Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS - Université de Montpellier - Université Paul Valéry Montpellier - EPHE, Montpellier, France.
Plant Biol (Stuttg). 2020 Sep;22(5):881-889. doi: 10.1111/plb.13104. Epub 2020 Jun 25.
Sexually deceptive orchid species from the Mediterranean genus Ophrys usually interact with one or a few pollinator species by means of specific floral scents. In this study, we investigated the respective role of pollinator-mediated selection and phylogenetic constraints in the evolution of floral scents in the section Pseudophrys. We built a phylogenetic tree of 19 Pseudophrys species based on three nuclear loci; we gathered a dataset on their pollination interactions from the literature and from our own field data; and we extracted and analysed their floral scents using solid phase microextraction and gas chromatography-mass spectrometry. We then quantified the phylogenetic signal carried by floral scents and investigated the link between plant-pollinator interactions and floral scent composition using phylogenetic comparative methods. We confirmed the monophyly of the section Pseudophrys and demonstrated the existence of three main clades within this section. We found that floral scent composition is affected by both phylogenetic relationships among Ophrys species and pollination interactions, with some compounds (especially fatty acid esters) carrying a significant phylogenetic signal and some (especially alkenes and alkadienes) generating dissimilarities between closely related Pseudophrys pollinated by different insects. Our results show that in the section Pseudophrys, floral scents are shaped both by pollinator-mediated selection and by phylogenetic constraints, but that the relative importance of these two evolutionary forces differ among compound classes, probably reflecting distinct selective pressures imposed upon behaviourally active and non-active compounds.
地中海属 Ophrys 中具有性欺骗性的兰花物种通常通过特定的花香与一种或几种传粉者相互作用。在这项研究中，我们研究了传粉者介导的选择和系统发育约束在 Pseudophrys 组中花香进化中的各自作用。我们基于三个核基因座构建了 19 种 Pseudophrys 物种的系统发育树；我们从文献和我们自己的野外数据中收集了它们的传粉相互作用数据集；我们使用固相微萃取和气相色谱-质谱法提取和分析了它们的花香。然后，我们量化了花香所携带的系统发育信号，并使用系统发育比较方法研究了植物-传粉者相互作用与花香组成之间的联系。我们证实了 Pseudophrys 组的单系性，并证明了该组内存在三个主要分支。我们发现，花香组成既受 Ophrys 物种之间的系统发育关系影响，也受传粉相互作用的影响，一些化合物（特别是脂肪酸酯）具有显著的系统发育信号，而一些化合物（特别是烯烃和二烯烃）在由不同昆虫授粉的密切相关的 Pseudophrys 之间产生差异。我们的结果表明，在 Pseudophrys 组中，花香受到传粉者介导的选择和系统发育约束的共同塑造，但这两种进化力量的相对重要性因化合物类别而异，这可能反映了对行为活跃和非活跃化合物施加的不同选择压力。
