Song performance is a condition-dependent dynamic trait honestly indicating the quality of paternal care in the Bull-headed Shrike

The good parent hypothesis in sexual selection predicts that if females can increase their fitness by mating with males who provide high-quality parental care, then female preferences for male phenotypes honestly indicating the quality of paternal care will evolve. In order to test this hypothesis, we investigated correlations between male song, the timing of pair formation of males, male feeding rate, and reproductive success, in the Bull-headed Shrike Lanius bucephalus (an altricial oscine passerine with biparental care). Analysis revealed that although the timing of pair formation was not correlated with most song characteristics (e.g. repertoire size), male morphological traits (e.g. tail length), or male territory size, it was negatively correlated with male singing tempo (i.e. the number of notes uttered per second). Those males that sang at higher speeds were in better body condition (i.e. body mass standardized by tarsus length3 was higher), fed their chicks frequently during th...

性选择中的优质亲代假说预测：若雌性可通过与提供高质量亲代抚育的雄性交配以提升自身适合度，则雌性对能够诚实反映父代抚育质量的雄性表型的偏好便会演化。为验证该假说，我们以兼具双亲抚育行为的晚成鸣禽雀形目鸟类——牛头伯劳（Lanius bucephalus）为研究对象，探究了雄性鸣唱特征、雄性配对时机、雄性育雏频率与繁殖成功率之间的相关性。分析结果显示，尽管雄性配对时机与多数鸣唱特征（如鸣唱曲目量）、雄性形态特征（如尾长）以及雄性领域面积均无显著相关性，但与雄性鸣唱节奏（即每秒发出的鸣唱音节数）呈负相关关系。鸣唱速度更快的雄性个体身体状况更佳（即经跗跖长度标准化后的体重更高），且在育雏期间会更频繁地向雏鸟递送食物……