Butterfly blues

Butterfly wings are absolutely amazing, the patterns produced by tiny scales, which are revealed by the use of a macro lens. The colours are remarkable too - the iridescent blues and greens found on butterflies are not produced using pigment. The following article from The Independent gives a bit more background detail.

The brilliant colours of a butterfly's wing are generated in the same way as the high-definition pictures of the trendiest plasma-screen TVs, scientists have found.

For the past 30 million years, African swallowtail butterflies have used the principles of light-emitting devices to generate the vivid colours of their wings, says Peter Vukusic, a physicist at Exeter University.

A new study shows butterflies' wings are coated with an ultra-thin layer of molecules that form microscopic air spaces where fluorescent pigments absorb ultraviolet light and re-emit it as vivid patches of blue and green.

The air spaces themselves have complex, multi-layered mirrors at the bottom to force light out through the top surface of the wings. Further analysis, published in the journal Science, has found that the airspaces are arranged in such a precisely uniform manner that the fluorescent light is prevented from leaking out sideways, to make sure the colours are even brighter and clearer.

Dr Vukusic said that the butterfly had essentially invented a biological version of the light-emitting diode (LED) millions of years before they were developed by electrical engineers.

This is definitely one from the blipbank - the disgusting weather and an incipient cold meant that I've not left the house today. I need to feel better quickly as I have a very busy day tomorrow.

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