Nicholls J A, Austin J J, Moritz C, Goldizen A W
School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia.
Evolution. 2006 Jun;60(6):1279-90.
Geographic variation in vocalizations is widespread in passerine birds, but its origins and maintenance remain unclear. One hypothesis to explain this variation is that it is associated with geographic isolation among populations and therefore should follow a vicariant pattern similar to that typically found in neutral genetic markers. Alternatively, if environmental selection strongly influences vocalizations, then genetic divergence and vocal divergence may be disassociated. This study compared genetic divergence derived from 11 microsatellite markers with a metric of phenotypic divergence derived from male bower advertisement calls. Data were obtained from 16 populations throughout the entire distribution of the satin bowerbird, an Australian wet-forest-restricted passerine. There was no relationship between call divergence and genetic divergence, similar to most other studies on birds with learned vocalizations. Genetic divergence followed a vicariant model of evolution, with the differentiation of isolated populations and isolation-by-distance among continuous populations. Previous work on Ptilonorhynchus violaceus has shown that advertisement call structure is strongly influenced by the acoustic environment of different habitats. Divergence in vocalizations among genetically related populations in different habitats indicates that satin bowerbirds match their vocalizations to the environment in which they live, despite the homogenizing influence of gene flow. In combination with convergence of vocalizations among genetically divergent populations occurring in the same habitat, this shows the overriding importance that habitat-related selection can have on the establishment and maintenance of variation in vocalizations.
鸣禽的鸣声地理变异十分普遍，但其起源和维持机制仍不清楚。一种解释这种变异的假说是，它与种群间的地理隔离有关，因此应该遵循一种类似于中性遗传标记中常见的替代模式。另一种观点认为，如果环境选择对鸣声有强烈影响，那么遗传分化和鸣声分化可能没有关联。本研究将11个微卫星标记得出的遗传分化与雄性园丁鸟求偶炫耀鸣声的表型分化指标进行了比较。数据来自于分布在整个分布范围内的16个缎蓝园丁鸟种群，这是一种澳大利亚仅限于潮湿森林的鸣禽。鸣声分化与遗传分化之间没有关系，这与大多数其他关于具有学习鸣声的鸟类的研究结果相似。遗传分化遵循替代进化模型，孤立种群发生分化，连续种群之间存在距离隔离。之前对紫园丁鸟的研究表明，求偶炫耀鸣声结构受不同栖息地声学环境的强烈影响。不同栖息地中遗传相关种群的鸣声分化表明，尽管基因流有同质化影响，但缎蓝园丁鸟会使其鸣声与它们生活的环境相匹配。结合同一栖息地中遗传分化种群间鸣声的趋同现象，这表明与栖息地相关的选择对鸣声变异的建立和维持具有至关重要的作用。
