A photonic heterostructure produces diverse iridescent colours in duck wing patches
A photonic heterostructure produces diverse iridescent colours in duck wing patches
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DOI：
10.1098/rsif.2012.0118
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发表时间：
2012-09-07
影响因子：
3.9
通讯作者：
Shawkey, Matthew D.
中科院分区：
文献类型：
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作者：
Eliason, Chad M.;Shawkey, Matthew D.
鸟类的颜色多种多样，但相对于它们能感知的颜色来说是有限的。这种不匹配可能部分是由它们的颜色产生机制的性质引起的。除了颜料，几类高度有序的纳米结构（薄膜，无定形三维阵列）可以产生一系列颜色。然而，任何单一的纳米结构类的可变性很少被探索。Dabbling鸭是一个speciose分支与实质性的种间差异的虹彩着色的翅膀补丁（specula）。在这里，我们使用电子显微镜，分光光度计，偏振和折射率匹配实验，和光学建模来检查这些颜色。我们发现，在所有物种的检查，窥器的颜色是由一个光子异质结构组成的一个单一的薄膜角蛋白和一个二维的六角形晶格的黑素体在羽毛pellicules。虽然这种异质结构的可能变化范围在理论上是广泛的，但只观察到相对紧密的，能量稳定的变体产生更饱和的颜色，这表明鸭子要么在物理上被限制在这些配置中，要么在选择它们产生的颜色。因此，这些数据揭示了以前未描述的生物光子结构，并表明单个纳米结构类内的物理可变性和约束可能有助于解释鸟类更广泛的颜色模式。
The colours of birds are diverse but limited relative to the colours they can perceive. This mismatch may be partially caused by the properties of their colour-production mechanisms. Aside from pigments, several classes of highly ordered nanostructures (thin films, amorphous three-dimensional arrays) can produce a range of colours. However, the variability of any single nanostructural class has rarely been explored. Dabbling ducks are a speciose clade with substantial interspecific variation in the iridescent coloration of their wing patches (specula). Here, we use electron microscopy, spectrophotometry, polarization and refractive index-matching experiments, and optical modelling to examine these colours. We show that, in all species examined, speculum colour is produced by a photonic heterostructure consisting of both a single thin-film of keratin and a two-dimensional hexagonal lattice of melanosomes in feather barbules. Although the range of possible variations of this heterostructure is theoretically broad, only relatively close-packed, energetically stable variants producing more saturated colours were observed, suggesting that ducks are either physically constrained to these configurations or are under selection for the colours that they produce. These data thus reveal a previously undescribed biophotonic structure and suggest that both physical variability and constraints within single nanostructural classes may help explain the broader patterns of colour across Aves.