One of Canada’s largest and most surprising aquatic insects, commonly known as the “toe-biter,” has been spotted across several Ontario municipalities this season, prompting experts to advise caution for those enjoying local lakes, rivers, and marshes.
Scientifically known as Lethocerus americanus, the giant water bug belongs to the belostomatidae family and is typically found in shallow, weedy freshwater areas. Growing up to six centimetres in length, this flat, oval-shaped insect has earned its nickname due to its ability to inflict a sharp and “excruciating” jab when disturbed, particularly if stepped on or handled. Though not aggressive, it will defend itself if it feels threatened.
The University of Guelph and biodiversity researchers describe the bug as an aquatic predator, using its powerful front legs to catch prey such as small fish, frogs, salamanders, snails, tadpoles, and insects. It subdues its catch using a piercing beak that injects digestive toxins before consuming its liquefied meal. Males are also known to take on a unique parenting role, caring for eggs laid either on plant stems or directly on their backs until they hatch.
Reports collected from iNaturalist.org confirm recent sightings of the giant water bug in Cambridge, Peterborough, Bala, Kingston, Prince Edward County, South River, Wellington, and Midland. While the insect typically stays in water, it is also capable of flight and may be seen taking to the skies at night, often drawn to light sources. Due to its size and flight pattern, it is sometimes mistaken for a bat.
Residents and visitors are encouraged to observe and enjoy Ontario’s diverse wildlife from a respectful distance and avoid handling unfamiliar insects, especially in natural aquatic habitats. While the toe-biter plays an important role in the ecosystem, its defense mechanisms can cause brief but intense pain, making caution the best policy when exploring nature this summer.