Butterfly Genetics Group, Department of Zoology, University of Cambridge, United Kingdom.
Smithsonian Tropical Research Institute, Panama City, Panama.
Evolution. 2018 Oct;72(10):2156-2166. doi: 10.1111/evo.13583. Epub 2018 Sep 5.
Adaptive coloration is under conflicting selection pressures: choosing potential mates and warning signaling against visually guided predators. Different elements of the color signal may therefore be tuned by evolution for different functions. We investigated how mimicry in four pairs of Heliconius comimics is potentially seen both from the perspective of butterflies and birds. Visual sensitivities of eight candidate avian predators were predicted through genetic analysis of their opsin genes. Using digital image color analysis, combined with bird and butterfly visual system models, we explored how predators and conspecifics may visualize mimetic patterns. Ultraviolet vision (UVS) birds are able to discriminate between the yellow and white colors of comimics better than violet vision (VS) birds. For Heliconius vision, males and females differ in their ability to discriminate comimics. Female vision and red filtering pigments have a significant effect on the perception of the yellow forewing band and the red ventral forewing pattern. A behavioral experiment showed that UV cues are used in mating behavior; removal of such cues was associated with an increased tendency to approach comimics as compared to conspecifics. We have therefore shown that visual signals can act to both reduce the cost of confusion in courtship and maintain the advantages of mimicry.
既要选择潜在的配偶，又要发出视觉警告以抵御视觉导向的捕食者。因此，颜色信号的不同元素可能会因不同的功能而被进化调整。我们从蝴蝶和鸟类的角度研究了四对 Heliconius comimics 的拟态是如何被潜在地看到的。通过对其视蛋白基因的遗传分析，预测了 8 种候选鸟类捕食者的视觉敏感度。我们使用数字图像颜色分析，结合鸟类和蝴蝶的视觉系统模型，探索了捕食者和同种蝴蝶如何可能看到拟态图案。与具有紫光视觉（VS）的鸟类相比，具有紫外线视觉（UVS）的鸟类能够更好地区分 comimics 的黄色和白色。对于 Heliconius 的视觉，雄性和雌性在区分 comimics 的能力上有所不同。女性的视觉和红色过滤色素对黄色前翅带和红色前翅图案的感知有显著影响。一项行为实验表明，紫外线线索被用于交配行为；与同种蝴蝶相比，去除这些线索会导致更多地接近 comimics。因此，我们已经表明，视觉信号可以既减少求偶时混淆的代价，又保持拟态的优势。
