Credit: J. C. ABBOTT/ABBOTT NATURE PHOTOGRAPHY

Am. Nat. doi:10.1086/651593 (2010)

The light reflected off the back of the jewel scarab beetle Chrysina gloriosa is unusual in being circularly polarized. Although the creatures blend into their juniper forest habitat under normal light (pictured left), they stand out clearly under circularly polarizing filters (pictured right). This raises the possibility that they can detect this polarized light and use it to spot one another.

So far, only certain Odontodactylus shrimp species are known to detect circular polarization. Parrish Brady and Molly Cummings of the University of Texas at Austin found that, at night, C. gloriosa fly more often towards brighter light sources, and also prefer linearly polarized over circularly polarized light. When presented with a dimmer unpolarized light source and a brighter circularly polarized source during night time, the beetles flew more often towards the former.

This suggests that C. gloriosa can perceive circular polarization. The authors say that the creatures may use this light during daytime or dusk to see and communicate with each other.