Backswimmer

Notonecta glauca

About

The Common Backswimmer, also known as the 'Water Boatman', is widespread and common in ponds, ditches and canals across the UK. Backswimmers swim upside-down through the water, often near the surface where they grab insects that have fallen in to the water film. They are active and voracious predators, hunting many smaller invertebrates, tadpoles and small fish. Sensing the vibrations of their prey, they charge at it with lightning speed and stab it with their 'beak', injecting toxic saliva so they can suck out the contents of the body. It can inflict a very painful bite on people who try handling it.

Common Backswimmers mate between December and May, laying eggs from February onwards. The larvae go through a number of moults into adulthood.

How to identify

The Common Backswimmer is light brown with large, reddish eyes. It has powerful oar-like hind legs which is uses as paddles as 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.

Where to find it

Widespread.

Habitats

When to find it

  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December

How can people help

Human activity, including the drainage of land for agriculture and the loss of ponds through development, has resulted in the disappearance of many wetlands. The Wildlife Trusts are working closely with planners, developers and farmers to ensure our wetlands are protected. You can help too: encourage all kinds of insects from backswimmers to dragonflies into your garden by having a wildlife-friendly pond. In turn, they'll provide vital food for other creatures such as frogs and toads. 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.

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Species information

Common name
Backswimmer
Latin name
Notonecta glauca
Category
Invertebrates
Bugs
Statistics
Length: 1.4cm
Conservation status
Common.