Butterfly, the total sun block

Claims that "shiny" butterflies carry hightech solar energy collectors on their wings have been disproved. Scientists have found that the iridescence of certain species of butterfly and moth instead acts as a sun block.

Daniel Koon, a physicist at St Lawrence University, New York, and student Andrew Crawford, compared an intact wing with one that had been stained with oil to rob it of its iridescence. The shinyness cut light absorption by up to 20 per cent rather than increasing it as previously claimed.

Two years ago, Dr Koon similarly debunked the 20-year theory that polar bear hairs acted as optical fibres to transmit ultraviolet light to the hide of the animal.

His latest research appears in Applied Optics Online.