Sexual maturity in Barn Owl (Tyto alba)

The age at first reproduction can significantly impact fitness. We investigated the possible source of variation in the age at first reproduction (“sexual maturity”) and its consequences for lifetime reproductive success in a wild population of barn owls. This raptor is sexually dimorphic for two melanin-based plumage traits shown to covary with sex-specific behaviour and physiology. We observed that females were sexually mature earlier than males, an effect that depended on the colour of their plumage and birth date. Among females born early in the season, dark melanic (i.e. more pheomelanic with large and many black feather spots) yearlings were sexually mature earlier than light melanic females. The relationship was in the opposite direction in those born late in the season. In yearling males, the opposite result, albeit less pronounced, was discovered, i.e. lightly melanic males born early in the season were sexually mature earlier than dark melanic males, an effect that was in the ...首次繁殖年龄对个体适合度具有显著影响。本研究以野生仓鸮种群为研究对象，探究了首次繁殖年龄（即性成熟（sexual maturity））的变异来源，及其对终生繁殖成功率的影响。该猛禽存在两种基于黑色素的羽毛性状的两性异形，且这两种性状已被证实与性别特异性的行为和生理特征相关联。我们观察到，雌性个体的性成熟早于雄性，且这一差异取决于其羽毛颜色与出生日期。在季节早期出生的雌性个体中，深色黑色素型（即褐黑素含量更高，且羽毛上存在更多大型黑色斑点）的一岁龄个体，其性成熟早于浅色黑色素型雌性个体；而在季节晚期出生的个体中，这种关联则呈现相反的趋势。对于一岁龄雄性个体，我们发现了相反的结果，尽管该效应相对较弱：季节早期出生的浅色黑色素型雄性个体，其性成熟早于深色黑色素型雄性，这一效应的……