Red flowers the trick to attracting birds

By Liz Emmett | March 7, 2013

Aussie flowers are switching to scarlet hues through evolution because they are birds’ favoured colours.

NATIVE AUSTRALIAN FLOWERS ARE evolving to bear the colour red in order to attract birds to pollinate them, according to new research.

The finding suggests that certain plants, such as some gum trees, have evolved to produce the colours that are most distinctive and visible to native birds.

“This is not just any red signal, it is very specific – to communicate directly with Australian native birds,” says Dr Adrian Dyer, one of the researchers behind the study.

Native Australian birds attracted to red

The researchers, from Monash and RMIT Universities in Melbourne, collected over 200 native Australian flowering plants and studied their genetic make-up to uncover clues about their evolution.

Their results, published in the journal New Phytologist, are among the first to show one species evolving to signal to another, says Adrian.

Previous studies have shown the evolution of flowering plants to attract bees, he says, however it was unclear why some plants had red signals. The work suggests that as the plants tended towards red colouring, they also shifted from using insect pollinators to using birds.

Birds are better pollinators than insects

“Bees don’t see red very well at all,” Adrian told Australian Geographic. “By mapping the history of the flower evolution, it was possible to show that red flowers pollinated by birds actually evolved from flowering plants that used to be insect-pollinated.”

A possible advantage of attracting birds, is that some insects can be inefficient pollinators. The change in colouring, Adrian says, “enables plants with red flowers to get efficient delivery of pollen to enable sexual reproduction, and avoid having nectar stolen by insects.”

Professor Marie Herberstein, an ecologist at Macquarie University in Sydney, says the discovery about the interaction between plants and their pollinators is very interesting.

Marie says that while it has been known for some time that insects are attracted to blue, this is the most complete study showing that bird pollinators are attracted to red.

“This is particularly significant in Australia as we have more bird pollinators than any other continent,” Marie says.

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