Laboratory of Plant Systematics and Evolutionary Biology, College of Life Sciences, Wuhan University, Wuhan, China.
Ann Bot. 2011 Oct;108(5):877-84. doi: 10.1093/aob/mcr216. Epub 2011 Aug 10.
Background and Aims The presence of co-flowering species can alter pollinator foraging behaviour and, in turn, positively or negatively affect the reproductive success of the focal species. Such interactions were investigated between a focal species, Pedicularis monbeigiana, and a co-flowering species, Vicia dichroantha, which was mediated by behaviour alteration of the shared bumble-bee pollinator. Methods Floral display size and floral colour change of P. monbeigiana were compared between pure (P. monbeigiana only) and mixed (P. monbeigiana and V. dichroantha) plots in two populations. Pollinator visitation rates, interspecific floral switching and successive within-plant pollinator visits were recorded. In addition, supplemental pollination at plant level was performed, and the fruit set and seed set were analysed in pure and mixed plots with different densities of P. monbeigiana. Key Results Pollinator visitation rates were dramatically higher in mixed plots than in pure plots. The higher pollinator visitation rates were recorded in both low- and high-density plots. In particular, successive flower visits within an individual plant were significantly lower in mixed plots. Supplemental pollination significantly increased fruit set and seed set of individuals in pure plots, while it only marginally increased seed set per fruit of plants in mixed plots. Conclusions The presence of V. dichroantha can facilitate pollination and increase female reproductive success of P. monbeigiana via both quantity (mitigating pollinator limitation) and quality (reducing geitonogamy) effects. This study suggests that successive pollinator movements among flowers within a plant, as well as pollinator visitation rates and interspecific flower switching, may be important determinants of the direction and mechanisms of interaction between species.
共存植物的存在可能会改变传粉者的觅食行为，从而对焦点植物的繁殖成功产生积极或消极的影响。本研究通过改变共享熊蜂传粉者的行为，调查了焦点植物Pedicularis monbeigiana 与共存植物 Vicia dichroantha 之间的这种相互作用。方法：在两个种群中，比较了纯（仅 P. monbeigiana）和混（P. monbeigiana 和 V. dichroantha）种植片中 P. monbeigiana 的花展示大小和花色变化。记录了传粉者访问率、种间花切换和同一植株内连续传粉者访问。此外，还在纯和混种植片中进行了植株水平的补充授粉，并分析了不同密度 P. monbeigiana 的纯和混种植片中的果实和种子设置。结果：与纯种植片相比，混种植片中的传粉者访问率明显更高。在低密度和高密度种植片中均记录到较高的传粉者访问率。特别是，同一植株内的连续花朵访问明显减少。在纯种植片中，补充授粉显著增加了个体的果实和种子设置，而在混种植片中，仅略微增加了植物每个果实的种子设置。结论：V. dichroantha 的存在可以通过数量（减轻传粉者限制）和质量（减少同株异花授粉）效应促进 P. monbeigiana 的授粉，并增加其雌性生殖成功。本研究表明，同一植株内花朵之间的连续传粉者运动以及传粉者访问率和种间花切换可能是物种间相互作用的方向和机制的重要决定因素。
