Lovely but lethal millipede discovered

The combination of beauty and danger is beloved in the arts because it is frequently seen in nature, in creatures such as blue-ringed octopuses (of the genus Hapalochlaena) and poison dart frogs (Dendrobates). A new millipede discovered recently in the United States by Paul Marek excels at both qualities – it is incredibly colourful, and its body is covered in cyanide.

Marek discovered Apheloria polychroma, a thumb-sized millipede, in the Cumberland Mountain forests of south-west Virginia. Along with displaying more colour combinations than any other millipede yet discovered, its cyanide coating ensures that any bird that snacks on the lovely but lethal invertebrate won’t do it a second time. 

Marek, from Virginia Polytechnic Institute and State University – better known as Virginia Tech – published his findings in the journal Zootaxa. The species is the tenth he has discovered and named in recent years. 

In 2015 Marek rediscovered a millipede (Xystocheir bistipita) that hadn’t been seen in 50 years, and which shed light on the evolution and function of bioluminescence in nature. And in 2016 he shared the discovery of a millipede (Illacme tobini) that has 414 legs – making it one of the leggiest creatures on earth – which also has 200 poison glands and four gonopods, the millipede equivalent of penises.

He says his work is focused on small things but his research helps tell the larger story of the quickly changing natural world. By documenting the many living organisms of the planet, he is helping avoid anonymous extinction – a process in which a species goes extinct before its existence, role in the ecosystem, or potential benefit to humanity is known.

“It is imperative to describe and catalog these species so we know what role they play in the ecosystem – and what impact we are having on them,” he says. “This region is ripe with biodiversity and is an excellent living laboratory to do this work.”

Lots of other millipedes that don’t have as much toxic defense mimic A. polychroma’s colouring in hopes of avoiding becoming another link in the food chain. These copycats use what is called Mullerian mimicry, named for the German naturalist Fritz Muller, who proposed the concept in 1878, in which different species adopt a shared warning signal to defend themselves against a common predator. 

The more frequently predators encounter what appears to be the same brightly coloured, yet unpalatable, millipede and memorise its warning traits, the better the collective advertisement of their noxiousness.

In addition to the millipede’s colourful exoskeleton, it also serves an important role in the ecosystem as a decomposer by breaking down decaying leaves, wood, and other vegetation to unlock and recycle their nutrients for future generations of forest life.