Female Spiders Attracted to Ultraviolet Bling

Male jumping spiders, known for their wicked dance moves (video), may have another trick for attracting mates: ultraviolet come-hither looks. The discovery, made by Jingjing Li from the Hubei University in China and published yesterday in Current Biology, is the first evidence that insects can detect UV-B rays. UV-A rays can be detected by many insects, birds, fish, and mammals, but UV-B rays are more energetic than UV-A rays (which makes them perfect for giving us cancer and sunburns), and it had been assumed that no animals had the right equipment for detecting them. But Li found evidence that a species of jumping spiders can not only detect UV-B rays—they find them sexy. First, Li discovered that both males and females of the species have patches on their backs and abdomens that reflect UV-B (but not UV-A), which are displayed during courtship. To determine whether these patches played a role ...