Monday and this anemone is ready to party. The deep blue mound in the centre is a bee magnet.
Human retinas are packed with banks of cone-shaped light receptors. Three different types are activated by long, medium or short light wavelengths. (sometimes referred to as red, green and blue cones)
We can distinguish a huge range of colours with three types of cone cells, how is this possible? Luckily each cone is sensitive to a range of wavelengths. Activated cone cells send electronic signals through the optic nerve to the brain for processing. The relative input from each type of cone determines what we see as colour. The brain is programmed when we learn our colours in childhood.
Bees use the same trick with three different cone types. The light they react to is shifted to shorter wavelengths, green, blue and ultraviolet light. (sensitivity shifted to shorter wavelengths.)