Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, Wilrijk, Belgium.
Faculty of Social Sciences, Antwerp School of Education, University of Antwerp, Antwerp, Belgium.
Sci Rep. 2017 Aug 9;7(1):7656. doi: 10.1038/s41598-017-08001-1.
Males often express traits that improve competitive ability, such as aggressiveness. Females also express such traits but our understanding about why is limited. Intraspecific aggression between females might be used to gain access to reproductive resources but simultaneously incurs costs in terms of energy and time available for reproductive activities, resulting in a trade-off. Although consistent individual differences in female behaviour (i.e. personality) like aggressiveness are likely to influence these reproductive trade-offs, little is known about the consistency of aggressiveness in females. To quantify aggression we presented a female decoy to free-living female great tits (Parus major) during the egg-laying period, and assessed whether they were consistent in their response towards this decoy. Moreover, we assessed whether female aggression related to consistent individual differences in exploration behaviour in a novel environment. We found that females consistently differed in aggressiveness, although first-year females were on average more aggressive than older females. Moreover, conform life history theory predictions, 'fast' exploring females were more aggressive towards the decoy than 'slow' exploring females. Given that personality traits are often heritable, and correlations between behaviours can constrain short term adaptive evolution, our findings highlight the importance of studying female aggression within a multivariate behavioural framework.
雄性通常表现出提高竞争能力的特征，如攻击性。雌性也表现出这种特征，但我们对其原因的理解是有限的。种内雌性之间的攻击性可能用于获得生殖资源，但同时会在能量和用于生殖活动的时间方面产生成本，从而产生权衡。尽管女性行为（即个性）的一致个体差异（如攻击性）可能会影响这些生殖权衡，但我们对雌性攻击性的一致性知之甚少。为了量化攻击性，我们在产卵期向自由生活的大山雀（Parus major）雌鸟展示了一个诱饵，并评估它们对这个诱饵的反应是否一致。此外，我们评估了女性攻击性是否与在新环境中探索行为的一致个体差异有关。我们发现，雌性在攻击性方面存在一致性差异，尽管初产雌性的攻击性平均高于老年雌性。此外，根据生活史理论的预测，“快速”探索的雌性比“缓慢”探索的雌性对诱饵的攻击性更强。鉴于个性特征通常是可遗传的，并且行为之间的相关性可以限制短期适应性进化，我们的研究结果强调了在多变量行为框架内研究雌性攻击性的重要性。
