Podos Jeffrey
Department of Zoology, Duke University, Durham, North Carolina, 27708-0325.
Evolution. 1997 Apr;51(2):537-551. doi: 10.1111/j.1558-5646.1997.tb02441.x.
Behavioral evolution can be influenced by constraints, for example, of phylogeny and performance. In this paper I describe a pattern in the evolution of birdsongs that may reflect a constraint on vocal performance. Trilled vocalizations from 34 species of songbirds (Passeriformes: Emberizidae) were analyzed. Two acoustic variables, trill rate and frequency bandwidth, were measured for different trill types. In most species, maximal values of frequency bandwidth were found to decrease with increasing trill rates. Further, trills with low trill rates exhibited wide variance in frequency bandwidth, and trills with high trill rates exhibited only narrow frequency bandwidths. The bounded nature of this pattern suggests that performance constraints have limited the evolutionary diversification of trills. In particular, I explore the role of constraints associated with vocal tract modulations during song production and evolution. Identification of this constraint may enhance our ability to explain particular patterns of trill evolution.
行为进化可能会受到诸如系统发育和表现等限制因素的影响。在本文中，我描述了一种鸟类歌声进化中的模式，该模式可能反映了对发声表现的一种限制。对34种鸣禽（雀形目：鹀科）的颤音发声进行了分析。针对不同的颤音类型，测量了两个声学变量，即颤音速率和频率带宽。在大多数物种中，发现频率带宽的最大值会随着颤音速率的增加而降低。此外，低颤音速率的颤音在频率带宽上表现出较大的差异，而高颤音速率的颤音仅表现出较窄的频率带宽。这种模式的受限性质表明，表现限制已经限制了颤音的进化多样性。特别是，我探讨了在歌声产生和进化过程中与声道调制相关的限制因素的作用。识别这种限制可能会增强我们解释颤音进化特定模式的能力。
