Generation time determines the pace of key demographic and evolutionary processes. Quantified as the weighted mean age at reproduction, it can be studied as a life-history trait that varies within and among populations and may evolve in response to ecological conditions. We combined quantitative genetic analyses with age- and density-dependent models to study generation time variation in a bird metapopulation. Generation time was heritable, and males had longer generation times than females. Individuals with longer generation times had greater lifetime reproductive success but not a higher expected population growth rate. Density regulation acted on recruit production, suggesting that longer generation times should be favoured when populations are closer to carrying capacity. Furthermore, generation times were shorter when populations were growing and longer when populations were closer to equilibrium or declining. These results support classic theory predicting that density regulation is an important driver of the pace of life-history strategies.

中文翻译：

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世代时间的变化表明密度调节是鸟类综合种群生活节奏的重要驱动因素

世代时间决定了关键人口统计和进化过程的速度。量化为繁殖时的加权平均年龄，它可以作为一种生活史特征进行研究，该特征在种群内部和种群之间变化，并且可能随着生态条件而进化。我们将定量遗传分析与年龄和密度相关模型相结合，研究鸟类综合种群的世代时间变化。世代时间是可遗传的，雄性的世代时间比雌性长。世代时间较长的个体终生繁殖成功率较高，但预期人口增长率并未较高。密度调节作用于新兵生产，这表明当种群接近承载能力时，应该有利于更长的世代时间。此外，当种群增长时，世代时间更短，而当种群接近平衡或下降时，世代时间更长。这些结果支持经典理论，预测密度调节是生活史策略步伐的重要驱动因素。