Leaf Chafer Beetle
September 29, 2011

Scientists Reveal True Colors of Fossilized Beetles

Dr. Maria McNamara of Yale University has done microscopic research that shows how the colors of fossilized beetles have shifted.

This new research, published in the Proceedings of the Royal Society B, gives paleontologists greater confidence in knowing what these ancient insects actually looked like. The color information revealed by the beetles further unveils the way a particular beetle lived its life.

Dr. McNamara told BBC News, “These kinds of colors have lots of visual functions. They might function in communication, for example, or in thermo regulation. And so it´s important to be able to reconstruct them properly so that we can say what those organisms were using the colors for in the first place.”

The metallic colors that many beetles show are actually the refraction of lightwaves in the very fine layers of material that is contained in their exoskeleton. There are small structures in this material that bends light to enhance certain wavelengths. The researchers found, according to Discovery News, that the structure of the beetle´s cuticles did not change during fossilization, which means the change in the refractive index was due to chemical processes.

Dr. McNamara explains, “What actually happens is - the refractive index of the cuticle changes. This is a measure of how much the light is bent. This means the chemistry must have changed because the refractive index in a material will depend on what it´s made from.”

The beetles the researchers studied were fossilized remains ranging from 15 to 47 million years old. They analyzed the beetles using an electron microscope to determine how the process of fossilization, where atoms and molecules of tissues can be replaced, changes the light-controlling properties in the remains. What they found was that because of the change in chemistry, the alteration was to “redshift” colors to longer wavelengths. For example a violet colored beetle would look blue when fossilized and a blue one would look green, according to the BBC.


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