As if their venom-injecting tails and crushing pincers weren't frightening enough, scorpions have long been known to glow blue-green under ultraviolet (UV) light. But just as the arachnids' claw size and venom potency vary from species to species, so does their ability to fluoresce, with some species lacking the ability altogether, new research shows. Arachnologist Wilson Lourenço of the National Museum of Natural History in Paris initially sought to test the fluorescing capabilities of four recently discovered, cave-dwelling scorpion species (one of which is shown above, left). To his surprise, his test subjects didn't prove to be noteworthy, but the species he compared them with—the soil-loving Chaerilus telnovi—apparently doesn't glow under UV light (seen above, right). Further tests showed that other species from the Chaerilidae family also don't fluoresce, no matter their habitat, suggesting their inability to glow isn't an ecological adaptation, Lourenço reports in the current issue of the journal Comptes Rendus Biologies . Nobody knows for sure why scorpions glow; the new discovery may help scientists finally illuminate this eerie phenomenon.
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