Flowers tone down their petals and avoid confusing bees

Flowers' iridescent petals, which may look plain to human eyes, are perfectly tailored to a bee's-eye-view so that these pollinators can find and recognise them more easily, research from the University of Bristol and the University of Cambridge has found. A new study by Dr Heather Whitney from Bristol's School of Biological Sciences , Professor Beverley Glover from Cambridge's Department of Plant Sciences and colleagues, shows that the petals of iridescent flowers are tailored to be the perfect signal for bees. When looking for nectar, bees need to be able to spot a flower from a distance and recognise which coloured flowers are full of food for them. The researchers found that iridescence - the shiny, colour-shifting effect that you see on soap bubbles - makes flower petals more obvious to bees, but too much iridescence confuses the bees' ability to distinguish the colours that help bees focus on the most food-filled flowers. While nature can produce amazingly brilliant and vivid iridescence (such as that found on peacock's tails) this study found that flowers use a more subtle, or imperfect, iridescence on their petals. This 'imperfect iridescence' actually creates an ideal signal for bees such that the flowers are more obvious but it doesn't interfere with the bees' ability to distinguish subtly different colours, such as different shades of purple. More vivid, perfect iridescence (like that found on the back of a CD, for example) would make it more difficult for bees to distinguish between subtle colour variations and cause them to make mistakes in their flower choices.