van der Kooi C J, Spaethe J
Groningen Institute for Evolutionary Biology, University of Groningen, Groningen, The Netherlands.
Department of Behavioral Physiology and Sociobiology, University of Würzburg, Würzburg, Germany.
Plant Biol (Stuttg). 2025 Mar;27(2):189-194. doi: 10.1111/plb.13767. Epub 2025 Jan 27.
Nature offers a bewildering diversity of flower colours. Understanding the ecology and evolution of this fantastic floral diversity requires knowledge about the visual systems of their natural observers, such as insect pollinators. The key question is how flower colour and pattern can be measured and represented to characterise the signals that are relevant to pollinators. A common way to interpret flower colours is using animal vision models that incorporate the spectral sensitivity of a focal observer (e.g. bees). These vision models provide a measure of colour contrast, which represents the perceived chromatic difference between two objects, such as a yellow flower against green leaves. Colour contrast is a behaviourally and physiologically validated proxy for relative conspicuousness of a stimulus. A growing number of studies attempt to interpret flower colouration through parameters that are grafted on to principles of human colour perception. A perpetuating measure to describe floral colours is via saturation, which is a metric in human perception describing a certain aspect of colourfulness and is, in pollination literature, often referred to as 'spectral purity'. We caution against the concept, calculation and biological interpretation of 'spectral purity' and similar measures that rest on an anthropocentric view, because it does not represent the diversity and complexity of animal visual systems that are the natural observers of flowers. We here discuss the strengths and weaknesses of common ways to interpret flower colouration and provide concrete suggestions for future colourful research.
自然界的花朵颜色纷繁多样，令人眼花缭乱。要理解这种奇妙的花卉多样性的生态和进化，需要了解其天然观察者的视觉系统，比如昆虫传粉者。关键问题在于如何测量和描述花朵的颜色及图案，以表征与传粉者相关的信号。一种常见的解释花朵颜色的方法是使用动物视觉模型，该模型纳入了目标观察者（如蜜蜂）的光谱敏感度。这些视觉模型提供了颜色对比度的度量，它代表了两个物体之间感知到的色差，比如黄色花朵与绿色叶子之间的色差。颜色对比度是一种在行为和生理上经过验证的刺激相对显著性的指标。越来越多的研究试图通过基于人类颜色感知原理的参数来解释花朵的着色。一种描述花卉颜色的常用方法是通过饱和度，饱和度是人类感知中的一个指标，用于描述色彩的某个方面，在传粉文献中，它常被称为“光谱纯度”。我们对“光谱纯度”以及基于人类中心视角的类似度量的概念、计算和生物学解释提出警示，因为它无法代表作为花朵天然观察者的动物视觉系统的多样性和复杂性。我们在此讨论解释花朵着色的常见方法的优缺点，并为未来丰富多彩的研究提供具体建议。
