Coloration is often key in animal communication, and is frequently subjected to strong natural and sexual selection, often with opposed directions: natural selection typically favors cryptic colorations whereas sexual selection may favor conspicuous colorations. Also, different coloration traits may convey different pieces of information. Plus, coloration may vary among habitats, mirroring local selective pressures. In this work, we test if color parameters (luminosity, chroma, and hue) of back and throat are related to different life-history and morphological traits in Epidalea calamita toads. Furthermore, we check possible variability of color parameters between agrosystem and natural habitat toads. Toad coloration was sexually dimorphic, which suggests a role of coloration in sexual communication. Moreover, coloration correlated with age, body size, hindlimb length, and sprint speed. These findings suggest communication based on coloration beyond sex recognition: coloration could act as a signal of overall quality of bearers, with a potential role in mate choice. Moreover, coloration differed between habitats. Greener backs in agrosystem toads could indicate greater intensity of predator pressure, while their higher saturation could indicate greater investment in mate attraction. This result is aligned with previous findings that agrosystem toads respond to reduced lifespan with greater reproductive investment.

中文翻译：

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超越性二态性和栖息地边界：着色与蟾蜍的形态，年龄和运动能力相关

着色通常是动物交流的关键，并且经常受到强烈的自然和性选择，而且方向往往相反：自然选择通常倾向于隐性着色，而性选择则可能倾向于明显的着色。同样，不同的颜色特征可以传达不同的信息。此外，栖息地之间的颜色可能会有所不同，反映了局部选择压力。在这项工作中，我们测试背部和喉咙的颜色参数（发光度，色度和色相）是否与Epidalea calamita中不同的生活史和形态特征有关蟾蜍。此外，我们检查了农业系统和自然栖息地蟾蜍之间颜色参数的可能差异。蟾蜍的着色是性二态性，表明着色在性交中起一定作用。而且，着色与年龄，体重，后肢长度和冲刺速度有关。这些发现表明，基于性别的交流超出了性别的认知范围：肤色可以作为承载者整体素质的信号，在伴侣选择中具有潜在的作用。此外，生境之间的颜色也不同。农业系统蟾蜍中的后背较绿可能表明捕食者的压力强度更大，而其较高的饱和度可能表明对伴侣吸引的投资更多。该结果与以前的研究结果一致，即农业系统蟾蜍通过增加生殖投资来应对寿命缩短。