Duffy K J, Johnson S D
School of Life Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa.
Plant Biol (Stuttg). 2017 May;19(3):438-443. doi: 10.1111/plb.12555. Epub 2017 Feb 26.
Rewardless plants can attract pollinators by mimicking floral traits of rewarding heterospecific plants. This should result in the pollination success of floral mimics being dependent on the relative abundance of their models, as pollinator abundance and conditioning on model signals should be higher in the vicinity of the models. However, the attraction of pollinators to signals of the models may be partially innate, such that spatial isolation of mimics from model species may not strongly affect pollination success of mimics. We tested whether pollination rates and fruit set of the rewardless orchid Disa pulchra were influenced by proximity and abundance of its rewarding model species, Watsonia lepida. Pollination success of the orchid increased with proximity to the model species, while fruit set of the orchid increased with local abundance of the model species. Orchids that were experimentally translocated outside the model population experienced reduced pollinaria removal and increased pollinator-mediated self-pollination. These results confirm predictions that the pollination success of floral mimics should be dependent on the proximity and abundance of model taxa, and thus highlight the importance of ecological facilitation among species involved in mimicry systems.
无回报植物可以通过模仿有回报的异种植物的花部特征来吸引传粉者。这应该会导致花部拟态植物的授粉成功取决于其模型的相对丰度，因为在模型附近传粉者的丰度以及对模型信号的条件作用应该更高。然而，传粉者对模型信号的吸引力可能部分是天生的，这样拟态植物与模型物种的空间隔离可能不会强烈影响拟态植物的授粉成功。我们测试了无回报的美丽兜蕊兰（Disa pulchra）的授粉率和坐果率是否受到其有回报的模型物种沃森花（Watsonia lepida）的接近程度和丰度的影响。兰花的授粉成功率随着与模型物种的接近程度而增加，而兰花的坐果率随着模型物种在当地的丰度而增加。通过实验被转移到模型种群之外的兰花经历了花粉块移除减少和传粉者介导的自花授粉增加。这些结果证实了花部拟态植物的授粉成功应该取决于模型类群的接近程度和丰度的预测，从而突出了参与拟态系统的物种之间生态促进作用的重要性。
