Researchers break the animal kingdom’s colour code

Posted on 16 April 2009

Research spearheaded by the University of York has used computer models to explain the evolution of the distinctive colouring of many species of wildlife.

Charles Darwin was fascinated by the colours of animals – he once wrote to his colleague Alfred Russell Wallace asking why certain animals were "so beautifully and artistically coloured".

The nastier the animal, the more it can 'afford' a bright and distinctive livery to copyright its appearance

Dr Dan Franks

It is a question that has intrigued biologists ever since. Now research spearheaded at the University of York (in collaboration with researchers from the University of Glasgow, and Carleton University in Canada) has used computer models to trace the evolution of this extravagant colouring.  

Researchers in the York Centre for Complex Systems Analysis (YCCSA) sought to explain why most animals that have an anti-predatory defence, such as a sting or poison, tend to be brightly coloured.

Mimicry is common in nature. Defenceless species frequently evolve to look like a nasty species, so that potential predators cannot distinguish between the two – a good meal or an unpleasant experience. 

Such mimicry is good for the defenceless species which predators can mistake for a daunting adversary, but is bad for nasty species which might be mistaken as a good meal. 

The YCSSA research, published in Evolution, suggests that nasty prey may have evolved bright colours to avoid this kind of mimicry. Bright colours are harder for defenceless prey to mimic because they have a survival cost of increased detectability by predators. There are also many ways to look distinctive when brightly coloured, but limited scope for doing so when camouflaged, because camouflage needs to blend in with the background.

Lead researcher Dr Dan Franks, of YCCSA, said: “Our computer models show that this way of looking at the evolution of bright colours explains why in nature we generally find that the nastier the prey species (e.g. the more poisonous) the brighter the animal. 

“The nastier the animal, the more it can 'afford' a bright and distinctive livery to copyright its appearance. It’s similar to the way that big companies closely guard their appearance in an attempt to build clear brand recognition.”

ENDS

Notes to editors:

  • D.W. Franks & G.D. Ruxton  & T.N. Sherratt (2009) Warning signals evolve to disengage Batesian mimics, Evolution , 63(1): 256-267 http://www3.interscience.wiley.com/journal/117958524/home 
  • York Centre for Complex Systems Analysis provides an inspiring multi-disciplinary research environment, bringing together resident researchers and visitors spanning the range of current disciplines contributing to complexity science, and to provide a platform for a range of new undergraduate, masters, and doctoral programmes in complexity science, training the next generation of multi-disciplinary scientists. The centre, which has an international reputation for high quality research and teaching, has 46 members from the following departments at York: Biological Sciences, Chemistry, Computer Science, Electronics, Economics, History, Management, Mathematics, Physics, Psychology, Social Policy and Social Work, and Sociology.

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