Ontario is home to all manners of fearsome critters, including one that ranks as the largest insect in all of Canada, packing a painful punch that will make you think twice about wading into the water this spring.
Living up to its name pretty much as accurately as a species can, the giant water bug (Lethocerus americanus) is an aquatic insect that measures in as Canada’s largest insect in terms of both weight and size.
The giant water bug makes its home in ponds, lakes and wetlands in a range that extends from coast to coast. Their native range spans throughout Ontario, including a dense population in the southern reaches of the province and regular sightings stretching far into the north.
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Aside from their fearsome size, the giant water bug can ruin your day in a gruesome way.
The carnivorous species have evolved a potent attack designed to immobilize prey like amphibians and crustaceans, but it can easily bring even an adult human to their knees should someone make the mistake of disturbing one.
The giant water bug attacks with a retractable proboscis that stabs through victims and injects a toxin that acts as a digestive solution. Basically, picture something stabbing your toe and said digit, then being digested into a slurry from within. I think, even without experiencing this, we can all agree it would hurt like hell.
It is this gruesome strike that has earned giant water bugs terrifying nicknames like toe biter and fish killer.
Oh yeah, and just in case this wasn’t all upsetting enough, they can also fly.
Like moths, these insects have a tendency to bounce around artificial lighting at night, which can be absolutely terrifying as their armoured exoskeletons bang into objects with the ferocity of a thrown rock.
The species is also known for carrying its eggs on its back, adding to the creature’s already alien-like appearance.
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Despite its fearsome reputation, giant water bug species are revered as a delicacy in many countries, and the critters are often fried up and sold as street food.
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And with winter now in the books and an unusually warm March upon us, the first giant water bugs of the season have already been spotted in Ontario.
One of the insects was recently spotted in Cambridge and another in Bathurst Township, marking the first two sightings reported on the social network biodiversity app iNaturalist in 2025. Both sightings occurred in areas where the critters have been known to inhabit in previous years.
So the question you may be asking yourself right now is, “should I be worried about the giant water bug?” For that, I can only offer an answer somewhere in the middle. If you are the type to wade barefoot through ponds and marshes, then yes, you should absolutely be worried.
However, the giant water bug is a native species and an integral part of the local ecosystems it inhabits, landing this fearsome critter a spot on our “do not squish” list.
