Abstract Angle dependent colors, such as iridescence, are produced by structures present on flower petals changing their visual appearance. These colors have been proposed to act as signals for plant–insect communication. However, there is a paucity of behavioral data to allow for interpretations of how to classify these colors either as a signal or a cue when considering the natural conditions under which pollination occurs. We sampled flowers from 6 plant species across various viewpoints looking for changes in the visual appearance of the petals. Spectral characteristics were measured with different instruments to simulate both the spectral and spatial characteristics of honeybee’s vision. We show the presence of color patches produced by angle dependent effects on the petals and the calyx of various species; however, the appearance of the angle dependent color patches significantly varies with viewpoint and would only be resolved by the insect eye at close distances. Behavior experiments with honeybees revealed that pollinators did not use angle dependent colors to drive behavior when presented with novel flower presentations. Results show that angle dependent colors do not comply with the requirements of a signal for plant–pollinator communication since the information transmitted by these colors would be unreliable for potential, free-flying pollination vectors. We thus classify angle dependent colors produced by micro- and ultra-structures as being a cue (a feature which has not evolved for communication), and observe no evidence supporting claims of these angle dependent colors having evolved as visual signal.

中文翻译：

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信号或提示：结构色在花朵授粉中的作用


摘要 依赖于角度的颜色（例如虹彩）是由花瓣上的结构产生的，改变了它们的视觉外观。这些颜色被提议作为植物与昆虫交流的信号。然而，在考虑授粉发生的自然条件时，缺乏行为数据来解释如何将这些颜色分类为信号或提示。我们从不同的角度对 6 种植物的花朵进行了采样，寻找花瓣视觉外观的变化。使用不同的仪器测量光谱特征，以模拟蜜蜂视觉的光谱和空间特征。我们展示了不同物种的花瓣和花萼上因角度相关效应而产生的色块的存在；然而，角度相关色块的外观随观察点的不同而显着变化，并且只能由近距离的昆虫眼睛来分辨。蜜蜂的行为实验表明，当呈现新奇的花朵时，传粉者不会使用依赖于角度的颜色来驱动行为。结果表明，角度相关的颜色不符合植物与传粉媒介通信信号的要求，因为这些颜色传输的信息对于潜在的自由飞行的授粉载体来说是不可靠的。因此，我们将微观和超结构产生的角度相关颜色归类为提示（尚未进化为通信的功能），并且没有观察到任何证据支持这些角度相关颜色已进化为视觉信号的说法。