In birds, extrapair paternity (EPP) constitutes an alternative mating strategy, with potentially important fitness consequences for both males and females and their offspring. Several factors have been identified that can influence the occurrence of EPP, but the role of environmental variability has so far received relatively little attention. Using long-term data set from a wild population of the blue tit (Cyanistes cearuleus), we assess the importance of ambient temperature in modulating the levels of extrapair paternity. Here, we showed that the variability of local thermal conditions affects the occurrence of EPP. Specifically, we found that the probability of EPP increased with rising variability in ambient temperature experienced by females prior to egg laying. This pattern is consistent with an idea of plastic female responses to unpredictable environments. Our results suggest that extrapair mating may represent an adaptive behavioral strategy to compensate for the potential negative effects of unstable environmental conditions.

中文翻译：

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温度变化与蓝山雀的外对亲子关系的发生有关

在鸟类中，配对外亲子关系（EPP）构成了另一种交配策略，对雄性和雌性及其后代都有潜在的重要健康影响。已经确定了几个可以影响 EPP 发生的因素，但环境变化的作用迄今为止受到的关注相对较少。使用来自蓝山雀（Cyanistes cearuleus）野生种群的长期数据集，我们评估了环境温度在调节外对亲子关系水平中的重要性。在这里，我们表明局部热条件的变化会影响 EPP 的发生。具体来说，我们发现 EPP 的概率随着雌性产卵前环境温度变化的增加而增加。这种模式与女性对不可预测的环境的可塑性反应的想法是一致的。我们的结果表明，配对外交可能代表一种适应性行为策略，以补偿不稳定环境条件的潜在负面影响。