Centro de Biologia Marinha, Universidade de São Paulo, Rod. Manoel Hypólito do Rego, km 131.5, São Sebastião, SP, 11612-109, Brazil.
Programa de Pós-Graduação em Biologia Comparada, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
Sci Rep. 2018 Oct 30;8(1):16028. doi: 10.1038/s41598-018-34470-z.
Camouflage has been a textbook example of natural selection and adaptation since the time of the earliest evolutionists. However, aside from correlational evidence and studies using artificial dummy prey, experiments directly showing that better camouflaged prey to predator vision are at reduced risk of attack are lacking. Here, we show that the level of camouflage achieved through colour adjustments towards the appearance of seaweed habitats is adaptive in reducing predation pressure in the prawn Hippolyte obliquimanus. Digital image analysis and visual modelling of a fish predator (seahorse) predicted that brown prawns would be imperfectly concealed against both brown and red seaweed respectively, whereas pink prawns should be well camouflaged only in red weed. Predation trials with captive seahorses (Hippocampus reidi), coupled with high-speed video analyses, closely matched model predictions: predation rates were similar for brown prawns between seaweed types, but pink individuals were attacked significantly less on red than brown weed. Our work provides some of the clearest direct evidence to date that colour polymorphism and colour change provides a clear adaptive advantage for camouflage, and also highlights how this can be asymmetric across morphs and habitats (i.e. dependent on the specific background-morph combination).
自早期进化生物学家开始，伪装一直是自然选择和适应的典型例子。然而，除了相关性证据和使用人工假猎物的研究之外，直接表明对捕食者视觉而言伪装得更好的猎物面临的攻击风险更低的实验还很少。在这里，我们表明，通过向海藻栖息地的外观进行颜色调整而实现的伪装水平可以适应减少对虾 Hippolyte obliquimanus 的捕食压力。对鱼类捕食者（海马）的数字图像分析和视觉建模预测，棕色对虾在棕色和红色海藻中分别会被不完全隐藏，而粉色对虾在红色海藻中应该伪装得很好。与圈养海马（ Hippocampus reidi ）进行的捕食试验以及高速视频分析非常吻合模型预测：在海藻类型之间，棕色对虾的捕食率相似，但在红色海藻上，粉色个体受到的攻击明显少于棕色海藻。我们的工作提供了迄今为止最清晰的直接证据之一，表明颜色多态性和颜色变化为伪装提供了明显的适应优势，并且还突出了这种优势在不同形态和栖息地之间可能是不对称的（即取决于特定的背景形态组合）。
