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Bug Bifocals

September 16, 2010

Biologists have discovered a beetle with built-in bifocals.


Beetles with bifocals…I’m Bob Hirshon and this is Science Update.

Scientists have discovered the first known creature with built-in bifocals. It’s the larva of a bug called the sunburst diving beetle. University of Cincinnati biologist Elke Buschback and her colleagues found that four of the larvae’s twelve eyes have true bifocal lenses. Not only that, each bifocal eye has two retinas as well.

ELKE BUSCHBACK (University of Cincinnati):
I think of it as it being two eyes in one, so it’s really that they can see with those two regions in the eye simultaneously.

That’s an advantage over our bifocal glasses; since human eyes have only one retina, we have to alternate between the lenses depending on our needs. Buschback says the beetle retinas are sensitive to different light wavelengths, and set at different distances from the lenses. She says that probably helps them spot and catch prey, though it’s not clear exactly how. I’m Bob Hirshon, for AAAS, the science society.