Noonan Brice P, Comeault Aaron A
Department of Biology, University of Mississippi, University, MS 38677, USA.
Biol Lett. 2009 Feb 23;5(1):51-4. doi: 10.1098/rsbl.2008.0586.
Demonstrations of interactions between diverse selective forces on bright coloration in defended species are rare. Recent work has suggested that not only do the bright colours of Neotropical poison frogs serve to deter predators, but they also play a role in sexual selection, with females preferring males similar to themselves. These studies report an interaction between the selective forces of mate choice and predation. However, evidence demonstrating phenotypic discrimination by potential predators on these polymorphic species is lacking. The possibility remains that visual (avian) predators possess an inherent avoidance of brightly coloured diurnal anurans and purifying selection against novel phenotypes within populations is due solely to non-random mating. Here, we examine the influence of predation on phenotypic variation in a polymorphic species of poison frog, Dendrobates tinctorius. Using clay models, we demonstrate a purifying role for predator selection, as brightly coloured novel forms are more likely to suffer an attack than both local aposematic and cryptic forms. Additionally, local aposematic forms are attacked, though infrequently, indicating ongoing testing/learning and a lack of innate avoidance. These results demonstrate predator-driven phenotypic purification within populations and suggest colour patterns of poison frogs may truly represent a 'magic trait'.
关于防御性物种中多种选择力对鲜艳颜色的相互作用的研究实例很少。最近的研究表明，新热带区毒蛙的鲜艳颜色不仅能威慑捕食者，还在性选择中发挥作用，雌性更喜欢与自己相似的雄性。这些研究报告了配偶选择和捕食这两种选择力之间的相互作用。然而，缺乏证据表明潜在捕食者对这些多态物种存在表型歧视。视觉（鸟类）捕食者可能天生就会避开颜色鲜艳的昼行性无尾目动物，而种群内针对新表型的净化选择可能仅仅是由于非随机交配。在这里，我们研究了捕食对多态毒蛙物种染色箭毒蛙（Dendrobates tinctorius）表型变异的影响。我们使用黏土模型证明了捕食者选择的净化作用，因为颜色鲜艳的新形态比当地的警戒色形态和保护色形态更容易受到攻击。此外，当地的警戒色形态虽然很少受到攻击，但这表明捕食者在持续进行测试/学习，且不存在先天的回避行为。这些结果证明了种群内捕食者驱动的表型净化，并表明毒蛙的颜色模式可能真的代表了一种“神奇性状”。
