Gohli Jostein, Kirkendall Lawrence R, Smith Sarah M, Cognato Anthony I, Hulcr Jiri, Jordal Bjarte H
Department of Natural History, University Museum of Bergen, University of Bergen, P.O. box 7800,, 5020, Bergen, Norway.
Department of Biology, University of Bergen, P.O. box 7800,, 5020, Bergen, Norway.
Evolution. 2017 May;71(5):1258-1272. doi: 10.1111/evo.13219. Epub 2017 Mar 27.
The study of species diversification can identify the processes that shape patterns of species richness across the tree of life. Here, we perform comparative analyses of species diversification using a large dataset of bark beetles. Three examined covariates-permanent inbreeding (sibling mating), fungus farming, and major host type-represent a range of factors that may be important for speciation. We studied the association of these covariates with species diversification while controlling for evolutionary lag on adaptation. All three covariates were significantly associated with diversification, but fungus farming showed conflicting patterns between different analyses. Genera that exhibited interspecific variation in host type had higher rates of species diversification, which may suggest that host switching is a driver of species diversification or that certain host types or forest compositions facilitate colonization and thus allopatric speciation. Because permanent inbreeding is thought to facilitate dispersal, the positive association between permanent inbreeding and diversification rates suggests that dispersal ability may contribute to species richness. Bark beetles are ecologically unique; however, our results indicate that their impressive species diversity is largely driven by mechanisms shown to be important for many organism groups.
对物种多样化的研究能够识别塑造整个生命之树物种丰富度模式的过程。在此，我们使用一个大型树皮甲虫数据集对物种多样化进行了比较分析。三个被考察的协变量——永久近亲繁殖（同胞交配）、真菌养殖和主要寄主类型——代表了一系列可能对物种形成很重要的因素。我们在控制适应过程中的进化滞后的同时，研究了这些协变量与物种多样化之间的关联。所有这三个协变量都与多样化显著相关，但真菌养殖在不同分析中呈现出相互矛盾的模式。在寄主类型上表现出种间变异的属具有更高的物种多样化速率，这可能表明寄主转换是物种多样化的一个驱动因素，或者某些寄主类型或森林组成促进了定殖，从而导致异域物种形成。由于永久近亲繁殖被认为有助于扩散，永久近亲繁殖与多样化速率之间的正相关表明扩散能力可能有助于物种丰富度。树皮甲虫在生态上具有独特性；然而，我们的结果表明，它们令人印象深刻的物种多样性在很大程度上是由对许多生物群体都很重要的机制驱动的。
