The role of colour patterns for the recognition of flowers by bees (dataset)

Bees discriminate between many different colours of flower petals, but it is not well understood how they perceive and learn patterns frequently found in flowers with colourful structures. We used multispectral imaging to explore chromatic cues in concentric flower patterns as they are seen through the low-resolution eyes of a honeybee. We find a diversity of colour combinations, which suggests that plants could exploit the sensory capabilities of pollinators, like bees, that learn colours easily. A consistent feature is that the surround of the pattern has a stronger chromatic contrast to the foliage background than the centre. This could potentially serve as a feature filter for the fast identification of colours in a scene as flower objects during a forager’s approach. We also trained and tested bees with three types of concentric patterns. Bees recognised and discriminated them accurately in most tests relying flexibly on both chromatic and spatial cues. Only in few situations, depending on the training stimulus, chromatic cues dominated and pattern cues were ignored. The variability of floral designs and the bees’ flexibility in recalling colour and spatial information suggest a role for colour vision in pattern processing. Implications for the signalling strategies of flowers are discussed.

蜜蜂能够区分花瓣的多种不同色彩，但学界对其如何感知与学习常见于带有彩色结构花朵的图案的机制，仍未得到充分阐释。我们采用多光谱成像（multispectral imaging）技术，以蜜蜂低分辨率复眼的视觉视角，探究同心圆花朵图案中的色彩线索。研究发现存在多样化的色彩组合，这表明植物或许可以利用蜜蜂这类易于学习色彩的传粉者（pollinators）的感官能力。一个一致的特征是：图案外围相较于图案中心，与叶片背景的色彩对比度更强。这一特征或可作为一种特征过滤器，帮助觅食蜂在接近花朵时快速识别场景中的色彩类花朵目标。我们还针对三种同心圆图案训练并测试了蜜蜂。在多数测试中，蜜蜂能够灵活结合色彩与空间线索（spatial cues）精准识别并区分这些图案。仅在少数特定情境下，根据训练刺激物的不同，蜜蜂会优先依赖色彩线索而忽略图案的空间线索。花卉图案的多样性，以及蜜蜂在回忆色彩与空间信息时的灵活性，表明色彩视觉在图案处理中发挥着重要作用。本文最后探讨了该研究对花卉信号策略的启示。