Einstein Science Reporting for Kids
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25-Jan-2007

Contact: Science Press Package
scipak@aaas.org
202-326-6440
American Association for the Advancement of Science

Jumping spiders glow in ultraviolet light



Under ultraviolet (UV) light, body parts of the ornate jumping spider Cosmophasis umbratica fluoresce, and excite the opposite sex's mating interest.

Yes, the same UV light we try to avoid by using sunscreen and wearing sunglasses, lights up body parts on these jumping spiders. UV light is a natural part of the full spectrum light that comes from the Sun.



These spiders have excellent eyesight that is sensitive to UV light. In UV light the males have fluorescent patches of scales on the face and body; the females have a bright green body part called a palp near the mouth that turns bright fluorescent green.

In the experiment, researchers watched the males and female jumping spiders interact under UV light and then used a filter that blocked that part of the light.

Under UV light, both sexes fluoresced and performed courtship rituals with partners of the opposite sex. Males flexed their abdomens and arched their legs. Females hunched their legs, bent their abdomen or ran away briefly.

Researchers observed male-female behavior when individuals of one sex were in full-spectrum light and the opposite-sex partners were in UV-deficient light. Without their partner being in UV light, females showed no interest. When the females were not in UV light, the males ignored the females or responded with less interest.

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