White beetle dazzles scientists [BBC 2007-01-18]
[Photo] Industry is likely to take a keen interest in the beetles. Photo by Peter Pukusic.
A dazzling insect could help the development of brilliant white, ultra-thin materials, a study suggests.
The finger-tip sized Cyphochilus beetle, found in south-east Asia, had a shell whiter than most other materials found in nature, UK researchers said.
Close inspection reveals a unique surface structure covered with scales 10 times thinner than human hair.
A report in Science magazine claims mimicking these scales could provide a range of applications for industry.
"Such pure bright whiteness is uncommon in insects," explained lead scientist Dr Pete Vukusic of Exeter University.
"You do see the odd bit of whiteness here and there, mainly in butterflies, but the whiteness is really incomparable with this little beetle."
In the study of the insect, Vukusic's team used a number of techniques such as optical microscopy, laser analysis and spectrometry.
The researchers found, according to the International Organization for Standardization measurements, the beetle was much brighter and whiter than milk and the average human tooth.
But, said Dr Vukusic, the group also wanted to find out the sort of system that would physically create such dazzling whiteness.
"And when I put them under the electron microscope, it was like another world had opened up; it was totally remarkable."
The researchers found the beetle's shell was covered with ultra-thin scales, measuring just five micrometres (millionths of a metre), with highly random internal 3D structures.
This irregular structure, explained Dr Vukusic, was the cause of the beetle's whiteness.
While colour, he explained, could be created through highly ordered structures, whiteness is achieved through very random features that scatter all colours simultaneously.
"The degree of whiteness given the scales' thinness is the really impressive thing," Dr Vukusic added.
"We can create this quality of white synthetically, but the materials need to be much thicker. This could have many applications."
The researchers believe industry might draw inspiration from the beetle to enhance the whiteness of synthetic objects, such as papers, plastics, paints or white-light displays.
The team thinks the beetle evolved to be so white because the colour provides camouflage in amongst the white fungi common to where it is found.