Common Pondskater Gerris (Gerris) lacustris

Length 8-10 mm. Also called ‘Water Striders’, these freshwater bugs have long thin brownish bodies with long legs. There are wingless Pond Skaters and winged, and the winged ones fly quite well. They move across the water by skating quite quickly, hence their vernacular name. This is amongst several similar species of the genus Gerris, but as identification markers the front femur is pale with two narrow black bands that extend from tip but end before base, and the sides of the sixth abdominal segment do not extend as spine.

Pond Skaters are insectivores, and use their agile ability to move upon the surface of the water to hunt and capture their prey. They are covered in very fine hairs which are water-repellent and allow them to stay buoyant upon the thin-film of the water’s surface. Combined with the water’s surface tension, they are able to sense the movement of other insects. They use their middle and rear legs to propel themselves over the water smoothly and easily, the rear legs acting as a kind of rudder.  They also have the ability to hop across the water. They use their two smaller front legs to seize prey, and then they puncture the insect’s body with their rostrum or beak, and suck the liquid soft innards to feed.

Adults maybe seen all year round, but in the coldest months they shelter in leaf litter and other debris. Found in various freshwater habitats, including streams, ponds, rivers, ditches and lakes. Common and widespread.

Class Insecta (Insects)
Order Hemiptera (True Bugs)
Family Gerridae (Pondskaters)
Species Gerris (Gerris) lacustris (Linnaeus, 1758)

Photos: Local pond, South Staffordshire. 16th October 2011. © Peter Hillman