Flowers evolved colors to attract birds

Some native Australian flowers have shifted away from using insects as pollinators by evolving their colors to a red hue favored by birds, research has shown. Scientists at Monash University said flower colors evolved to attract bees but some flowers have changed to suit particular pollinators -- like birds -- and may continue to evolve in particular environments depending on the availability of effective pollinators. "We found that flowers exclusively pollinated by birds had initially evolved to suit insect vision, but more recently the spectral signature of bird pollinated flowers had shifted towards longer wavelengths," Monash researcher Mani Shrestha said. The longer color wavelengths better suit the tetrachomatic (four color) vision of many Australian native birds, he said in a Monash release Tuesday. "Bird pollinated flowers may have evolved red signals to be inconspicuousness to some insects that are poor pollinators, whilst also enhancing the discrimination of bird pollinators." The findings suggest flower colors have long been evolving to attract particular pollinators, the researchers said. "The color cues in Australian flowers would be easily detected by honeyeaters, the most important family of nectar feeding birds in Australia. Hummingbirds in the Americas have similar visual systems to honeyeaters, so we expect to find similar color signals among American flowers," researcher Martin Burd said. "But in Asia and Africa, birds with a different type of color vision are the primary avian pollinators. If flower colors in these regions are tuned to the specific capacities of their own birds, we would have strong evidence that we've cracked the code that plants use to communicate with birds."