Coming soon to a backyard or forest near you: the invasive Asian jumping worm

Larry Hodgson says if you want to see where the Asian jumping worm gets its name, simply put it in a bowl. Then stand back and watch. 

"They'll get out of it," said the Quebec City-based gardening writer, who also goes by the epithet the Laidback Gardner. "These things literally jump. A regular earthworm would have a hard time with that. They just sort of leap and they're quite amazing to watch."

Watching is exactly what Hodgson and the rest of the Canadian gardening world have been doing these past few years as this army of creepy crawlies slowly advances north from Canada's southern border. 

First discovered in the Windsor area as far back as 2014, the worms were found last summer in other Ontario communities, including Wheatley, St Catharines, Dundas and the Greater Toronto Area. They've also been discovered in New Brunswick, in the Fredericton-Oromocto area.

"I recorded the first ones and it was a real surprise in 2014," said John Reynolds of Kitchener, Ont.

As a PhD taxonomist, Reynolds is one of the world's foremost experts in earthworms, and has been documenting their arrival in the Great White North since the beginning. 

At first glance, the Asian jumping worms look pretty similar to European nightcrawlers, or dew worms, also an invasive species and familiar to most of us.

The way to tell them apart is by their clitellum — the little fleshy band around their body. On a jumping worm, it wraps all the way around and is grey or white; on a dew worm, it's pink and only covers the top, similar to a saddle. The easiest way, however, is to watch them move, according to Reynolds. 

"When I first saw them, I thought they were little green snakes until I picked them up," he said. "If you picked one up, you would know." 

Reynolds said the worms typically arrive hidden in soil, either in bags or potted plants, or sometimes in containers of fishing bait imported from the United States. 

"They've only been recognized in Canada recently," he said. "We have four species in Ontario and some of the same in New Brunswick." 

Once they've established themselves, they're difficult, if not impossible, to get them out. Unlike European earthworms, which can live for years, Asian jumping worms live only a single season, hatching, reaching adulthood and dying by the time the ground freezes.

How they survive is the same thing that makes them difficult to remove and easy to spread. Before they die, they leave behind tiny, nearly un-seeable cocoons, which hatch into more worms. Unlike their European cousins,  Asian worms are parthenogenetic — a small subset of animals that can have offspring without mating. 

Asian jumping worms are also voracious, consuming so many nutrients from the first five centimetres of top soil that they can displace other earthworms and reduce the diversity of other soil-dwelling organisms, such as bacteria, fungi, millipedes, salamanders, even some ground-nesting birds – and that's what has gardeners worried about their arrival.