Am Nat. 2019 Oct;194(4):441-454. doi: 10.1086/704774. Epub 2019 Aug 19.
Many animals communicate using multiple signals. Historically, most attention was paid to how multiple signals evolve and function in isolation, but recent work has focused on how they may interact with one another and produce unique signal interaction properties. These interaction properties vary within species, but little is known about how they vary among species, especially in regard to how the expression of particular signals may drive different signal interaction mechanisms. We studied the evolutionary relationships between iridescent plumage, courtship (shuttle) displays, solar environment, and male color appearance during a display (i.e., the signal interaction property) among six species of North American bee hummingbirds. We found that color appearances covary with behavioral and plumage properties, which themselves negatively covary, such that species with more exaggerated displays appeared flashier during courtship, while species with more exaggerated plumage appeared brighter/more colorful with minimal color changes. By understanding how signal interaction properties covary with signals, we were able to discover the complex multilayered evolutionary relationships underlying these traits and uncover new potential drivers of signal evolution. Our results highlight how studying the interaction properties between animal signals provides a richer understanding of how those traits evolved and diversified.
许多动物使用多种信号进行交流。历史上，大多数人关注的是多种信号如何在孤立的情况下进化和发挥作用，但最近的研究工作集中在它们如何相互作用并产生独特的信号相互作用特性上。这些相互作用特性在物种内有所不同，但对于它们在物种间的差异知之甚少，尤其是关于特定信号的表达如何驱动不同的信号相互作用机制。我们研究了北美六种蜂鸟的彩虹色羽毛、求偶（穿梭）展示、太阳环境和雄性展示时的颜色外观（即信号相互作用特性）之间的进化关系。我们发现，颜色外观与行为和羽毛特性相关，这些特性本身也呈负相关，例如，展示更夸张的物种在求偶时显得更鲜艳，而羽毛更夸张的物种在颜色变化最小的情况下显得更鲜艳/更丰富多彩。通过了解信号相互作用特性与信号之间的相互关系，我们能够发现这些特征背后复杂的多层次进化关系，并发现信号进化的新潜在驱动力。我们的研究结果强调了研究动物信号之间的相互作用特性如何为我们提供了更深入的了解这些特征是如何进化和多样化的。
