杏吧原创

Species: Psammodesmus bryophorus
Habitat: rainforests in south-west Colombia, not being a rolling stone

Nowadays soldiers wear khaki and other drab colours, but this camouflage clothing is a recent development. Until the early 20th century, most national armies wore brightly coloured uniforms. This behaviour sent a clear signal to the enemy: 鈥淗ello chaps, here we are, do please go ahead and shoot us.鈥�

Camouflage uniforms were commonplace by the first world war, but didn鈥檛 meet with universal approval. As late as 1913, the idea of getting rid of the French army鈥檚 traditional red trousers so incensed minister of war Eug猫ne 脡tienne that he cried: 鈥溾��

If only 脡tienne had taken a trip to Colombia and seen a Psammodesmus bryophorus. These millipedes have had camouflage jackets for much longer than the French army. But theirs do not employ any fabric that humans might wear. They are made of moss.

Mystery millipede

脡tienne would have been unlikely to know about 笔.听产谤测辞辫丑辞谤耻蝉 back in 1913: as far as science is concerned, they were discovered only in April last year, by a party of students on an expedition to Colombia鈥檚 led by Alvaro Eduardo Fl贸rez of the National University of Colombia in Bogot谩.

The millipedes are about 6聽centimetres long. Their backs 鈥� when unclothed 鈥� are black with splashes of ivory white, while their undersides and legs are reddish-brown. Like all millipedes, they don鈥檛 have anything like 1000 legs 鈥� more like 60.

Fl贸rez鈥檚 PhD student Daniela Martinez Torres is taking a closer look at the millipedes, but so far almost nothing is known about them. We don鈥檛 know what they eat: most millipedes eat dead and rotting plant material, but Martinez Torres suspects they may also eat moss. Their mating system and lifespan remains a mystery.

It鈥檚 also unclear whether the millipedes are threatened, because we don鈥檛 know how widespread they are. However, Martinez Torres says the known population has seven males to every female. That鈥檚 a bad set-up: one male can inseminate many females, so males shouldn鈥檛 outnumber females. 鈥淚t is not conducive to the success of a species,鈥� Martinez Torres says.

Moss in motion

Uniquely, the millipedes鈥� backs are draped with mosses and . Of 18 individuals found, 11 were carrying these simple plants, often more than 400 each. So far Martinez Torres has identified 10 plant species, from five families. Some normally , while .

Martinez Torres has taken a closer look at the partnership, and her findings will be published in the . She thinks the creepy-crawlies and plants have formed a mutualistic relationship in which each side benefits.

The upside for the millipedes seems to be camouflage. Millipedes have plenty of predators, from insects and scorpions to mammals and birds. P. bryophorus鈥榮 natural black-and-white colour wouldn鈥檛 be much of a disguise in the forest, so a coat of moss could come in handy.

For their part, the mosses and liverworts may be using the millipedes as a shuttle service. By hopping on a millipede鈥檚 back, each moss can travel around the neighbourhood, spreading its spores across a wide area. Fortunately, that isn鈥檛 typical behaviour for a camouflage jacket.

Journal reference:

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