Scaccabarozzi Daniela, Lunau Klaus, Guzzetti Lorenzo, Cozzolino Salvatore, Dyer Adrian G, Tommasi Nicola, Biella Paolo, Galimberti Andrea, Labra Massimo, Bruni Ilaria, Pattarini Giorgio, Brundrett Mark, Gagliano Monica
School of Pharmaceutical Science and Technology Tianjin University Tianjin China.
School of Molecular and Life Sciences Curtin University Bentley Western Australia Australia.
Ecol Evol. 2023 Jan 29;13(1):e9759. doi: 10.1002/ece3.9759. eCollection 2023 Jan.
Flowers have many traits to appeal to pollinators, including ultraviolet (UV) absorbing markings, which are well-known for attracting bees at close proximity (e.g., <1 m). While striking UV signals have been thought to attract pollinators also from far away, if these signals impact the plant pollinia removal over distance remains unknown. Here, we report the case of the Australian orchid , a nonrewarding species, pollinated by bees via mimicry of the rewarding pea plant . When distant from the pea plant, was hypothesized to enhance pollinator attraction by exaggeratedly mimicking the floral ultraviolet (UV) reflecting patterns of its model. By experimentally modulating floral UV reflectance with a UV screening solution, we quantified the orchid pollinia removal at a variable distance from the model pea plants. We demonstrate that the deceptive orchid attracts bee pollinators by emphasizing the visual stimuli, which mimic the floral UV signaling of the rewarding model . Moreover, the exaggerated UV reflectance of flowers impacted pollinators' visitation at an optimal distance from , and the effect decreased when orchids were too close or too far away from the model. Our findings support the hypothesis that salient UV flower signaling plays a functional role in visual floral mimicry, likely exploiting perceptual gaps in bee neural coding, and mediates the plant pollinia removal at much greater spatial scales than previously expected. The ruse works most effectively at an optimal distance of several meters revealing the importance of salient visual stimuli when mimicry is imperfect.
花朵具有许多吸引传粉者的特征，包括吸收紫外线（UV）的斑纹，这些斑纹以在近距离（例如，<1米）吸引蜜蜂而闻名。虽然引人注目的紫外线信号被认为也能在远距离吸引传粉者，但这些信号是否会影响植物花粉块在远距离的移除尚不清楚。在这里，我们报告了澳大利亚兰花的案例，这是一种不提供花蜜的物种，通过模仿提供花蜜的豌豆植物来吸引蜜蜂传粉。当远离豌豆植物时，人们推测它通过过度模仿其模型的花朵紫外线（UV）反射模式来增强对传粉者的吸引力。通过用紫外线筛选溶液实验性地调节花朵的紫外线反射率，我们量化了在距模型豌豆植物不同距离处兰花花粉块的移除情况。我们证明，这种欺骗性的兰花通过强调视觉刺激来吸引蜜蜂传粉者，这些视觉刺激模仿了提供花蜜的模型的花朵紫外线信号。此外，兰花花朵夸张的紫外线反射率在距其最佳距离处影响传粉者的访花行为，当兰花与模型靠得太近或太远时，这种影响就会减弱。我们的研究结果支持了这样一种假设，即显著的花朵紫外线信号在视觉花朵拟态中发挥功能性作用，可能利用了蜜蜂神经编码中的感知间隙，并在比以前预期大得多的空间尺度上介导植物花粉块的移除。当拟态不完善时，这种策略在几米的最佳距离下效果最佳，这揭示了显著视觉刺激的重要性。
