Disruption or aposematism? Significance of dorsal zigzag pattern of European vipers
Disruption or aposematism? Significance of dorsal zigzag pattern of European vipers
复制标题
破坏还是警戒？
作者：
J. Valkonen;M. Niskanen;M. Björklund;J. Mappes
欧洲蝰蛇（蝰蛇属）是有毒的，通常有一个独特的背部锯齿形图案。毒蛇的锯齿形图案被认为是破坏性着色的一个例子，它降低了蛇的可检测性。然而，最近的研究表明，图案具有警戒功能，尽管这些实验并没有排除破坏性着色的可能性。我们用橡皮泥复制品的蛇，以研究是否之字形图案的欧洲毒蛇提供保护，从鸟类捕食者的攻击，通过破坏性或警戒功能，或者如果之字形图案可能同时服务于这两个antipredatory功能。实验在西班牙南部的Coto Doñana国家公园进行。在实验中，鸟类引起的捕食压力之间的锯齿形图案（图案被画有和没有破坏性的效果，即打破身体轮廓或不），经典的破坏性着色（非随机放置的图案，打破身体轮廓）和控制标记（复制品的长度方向的条纹和模型没有画图案）在自然和控制的背景进行了比较。我们发现，锯齿形图案的蛇复制品遭受较少的捕食比条纹的，无论背景，提供了进一步的证据，欧洲毒蛇的锯齿形图案作为一个警告信号，对捕食者。然而，我们没有发现证据表明锯齿形模式涉及破坏性影响。
European vipers (genus Vipera) are venomous and often have a distinctive dorsal zigzag pattern. The zigzag pattern of vipers has been suggested to be an example of disruptive colouration which reduces the detectability of a snake. However, recent studies suggest that the patterns have an aposematic function, although those experiments did not exclude the possibility of disruptive colouration. We used plasticine replicas of snakes to examine whether the zigzag pattern of European vipers provides protection from avian predator attacks via disruptive or aposematic function, or if the zigzag pattern might simultaneously serve both antipredatory functions. Experiments were conducted in the Coto Doñana National Park southern Spain. In the experiment, predation pressure caused by birds was compared between zigzag pattern (patterns were painted with and without disruptive effect i.e. breaking body outline or not), classical disruptive colouration (non-randomly placed patterns that breaks body outline) and control markings (replicas with length wise stripes and models without painted pattern) on natural and controlled backgrounds. We found that zigzag patterned snake replicas suffered less predation than striped ones regardless of the background, providing further evidence that the zigzag pattern of European vipers functions as a warning signal against predators. However, we did not find evidence that the zigzag pattern involves a disruptive effect.