Great diving beetle

Great Diving Beetle

Great Diving Beetle ©Jack Perks

Great diving beetle

Scientific name: Dytiscus marginalis
The Great diving beetle is a large and voracious predator of ponds and slow-moving waterways. Blackish-green in colour, it can be spotted coming to the surface to replenish the air supply it stores beneath its wing cases.

Species information


Length: 3cm

Conservation status


When to see

January to December


The Great diving beetle is a very large diving beetle that can be found in ponds and slow-moving water. It is a voracious predator, hunting smaller invertebrates, tadpoles and even small fish. The larvae are large, fearsome-looking beasts, with big, biting jaws: they look a bit like pale brown, underwater Devil's Coach Horses. They use damp soil by the edge of the water to pupate in. Adults can be spotted poking the tips of their abdomens out of the surface of the water in order to replenish the air supply stored beneath their wing cases.

How to identify

The Great diving beetle is blackish-green in colour, with a yellow border to the thorax and around the wing cases. It is one of our largest beetles.



Did you know?

Male Great diving beetles have suction pads on their front feet in order to grip the females when mating; females have a series of deep grooves running along their wing cases.

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.