This insect swims upside-down, propelled by two long legs which paddle like oars, making it look like a rowing boat.

Statistics
Water boatmen grow up to 20mm in length.

Physical description
A small brown or green insect with large reddish eyes. Its front two pairs of legs are quite short but the rear pair are long and fringed with hairs at the end. Their overall appearance resembles a rowing boat. This insect swims upside-down and carries a bubble of air on its ventral side which gives it a silvery appearance. The ventral side is covered in hairs which prevent water from covering the spiracles that the insect uses to breathe.

Distribution
They are widespread throughout Europe.

Habitat
They inhabit ponds, ditches and canals.

Diet
Water boatmen eat tadpoles, small fish and aquatic insects.

Behaviour
Water boatmen rest on the surface of the water sensing vibrations. If there is something disturbing the water they will immediately dive to investigate. When the boatmen are within one or two inches of their prey they can begin to track it using their eyesight. They kill the prey by jabbing it with its rostrum (feeding tube) and injecting its toxic saliva.

Water boatmen are very effective predators and can catch and eat tadpoles, small fish and even the fearsome larvae of the diving beetle (Dytiscus marginalis). They will also eat airborne insects that have accidentally fallen onto the surface of the water. Adults can fly and will move between different ponds.

Reproduction
Mating occurs between December and May and eggs are laid between February and May of the following year. Eggs are elongate and oval and are laid in aquatic plant stems.

Notes
The water boatmans saliva is toxic and its bite is quite painful. It is otherwise harmless.

The lesser water boatman (Corixa punctata) is not actually closely related to the water boatman. It swims on its front and feeds on algae.