It’s not a millipede party until someone starts glowing. At least that is how the millipedes known as M. bistipita let their hair down.

And right now they have a lot to celebrate.

Paul Marek, assistant professor of entomology in the College of Agriculture and Life Sciences who studies the arthropods, recently re-categorized them as belonging to the genus Motyxia, the only genus that is known to glow in the Western Hemisphere.

M. bistipita is also not as showy as its brighter relatives. Diminutive in size compared to other millipedes, the species lives at a lower elevation with few predators and was not thought to belong to the genus of millipedes that glow.

Marek rediscovered a significant piece of the luminosity puzzle while revisiting a Californian millipede that had been literally sitting on a shelf for half a century — Xystocheir bistipita. It had been collected in 1967 and was not seen again until Marek rediscovered it during fieldwork in the foothills of San Luis Obispo, California.

After sequencing their DNA, Marek found that the millipede was in fact related to its luminous cousins, and changed its name to Motyxia bistipita.

Unlike fireflies that glow because of an enzymatic reaction between a luciferase and a luciferin, M. bistipita owes its soft green-blue glow to the reaction of a photoprotein that requires magnesium and is thought to have initially evolved for its antioxidant properties to cope with the oxidative stress of living in a low-lying, dry environment. Bioluminescence was then repackaged as a nocturnal warning signal in millipedes that live at a higher elevation and contend with many more predators.

“Living things glow in many different colors and for many different reasons, but now we know that the early evolutionary role of bioluminescence may be completely different than its modern day function,” he said. “This discovery clarifies the evolutionary origins of many complex traits, not just bioluminescence.”

As their own built-in luminous party favors, Marek has crowned M. bistipita the belle of the creepy crawly ball.

Now they just have to master performing a celebratory conga line in unison with their collective feet.


Image: Courtesy of National Geographic Society Expeditions Council