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Common Backswimmer

Common Backswimmer ©Malcolm Storey

Common backswimmer

Scientific name: Notonecta glauca
The fearsome Common backswimmer hunts insects, tadpoles and fish. It uses its oar-like legs to swim upside-down under the water's surface where unsuspecting prey can be found. Handle with care - it can inflict a painful bite!

Species information

Category

Statistics

Length: 1.4cm

Conservation status

Common.

When to see

January to December

About

The Common backswimmer, also known as the 'Water Boatman', is widespread and common in ponds, ditches and canals across the UK. It can swim upside-down through the water, often near the surface where it grabs insects that have fallen into the water film. It is an active and voracious predator, hunting many smaller invertebrates, tadpoles and small fish. Sensing the vibrations of its prey, it charges at it with lightning speed and stabs it with its 'beak', injecting toxic saliva into the wound so it can suck out the contents of the body. Common Backswimmers mate between December and May, laying eggs from February onwards. The larvae go through a number of moults before reaching adulthood.

How to identify

The Common backswimmer is light brown with large, reddish eyes. It has powerful, oar-like hind legs, which it uses as paddles when it swims upside-down. Its body resembles the shape of a boat, hence its other common name. It may have a silvery appearance due to trapped air bubbles on its lower surface, which allow it to breathe.

Distribution

Widespread.

Habitats

Did you know?

There are actually four species of backswimmer (family Notonectidae, also known as 'Greater Water Boatmen') in the UK. They can be found in almost any waterbody, including open water butts and water tanks. But beware if you handle them - their bite can be quite painful.

How people can help

Whether you live in town or country, you can help to look after garden wildlife by providing food, water and shelter. To find out more about encouraging wildlife into your garden, visit our Wild About Gardens website: a joint initiative with the RHS, there's plenty of facts and tips to get you started. To encourage invertebrates, amphibians and other wetland wildlife into your garden, try having a wildlife-friendly pond and leaving piles of logs for hibernating animals. To buy bird and animal food, feeders and homes, visit the Vine House Farm website - an award-winning wildlife-friendly farm which gives 5% of all its takings to The Wildlife Trusts.