For almost twenty years, a specter has been haunting France: flatworms. After years ofd scattered claims, scientists have confirmed that the nation is indeed infested with hammerhead flatworms and has been for nearly two decades.
Upon receiving a photo of one such worm from an amateur naturalist, Jean-Lou Justin of the National Museum of Natural History in Paris thought somebody was playing a prank on him. He knew that the genera Bipalium and Diversibipalium, colloquially known as hammerhead flatworms, are natural to the warmer parts of Asia. They've also invaded warm, humid regions of the United States like Louisiana, but Justin felt confident they had stayed clear of Europe.
The amateur naturalist kept sending Justin photos, much to his frustration. He described his reaction to : “The man is bringing back worms from his travels, and he pretends he finds them in his garden!”
But now, Justin and the naturalist, Pierre Gros, have co-written a paper together in the showing just how real the worms are.
Using a four year survey that made use of citizen science, Justin and Gros were able to show that the giant flatworms have inhabited France and French overseas territories for a number of years.
The citizen science came through a public call looking for information. Both local news stations and websites started asking the public to send in any pictures they had of the giant flatworms, which can measure out to 3 feet (1 meter) long. In total, the team got 111 worthy specimens. These ranged from 1999 VHS tapes to the claims from kindergarteners in 2013 that giant worms were all around them. There was also a Twitter account dedicated to the cause, which sent out photos the team had received.
These cases allowed Justin to gain a better understanding of these worms had adapted to the French climate. Sightings seemed to generally stem from the south of France, where the summers are rainy and the winters are milder. While not ideal, these are certainly conditions under which these worms could live.
Overseas on the island of Mayotte, which is off the East African coast of Madagascar but still a region of France, what appeared to be a completely new species of worm was found.
While Mayotte and France have very different geographies, what unites them is trade. In their paper, Justin and Gros note that Mayotte has "experienced intense human trade from centuries with the close islands and Madagascar and more distant territories including Asia. Any of these could be the origin of this species."
It's hard to know exactly how these worms have been affecting the French ecosystem. The team "received several reports by citizens mentioning dozens of specimens in their gardens; in some cases, citizens repeatedly reported high numbers, even when worms were removed by hand and destroyed. Such reports justify the species as ‘invasive’ in the common, public sense of the word."
But while anecdotal evidence suggests that the worms could be invasive, Justin and Gros don't sound the alarm quite yet. Further study is required to understand how these animals have been changing the French landscape.
It's been a good year for the power of citizen science. An amateur fossil-hunter in Maryland found rare evidence of dinosaurs and mammals interacting, and an Italian locksmith captured a never-before seen first burst of light from the supernova explosion of a massive star.