Some Australian Flowers Evolved Red Hues to Attract Bird Pollinators: Study

A new study finds that some Australian native flowers pollinated by birds have evolved color spectral signatures to suit bird vision.

It is known that some flowers evolve colors to suit insect vision, so as to attract them for pollination. But for the first time, researchers from RMIT and Monash universities in Australia have found that some native flowers of the country have evolved red hues favored by bird pollinators.

The research team collected spectral data from more than 200 flowering plants and identified that the pollinators were either birds or insects. They found that the flowers pollinated by birds initially had colors to suit insect vision. They noticed that the spectral signature of bird-pollinated flowers had shifted toward longer wavelengths to match the long wavelength tetrachromatic (four-color) vision of many Australian native birds.

For instance, some flowers evolved red hues to attract the birds. Rather than having any type of red reflection, the birds targeted specific wavelengths that would not be noticeable to some insects that were poor pollinators, but could be seen by many native birds.

Researchers believe that the findings could help in understanding how flowers evolved colors to match certain pollinators, and how they might continue to evolve different colors depending on the availability of specific pollinators in specific environments.

Honeyeater birds in Australia can easily detect color cues in Australian flowers. Hummingbirds in the Americas also have the same type of color vision as the Australian honeyeaters. So, researchers believe that hummingbirds could also easily determine color signals among American flowers.

However, birds with a different type of color vision are the main pollinators of flowers in Asia and Africa. If flowers in these regions evolved with colors that match the vision of these native birds, it would provide strong evidence suggesting that flowering plants communicate with birds, said researcher Martin Burd, from the Monash School of Biological Sciences.

The findings of the study are published in the journal New Phytologist.