Data from: Mutual plumage ornamentation and biparental care: consequences for success in different environments

According to the good parent and differential allocation models, parental behavior could depend on the individual’s own quality, and it could be adjusted to the coinvestor’s parental care and sexual ornamentation. These investment patterns may interact with environmental conditions and offspring quality in determining reproductive success. Few studies have considered ornament-related own and partner care of both parents and their consequences in relation to environmental conditions. In a brood size manipulation experiment on collared flycatchers (Ficedula albicollis), we measured nestling feeding rates, white patch sizes and plumage reflectance properties of both parents, and quantified nestling growth and reproductive success. We found little relationship between ornamentation and own feeding rate irrespective of manipulation. Parental quality, measured as nestling biomass production per unit feeding effort, was related to male structural plumage brightness in a manipulation-dependent manner. Male wing patch size and the female’s structural plumage brightness were linked to the partner’s feeding rate, and this did not vary with experimental environment. Finally, relationship of pre-fledging nestling size with male forehead patch size was environment-dependent, and this pattern was apparently due to intrinsic nestling characteristics. Reproductive success only partly reflected these findings. Our results indicate how integrated studies of mutual ornamentation and mutual care with environmental and offspring quality may help us better grasp the selection forces shaping sexual ornaments.基于好父母模型（good parent model）与差异分配模型（differential allocation model），亲代抚育行为既取决于个体自身的品质，也会随配偶亲本的亲代抚育投入与性饰特征（sexual ornamentation）进行调整。这类投资模式在决定繁殖成功率（reproductive success）的过程中，可能会与环境条件以及后代品质产生交互作用。目前鲜有研究同时关注双亲自身及配偶的性饰相关抚育行为，以及这些行为与环境条件相关的影响。 本研究针对白领姬鹟（Ficedula albicollis）开展窝卵数操控实验（brood size manipulation experiment），测定了双亲的雏鸟喂食率、白色斑块面积以及羽毛反射光谱特性，并量化了雏鸟生长状况与繁殖成功率。研究发现，无论是否进行窝卵数操控，性饰特征与亲本自身的喂食率之间均几乎不存在关联。以单位喂食投入对应的雏鸟生物量为指标的亲代品质（parental quality），与雄性的羽毛结构色亮度（structural plumage brightness）呈显著关联，且该关联受窝卵数操控处理的调控。雄性的翼斑面积与雌性的羽毛结构色亮度，均与配偶的喂食率存在关联，且该关联不受实验环境的影响。最后，离巢前雏鸟体型与雄性额斑面积之间的关联受实验环境调控，该模式显然源于雏鸟自身的固有特征。繁殖成功率仅能部分反映上述研究结果。本研究结果表明，将双向性饰、双向抚育与环境条件及后代品质相结合的整合性研究，可帮助我们更深入地理解塑造性饰特征的选择压力机制。