Department of Environmental Ecology, Faculty of Natural Sciences, Comenius University , Bratislava, Slovakia.
Institute of Zoology, Slovak Academy of Sciences , Bratislava, Slovakia.
Plant Signal Behav. 2020 Nov 1;15(11):1807153. doi: 10.1080/15592324.2020.1807153. Epub 2020 Aug 15.
Flower shapes, colors, sizes and fragrances are shaped mostly for pollinator attraction. Flower phenotypes are, however, subjected to conflicting selection directed by both pollinators and non-pollinating agents. We investigated flower attractiveness to a model pollinator in the snowdrop ( L.) under laboratory conditions. Naïve bumblebees ( L.) showed strong, innate preferences for experimentally altered upward positioned flowers, suggesting that the natural, downward orientation did not evolve to attract pollinators. Experimentally treated green marks on inner tepals decreased pollinator attraction compared with flowers expressing intact marks, suggesting that green marks serve to guide/attract pollinators. Attractiveness of green marks was significantly compromised by flower orientation; green marks were attractive only for untreated downward-oriented flowers, but they did not improve the attractiveness of upward-oriented flowers. Our results suggest that downward flowers in snowdrop evolved under conflicting selection directed by biotic and abiotic factors, and that green marks on inner tepals could evolve later to enhance flower attractiveness.
花的形状、颜色、大小和香气主要是为了吸引传粉者而形成的。然而，花的表型受到传粉者和非传粉者的相互矛盾的选择。我们在实验室条件下研究了雪花莲（L.）对模型传粉者的花朵吸引力。天真的熊蜂（L.）对实验中向上放置的花朵表现出强烈的、先天的偏好，这表明自然的向下方向并不是为了吸引传粉者而进化的。与表达完整标记的花朵相比，内花瓣上的绿色标记处理实验降低了传粉者的吸引力，这表明绿色标记可以引导/吸引传粉者。花的方向显著影响了绿色标记的吸引力；绿色标记只对未处理的向下定向的花朵有吸引力，但不能提高向上定向的花朵的吸引力。我们的结果表明，雪花莲向下的花朵是在生物和非生物因素的相互矛盾的选择下进化而来的，内花瓣上的绿色标记可能是后来进化而来的，以增强花朵的吸引力。
