National Institute of Water & Atmospheric Research Ltd, Private Bag 99940, Auckland, New Zealand.
Nat Commun. 2011;2:332. doi: 10.1038/ncomms1330.
Pelagic seabirds are highly mobile, reducing the likelihood of allopatric speciation where disruption of gene flow between populations is caused by physically insurmountable, extrinsic barriers. Spatial segregation during the non-breeding season appears to provide an intrinsic barrier to gene flow among seabird populations that otherwise occupy nearby or overlapping regions during breeding, but how this is achieved remains unclear. Here we show that the two genetically distinct populations of Cook's petrel (Pterodroma cookii) exhibit transequatorial separation of non-breeding ranges at contemporary (ca. 2-3 yrs) and historical (ca. 100 yrs) time scales. Segregation during the non-breeding season per se appears as an unlikely barrier to gene flow. Instead we provide evidence that habitat specialization during the non-breeding season is associated with breeding asynchrony which, in conjunction with philopatry, restricts gene flow. Habitat specialization during breeding and non-breeding likely promotes evolutionary divergence between these two populations via local adaptation.
远洋海鸟具有很强的移动性，减少了异域物种形成的可能性，因为种群之间的基因流动因物理上无法逾越的外部障碍而中断。在非繁殖季节的空间隔离似乎为海鸟种群之间的基因流动提供了内在障碍，否则这些种群在繁殖期间会占据附近或重叠的区域，但这种隔离是如何实现的尚不清楚。在这里，我们表明，两种遗传上不同的库克凤头鹦鹉（Pterodroma cookii）种群在当代（约 2-3 年）和历史（约 100 年）的时间尺度上表现出非繁殖范围的跨赤道分离。非繁殖季节的隔离本身似乎不太可能成为基因流动的障碍。相反，我们提供的证据表明，非繁殖季节的栖息地特化与繁殖不同步有关，而繁殖不同步与亲代定居相结合，限制了基因流动。繁殖和非繁殖期间的栖息地特化可能通过本地适应促进了这两个种群之间的进化分歧。
