Conservatism and divergence in communication systems: sound signals of shorebirds and woodpeckers

动物的声音是多样的，具有不同的功能和应用。声音被广泛用于保护和管理，以检测或监测不同的物种，包括稀有和濒危物种。例如，啄木鸟用它们的喙敲打树木以吸引配偶或宣布领土主张(击鼓)。生物学家可以利用这些响亮的鼓声来确定不同啄木鸟物种的存在和数量。不同物种的声音独一无二的常见原因是(1)要求有效地识别同一物种的成员，以及(2)当种群之间被某些屏障(如山脉)隔开时，它们之间的快速分化进化。最近的研究令人惊讶地表明，许多动物的声音进化得极其缓慢。一个例子是滨鸟，一个出现在恐龙时代的群体，但即使在遥远的近亲物种之间，这也显示出许多声音上的相似之处。这项拟议的研究计划将调查不同种类的滨鸟和啄木鸟之间的声音显示有何不同，以及这些差异如何符合数百万年来进化保守主义的更大图景。这些声音之所以进化得很慢，是因为发音器官(“空洞”)非常简单吗？显示曲目中的不同叫声是否作为一组一起进化，因为所有的叫声都是由一个发声器官产生的？如果是这样的话，每个物种都应该有特定的品质。或者，它们是否可以相互独立地进化，因为它们各自以不同的方式产生？如果一个物种的不同叫声可以或多或少地独立进化，那么有些种类可能进化得很快(例如，性叫声)，而另一些种类可能进化得很慢(例如，通用警报叫声)，这种模式将通过检查该物种的系统发育背景下的发声(“家谱”)得到明显的体现。拼图的最后一部分是发声器官(空洞器)，它将从博物馆标本中解剖出来，并与声学展示一起观察，以提供鸟类本能声音和声音产生如何进化的大致图景。

Animal sounds are diverse and have diverse functions and applications. Sounds are widely used in conservation and management to detect or monitor different species, including rare and endangered species. Woodpeckers for example, strike trees with their bills to attract mates or announce territorial claims (drumming"). Biologists can use these loud drumming sounds to determine presence and abundance of different woodpecker species. Common reasons for sounds of different species to be unique are (1) requirements to efficiently identify members of the same species, and (2) rapid divergent evolution between populations when they are separated geographically by some barrier, such as a mountain range. Recent research has surprisingly shown that many animal sounds have evolved extremely slowly. An example is shorebirds, a group that arose in the time of dinosaurs, but that shows many similarities in voice even between distantly related species. The proposed program of research will investigate how sound displays differ among different species of shorebirds and woodpeckers, and how these differences fit into the bigger picture of evolutionary conservatism over millions of years. Do these sounds evolve slowly because the organ of voice ("syrinx") is very simple? Do different calls in the display repertoire evolve together as a set, because all are produced by a single vocal organ? If so, particular qualities should pervade each species' repertoire. Or can they evolve independently of one another, because each is produced in a different way? If different calls of a species can evolve more-or-less independently, then some kinds probably evolve quickly (e.g. sexual calls), and others slowly (e.g. general-purpose alarm calls), a pattern that will be evident by examining vocalizations in the context of the group's phylogeny ("family tree"). The last part of the puzzle is the vocal organ (syrinx), which will be dissected from museum specimens, and viewed alongside acoustic displays, to give a broad picture of how instinctive sounds and sound production evolve in birds.