Whirligig Beetles

Family Gyrinidae

Large whirligig beetle (Dineutes discolor). Photo:Stephanie Boucher

The Gyrinidae are shiny black aquatic beetles. Their eyes are divided on each side of the head into two equal parts: one eye section for seeing above the water surface, and one for seeing underwater. They have long front legs and short and flat middle and hind legs for swimming. The whirligig beetles are often seen in large colonies gliding in a circular movement on the surface of ponds and quiet streams. They are rapid swimmers, and are also found beneath the water surface.The adults feed on insects that fall onto the surface of the water, and the larvae feed on small aquatic animals, mostly insects (including other whirligig beetles).