Data from: Discrimination of signal carotenoid content using multidimensional chromatic information

Red, orange and yellow carotenoid-based ornaments, which are widely used as sexual signals in many birds, fish and reptiles, are known to exhibit multidimensional chromatic variation as a result of both the concentration and relative proportions of different constituent carotenoids with differing spectral properties. This is thought to reflect intrinsic variation in signaller quality, making it a useful basis for female choice. However, whether females are able to discriminate relevant variation in carotenoid concentration and/or composition independently of each other, and of other phenotypic or behaviour traits, and if so, how this mediates their choice, is poorly understood. Here, female three-spined sticklebacks (Gasterosteus aculeatus) were presented with computer-animated courting males that varied exclusively in the appearance of their carotenoid-based colouration; specifically, each male’s signal provided a perceptual match for carotenoid colouration expressed by live males with known underlying carotenoid content, thereby providing a biologically-relevant signal while precluding confounding traits influencing female choice. Females were able to discriminate between prospective mates solely on the basis of perceived variation in the allocation of carotenoids to males’ sexual signals, and exhibited a strong preference for males with colouration indicative of higher concentrations of carotenoids in their signal, rather than in response to perceived variation in the relative proportion of constituent carotenoids. This has important implications for our understanding male signalling strategies and the information content of carotenoid-based sexual signals.基于类胡萝卜素的红、橙、黄色饰色广泛应用于众多鸟类、鱼类和爬行类的性信号传递，这类饰色因不同组成类胡萝卜素的浓度与相对比例（二者光谱特性各异）而呈现出多维色彩变异。此前研究认为，这种变异可反映信号发出者的内在品质差异，因此成为雌性选择配偶的重要依据。然而，雌性能否独立辨别类胡萝卜素浓度和/或组成的相关变异，且不受其他表型或行为性状的干扰？若可以，这种辨别又如何介导雌性的择偶决策？目前学界对此仍知之甚少。本研究以雌性三刺鱼（Gasterosteus aculeatus）为对象，向其展示仅在类胡萝卜素基体色外观上存在差异的计算机动画求偶雄性；具体而言，每个雄性的信号均与体内已知类胡萝卜素含量的野生雄性所表达的类胡萝卜素体色形成感知匹配，这既保证了信号的生物学相关性，又排除了影响雌性选择的混淆性状。实验结果显示，雌性仅通过感知雄性性信号中类胡萝卜素分配的变异即可辨别潜在配偶，且对体色信号中类胡萝卜素浓度更高的雄性表现出强烈偏好，而非对类胡萝卜素组成的相对比例变化做出响应。该研究结果对于我们理解雄性信号策略以及基于类胡萝卜素的性信号的信息内涵具有重要意义。