Ecology and evolution of blood oxygen-carrying capacity in birds

Blood oxygen-carrying capacity is one of important determinants of oxygen amounts supplied to the tissues per unit time and plays a key role in oxidative metabolism. In wild vertebrates, blood oxygen-carrying capacity is most commonly measured with the total blood haemoglobin concentration (Hb) and haematocrit (Hct), which is the volume percentage of red blood cells in blood. Here, I used published estimates of avian Hb and Hct (nearly one thousand estimates from 300 species) to examine macroevolutionary patterns in blood oxygen-carrying capacity of blood in birds. Phylogenetically-informed comparative analysis indicated that blood oxygen-carrying capacity was primarily determined by species distribution (latitude and elevation) and morphological constraints (body mass). I found little support for the effect of life history components on blood oxygen-carrying capacity, except for a positive association of Hct with clutch size. Hb was also positively associated with diving behaviour, bu...血液携氧能力（Blood oxygen-carrying capacity）是决定单位时间内组织供氧总量的重要因素之一，在氧化代谢过程中发挥关键作用。对于野生脊椎动物而言，血液携氧能力通常通过血液总血红蛋白浓度（haemoglobin, Hb）与红细胞比容（haematocrit, Hct）进行量化评估，其中红细胞比容指血液中红细胞所占的体积百分比。本研究采用已发表的鸟类血红蛋白与红细胞比容数据集（涵盖300个物种的近千条观测数据），旨在探究鸟类血液携氧能力的宏观进化模式。基于系统发育信息的比较分析（phylogenetically-informed comparative analysis）结果显示，鸟类血液携氧能力主要受物种分布特征（纬度与海拔）及形态学约束因素（体质量）调控。本研究未发现生活史组分对血液携氧能力存在显著影响的证据，仅观察到红细胞比容与窝卵数（clutch size）呈显著正相关关系。此外，血红蛋白浓度亦与潜水行为呈正相关……