Published Oct 18, 2017 at 4:18 PM | Updated at 4:46 PM PDT on Oct 18, 2017
Some flowers have found a nifty way to get the blues.
They create a blue halo, apparently to attract the bees they need for pollination, scientists reported Wednesday. Bees are drawn to the color blue, but it's hard for flowers to make that color in their petals.
Instead, some flowers use a trick of physics. They produce a blue halo when sunlight strikes a series of tiny ridges in their thin waxy surfaces. The ridges alter how the light bounces back, which affects the color that one sees.
The halos appear over pigmented areas of a flower, and people can see them over darkly colored areas if they look from certain angles.
The halo trick is uncommon among flowers. But many tulip species, along with some kinds of daisy and peony, are among those that can do it, said Edwige Moyroud of Cambridge University in England.
"The striations that create the blue halo are only found on the region darkly pigmented at the base of the petal so the halo is only present there," Moyroud told NBC4 in an email.
In a study published Wednesday by the journal Nature, Moyroud and others analyze the flower surfaces and used artificial flowers to show that bumblebees can see the halos.
An accompanying commentary said the paper shows how flowers that aren't blue can still use that color to attract bees. Further work should see whether the halo also attracts other insects, wrote Dimitri Deheyn of the Scripps Institution of Oceanography in La Jolla, California.