Ommatoiulus moreletii, at home and abroad

This is Ommatoiulus moreletii, the Portuguese millipede. It’s a friendly sort of critter, minding its own business and spending most of its time tucked away under logs, rocks, and in quiet corners. As the name would indicate, it’s native to Portugal (actually, southern Iberia).

Portuguese millipedes are herbivores and detritivores, meaning they’re the clean-up crew of the ecosystem. When it rains, they come out in droves, because rain = moist soil and leaf litter = food.

It rained here last week. And when my wife and I went for a walk up in the hills, we found one big millipede party going on. They were everywhere, thousands of them, on the dirt road, the hiking path, climbing up stone walls…everywhere. At one point we were practically walking on tiptoe, because the hiking path had narrowed and the millipedes were covering most of the available walking space. We’re both very much anti-squish sort of people (with an exception made for cockroaches, in my wife’s case), so we tried to avoid squishing of any kind.

Which put me in mind of an article I ran across in The Atlantic back in early September. Our millipedes were accidentally introduced to southern Australia in the 1950s, and with no natural predators to keep their numbers down, their population has now reached plague level. In fact, when I did a Google search on the millipede by scientific name, half of the hits on the first page were Australian writings on insecticides, predators, and distribution/population studies. Seems that Ommatoiulus moreletii gets a lot more attention in Australia than it does here.

What caught my eye in that article was not the fact of its introduction or swelling numbers. It was that this millipede was being blamed for a minor train crash.

Earlier this week, 25 miles north of Perth, a train pulling into a station in the town of Clarkson ended up rear-ending a train that was parked at the station. And Australia’s transit authority is blaming the accident on … the millipedes.

The creatures have a tendency to hang out on train tracks, it seems, their shiny-black exoskeletons acting as perfect camouflage. And when a train comes along, they … well, you know. And when there are a lot of millipedes being squished at the same time, that leads to tracks that are much less friction-filled than normal. “The train loses traction and the train has slipped,” explained David Hynes, a spokesman for the Public Transport Authority of Western Australia.

In other words, there were so many millipedes on the tracks that when the train crushed them, it turned the tracks into snot, making braking distances much longer than normal. Fortunately, the train wasn’t going too fast when it arrived at the station, merely bumping the train in front of it. The only injuries were a few stiff necks. Well, and all those poor millipedes.

The Atlantic article observed that this isn’t the first time that Ommatoiulus moreletii has been blamed for train issues:

In 2002, Minibeast Wildlife notes, “There were so many Portuguese Millipedes on the train lines between Melbourne and Ballarat that 50 trains were prevented from running.” And in 2009, thousands of the millipedes overtook more than a mile — more than a mile! — of track near Melbourne, causing train delays and cancellations.

One thing the article didn’t point out was the smell. Like several millipede species, Ommatoiulus moreletii has an effective defense against predation. Besides the hard exoskeleton, and the habit of coiling up into a little disc to protect its head when disturbed, this millipede can eject an offensive liquid containing hydrogen cyanide, which is seriously stinky. It’s great for making predators change their minds about eating them, but doesn’t work so well against trains or human feet. Still, it does give one pause to think about the stench produced by thousands of crushed millipedes.

Snot, a train crash, and a disgusting smell — I must remember to tell this to my son.

About Fletcher DeLancey

Socialist heathen and Mac-using author of the Chronicles of Alsea, who enjoys pondering science, politics, well-honed satire (though sarcastic humor can work, too) and all things geeky.
This entry was posted in biology, life. Bookmark the permalink.

9 Responses to Ommatoiulus moreletii, at home and abroad

  1. xenatuba says:

    What would be more appealing to a young man than stench, snot and bugs? The sliding trains also lend themselves to the cartoonist (alas, I am not one. Stick figures are embarrassed to have been drawn by me and often leave the page, if they can get their mismatched stick legs to work.)

  2. Deb says:

    Unfortunately these millipedes are just one of a number of animals introduced into Australia that have no native predators. Rabbits, foxes and cane toads just to mention a few.

  3. Cathy White says:

    Millipedes on the line is far more exotic than the British Rail autumn standard of leaves on the line lol

    • oregon expat says:

      “Leaves on the line,” that sounds SO British.

      • Cathy White says:

        It gets worse, another standard , for Winter, the wrong kind of snow!!! Lol

      • Alma says:

        Hahaha! I think this may be an international thing. “Today, your trip could take a little longer than usual. We are currently driving at reduced speeds due to leaves on the tracks.” – common autumnal message in the Stockholmian metro. Also, each winter, SL (the Stockholm County public transport network) is shocked to discover the existence of snow. “What is this white fluff stopping the trains and buses??” they wonder in utter perplexity. “Maybe we should get some kind of plows? Melters? Nah, I bet it won’t come back next year!”
        The millipedes are somewhat cooler though. Also squickier. 😀

  4. Robyn says:

    Where I used to live in Melbourne they weren’t in plague proportions but sometimes would find several of them indoors. The dog would investigate but learned to leave them alone!

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