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How do bees use ultraviolet, blue, and green photoreceptors for colour vision?

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details of the mammalian eye — Photoreception The mammalian eye has a cornea and a lens and functions as a dioptric system, in which light rays are refracted to focus on the retina.

Bees possess a trichromatic colour vision system based on three distinct photopigments located within each ommatidium of their compound eyes. These photoreceptors have maximum spectral sensitivities in the ultraviolet, blue, and green regions of the spectrum.1

By utilizing these three receptors, bees can accurately distinguish between different flower colours, many of which appear differently to them than to humans. For instance, while some flowers may appear entirely yellow to the human eye, they may reflect ultraviolet radiation from the outer petals. The bee’s ability to perceive this ultraviolet light allows it to see patterns that direct it toward the nectar source, which might otherwise be invisible to the human eye.21

This system is fundamental to how bees navigate and forage, as they rely on these color combinations and patterns to identify food sources and orient themselves in their environment.21