Meet the giant water bug

giant water bug on a rock Photo by Mark Byer/Shutterstock

Giant water bugs (also known as toe-biters) can play dead, audibly squeak, and even release a stinky fluid

This flat-bodied, bulging-eyed bugs lurk in the weedy shallows of vernal ponds, sluggish backwater streams, still lake margins, and wetlands across Canada. Imperceptibly concealed in mats of submerged plants, the predator siphons air through an abdominal snorkel into an underwater bubble trapped beneath its wings. When the bug dives, the bubble goes with it, slowly diffusing oxygen through pores in its armour.

Giant water bugs are most often in flight at night. They’re attracted to lights, commonly while cruising to new mating sites in late spring or early summer. They’re strong flyers and can be mistaken for small bats.

This big bug can inflict an excruciating jab with its legs if stepped upon or picked up, though it almost invariably darts swiftly away from wading human feet.

With a lightning lunge of its brawny, hooked forelegs, the water bug ambushes other insects, snails, crayfish, tadpoles, salamanders, and even small fish and frogs, which it may take a couple of minutes to subdue.

The assailant’s piercing beak injects neurotoxins and digestive enzymes to dissolve the victims’ insides, which it then suctions up, a process that can last up to hours for big meals.

Between multiple bouts of mating over several hours, a female water bug lays a tight cluster of about 100 eggs around a plant stem, stick, or log just above the water. After she leaves, her dedicated partner remains to vigilantly guard the eggs from just below the surface, occasionally rising to rinse them, keeping them moist and clean until they hatch about a week later.

Canada’s biggest aquatic insect, reaching about the length of a mini lighter, is one of the world’s 150 or so species of giant water bugs.

This article was originally published in the June/July 2023 issue of Cottage Life.

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