In the UK the Whirligig Beetle family (Gyrinidae) is one of a group of 12 very similar species. They can be found on almost any body of water, from ponds and lakes to canals, ditches and slow-flowing rivers. Whirligig Beetles live on the surface of the water, often in large groups, gyrating as they search for prey. They hunt small invertebrates that fall onto the water's surface or dive underwater to catch other animals. The back two pairs of legs are modified into short, flat paddles. These beetles are often accompanied by Water Skaters, family Gerridae of the order Hemiptera. These beetle spin around in circles at high speed and are not easy to photograph.
Below. Pools in wet meadow with Water Skaters near Oban, Scotland. June 2013.
Below. River Thames. Aston Keynes, Glos. May 2014.