SPIDER SEDUCTION REQUIRES UV LIGHT

Abstract

WHEN SOME SPIDERS desire a little romance in their lives, they use ultraviolet light as the aphrodisiac. Biologists in Singapore and England have now added the ornate jumping spider Cosmophasis umbratica to a growing list of critters—including parrots, butterflies, and fish—that rely on UV reflection and fluorescence to socialize ( Science 2007,315,481). What makes these spiders' use of UV light stand out—besides the afterglow—is that UV reflectance and UV-induced fluorescence are employed on a sex-specific basis. Without UV wavelengths, these spiders get no love. Males reflect UV light off scales on their faces and bodies during the mating game, whereas females have sensory organs called palps, typically used to capture prey, that fluoresce bright green when excited by UV light. In the absence of UV light, the success rate for consummating courtships decreases, explains senior author Daiqin Li of the National University of Singapore. Although he suspected the jumping spider might ...