Colour-changing dragons to reveal their secrets

Embargoed

Colour-changing dragons to reveal their secrets

A zoological mystery that could change medicine and solar energy?

Media call and release 11 am, Sunday 7 April with bearded dragons at the Zoology Department, University of Melbourne, Parkville.

 

Credit: Devi Stuart-Smith.

Credit: Devi Stuart-Fox.

An international research initiative led by the University of Melbourne’s Dr Devi Stuart-Fox will investigate how and why animals change colour — and what it costs them.

It will also open the way for scientists to imitate lizards and develop new materials that respond to light and temperature for energy and medical applications.

“It’s cool watching lizards, birds, insects and octopuses change colour. But we know so little about how and why they do it. So we’re going to work with Australian bearded dragons to understand more about how and why animals change colour,” says Dr Stuart-Fox.

The $470,000 project launched today follows acclaim in Paris last week for Dr Stuart-Fox when she received the 2013 L’Oréal-UNESCO Special Fellowship, and $40,000, for her discoveries about colour-changing animals.

Dr Stuart-Fox has already shown that chameleons evolved colour change not for camouflage but for social and territorial display. Ten years ago she and her husband studied the 16 species of southern African dwarf chameleons with the support of a UNESCO-L’Oréal International Fellowship. They found the greatest range of colours was exhibited in aggressive male flashing contests, often contrasting rather than blending with background vegetation. Last year she showed that female Lake Eyre dragon lizards use colour to tell the males either to court them or leave them alone.

She’s also realised that she has to look at things from a lizard’s perspective. Many animals can see into the ultra-violet and some can sense infra-red light.

Now Devi and her colleagues from Deakin University and the University of Wisconsin are going further.

“It’s amazing how little we know about colour change — the mechanism, the function, and how widespread it is. Wildlife film-makers have shown us this miracle of life but we still don’t really understand it. Bearded dragons will be our model. They’re large and easy to work with.”

Anecdotally we have a sense of what’s happening, says Dr Stuart-Fox.

“Take a day in the life of a typical male bearded dragon. He wakes up, it’s a cold day so he finds somewhere to bask in the sun. His skin stays dark to absorb the sun’s heat. As he warms up, his skin will lighten and reduce absorption. If another lizard comes by, his beard goes jet black, his body goes from drab grey-brown to bright yellow or orange with black markings — high contrast colours  scaring off male competition and attracting potential mates. And we think the colour change is affected by testosterone — the colour changes are bolder in the breeding season.”

“We hope that our study will confirm these observations and tell us how, why and when. What are the mechanisms? What role do hormones play? What are the triggers? What do these changes ‘cost’ the lizard? What role does colour and colour change play in the evolution of new species?”

There are also likely to be some practical outcomes. CSIRO materials scientist Mr Phil Casey is watching the work closely. He and his colleagues are keenly interested in stimuli-responsive materials, particularly those that change colour in response to changes in temperature.

“CSIRO has already developed thermochromic fibres that can be made into bandages for wound management, that change colour in response to slight changes in the temperature of the wound. The colour change can potentially indicate when a wound is infected without removing the bandage. We now hope that by understanding how the dragons change colour we will be able to develop new kinds of thermochromic compounds inspired by nature for use in solar energy, sensors and in new biomedical applications,” he says.

A full profile of Dr Devi Stuart-Fox is available at http://www.scienceinpublic.com.au/embargoed/lizardbackground together with photos and video and her thoughts on women in science.

There’s HD footage of Devi at the ceremony in Paris and a short profile video of Devi and her research available here https://www.dropbox.com/sh/m7iuseba8q3uscp/8B7MBULiPh along with photos. More photos below.

For interviews contact Niall Byrne on 0417 131 977 or AJ Epstein on 0433 339 141.

One of the bearded dragons that Dr Devi Stuart-Fox studies.

One of the bearded dragons that Dr Devi Stuart-Fox studies.

Credit: Devi Stuart-Smith.

Credit: Devi Stuart-Fox.

A bearded dragon (Pogona vitticeps) at Simpsons Gap, NT. Credit: Devi Stuart-Fox.

A bearded dragon (Pogona vitticeps) at Simpsons Gap, NT. Credit: Devi Stuart-Fox.

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