Bees feeling blue for flowers
6 Dec 2017 by Evoluted New Media
Researchers from the University of Cambridge have discovered that flowers have nanoscale ridges that create a ‘blue halo’, when viewed at certain angles, that attract bees.
Researchers from the University of Cambridge have discovered that flowers have nanoscale ridges that create a ‘blue halo’, when viewed at certain angles, that attract bees. Although these ridges and grooves vary, both on individual petals and also between different flower (species), they all produce a similar ‘blue halo’ effect.
Professor Beverly Glover, plant scientist at the University of Cambridge, said: “We had always assumed that the disorder we saw in our petal surfaces was just an accidental by-product of life - that flowers couldn't do any better. It came as a real surprise to discover that the disorder itself is what generates the important optical signal that allows bees to find the flowers more effectively."
Previous studies have shown that many bee species have an innate preference for colours in the violet-blue range. The researchers artificially recreated ‘blue halo’ nanostructures and used them as surfaces for artificial flowers at a lab in Cambridge. Bees were able to perceive the difference between flowers with this ‘blue halo’ against those without.
The researchers used a sugar solution in one type of artificial flower and another with a bitter quinine solution in the other and found that bees used the blue halos to learn which surface had the reward. All flowering plants belong to the angiosperm lineage. Researchers analysed some of the earliest diverging plants from this species, and found no evidence of halo-producing petal ridges. They did, however, found several examples of major flower groups – monocots and eudicot – that emerge during the Cretaceous period. This coincides with the early evolution of flower-visiting insects.
Dr Silvia Vignolini, also from the University, said: “The huge variety of petal anatomies, combined with the disordered nanostructures, would suggest that different flowers should have different optical properties. However, we observed that all these petal structures produce a similar visual effect in the blue-to-ultraviolet wavelength region of the spectrum - the blue halo."
The study was published in Nature.
