Not seen for nearly 50 years, the small, blind millipede Xystocheir bistipita, was recently rediscovered in the foothills of San Luis Obispo, Calif. by entomologist Paul Merek of the Virginia Polytechnic Institute.
During the day, it’s a light tan color with salmon pink spots. But at night, this millipede has a very faint blue-green glow, which was only noticed on its rediscovery.
Analysis of Xystocheir bistipita‘s DNA revealed that the millipede actually belonged to a different genus, Motyxia — the only genus of bioluminescent millipede in the western hemisphere. The identity-challenged millipede was then renamed Motyxia bistipita.
The researchers ranked the light intensity and toxicity of all the millipedes in its newly acquired family and found that M. bistipita is pretty dull and less toxic compared to its mountain-dwelling cousins, which are larger and much more luminous.
The brighter the millipedes were, the more cyanide they contained, which suggests the millipedes at higher elevations use bioluminescence as a forewarning to predators.
But M. bistipita has very few predators — so why does it still glow in the dark?
Unlike fireflies that glow because of an enzymatic reaction that converts a pigment called luciferin into a new compound that emits light, bioluminescence in millipedes is caused by the reaction of a photoprotein that uses magnesium and molecules that contain oxygen.
This reaction may have initially evolved to help the millipede survive the oxidative stress of living in a hot, dry environment, reports Wendy Moore from the University of Arizona in the Proceedings of the National Academy of Sciences. The millipede’s glow may then be a by-product of this process.
Read more at Discovery News
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