Many plants produce colourful flowers that play a role in pollinator attraction. These floral visual signals may have distinct optical properties that differ in biological relevance. In this review, van der Kooi et al. discuss the optical properties and functional significance of common and uncommon aspects of floral visual signals.
Drawing on a large body of literature covering the ecology, optics and anatomy of flowers, as well as studies on the behaviour and visual systems of pollinators, they explain how different visual effects come about, their relevance for signalling to pollinators, and highlight fruitful avenues for future research.