论文标题：Predictable evolution towards larger brains in birds colonizing oceanic islands

期刊：Nature Communications

作者：Ferran Sayol, Philip A. Downing, Andrew N. Iwaniuk, Joan Maspons & Daniel Sol

发表时间：2018/07/31

数字识别码：10.1038/s41467-018-05280-8

原文链接：https://www.nature.com/articles/s41467-018-05280-8?utm_source=Other_website&utm_medium=Website_links&utm_content=RenLi-Nature-Nature_Comms-Animal_Sciences-China&utm_campaign=NATCOMMS_USG_JRCN_RL_sciencenet_largerbrainsinbirds_Aug_2nd

微信链接：https://mp.weixin.qq.com/s/J0gxRsCdJfpUBUGmH59vNg

《自然-通讯》发表一项最新研究Predictable evolution towards larger brains in birds colonizing oceanic islands称，海岛（由地震或火山活动引起洋底隆起形成的岛屿）上鸟类的大脑比其大陆近缘种的大脑更大。研究指出，这是由于海岛上发生的一系列演化过程而不是鸟类成功定居的差异所造成的。

图1：新西兰南岛的一只雌性山雀（Petroica macrocephala）在树枝上栖息，它的名字（tomtit）本意就有大头的意思。Credit: Jon Sullivan

新喀里多尼亚鸦、夏威夷乌鸦和拟?树雀都善于使用工具，这一现象说明岛屿可能有利于高级认知功能的演化。迄今为止，只有两项研究考察过岛屿物种与大陆物种的相对脑部大小差异——分别以乌鸦和灵长目为研究对象，但都未发现脑部（相对身体）大小与海岛生活有任何相关性。

图2：岛屿对于鸟类大脑相对大小的影响。图源：Sayol et al.

西班牙生态研究与林业应用中心（CREAF）的Ferran Sayol及同事考察了来自1931种鸟类（110种海岛鸟类以及1821种大陆鸟类）的11554个脑部大小样本的数据集。作者发现，生活在海岛上的鸟类比它们的大陆近缘种的脑部更大。对此，作者认为是海岛环境的不可预测性导致了对更大脑容量的自然选择。海岛环境一旦恶化，鸟类的扩散选择极其有限，或间接迫使个体探索并仰赖更复杂的行为反应。

图3：左：新西兰南岛山里的啄羊鹦鹉（Nestor notabilis），以行为灵活而著称，拥有鹦形目鸟类中最大的大脑之一；右：在澳大利亚昆士兰觅食的黄斑吸蜜鸟（Meliphaga notate）。Credit: Jon Sullivan/Andrew N. Iwaniuk

摘要：Theory and evidence suggest that some selective pressures are more common on islands than in adjacent mainland habitats, leading evolution to follow predictable trends. The existence of predictable evolutionary trends has nonetheless been difficult to demonstrate, mainly because of the challenge of separating in situ evolution from sorting processes derived from colonization events. Here we use brain size measurements of >1900 avian species to reveal the existence of one such trend: increased brain size in island dwellers. Based on sister-taxa comparisons and phylogenetic ancestral trait estimations, we show that species living on islands have relatively larger brains than their mainland relatives and that these differences mainly reflect in situ evolution rather than varying colonization success. Our findings reinforce the view that in some instances evolution may be predictable, and yield insight into why some animals evolve larger brains despite substantial energetic and developmental costs.

阅读论文全文请访问：https://www.nature.com/articles/s41467-018-05280-8?utm_source=Other_website&utm_medium=Website_links&utm_content=RenLi-Nature-Nature_Comms-Animal_Sciences-China&utm_campaign=NATCOMMS_USG_JRCN_RL_sciencenet_largerbrainsinbirds_Aug_2nd

（来源：科学网）