Ingram Abigail L, Lousse Virginie, Parker Andrew R, Vigneron Jean Pol
Natural History Museum, Cromwell Road, London, UK.
J R Soc Interface. 2008 Nov 6;5(28):1387-90. doi: 10.1098/rsif.2008.0227.
Iridescent butterfly wing colours result from the interaction of light with sub-micrometre structures in the scales. Typically, one scale contains one such photonic structure that produces a single iridescent signal. Here, however, we show how the dorsal wings of male Lamprolenis nitida emit two independent signals from two separate photonic structures in the same scale. Multiple independent signals from separate photonic structures within the same sub-micrometre device are currently unknown in animals. However, they would serve to increase the complexity and specificity of the optical signature, enhancing the information conveyed. This could be important during intrasexual encounters, in which iridescent male wing colours are employed as threat displays. Blazed diffraction gratings, like those found in L. nitida, are asymmetric photonic structures and drive most of the incident light into one diffraction order. Similar gratings are used in spectrometers, limiting the spectral range over which the spectrometer functions. By incorporating two interchangeable gratings onto a single structure, as they are in L. nitida, the functional range of spectrometers could be extended.
彩虹色蝴蝶翅膀的颜色是由光线与鳞片中的亚微米结构相互作用产生的。通常，一个鳞片包含一个这样的光子结构，产生一个单一的彩虹色信号。然而，我们在此展示了雄性丽金龟的背翅如何从同一鳞片中的两个独立光子结构发出两个独立信号。在动物中，同一亚微米装置内不同光子结构产生多个独立信号目前尚属未知。然而，它们将有助于增加光学信号的复杂性和特异性，增强所传达的信息。这在同性相遇时可能很重要，在这种情况下，彩虹色的雄性翅膀颜色被用作威胁展示。像在丽金龟中发现的那种闪耀衍射光栅是不对称光子结构，会将大部分入射光驱入一个衍射级。光谱仪中也使用类似的光栅，这限制了光谱仪发挥作用的光谱范围。通过像丽金龟那样在单个结构上并入两个可互换的光栅，光谱仪的功能范围可以得到扩展。
