Carnivorous plants do not use colours to attract prey

The widespread belief that carnivorous plants are brightly coloured to attract prey does not hold much water, contends a study.

Prey attraction to red carnivorous plant traps is yet to be conclusively demonstrated for any species, the researchers noted.

"Our results suggest that the red pigments called anthocyanins, which create these bright colours, might serve a different role in the biology of the plants," said Jonathan Millett of Loughborough University in Britain.

To determine the role of plant colour in attracting prey, the researchers investigated the Sundew plant, whose red leaves catch prey using sticky glue secreted on the end of stalked tentacles.

They designed artificial traps to isolate the influence of colour and observed living plants in their natural habitat, and capture rates were logged.

Findings showed prey were not attracted to green traps, and were actually deterred from red traps and there was no evidence the camouflaged traps caught more prey.

This is one of the first studies to provide proof the red colour of the plants has not evolved to attach prey, which suggests the vivid colouring may serve another purpose.

The study appeared in the journal Biology Letters.