Marine Biological Laboratory, Woods Hole, MA 02543, USA.
Proc Natl Acad Sci U S A. 2011 May 31;108(22):9148-53. doi: 10.1073/pnas.1019090108. Epub 2011 May 16.
Camouflage is a widespread phenomenon throughout nature and an important antipredator tactic in natural selection. Many visual predators have keen color perception, and thus camouflage patterns should provide some degree of color matching in addition to other visual factors such as pattern, contrast, and texture. Quantifying camouflage effectiveness in the eyes of the predator is a challenge from the perspectives of both biology and optical imaging technology. Here we take advantage of hyperspectral imaging (HSI), which records full-spectrum light data, to simultaneously visualize color match and pattern match in the spectral and the spatial domains, respectively. Cuttlefish can dynamically camouflage themselves on any natural substrate and, despite their colorblindness, produce body patterns that appear to have high-fidelity color matches to the substrate when viewed directly by humans or with RGB images. Live camouflaged cuttlefish on natural backgrounds were imaged using HSI, and subsequent spectral analysis revealed that most reflectance spectra of individual cuttlefish and substrates were similar, rendering the color match possible. Modeling color vision of potential di- and trichromatic fish predators of cuttlefish corroborated the spectral match analysis and demonstrated that camouflaged cuttlefish show good color match as well as pattern match in the eyes of fish predators. These findings (i) indicate the strong potential of HSI technology to enhance studies of biological coloration and (ii) provide supporting evidence that cuttlefish can produce color-coordinated camouflage on natural substrates despite lacking color vision.
伪装是自然界中普遍存在的现象,也是自然选择中一种重要的反捕食策略。许多视觉捕食者具有敏锐的颜色感知能力,因此伪装图案除了图案、对比度和纹理等其他视觉因素外,还应该提供一定程度的颜色匹配。从生物学和光学成像技术的角度来看,量化捕食者眼中的伪装效果是一个挑战。在这里,我们利用高光谱成像(HSI)来记录全光谱光数据,分别在光谱域和空间域中同时可视化颜色匹配和图案匹配。墨鱼可以在任何自然基质上动态伪装自己,尽管它们是色盲,但当直接用人眼或 RGB 图像观察时,它们的身体图案看起来与基质具有高度逼真的颜色匹配。利用 HSI 对生活在自然背景下的伪装墨鱼进行成像,随后的光谱分析表明,大多数个体墨鱼和基质的反射光谱相似,这使得颜色匹配成为可能。对墨鱼潜在的二色和三色鱼类捕食者的颜色视觉建模证实了光谱匹配分析的结果,并表明在鱼类捕食者的眼中,伪装的墨鱼具有良好的颜色匹配和图案匹配。这些发现(i)表明 HSI 技术具有增强生物颜色研究的强大潜力,(ii)提供了支持证据,表明墨鱼可以在自然基质上产生颜色协调的伪装,尽管它们缺乏颜色视觉。