Hogan Benedict G, Stoddard Mary Caswell
Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America.
PLoS Biol. 2024 Dec 3;22(12):e3002867. doi: 10.1371/journal.pbio.3002867. eCollection 2024 Dec.
Hyperspectral imaging-a technique that combines the high spectral resolution of spectrophotometry with the high spatial resolution of photography-holds great promise for the study of animal coloration. However, applications of hyperspectral imaging to questions about the ecology and evolution of animal color remain relatively rare. The approach can be expensive and unwieldy, and we lack user-friendly pipelines for capturing and analyzing hyperspectral data in the context of animal color. Fortunately, costs are decreasing and hyperspectral imagers are improving, particularly in their sensitivity to wavelengths (including ultraviolet) visible to diverse animal species. To highlight the potential of hyperspectral imaging for animal coloration studies, we developed a pipeline for capturing, sampling, and analyzing hyperspectral data (here, in the 325 nm to 700 nm range) using avian museum specimens. Specifically, we used the pipeline to characterize the plumage colors of the King bird-of-paradise (Cicinnurus regius), Magnificent bird-of-paradise (C. magnificus), and their putative hybrid, the King of Holland's bird-of-paradise (C. magnificus x C. regius). We also combined hyperspectral data with 3D digital models to supplement hyperspectral images of each specimen with 3D shape information. Using visual system-independent methods, we found that many plumage patches on the hybrid King of Holland's bird-of-paradise are-to varying degrees-intermediate relative to those of the parent species. This was true of both pigmentary and structurally colored plumage patches. Using visual system-dependent methods, we showed that only some of the differences in plumage patches among the hybrid and its parent species would be perceivable by birds. Hyperspectral imaging is poised to become the gold standard for many animal coloration applications: comprehensive reflectance data-across the entire surface of an animal specimen-can be obtained in a matter of minutes. Our pipeline provides a practical and flexible roadmap for incorporating hyperspectral imaging into future studies of animal color.
高光谱成像技术将分光光度法的高光谱分辨率与摄影的高空间分辨率相结合，在动物色彩研究方面具有巨大潜力。然而，高光谱成像在动物色彩的生态与进化问题研究中的应用仍然相对较少。该方法可能成本高昂且操作不便，而且我们缺乏在动物色彩背景下捕获和分析高光谱数据的用户友好型流程。幸运的是，成本在下降，高光谱成像仪也在改进，尤其是在对不同动物物种可见的波长（包括紫外线）的敏感度方面。为了突出高光谱成像在动物色彩研究中的潜力，我们开发了一种使用鸟类博物馆标本捕获、采样和分析高光谱数据（此处为325纳米至700纳米范围）的流程。具体而言，我们使用该流程来描述国王天堂鸟（丽色风鸟）、华美天堂鸟及其假定杂交种——荷兰国王天堂鸟（华美天堂鸟×丽色风鸟）的羽毛颜色。我们还将高光谱数据与三维数字模型相结合，用三维形状信息补充每个标本的高光谱图像。使用与视觉系统无关的方法，我们发现荷兰国王天堂鸟杂交种身上的许多羽毛斑块在不同程度上相对于亲本物种来说是中间型的。色素沉着和结构色羽毛斑块都是如此。使用与视觉系统相关的方法，我们表明杂交种与其亲本物种之间羽毛斑块的差异只有一些能被鸟类察觉到。高光谱成像有望成为许多动物色彩应用的黄金标准：在几分钟内就能获取动物标本整个表面的全面反射率数据。我们的流程为将高光谱成像纳入未来动物色彩研究提供了一个实用且灵活的路线图。
