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Polarized Mirages

February 4, 2009

Insects and other animals may mistake shiny, hard surfaces for water, disrupting their life cycle.


Man-made mirages. I’m Bob Hirshon and this is Science Update.

Glass, steel, and asphalt may look just like inviting pools of water to some animals. And that’s messing up their lives. Michigan State University ecologist Bruce Robertson explains that certain creatures, especially insects, are attracted to a polarized light: in other words, light waves that vibrate in one particular direction. Water polarizes light, but so do smooth, dark, man-made surfaces.

BRUCE ROBERTSON (Michigan State University):
And they may actually polarize light more strongly than water does.

As a result, mayflies are wasting their short lives laying eggs on buildings, while diving beetles and dragonflies are staking out breeding grounds on car hoods. If these mistakes significantly impact the bug populations, it could eventually cause a domino effect that disrupts other species. I’m Bob Hirshon for AAAS, the Science Society.