Boberg Elin, Alexandersson Ronny, Jonsson Magdalena, Maad Johanne, Ågren Jon, Nilsson L Anders
Department of Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
Ann Bot. 2014 Jan;113(2):267-75. doi: 10.1093/aob/mct217. Epub 2013 Oct 29.
Plant-pollinator interactions are thought to have shaped much of floral evolution. Yet the relative importance of pollinator shifts and coevolutionary interactions for among-population variation in floral traits in animal-pollinated species is poorly known. This study examined the adaptive significance of spur length in the moth-pollinated orchid Platanthera bifolia.
Geographical variation in the length of the floral spur of P. bifolia was documented in relation to variation in the pollinator fauna across Scandinavia, and a reciprocal translocation experiment was conducted in south-east Sweden between a long-spurred woodland population and a short-spurred grassland population.
Spur length and pollinator fauna varied among regions and habitats, and spur length was positively correlated with the proboscis length of local pollinators. In the reciprocal translocation experiment, long-spurred woodland plants had higher pollination success than short-spurred grassland plants at the woodland site, while no significant difference was observed at the grassland site.
The results are consistent with the hypothesis that optimal floral phenotype varies with the morphology of the local pollinators, and that the evolution of spur length in P. bifolia has been largely driven by pollinator shifts.
植物 - 传粉者的相互作用被认为在很大程度上塑造了花的进化。然而，传粉者转变和协同进化相互作用对动物传粉物种花部性状种群间变异的相对重要性却鲜为人知。本研究调查了蛾类传粉的二叶舌唇兰（Platanthera bifolia）花距长度的适应性意义。
记录了二叶舌唇兰花距长度在斯堪的纳维亚半岛各地的地理变异情况，并将其与传粉动物区系的变异相关联。此外，在瑞典东南部对一个长花距的林地种群和一个短花距的草地种群进行了相互移栽实验。
花距长度和传粉动物区系在不同地区和栖息地存在差异，花距长度与当地传粉者的喙长呈正相关。在相互移栽实验中，长花距的林地植物在林地生境中的授粉成功率高于短花距的草地植物，而在草地生境中未观察到显著差异。
这些结果与以下假设一致，即最佳花部表型随当地传粉者的形态而变化，并且二叶舌唇兰花距长度的进化在很大程度上是由传粉者转变驱动的。
