Speaking of blue bioluminescence, did you know that scorpions and some other arthropods glow blue under ultraviolet light? A fascinating post from Wired explains the mechanism and some reasons scientists have hypothesized for why these creatures glow as they do. Below is an interesting excerpt from the post, but you’ll really want to click through to read the read the rest — and see the pictures.
For scorpions, the mechanism of the glow has been studied in more detail. Scorpions have “cuticular fluorescence.” Basically, compounds in their exoskeleton absorb and re-emit ultraviolet light as visible light (light humans can see). The exoskeleton of an arthropod is made from composite materials that are both strong and flexible. It’s the outermost layer, epicuticle, that produces the glow, and it seems to be something that changes chemically as the animals grow.
Two compounds are involved in scorpion UV fluorescence: beta-carboline and 4-methyl, 7-hydroxycoumarin. You might recognize coumarin as a common plant compound, and it’s often used as a perfume or in cinnamon flavors.