Floral traits differentiate pollination syndromes and taxa but fail to predict the identity of floral visitors to Castilleja

Premise of the Study: Animal pollination is critical to plant reproduction and may cause convergent evolution of pollination syndromes. Pollination syndromes in Castilleja are hypothesized based on floral traits and historical observations of floral visitors. Here we address these questions: (i) Can pollination syndromes be distinguished using floral morphological traits or volatile organic compound emissions? (ii) Is there significant variation in floral traits within a pollination syndrome, at the level of populations or species? and (iii) Do pollination syndromes predict the most frequent floral visitor to Castilleja?

Methods: Floral traits and visitation were measured for five co-occurring Castilleja species (C. applegatei, C. linariifolia, C. miniata, C. nana, and C. peirsonii), representing three pollination syndromes (bee, fly, and hummingbird), at four sites in the Sierra Nevada Mountains. We used non-metric multidimensional scaling (NMDS) and multiple linear regressions to a...

研究前提：动物传粉对植物繁殖至关重要，且可能引发传粉综合征的趋同演化。此前学界基于花部性状与传粉者的历史观测，对山玄参属（Castilleja）的传粉综合征提出了相关假说。本研究旨在解答以下三个问题：（1）能否通过花部形态性状或挥发性有机化合物（volatile organic compound, VOC）的排放特征区分传粉综合征？（2）同一传粉综合征下，种群或物种水平的花部性状是否存在显著变异？（3）传粉综合征能否预测山玄参属植物最常见的传粉者？

方法：本研究于内华达山脉（Sierra Nevada Mountains）的4个样地，对隶属于3种传粉综合征（蜂类、蝇类、蜂鸟类）的5种同域分布山玄参属植物（C. applegatei、C. linariifolia、C. miniata、C. nana及C. peirsonii）的花部性状与访花情况进行了测定。我们采用非度量多维标度（non-metric multidimensional scaling, NMDS）与多元线性回归分析方法对……