DYTISCIDAE

Water Beetles or Predacious Diving Beetles

This is a large family of predacious aquatic beetles that are recognisable by their smooth, elongated, oval shaped bodies ranging from 1 to 40 millimetres in length. The hind legs are elongated and paddle-shaped, and have a border of long hairs acting as oars when the legs beat in unison. The adults breathe by coming to the water surface backwards and drawing in a bubble of air, which they store under the elytra.

Both adults and larvae are carnivorous feeding on a variety of aquatic animals. Adults prey upon small fish, frogs, molluscs and tadpoles depending on their size. The beetles bite of small sections of prey, which are swallowed whole. The larvae eat only liquid foods and feed by injecting digestive fluids into the body of their prey and sucking out the body fluids by means of a narrow groove on the inner margin of their mandibles.

Both adult and larval dysticids are able to survive out of water for considerable lengths of time. Adult beetles have well developed wings and will move to new habitats while the larvae leave the water to search for a place to pupate.