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UV Light & Spider Sex

March 13, 2007

A type of spider uses ultraviolet light in its mating game.


Seeing spider romance in a new light. I’m Bob Hirshon and this is Science Update.

Ultraviolet light is invisible to humans, but it’s an aphrodisiac to jumping spiders. This according to biologist Daiqin Li of the National University of Singapore. Li explains that UV light reflects off scales on the male spiders’ faces, and makes the arm-like appendages of females turn fluorescent green. And when he and his colleagues selectively blocked the UV light over either a male or female spider, spiders of the opposite sex weren’t interested in mating with it.

DAIQIN LI (National University of Singapore):
So the sexual coloration with UV is crucial for courtship behavior in the species.

Li says that while many animals can see UV light, only a small parrot called the budgie also seems to use it in picking a mate. Even so, the UV appears to be more critical in spider sex, and unlike the budgies, it affects male and female spiders in different ways. I’m Bob Hirshon, for AAAS, the science society.