Breitkopf Hendrik, Onstein Renske E, Cafasso Donata, Schlüter Philipp M, Cozzolino Salvatore
Department of Biology, University of Naples Federico II, Naples, Italy.
Institute of Biochemistry and Biology, Biodiversity Research/Systematic Botany, University of Potsdam, Potsdam, Germany.
New Phytol. 2015 Jul;207(2):377-389. doi: 10.1111/nph.13219. Epub 2014 Dec 17.
Episodes of rapid speciation provide unique insights into evolutionary processes underlying species radiations and patterns of biodiversity. Here we investigated the radiation of sexually deceptive bee orchids (Ophrys). Based on a time-calibrated phylogeny and by means of ancestral character reconstruction and divergence time estimation, we estimated the tempo and mode of this radiation within a state-dependent evolutionary framework. It appears that, in the Pleistocene, the evolution of Ophrys was marked by episodes of rapid diversification coinciding with shifts to different pollinator types: from wasps to Eucera bees to Andrena and other bees. An abrupt increase in net diversification rate was detected in three clades. Among these, two phylogenetically distant lineages switched from Eucera to Andrena and other bees in a parallel fashion and at about the same time in their evolutionary history. Lack of early radiation associated with the evolution of the key innovation of sexual deception suggests that Ophrys diversification was mainly driven by subsequent ecological opportunities provided by the exploitation of novel pollinator groups, encompassing many bee species slightly differing in their sex pheromone communication systems, and by spatiotemporal fluctuations in the pollinator mosaic.
快速物种形成事件为深入了解物种辐射和生物多样性模式背后的进化过程提供了独特视角。在此，我们研究了性欺骗型蜂兰（Ophrys）的辐射现象。基于一个经过时间校准的系统发育树，并通过祖先性状重建和分歧时间估计，我们在一个状态依赖的进化框架内估计了这种辐射的节奏和模式。看起来，在更新世，蜂兰的进化以快速多样化事件为特征，这些事件与向不同传粉者类型的转变相吻合：从黄蜂到尤西拉蜂，再到地蜂和其他蜜蜂。在三个分支中检测到净多样化率的突然增加。其中，两个系统发育关系较远的谱系以平行方式且在其进化历史中的大致相同时间从尤西拉蜂转变为地蜂和其他蜜蜂。与性欺骗这一关键创新的进化相关的早期辐射缺失表明，蜂兰的多样化主要是由利用新的传粉者群体所提供的后续生态机会驱动的，这些传粉者群体包括许多在性信息素通讯系统上略有不同的蜜蜂物种，以及传粉者镶嵌体的时空波动。
