Giant Hammerhead Flatworms Which Can Regenerate Themselves are a Growing Problem in France

Tuesday, 22 May 2018 - 8:17PM
Earth
Tuesday, 22 May 2018 - 8:17PM
Giant Hammerhead Flatworms Which Can Regenerate Themselves are a Growing Problem in France
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It would be one thing if a single invasive species began making a home somewhere it wasn't supposed to. But when there's several invasive species of the same worm family in a single country, something seems afoot.

And indeed, new research published in PeerJ documents that for at least a couple decades, France has had a problem with several species of invasive predatory, hammerhead flatworms which managed to escape detection until recently. Brightly colored and with an unusual "hammerhead" on top of their footlong squishy worm bodies, hammerhead flatworms feed on smaller earthworms which help keep soil fertile.

There had been sightings of course, since these things are extremely bizarre looking. But it wasn't until Jean-Lou Justine from the National Museum of History in Paris began compiling sightings that he realized there were at least 111 documented sightings from 1999 to 2017.

And since these worms live primarily beneath the soil, drilling through it with their blade-like noggins, there are likely many more that go unseen. 



It's not entirely clear how so many of these animals, typically native to Asia (Justine's first specimen was a Bipalium kewense species native to Southeast Asia), found their way here. But the most widely accepted explanation is that they're stowaways on important plants and soil, since France is hardly the only country with invasive flatworms. It's just that most other locales don't have this much variety in their invading flatworms.

In fact, Justine and the other researchers also came across a species of blue hammerhead flatworm that had never been seen before, and is probably a new species. And since flatworms, like certain other worms, can regenerate themselves when a piece of them gets cutoff, they're an extraordinarily difficult invader to deal with.




The problem is that since hammerhead flatworms eat so many earthworms, they've made no friends among local farmers. Earthworms can add nutrients to the soil they burrow through, making them extremely helpful to have on farms, but the hammerhead flatworms which eat them do no such things, and leave behind noxious, foul-smelling substances instead as a means of warding off other predators.

Obviously, things aren't serious at the moment, since it's taken almost 20 years for this problem to be identified. But they're a problem that could keep growing back as the flatworms continue reproducing and cloning themselves.
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