Backswimmers - Water Boatmen

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Scientific name:  Notonecta glauca

Size:  Up to 18mm long

Distribution:  Found throughout the UK

Months seen:  All year round

Life Span:  Approximately 6 - 9 months

Habitat:  Ponds, lakes, canals and ditches

Food:  Insects, small fish and tadpoles

Special features:  Backswimmers are true bugs.  They are light brown in colour with reddish coloured eyes.  As the name suggests, the Backswimmer swims upside-down, propelling itself through the water with its rear pair of legs which are fringed with tiny hairs.  When in motion the rear legs resemble the oars in a rowing boat.  This gives rise to its other common name of 'Greater Water Boatmen'.  Adult Backswimmers have wings and are able to fly.

Their ventral sides are covered with hairs which trap air and give the insects a silvery appearance in the water.

They hunt their prey by floating motionless on the water surface.  When they detect movement in the water they swim towards it to see if it is worth catching.  The bite/stab from a Backswimmer can be painful as their saliva is toxic.

Backswimmers should not be confused with the very similar looking insect called the Lesser Water Boatman (Corixa punctata).  The Lesser Water Boatman swims on its front and feeds on algae.

Related Pages

• Freshwater Wildlife Section
• Identify other wildlife
• What's Out Now?