Jeon Deok-Jin, Ji Seungmuk, Lee Eunok, Kang Jihun, Kim Jiyeong, D'Alba Liliana, Manceau Marie, Shawkey Matthew D, Yeo Jong-Souk
School of Integrated Technology, Yonsei Institute of Convergence Technology, Yonsei University, Incheon 21983, Republic of Korea.
Department of Research Planning, National Institute of Ecology, Chungcheongnam-do 33657, Republic of Korea.
R Soc Open Sci. 2023 Jan 11;10(1):220786. doi: 10.1098/rsos.220786. eCollection 2023 Jan.
The bright, saturated iridescent colours of feathers are commonly produced by single and multi-layers of nanostructured melanin granules (melanosomes), air and keratin matrices, surrounded by an outer keratin cortex of varying thicknesses. The role of the keratin cortex in colour production remains unclear, despite its potential to act as a thin film or absorbing layer. We use electron microscopy, optical simulations and oxygen plasma-mediated experimental cortex removal to show that differences in keratin cortex thickness play a significant role in producing colours. The results indicate that keratin cortex thickness determines the position of the major reflectance peak (hue) from nanostructured melanosomes of common pheasant () feathers. Specifically, the common pheasant has appropriate keratin cortex thickness to produce blue and green structural colours. This finding identifies a general principle of structural colour production and sheds light on the processes that shaped the evolution of brilliant iridescent colours in the common pheasant.
羽毛鲜艳、饱和的虹彩颜色通常由单层和多层纳米结构的黑色素颗粒（黑素体）、空气和角蛋白基质产生，其周围是厚度各异的外层角蛋白皮层。尽管角蛋白皮层有潜力充当薄膜或吸收层，但其在颜色产生中的作用仍不明确。我们利用电子显微镜、光学模拟以及氧等离子体介导的实验性皮层去除方法，来证明角蛋白皮层厚度的差异在颜色产生中起着重要作用。结果表明，角蛋白皮层厚度决定了雉鸡羽毛纳米结构黑素体主要反射峰（色调）的位置。具体而言，雉鸡具有合适的角蛋白皮层厚度以产生蓝色和绿色结构色。这一发现确定了结构色产生的一般原理，并揭示了塑造雉鸡绚丽虹彩颜色进化过程的相关机制。
