Did you know that Scorpions glow when you put them under an ultraviolet light? Ecological artist The Butterfly Babe (Sarah Folts) has shared a video showing a mother scorpion with her young gathered on her back and glowing a bright blue and purple under ultraviolet light.
As spotted by Laughing Squid, this fluorescent feature is due to specific proteins in scorpion exoskeletons, although the reason for its evolutionary usage is not entirely clear.
What is clear is that subjecting the large arachnids to ultraviolet light makes for some stunning photo and video opportunities, as different species of scorpions glow different colors. As shown in the video above, even differently aged scorpions of the same species fluoresce different colors.
The glow is caused by chemicals in its outer shell (cuticle / Hyaline layer) absorbing and then re-emitting the light at a lower wavelength, which creates the soft blue-green color. This hyaline layer is incredibly strong and stands up to time incredibly well: scientists have found that even fossilized scorpions can glow when a UV light source is placed on them.
It has even been shown that when scientists preserve scorpion samples in liquid-filled jars, the hyaline layer can make the liquid glow. An interesting thing observed by researchers is the creatures don’t glow immediately after molting. Instead, the cuticles have to completely harden before they start to shine blue/green.
“We don’t really know exactly why they do it — it could just be an accident, a freak of nature, that all scorpions fluoresce,” Owen Seeman, the collection manager for arachnids at the Queensland Museum, said in an interview with ABC in 2017.
In fact, it is still unknown if the glowing material comes from a chemical reaction in the hardening process or if the scorpions actually secrete the chemicals that create the glowing reaction.
Some theorize that it could help scorpions find each other while others think it is just a fluke of evolution and has no purpose at all. Another theory is that scorpions use the glow to see at night, as their eyes are more sensitive to the blue-green colors. However, there is very little UV light at night which makes this explanation unlikely. Another theory is the fluorescence makes their bodies more sensitive to light, which in turn makes it easier for them to find a shade-covered hiding spot. Because scorpions avoid sunlight in general and UV light in particular, Carl Kloock, an arachnologist at California State University, postulates that the glow actually helps them determine if they are safe to come out or if they need to stay hidden based on how much UV light shines on them.
Even though the reason for the glow remains a mystery to scientists, it can definitely make things easier for researchers while out in the field since they can easily spot scorpions at night by simply using a UV flashlight.