Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA.
Am Nat. 2012 Oct;180(4):425-37. doi: 10.1086/667575.
Performance limitations on signal production constrain signal evolution. Variation in signaling performance may be related to signaler quality and therefore is likely to be a salient aspect of communication systems. When multiple signal components are involved in communication, there may be trade-offs between components, and performance can be measured as the degree to which signalers approach the upper limits of the trade-off function. We examined vocal performance in the gray tree frog Hyla versicolor, in which females prefer values of call duration and rate exceeding the usual range of variation within and among males. We recorded interactions between pairs of males calling on mobile platforms that allowed us to manipulate intermale distance and place males in highly competitive environments. We found that, although there was a clear upper boundary on the ability of males to maximize call duration and call rate simultaneously, call effort did not remain constant in this highly competitive situation. Our estimates of an upper limit to vocal performance were corroborated by analyses of calling behavior in the context of close-range mate attraction. We discuss potential constraints on signaling performance and the relevance of this measure of performance for both intrasexual and intersexual communication.
信号产生的性能限制制约着信号的进化。信号表现的变化可能与信号者的质量有关，因此很可能是通信系统的一个显著方面。当多个信号成分参与通信时，成分之间可能存在权衡，性能可以衡量信号者接近权衡函数上限的程度。我们研究了灰色树蛙 Hyla versicolor 的发声表现，在这种青蛙中，雌性更喜欢叫声持续时间和频率的值，这些值超出了雄性内部和雄性之间通常的变化范围。我们记录了在移动平台上呼叫的雄性对之间的相互作用，这使我们能够操纵雄性之间的距离，并使雄性处于高度竞争的环境中。我们发现，尽管雄性同时最大化叫声持续时间和叫声频率的能力有一个明显的上限，但在这种高度竞争的情况下，叫声努力并没有保持不变。我们对发声性能上限的估计得到了近距离求爱过程中叫声行为分析的证实。我们讨论了对信号表现的潜在限制，以及这种性能衡量对同性和异性间通信的相关性。
