Iridescence is an optical effect that produces angle dependent coloration in animals. Recently, studies have attempted to unveil structures behind such elaborated visual signals and associated behaviors in Odonata. Here, we studied males of the Amazonian damselfly Chalcopteryx scintillans, which have hindwings that exhibit pronounced iridescence. This optical feature is used by the damselflies for intra-specific communication during territorial fights and courtship. The main question we addressed was whether male wing structural coloration may predict the outcome of male-male contests. We also studied the wing ultrastructure, in order to reveal the mechanisms that are responsible for wing coloration. Using various microscopal and spectroscopal techniques, we demonstrate that hindwing coloration is derived from two main effects: (1) light interference in the cuticle multilayer and (2) a specific angle dependent light scattering and antireflective properties of the epicuticular wax coverage. The results of our field experiment show that wing pigmentation and the hue of the dorsal surface of the hindwings is correlated with the outcome of territorial contests. This is one of the first studies showing that structural coloration derived from multilayer interference may influence the outcome of intrasexual agonistic interactions. This indicates that multicomponent structural coloration in visually guided insects may be under selective forces of male-male competition for resources and females.

中文翻译：

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结构性着色可预测亚马逊豆娘蜻蜓（Chalcopteryx）scintillans（Odonata：Polythoridae）中雄性竞争的结果。

虹彩是一种在动物中产生依赖于角度的着色的光学效应。最近，研究试图揭示在Odonata中这种精心设计的视觉信号和相关行为背后的结构。在这里，我们研究了亚马逊豆娘蜻蜓轮虫的雄性，它们的后翅表现出明显的虹彩。在领土战斗和求爱期间，豆娘将这种光学功能用于种内通讯。我们解决的主要问题是雄性机翼的结构着色是否可以预测雄性-雄性竞争的结果。我们还研究了机翼的超微结构，以揭示引起机翼着色的机制。使用各种微观和光谱技术，我们证明了后wing着色源自两个主要作用：（1）角质层多层中的光干涉，和（2）表皮蜡覆盖层的特定角度依赖性光散射和抗反射特性。我们的野外实验结果表明，机翼色素沉着和后机翼背面的色调与领土比赛的结果相关。这是最早的一项研究，表明源自多层干扰的结构着色可能影响性内激动相互作用的结果。这表明视觉引导的昆虫中的多组分结构着色可能是在雄性对雄性资源和雌性竞争的选择性作用下。我们的野外实验结果表明，机翼色素沉着和后机翼背面的色调与领土比赛的结果相关。这是最早的一项研究，表明源自多层干扰的结构着色可能影响性内激动相互作用的结果。这表明视觉引导的昆虫中的多组分结构着色可能是在雄性对雄性资源和雌性竞争的选择性作用下。我们的野外实验结果表明，机翼色素沉着和后机翼背面的色调与领土比赛的结果相关。这是最早的一项研究，表明源自多层干扰的结构着色可能影响性内激动相互作用的结果。这表明视觉引导的昆虫中的多组分结构着色可能是在雄性对雄性资源和雌性竞争的选择性作用下。