Chazot Nicolas, Willmott Keith R, Condamine Fabien L, De-Silva Donna Lisa, Freitas André V L, Lamas Gerardo, Morlon Hélène, Giraldo Carlos E, Jiggins Chris D, Joron Mathieu, Mallet James, Uribe Sandra, Elias Marianne
Institut de Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 - CNRS MNHN UPMC EPHE, Muséum national d'Histoire naturelle, Sorbonne Universités, 57 rue Cuvier CP50, F-75005, Paris, France.
Department of Biology, University of Lund, 223 62, Lund, Sweden.
Mol Ecol. 2016 Nov;25(22):5765-5784. doi: 10.1111/mec.13773. Epub 2016 Oct 8.
Understanding why species richness peaks along the Andes is a fundamental question in the study of Neotropical biodiversity. Several biogeographic and diversification scenarios have been proposed in the literature, but there is confusion about the processes underlying each scenario, and assessing their relative contribution is not straightforward. Here, we propose to refine these scenarios into a framework which evaluates four evolutionary mechanisms: higher speciation rate in the Andes, lower extinction rates in the Andes, older colonization times and higher colonization rates of the Andes from adjacent areas. We apply this framework to a species-rich subtribe of Neotropical butterflies whose diversity peaks in the Andes, the Godyridina (Nymphalidae: Ithomiini). We generated a time-calibrated phylogeny of the Godyridina and fitted time-dependent diversification models. Using trait-dependent diversification models and ancestral state reconstruction methods we then compared different biogeographic scenarios. We found strong evidence that the rates of colonization into the Andes were higher than the other way round. Those colonizations and the subsequent local diversification at equal rates in the Andes and in non-Andean regions mechanically increased the species richness of Andean regions compared to that of non-Andean regions ('species-attractor' hypothesis). We also found support for increasing speciation rates associated with Andean lineages. Our work highlights the importance of the Andean slopes in repeatedly attracting non-Andean lineages, most likely as a result of the diversity of habitats and/or host plants. Applying this analytical framework to other clades will bring important insights into the evolutionary mechanisms underlying the most species-rich biodiversity hotspot on the planet.
理解为何物种丰富度在安第斯山脉沿线达到峰值是新热带生物多样性研究中的一个基本问题。文献中已经提出了几种生物地理和多样化情景，但对于每种情景背后的过程存在混淆，并且评估它们的相对贡献并非易事。在此，我们建议将这些情景细化为一个框架，该框架评估四种进化机制：安第斯山脉地区较高的物种形成速率、安第斯山脉地区较低的灭绝速率、较早的定殖时间以及来自相邻地区的安第斯山脉地区较高的定殖速率。我们将这个框架应用于新热带蝴蝶的一个物种丰富的亚族，即戈迪里蝶亚族（蛱蝶科：伊托米ini族），其多样性在安第斯山脉达到峰值。我们生成了戈迪里蝶亚族的时间校准系统发育树，并拟合了时间依赖的多样化模型。然后，我们使用性状依赖的多样化模型和祖先状态重建方法比较了不同的生物地理情景。我们发现有力的证据表明，进入安第斯山脉的定殖速率高于相反方向。与非安第斯山脉地区相比，这些定殖以及随后在安第斯山脉和非安第斯山脉地区以相同速率进行的本地多样化在机械上增加了安第斯山脉地区的物种丰富度（“物种吸引者”假说）。我们还发现支持与安第斯山脉谱系相关的物种形成速率增加的证据。我们的工作强调了安第斯山脉山坡在反复吸引非安第斯山脉谱系方面的重要性，这很可能是由于栖息地和/或寄主植物的多样性所致。将这个分析框架应用于其他类群将为这个地球上物种最丰富的生物多样性热点地区背后的进化机制带来重要见解。
