Grouping is a widespread form of predator defence, with individuals in groups often performing evasive collective movements in response to attack by predators. Individuals in these groups use behavioural rules to coordinate their movements, with visual cues about neighbours’ positions and orientations often informing movement decisions. Although the exact visual cues individuals use to coordinate their movements with neighbours have not yet been decoded, some studies have suggested that stripes, lines, or other body patterns may act as conspicuous conveyors of movement information that could promote coordinated group movement, or promote dazzle camouflage, thereby confusing predators. We used phylogenetic logistic regressions to test whether the contrasting achromatic stripes present in four different taxa vulnerable to predation, including species within two orders of birds (Anseriformes and Charadriiformes), a suborder of Artiodactyla (the ruminants), and several orders of marine fishes (predominantly Perciformes) were associated with group living. Contrasting patterns were significantly more prevalent in social species, and tended to be absent in solitary species or species less vulnerable to predation. We suggest that stripes taking the form of light-coloured lines on dark backgrounds, or vice versa, provide a widespread mechanism across taxa that either serves to inform conspecifics of neighbours' movements, or to confuse predators, when moving in groups. Because detection and processing of patterns and of motion in the visual channel is essentially colour-blind, diverse animal taxa with widely different vision systems (including mono-, di-, tri-, and tetrachromats) appear to have converged on a similar use of achromatic patterns, as would be expected given signal-detection theory. This hypothesis would explain the convergent evolution of conspicuous achromatic patterns as an antipredator mechanism in numerous vertebrate species.

中文翻译：

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对比条纹是生活在鸟类、哺乳动物和鱼类中的群体的普遍特征

分组是一种普遍的捕食者防御形式，群体中的个体经常进行躲避集体运动以应对捕食者的攻击。这些群体中的个体使用行为规则来协调他们的运动，而关于邻居位置和方向的视觉线索通常会为运动决策提供信息。虽然个人用来与邻居协调他们的运动的确切视觉线索尚未被解码，但一些研究表明，条纹、线条或其他身体模式可能充当运动信息的显眼传送器，可以促进协调的群体运动，或促进炫目伪装，从而迷惑捕食者。我们使用系统发育逻辑回归来测试四种不同的易受捕食的分类群中是否存在对比鲜明的无色条纹，包括两个鸟类目（Anseriformes 和 Charadriiformes）、偶蹄目亚目（反刍动物）和几个海洋鱼类目（主要是鲈形目）中的物种与群体生活有关。对比模式在社会物种中明显更为普遍，而在独居物种或不易受到捕食的物种中往往不存在。我们建议在深色背景上采用浅色线条形式的条纹，反之亦然，提供了一种跨类群的广泛机制，可以在群体移动时告知同种邻居的运动，或混淆捕食者。因为视觉通道中模式和运动的检测和处理本质上是色盲、具有广泛不同视觉系统（包括单、双、三、和四色视者）似乎已经收敛于消色差模式的类似使用，正如在给定信号检测理论的情况下所预期的那样。这一假设将解释显着的消色差图案的趋同进化作为众多脊椎动物物种中的一种反捕食者机制。