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Insects and other arthropods

Giant water bug

Lethocerus americanus

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The giant water bug is the largest aquatic insect in Quebec. Its flat, hydrodynamic body and the long hairs on its middle and back legs make it a fast and efficient swimmer. It has large compound eyes on its head. It eats using piercing-sucking mouthpieces that form a sort of short, pointed beak, called a rostrum, under its head. It has a short respiratory tube at the end of its abdomen that consists of two flexible, retractable parts that can move back and forth.

Life cycle

In our latitudes, the giant water bug lays its eggs in May and June. The female attaches her pale brown eggs onto aquatic vegetation. She can lay up to 150 eggs over the course of the breeding season. A larva (sometimes called a pupa) hatches from the egg. It will undergo five moults before reaching adulthood, and the beginnings of wings will appear after the next to the last moult. Adult giant water bugs can be observed from June to November. Mating takes place on warm summer nights, probably on land during large gatherings. The insect overwinters in the adult stage, buried in mud and plant debris at the bottom of lakes and ponds.


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