Department of Biology, Faculty of Science, Shinshu University 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.
Sugadaira Montane Research Center, University of Tsukuba Ueda, Nagano, 386-2201, Japan.
Ecol Evol. 2014 Sep;4(17):3395-407. doi: 10.1002/ece3.1191. Epub 2014 Aug 18.
Geographic trait variations are often caused by locally different selection regimes. As a steep environmental cline along altitude strongly influences adaptive traits, mountain ecosystems are ideal for exploring adaptive differentiation over short distances. We investigated altitudinal floral size variation of Campanula punctata var. hondoensis in 12 populations in three mountain regions of central Japan to test whether the altitudinal floral size variation was correlated with the size of the local bumblebee pollinator and to assess whether floral size was selected for by pollinator size. We found apparent geographic variations in pollinator assemblages along altitude, which consequently produced a geographic change in pollinator size. Similarly, we found altitudinal changes in floral size, which proved to be correlated with the local pollinator size, but not with altitude itself. Furthermore, pollen removal from flower styles onto bees (plant's male fitness) was strongly influenced by the size match between flower style length and pollinator mouthpart length. These results strongly suggest that C. punctata floral size is under pollinator-mediated selection and that a geographic mosaic of locally adapted C. punctata exists at fine spatial scale.
地理特征的变异通常是由局部不同的选择机制引起的。由于海拔高度的急剧环境梯度强烈影响适应性特征，因此山地生态系统是探索短距离适应分化的理想场所。我们在日本中部的三个山区的 12 个种群中调查了钟花党参（Campanula punctata var. hondoensis）的海拔花径变化，以检验海拔花径变化是否与当地熊蜂传粉者的大小相关，以及是否由传粉者大小选择了花径大小。我们发现，随着海拔高度的变化，传粉者组合在地理上发生了明显的变化，从而导致了传粉者大小的地理变化。同样，我们发现了花径的海拔变化，这证明与当地传粉者的大小有关，但与海拔本身无关。此外，花粉从花柱上被蜜蜂带走（植物的雄性适合度）强烈受到花长和传粉者口器长度之间大小匹配的影响。这些结果强烈表明，钟花党参的花径大小受到传粉媒介介导的选择，并且在精细的空间尺度上存在着具有局部适应性的钟花党参地理镶嵌体。
