Sound Fields and Mate Choice

许多动物声音产生系统的适应性设计强烈地受到增加叫声幅度的选择和向预定接收者方向有效地投射这些声音的影响。在一些系统中，特定的结构对体积和方向性都有深远的影响。在许多不同的脊椎动物群体的声音产生系统中作为辅助器官出现的这样一种结构是充气气囊。虽然这种适应性显然是这些系统的一个重要特征，但我们对气囊如何影响音量和方向性知之甚少。本研究将利用新开发的多轨录音技术，重点研究几种松鸡的鸣叫幅度、鸣叫的方向性以及声囊的形状和数量之间的关系。我们之所以选择松鸡，是因为不同种类的松鸡在气囊的位置和操作上有很大的不同。有些松鸡有成对的外部气囊。初步证据表明，雄性艾草松鸡可能会利用它们的双囊系统向雌性发送交配信号，而不考虑雄性的相对方向。这些数据也将用于重新研究振幅在雌性艾草松鸡择偶中的作用。艾草松鸡leks是研究得最好的系统之一，其中雌性选择配偶完全基于雄性表型；呼叫幅值是唯一一个无法正确测量的参数。我们现在有了进行这些测量和完成分析的方法。我们希望，这项比较研究将产生可以应用于其他群体声囊功能的模型，更广泛地说，有助于我们理解振幅和方向性在雌性选择偏向性交配系统中的重要性。

9723521 Bradbury The adaptive design of many animal sound production systems is strongly influenced by selection for increased call amplitude and efficient projection of those sounds in the direction of intended recipients. In some systems, specific structures have profound effects on both volume and directionality. One such structure which appears as an accessory organ in the sound production systems of many diverse vertebrate groups is an inflatable air sac. While this adaptation is clearly an important feature of these systems, very little is known about how air sacs affect sound volume and directionality. Using newly developed multitrack recording techniques, this study will focus on several species of lekking grouse to clarify the relationship between display call amplitude, the directionality of the call, and the shape and number of vocal sacs. We have chosen grouse because of the degree of interesting variations in air sac position and operation in the different species. Some grouse have paired external air sacs. Preliminary evidence suggests that sage grouse males may use their two-sac system to beam certain components of their mating displays toward females regardless of the males' relative orientation. These data will also be used to re-examine the role of amplitude in mate choice of female sage grouse. Sage grouse leks are one of the best studied systems in which females choose mates solely on the basis of male phenotype; call amplitude is the only parameter which has remained resistant to proper measurement. We now have the means to make these measurements and complete the analysis. Our hope is that this comparative study will generate models that can be applied to vocal sac function in other groups and, more broadly, contribute to our understanding of the importance of amplitude and directionality in female choice biased mating systems.