An invasive and toxic worm that can grow up to three feet long has made its way to Ontario, and gardeners and pet owners are being warned about its presence.
Hammerhead flatworms are an invasive species from Asia and gets its nickname from the flat shape of its head. The worms produce a neurotoxin used to paralyze prey, including earthworms, and there is the potential for harm to humans and pets if these worms are touched. The paralyzing toxin is made of the same molecule as that of a puffer fish—one of the most poisonous in the world.
Sightings of these worms tend to spike in the damp spring and fall months and they have already been seen in numerous locations across southern Ontario this spring. So far this year there have been reported sightings in Woolwich, Hamilton, and Newmarket, but the worms seem to be most prevalent in Toronto. In neighbouring Quebec, there has been sightings in Gatineau, Montreal, and Trois-Rivières. Experts say the worms are being spread by plants and soil being moved from one place to another.
In an article by the CBC, Université de Montréal entomologist Étienne Normandin said while the toxin quantity that hammerhead flatworms produce is very small, he is concerned about the potential impact on babies and children if they put the worm in their mouth. The chemical can cause illness and even death if ingested by pets, so seek emergency attention immediately. Humans handling these worms may suffer skin irritation, and experts advise not to directly touch a hammerhead.
Another cause for concern is their ability to disrupt local ecosystems by preying on native earthworms, snails, slugs, or feeding on the larvae of grounding pollinators and altering soil composition. Since Hammerhead worms don’t have predators, pathogens or parasites, their population can grow fast.
If you see the Hammerhead Flatworms, please report it to the Invasive Species Centre or the online platform iNaturalist.
