Many species – humans included – employ color as an instrument of deception. One intriguing example of this resides in the conspicuous abstract color patterns displayed on the bodies of female orb weaving spiders. These displays increase prey interception rates and thereby function at least as visual lures. Their chromatic properties however vary extensively, both across and within species, with discrete forms often co-existing in the manner of a stable polymorphism. Variation is principally expressed in terms of signal hue (color per se), but it is unclear how attractiveness scales with this property and if extant morphs are maximally attractive relative to a graded range of potential alternatives. We examined these questions by assessing catch rates among color-manipulated females of the dimorphic jeweled spider Gasteracantha fornicata in their natural webs. The manipulation altered dorsal appearance in a manner akin to adding six new variants of their existing white/yellow phenotypes. This magnified the natural variation in stimulus hue independently of chroma (saturation) across a range spanning most of the color spectrum. Catch rate varied across treatments in simple accordance with how greatly stimulus hue deviated from either of the two extant spider phenotypes. Predictions based on fly-perceived chromatic and achromatic background contrast were clearly unsupported despite dipterans constituting ~60 % of identifiable prey. This study supports the importance of signal coloration per se in G. fornicata and suggests that extant lure phenotypes reside in a broadly optimal spectral range for stimulating their aggregate prey community.

中文翻译：

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迷人的色彩：多态猎物诱饵中最佳刺激设计的证据

许多物种——包括人类——使用颜色作为欺骗的工具。一个有趣的例子是雌性圆蛛身体上显眼的抽象色彩图案。这些显示器提高了猎物拦截率，从而至少起到视觉诱饵的作用。然而，它们的颜色特性在物种之间和物种内部都有很大差异，离散形式通常以稳定的多态性的方式共存。变化主要以信号色调（颜色本身）表示，但目前尚不清楚吸引力如何随此属性扩展，以及现存的变形相对于潜在替代品的分级范围是否具有最大的吸引力。我们通过评估二态宝石蜘蛛 Gasteracantha fornicata 的颜色处理雌性在其天然网中的捕获率来研究这些问题。该操作以类似于添加现有白色/黄色表型的六个新变体的方式改变了背部外观。这在跨越大部分色谱的范围内放大了与色度（饱和度）无关的刺激色调的自然变化。捕获率因治疗而异，这取决于刺激色调与两种现存蜘蛛表型中任一种的偏离程度。尽管双翅目构成约 60% 的可识别猎物，但基于苍蝇感知的彩色和无彩色背景对比度的预测显然不受支持。这项研究支持信号着色本身在 G 中的重要性。