Department of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, Ohio, 43210.
Department of Mammalogy and Herpetology, Division of Vertebrate Zoology, American Museum of Natural History, New York, New York, 10024.
Evolution. 2019 Nov;73(11):2263-2280. doi: 10.1111/evo.13849. Epub 2019 Oct 24.
Adaptive radiations are defined as rapid diversification with phenotypic innovation led by colonization to new environments. Notably, adaptive radiations can occur in parallel when habitats with similar selective pressures are accessible promoting convergent adaptions. Although convergent evolution appears to be a common process, it is unclear what are the main drivers leading the reappearance of morphologies or ecological roles. We explore this question in Myotis bats, the only Chiropteran genus with a worldwide distribution. Three foraging strategies-gleaning, trawling, and aerial netting-repeatedly evolved in several regions of the world, each linked to characteristic morphologies recognized as ecomorphs. Phylogenomic, morphometric, and comparative approaches were adopted to investigate convergence of such foraging strategies and skull morphology as well as factors that explain diversification rates. Genomic and morphometric data were analyzed from ∼80% extant taxa. Results confirm that the ecomorphs evolved multiple times, with trawling evolving more often and foliage gleaning most recently. Skull morphology does not reflect common ancestry and evolves convergently with foraging strategy. Although diversification rates have been roughly constant across the genus, speciation rates are area-dependent and higher in taxa with temperate distributions. Results suggest that in this species-rich group of bats, first, stochastic processes have led divergence into multiple lineages. Then, natural selection in similar niches has promoted repeated adaptation of phenotypes and foraging strategies. Myotis bats are thus a remarkable case of ecomorphological convergence and an emerging model system for investigating the genomic basis of parallel adaptive radiation.
适应性辐射是指通过殖民到新环境来实现表型创新的快速多样化。值得注意的是，当可获得具有相似选择压力的栖息地时，适应性辐射可以并行发生，从而促进趋同适应。虽然趋同进化似乎是一个常见的过程，但不清楚是什么主要驱动力导致形态或生态角色的重现。我们在蝙蝠中探索了这个问题，蝙蝠是唯一具有全球分布的翼手目属。三种觅食策略——掠食、拖网和空中网捕——在世界上的几个地区反复进化，每种策略都与被认为是生态型的特征形态相关联。采用系统发育基因组学、形态计量学和比较方法来研究这些觅食策略和头骨形态的趋同以及解释多样化率的因素。对来自约 80%现存分类群的基因组和形态计量学数据进行了分析。结果证实，生态型多次进化，拖网进化更为频繁，叶片掠食最近。头骨形态不反映共同祖先，而是与觅食策略趋同进化。尽管分化速率在整个属中大致保持不变，但物种形成速率取决于地区，在具有温带分布的分类群中更高。结果表明，在这个蝙蝠物种丰富的群体中，首先，随机过程导致了多个谱系的分歧。然后，相似生态位的自然选择促进了表型和觅食策略的反复适应。因此，Myotis 蝙蝠是趋同形态的一个显著案例，也是一个新兴的模型系统，用于研究平行适应性辐射的基因组基础。
