Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
Proc Biol Sci. 2013 Feb 13;280(1756):20122852. doi: 10.1098/rspb.2012.2852. Print 2013 Apr 7.
It is well established that the expression of many ornamental traits is dependent on the current condition of the bearer. However, conditions experienced in early life are also known to be important for an individual's subsequent fitness and therefore, directly or indirectly, for the fitness of their mate. Specifically, a recent hypothesis suggests that sexually selected traits might be sensitive to conditions experienced during early-life development and thereby function as honest indicators of developmental history. Whether this applies to colourful male plumage, however, is largely unknown. We tested this idea with a field experiment by manipulating neonatal nutrition in a sexually dichromatic passerine, the hihi (Notymystis cincta). We found that carotenoid supplementation increased nestling plasma carotenoid concentration, which was in turn correlated with increased yellow saturation in male breeding plumage after moulting. We also found that the post-moult luminance (lightness) of the white ear-tufts tended to be reduced in males that had received an all-round nutritional supplement as nestlings. Black breeding plumage was not affected by neonatal nutritional treatment. Although the mechanisms that generate colourful plumage are evidently diverse, our results show that at least some parts of this display are accurate indicators of environmental conditions during development.
众所周知，许多装饰性特征的表达取决于载体的当前状态。然而，人们也知道，早期生活经历对个体的后续适应度很重要，因此，也会直接或间接地对其配偶的适应度产生影响。具体来说，最近的一个假设表明，性选择特征可能对早期发育过程中经历的环境条件敏感，从而成为发育史的诚实指标。然而，这种情况是否适用于雄性色彩斑斓的羽毛，在很大程度上还不得而知。我们通过对一种具有两性异形的雀形目鸟类——辉蓝细尾鹩莺（Notymystis cincta）进行的现场实验来检验这一想法，该实验通过操纵新生期的营养来实现。我们发现，类胡萝卜素补充剂增加了巢雏血浆中的类胡萝卜素浓度，而这种浓度反过来又与雄性繁殖羽在换羽后黄色饱和度的增加有关。我们还发现，在接受全面营养补充的巢雏雄性中，白色耳羽簇的换羽后亮度（明度）往往会降低。黑色繁殖羽不受新生期营养处理的影响。尽管产生彩色羽毛的机制显然是多种多样的，但我们的结果表明，这种展示的至少某些部分是发育过程中环境条件的准确指标。
