Data from: Covariation in life-history traits: differential effects of diet on condition, hormones, behavior and reproduction in genetic finch morphs

The relative contribution of genetic and environmental factors in determining variation in life-history traits is of central interest to evolutionary biologists, but the physiological mechanisms underlying these traits are still poorly understood. Here we experimentally demonstrate opposing effects of nutritional stress on immune function, endocrine physiology, parental care and reproduction between red and black head-color morphs of the Gouldian finch (Erythrura gouldiae). Although body condition of black morphs was largely unaffected by diet manipulation, red birds were highly sensitive to dietary changes, exhibiting considerable within-individual changes in condition and immune function. Consequently, nutritionally stressed red birds delayed breeding, produced smaller broods and reared fewer and lower-quality foster offspring than black morphs. Differences in offspring quality were largely due to morph-specific differences in parental effort; red morphs reduced parental provisioning, whereas black morphs adaptively elevated their provisioning effort to meet the increased nutritional demands of their foster brood. Nutritionally stressed genetic morphs also exhibited divergent glucocorticoid responses. Black morphs showed reduced corticosterone-binding globulin (CBG) concentrations and increased levels of free corticosterone, whereas red morphs exhibited reduced free corticosterone levels and elevated CBG concentrations. These opposing glucocorticoid responses highlight intrinsic differences in endocrine sensitivities and plasticity between genetic morphs, which may underlie the morph-specific differences in condition, behavior and reproduction, and thus ultimately contribute to the evolution and maintenance of color polymorphism.

Usage Notes
Pryke et al. Am Nat 52740

遗传与环境因素对生活史性状变异的相对贡献，始终是进化生物学家关注的核心议题，但这类性状背后的生理机制仍有待深入解析。本研究通过实验证实，营养胁迫对Gouldian雀（Gouldian finch, Erythrura gouldiae）的红、黑头色色型个体的免疫功能、内分泌生理学、育幼行为与繁殖产出具有相反的调控效应。尽管黑头色色型个体的身体状况基本不受日粮处理的影响，红体型个体却对日粮变化极为敏感，其身体状况与免疫功能均出现显著的个体内变异。因此，与黑头色色型个体相比，遭受营养胁迫的红体型个体繁殖延迟，所产窝雏数更少，抚育的寄养后代数量更少且质量更低。后代质量的差异主要源于亲本抚育投入的形态特异性差异：红体型个体降低了育幼投喂频次，而黑头色色型个体则适应性地提升了投喂投入，以满足寄养雏鸟增加的营养需求。遭受营养胁迫的不同遗传色型个体还表现出分化的糖皮质激素响应模式。黑头色色型个体的皮质酮结合球蛋白（corticosterone-binding globulin, CBG）浓度降低，游离皮质酮水平升高；而红体型个体则呈现出游离皮质酮水平降低、CBG浓度升高的响应特征。这类相反的糖皮质激素响应模式，凸显了不同遗传色型在内分泌敏感性与可塑性上的内在差异，这可能是不同色型个体在身体状况、行为与繁殖上出现分化的基础，并最终推动色多态性的演化与维持。
使用说明：Pryke等，《美国博物学家》（Am Nat），52740