| Great diving beetle - Dytiscus marginalis - Family: Dytiscidae
   Great diving beetle - Dytiscus marginalis© Roger Key/English NatureOne of our largest beetles, this species has a dark, olive-brown, almond-shaped oval body, about three centimetres long, with the thorax bordered by dull yellow. The males have suction discs on the front feet for gripping the female while mating and smooth wing cases, on which the females have deep groves. This beetle is very common in weedy, standing or slow-flowing water and is often found in garden ponds. Great diving beetles periodically come to the surface, extruding the tip of the abdomen to replenish an air supply kept under the wings. They are able to leave the water and fly off to colonise new ponds, sometimes landing in error on shiny car roofs or cold-frames in mistake for a water surface! The larvae are yellowish brown in colour, growing to about five centimetres in length, and possess a fierce pair of jaws - handle with care! They need damp soil by the edge of the water in order to pupate successfully. This can be provided by placing a soil-filled planting basket at a slight angle, so that shallow water grades into damp soil. This species will sometimes fly to outside lights at night. FoodPredatory as adults and larvae, eating anything they can tackle, including other water insects, tadpoles and even very small fish. PreyCommon frog, Common toad, Corixa punctata, Culiseta annulata, Dragonflies and damselflies, Non-biting midge, Small fish, Smooth newt, Tadpoles, Water invertebrates PredatorsGrey heron |
