Colorful sexual traits are shaped by the opposing pressures of natural and sexual selection. Although increased conspicuousness improves mating success, an individual bearing brighter sexual traits may pay direct costs in terms of detectability to predators. While it is well established that the mere presence of non-aposematic, conspicuous sexual traits influences predation risk, little empirical work has examined how within-sex variability in sexual trait coloration affects attack rates; of these studies, results are equivocal. We experimentally tested the hypothesis that, within a single sex, brighter sexually selected traits impose a greater survival risk. We created clay models resembling male water anoles (Anolis aquaticus) and manipulated the coloration (bright red vs. brown-orange) of their colorful sexual ornament, the dewlap. Models were placed and monitored within A. aquaticus habitat. Our results suggest that a more conspicuous dewlap coloration is a cause of increased attack: redder models were attacked more than twice as often as less red models. Although previous studies have found correlational relationships between conspicuous coloration and predation, or have demonstrated long-term evolutionary changes in sexual dichromatism caused by a change in predator regime, our results show direct, within-lifetime costs of conspicuous sexual coloration among individuals of the same sex. These findings correspond well with a contemporary understanding of the drivers of female choice for costly male traits. These results also suggest the need for additional study on the effects of predation on the evolution of intrasexual variation in colorful sexual traits.

中文翻译：

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显着社会信号的性内变异影响蜥蜴模型在实验测试中的攻击率

丰富多彩的性特征是由自然选择和性选择的相反压力塑造的。虽然增加的显眼性提高了交配成功率，但具有更鲜明性特征的个体可能会在被捕食者的可察觉性方面付出直接的代价。虽然众所周知，仅仅存在非显性的、显眼的性特征会影响捕食风险，但很少有实证工作研究性特征着色的性别差异如何影响攻击率。在这些研究中，结果是模棱两可的。我们通过实验测试了这样一个假设，即在单一性别中，更明亮的性选择特征会带来更大的生存风险。我们制作了类似雄性水蝾螈 (Anolis Aquaticus) 的粘土模型，并操纵了它们五颜六色的性装饰品——赘肉的颜色（鲜红色与棕橙色）。在 A.aquaticus 栖息地内放置和监测模型。我们的结果表明，更明显的赘肉颜色是增加攻击的原因：红色模型受到攻击的频率是红色模型较少的两倍多。尽管之前的研究已经发现显着颜色和捕食之间的相关关系，或者已经证明了由于捕食者制度的变化引起的性二色性的长期进化变化，但我们的结果表明，显着性颜色的个体在生命周期内的直接成本是相同的。性别。这些发现与当代对女性选择昂贵男性特征的驱动因素的理解非常吻合。这些结果还表明需要进一步研究捕食对多彩性特征的性内变异进化的影响。