Data from: Distance-dependent aposematism and camouflage in the cinnabar moth caterpillar (Tyria jacobaeae Erebidae)

Defended prey often use distinctive, conspicuous, colours to advertise their unprofitability to potential predators (aposematism). These warning signals are frequently made up of salient, high contrast, stripes which have been hypothesised to increase the speed and accuracy of predator avoidance learning. Limitations in predator visual acuity, however, mean that these patterns cannot be resolved when viewed from a distance, and adjacent patches of colour will blend together (pattern blending). We investigated how saliency changes at different viewing distances in the toxic and brightly coloured cinnabar moth caterpillar (Tyria jacobaeae). We found that although the caterpillars’ orange-and-black stripes are highly salient at close-range, when viewed from a distance the colours blend together to match closely those of the background. Cinnabar caterpillars therefore produce a distance-dependent signal combining salient aposematism with targeted background matching camouflage, without necessarily compromising the size or saturation of their aposematic signal.

具有防御机制的猎物常借助独特醒目的色彩，向潜在捕食者传递自身不可食用的信号（警戒色（aposematism)）。这类警戒信号多由高显著性、高对比度的条纹构成，学界曾假设此类条纹可提升捕食者规避此类猎物学习的速度与准确性。然而捕食者的视觉敏锐度存在局限，导致远距离下无法分辨此类图案，相邻色块会发生融合（模式融合（pattern blending)）。本研究针对色彩艳丽且具有毒性的朱砂蛾幼虫（Tyria jacobaeae），探究了不同观测距离下其色彩视觉显著性的变化情况。研究结果显示，尽管该幼虫的橙黑条纹在近距离下显著性极高，但在远距离观测时，其色彩会发生融合并与背景高度匹配。因此，朱砂蛾幼虫会构建一种随距离动态变化的信号：兼具高显著性的警戒色与针对性的背景匹配保护色，且无需牺牲警戒色信号的面积与饱和度。