面的重要意义。