Directional reflectance and milli-scale feather morphology of the African Emerald Cuckoo, Chrysococcyx cupreus
Directional reflectance and milli-scale feather morphology of the African Emerald Cuckoo, Chrysococcyx cupreus
复制标题
DOI：
10.1098/rsif.2013.0391
复制
发表时间：
2013-09-06
影响因子：
3.9
通讯作者：
Marschner, Steve
中科院分区：
文献类型：
--
作者：
Harvey, Todd Alan;Bostwick, Kimberly S.;Marschner, Steve
通过复杂的形态变化，鸟类之间进化出了不同的羽毛。我们研究了光与表面和亚表面羽毛形态的相互作用如何决定光的传播方向，这是鸟类视觉信号研究较少的一个方面。我们假设，微尺度的羽毛修饰会产生各向异性的反射率，其方向可以通过微尺度结构的取向来预测。这项研究的对象是非洲翡翠杜鹃，金尾鱼，以其闪闪发光的绿色虹彩外观而闻名。使用球面龙门，我们测量了羽毛表面和入射照明方向的半球上的方向反射率的变化。使用显微CT扫描仪，我们还研究了倒钩的结构分支的形态。我们跟踪了CT数据中观察到的结构分支方向的方向反射率的变化。我们的结论是：(I)羽毛的远场信号由多个镜面反射分量组成，每个镜面反射分量与不同的结构分支相关联；(Ii)每个镜面反射分量的方向与相应结构的方向相关。
Diverse plumages have evolved among birds through complex morphological modifications. We investigate how the interplay of light with surface and subsurface feather morphology determines the direction of light propagation, an understudied aspect of avian visual signalling. We hypothesize that milli-scale modifications of feathers produce anisotropic reflectance, the direction of which may be predicted by the orientation of the milli-scale structure. The subject of this study is the African Emerald Cuckoo, Chrysococcyx cupreus, noted for its shimmering green iridescent appearance. Using a spherical gantry, we measured the change in the directional reflectance across the feather surface and over a hemisphere of incident lighting directions. Using a microCT scanner, we also studied the morphology of the structural branches of the barb. We tracked the changes in the directional reflectance to the orientation of the structural branches as observed in the CT data. We conclude that (i) the far-field signal of the feather consists of multiple specular components, each associated with a different structural branch and (ii) the direction of each specular component is correlated to the orientation of the corresponding structure.