School of Life Sciences, University of Lincoln, Brayford Pool, Brayford Pool, Lincoln LN6 7TS, UK.
Department of Biodiversity Studies and Bioeducation, Faculty of Biology and Environmental Protection, University of Łódź, ul. Uniwersytecka 3, 90-137 Łódź, Poland.
Integr Comp Biol. 2022 Aug 13;62(1):71-80. doi: 10.1093/icb/icab195.
The size and shape of red blood cells (erythrocytes) is determined by key life history strategies in vertebrates. They have a fundamental role to deliver oxygen to tissues, and their ability to do so is shaped by the tissue's need and their shape. Despite considerable interest in how other components of blood are shaped by ecology and life history, few studies have considered erythrocytes themselves. We tested how erythrocyte size and shape varied in relation to energetically demanding activities using a dataset of 631 bird species. We found that in general, birds undergoing greater activities such as long distance migration had smaller and more elongated cells, while those with greater male-male competition had smaller and rounder cells. Smaller, more elongated erythrocytes allow more rapid oxygenation/deoxygenation and support greater aerobic activity. The rounder erythrocytes found in species with strong male-male competition may stem from younger erythrocytes deriving from androgen-induced erythropoiesis rates. Finally, diving species of bird had larger erythrocytes, indicating that erythrocytes are acting as a vital oxygen store. In summary, erythrocyte size and shape in birds are driven by the need to deliver oxygen during energetically costly activities.
红细胞（红血球）的大小和形状取决于脊椎动物的关键生活史策略。它们在向组织输送氧气方面起着基本作用，其输送氧气的能力取决于组织的需求和它们的形状。尽管人们对血液的其他成分如何受到生态和生活史的影响很感兴趣，但很少有研究考虑过红细胞本身。我们使用 631 种鸟类物种的数据集，测试了红细胞大小和形状如何与高能量需求活动相关变化。我们发现，一般来说，进行长距离迁徙等活动较多的鸟类，其红细胞体积较小，形状更为狭长；而雄性间竞争较大的鸟类，其红细胞体积较小，形状更为圆钝。较小、更为狭长的红细胞可以实现更快的氧合/去氧作用，从而支持更高的有氧活动。在雄性间竞争较强的物种中发现的较为圆钝的红细胞，可能源于源自雄激素诱导的红细胞生成率的较年轻的红细胞。最后，潜水鸟类的红细胞体积较大，表明红细胞充当了重要的氧气储存库。总之，鸟类红细胞的大小和形状是由在高能量消耗活动期间输送氧气的需求所驱动的。
