Stripes for warning and stripes for hiding: spatial frequency and detection distance
Stripes for warning and stripes for hiding: spatial frequency and detection distance
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DOI：
10.1093/beheco/arw168
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发表时间：
2017-03-01
影响因子：
2.4
通讯作者：
Cuthill, Innes C.
中科院分区：
文献类型：
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作者：
Barnett, James B.;Redfern, Annabelle S.;Cuthill, Innes C.
条纹图案在自然界中很常见，既可用作警告信号，也可用作伪装。它们在任何一个角色中的有效性都取决于它们的颜色和空间频率，以及它们与背景的比较情况。虽然这一一般原则已经确立，但视觉质地如何影响防御性着色的具体细节仍未在现场进行测试。特别是对于失语症模式，很少有研究集中于模式成分(而不是颜色)如何影响警告信号的有效性。通过向野生鸟类捕食者和人类观察者提供钉在树皮上的人工蛾子样刺激，我们检查了条纹的空间频率和方向如何影响黄黑(厌恶)和橄榄黑(神秘)图案的存活率和可检测性。对于神秘的条纹，我们发现匹配背景的主要空间频率和方向可以提高对抗鸟类捕食的存活率，并缩短人类首次发现目标的距离。然而，对于厌恶条纹，对鸟类的生存在空间频率上达到峰值，这种空间频率既不匹配主要背景空间频率，也不最大化目标和背景之间的失配。在中等空间频率下的存活率峰值与人类的可探测性不匹配：不同空间频率的条纹之间的初始检测距离没有差异，尽管可以分辨条纹的距离确实不同。我们认为，尽管最好的隐蔽策略是尽可能接近地匹配背景的主要成分，但最佳的无符号信号是一种平衡信号区分性和远距离识别的信号。
Striped patterns are common in nature and are used both as warning signals and camouflage. Their effectiveness in either role depends on their color and spatial frequency, and how these compare to the background. Although this general principle is well established, the specific detail of how visual texture influences defensive coloration remains untested in the field. For aposematic patterns, especially, little work has focused on how pattern components, as opposed to color, affect warning signal efficacy. By presenting artificial moth-like stimuli, pinned to tree bark, to wild avian predators, and human observers, we examine how the spatial frequency and orientation of stripes affects the survival and detectability of yellow-and-black (aversive) and olive-and-black (cryptic) patterns. For the cryptic stripes, we find that matching the dominant spatial frequency and orientation of the background increases survival against bird predation and decreases the distance from which humans first detect the target. For aversive stripes, however, survival against birds peaked at spatial frequencies that neither matched the dominant background spatial frequency nor maximized the mismatch between target and background. This peak in survival at intermediate spatial frequencies did not match detectability by humans: there was no difference in the initial detection distance between stripes of different spatial frequencies, although the distance at which stripes could be resolved did differ. We suggest that, although the best cryptic strategy is to match the dominant components of the background as closely as possible, the optimal aposematic signal is one that balances signal distinctiveness and recognition at a distance.