why do scorpions glow under black light

The horror, the horror: As if scorpions weren't frightening enough, when illuminated by ultraviolet rays from a black light, the armored arachnids glow an unnatural neon blue. UV light that hits these creepy crawlies gets converted by proteins in their exoskeletons into light of a blue hue, which is visible to the human eye. Scorpions are already outfitted with armor, pinchers and painful and poisonous stingers, so one has to wonder: Is glowing in the dark really necessary? Actually, arachnologists have spent untold hours trying to answer that very question. What, they wonder, is scorpion fluorescence good for? Some say glowing might help scorpions find each other; their earth-tone coloring makes them otherwise difficult to spot in the desert. Others think they do it to dazzle prey.


Alternatively, the light conversion effect could act as a sunscreen. Upon experimental investigation, however, none of these hypotheses hold up to scrutiny, leading some arachnologists to speculate that scorpion fluorescence has no function at all. Perhaps, they say, it's just a random act of evolution. California State University arachnologist Carl Kloock thinks otherwise. Over the past few months, Kloock and his colleagues have started unraveling the mystery of why scorpions glow. "They may be using UV as a way to determine whether or not to come to the surface to look for prey, based on the light levels," Kloock told. All lightning on Earth may have its roots in space, new research suggests. Scorpions are nocturnal creatures. They abhor the heat and evaporative, and it turns out they specifically avoid UV light too.


In a recent issue of the Journal of Arachnology, the Cal State team reported that the arachnids adjust their activity level depending on the amount of UV shining on them. When flooded in UV, they are less active than when lights are dim. "My thinking at this point for why they would respond to UV is that there is a UV component in moonlight," Kloock wrote in an email. If scorpions are hungry, he explained, they'll come out and hunt regardless of light levels. But if they're satiated, research shows they tend to lie low on moonlit nights, especially around. "(Fluorescence) may be part of the mechanism by which the scorpions respond to moonlight," Kloock wrote. He is preparing a follow-up experiment to test the idea directly.


Perhaps, to the
satisfaction of scorpion scientists everywhere, the question of why scorpions glow under UV light may finally be getting answered. As for everyone else в especially people who live around deadly species of scorpions в their fluorescence allows for a very different sort of satisfaction. By patrolling the house with a black light, you can easily find and kill them. Follow Natalie Wolchover on Twitter @. В 2013 LifesLittleMysteries. com. All rights reserved. All scorpions fluoresce under ultraviolet light, such as an electric black light or natural moonlight. The blue-green glow comes from a substance found in the hyaline layer, a very thin but super tough coating in a part of the scorpion s exoskeleton called the cuticle.


Scientists have noticed that, right after a scorpion molts, or sheds its shell, it doesn t glow until the new cuticle hardens. According to scorpion expert Dr. Scott A. Stockwell, this could mean that the substance that causes fluorescence is a byproduct of the hardening process itself, or it might be secreted not long after the creature molts. Whatever its source, the glowing property is surprisingly long-lasting. When scorpions are preserved in alcohol, the liquid itself sometimes glows under UV light. And the hyaline layer is amazingly durable: It can survive millions of years, Stockwell says; it s often found in scorpion fossils even when all other parts of the cuticle have vanished. What s more, even fossilized hyaline fluoresces! Still, scientists don t know what purpose the fluorescence serves.


Some theories: в It protects scorpions from sunlight. в It helps them find each other. в It might confuse their prey. An article on the news website LiveScience reported another theory, by California State University arachnologist Carl Kloock. Because scorpions avoid sunlight in general and UV light in particular, he thinks the glow actually helps them figure out whether to come to the surface or stay underground, based on how much UV light shines on them. For example, these nocturnal creatures are less active on moonlit nights and during the full moon. For humans, one benefit of the scorpion s glow is that it makes these stingersВ easier to see in the dark. Which is perfect, whether you re trying to study them or avoid them!