It takes two: heritable male effects on reproductive timing but not clutch size in a wild bird population

Within-population variation in the traits underpinning reproductive output has long been of central interest to biologists. Since they are strongly linked to lifetime reproductive success, these traits are expected to be subject to strong selection and, if heritable, to evolve. Despite the formation of durable pair bonds in many animal taxa, reproductive traits are often regarded as female-specific, and estimates of quantitative genetic variation seldom consider a potential role for heritable male effects. Yet reliable estimates of such social genetic effects are important since they influence the amount of heritable variation available to selection. Based on a 52-year study of a nestbox-breeding great tit (Parus major) population, we apply ‘extended’ bivariate animal models in which the heritable effects of both sexes are modelled to assess the extent to which males contribute to heritable variation in seasonal reproductive timing (egg laying date) and clutch size, while accommodating ...长期以来，构成繁殖产出基础的性状的种群内变异一直是生物学家关注的核心议题。鉴于这些性状与个体终生繁殖成功率高度相关，它们预计会受到强烈的选择作用，若具备可遗传性，则会发生演化。尽管诸多动物类群会形成持久的配偶结对关系，但繁殖性状常被视作雌性特有，而数量遗传变异的评估却极少考虑可遗传雄性效应的潜在作用。然而，这类社会遗传效应的可靠评估至关重要，因为其会影响选择可利用的可遗传变异总量。本研究基于对一个巢箱繁殖的大山雀（Parus major）种群开展的长达52年的监测研究，采用纳入两性可遗传效应的“扩展”双变量动物模型，评估雄性对季节性繁殖时间（产卵日期）与窝卵数的可遗传变异的贡献程度，同时适配……