Structural coloration frequently originates from the interaction of light with multilayers of thin films in living organisms. One example where structural colors are created by multilayers is the jewel beetle, Chrysochroa fulgidissima, which has highly iridescent green elytra with longitudinal red stripes. We examine the structure, chemical information, and physical properties of the epicuticle of the jewel beetle by using atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nanoindentation, and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). AFM and SEM were used to analyze the surface structures of the green elytra and red stripes of the jewel beetle's wing. SEM and TEM images obtained from the cross‐sectioned cuticle samples of green and red areas indicated that the color arises from interference reflectors and reflectors consist of successive repeating layers of different electronic densities. Nanoindentation results showed that the green area of the elytron possesses a higher hardness and reduced modulus compared with the red area. To analyze the surface of the elytra and to compare multilayers of the green area with those of the red area, mass spectra and depth profiles were acquired by ToF‐SIMS with C₆₀ and Ar cluster ion beams. The epicuticle consists of several layers with alternating high and low abundances of inorganic and organic fragment ions, with approximately 16 layers in the green and 12 layers in the red area. Therefore, ToF‐SIMS combined with other analytical techniques indicate that multilayer reflection is a major mechanism of the jewel beetle's iridescence causing structural coloration.

中文翻译：

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使用表面分析技术的金龟子甲壳虫（Crysochroa fulgidissima）中鞘翅目的结构颜色和物理性质

结构着色通常源自光与活生物体中多层薄膜的相互作用。多层甲可以产生结构颜色的一个例子是甲壳虫金龟（Chrysochroa fulgidissima），具有高度虹彩的绿色鞘翅，并带有纵向红色条纹。我们使用原子力显微镜（AFM），扫描电子显微镜（SEM），透射电子显微镜（TEM），纳米压痕和飞行时间二次检查宝石甲虫表皮的结构，化学信息和物理性质离子质谱（ToF‐SIMS）。原子力显微镜和扫描电镜被用来分析甲虫的绿色鞘翅和红色条纹的表面结构。从绿色和红色区域的横截面角质层样本获得的SEM和TEM图像表明，颜色来自干涉反射器，并且反射器由不同电子密度的连续重复层组成。纳米压痕结果表明，与红色区域相比，elytron的绿色区域具有更高的硬度和降低的模量。为了分析Elytra的表面并比较绿色区域和红色区域的多层，ToF‐SIMS用C采集了质谱图和深度图₆₀和Ar簇离子束。表皮由几层无机和有机碎片离子的高低交替变化组成，绿色约16层，红色约12层。因此，ToF-SIMS与其他分析技术的结合表明，多层反射是珠宝甲虫虹彩导致结构着色的主要机制。