What Bug Is That? The guide to Australian insect families.

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The water striders are found world wide in a range of habitats from still lakes and ponds to the open ocean. These distinctive insects include the largest semi-aquatic bugs and are the only insects to have successfully exploited the open oceans as a habitat.

Like other semi-aquatic bugs, the Gerridae maintain their position on the water surface through a fine layer of hairs on their legs which serve to shed the water displaced by their weight, keeping them afloat. They use their middle pair of legs to row themselves along the surface of the water. When alarmed the increased rate that they move their legs gives them the appearance of jumping or leaping.

Their diet includes live crustaceans and insects as well as the dead bodies of arthropods that are floating on the surface of the water. The vibrations given out by organisms trapped in the surface layer of the water are used in conjunction with visual clues to detect prey. The raptorial forelegs are used to sieze and hold their prey.

Gerridae are not commonly encountered in flight and a great deal of variation is found in the wings of the Gerridae. Some species have fully winged, wing reduced and wingless forms and some marine species lack wings entirely.


There are a total of 29 species in 10 genera and 4 subfamilies reported as occuring in Australia. The subfamily Gerrinae contains 5 genera, Aquarius , Limnogonus , Limnometra , Tenagogonus and Tenagogerris and 13 species. The Halobatinae contain the marine-inhabiting genus Halobates which has 11 species recorded from Australia and the genus Austrobates , which has only one species recorded from Queensland. The Rhagadotarsinae are represented by a single species belonging to the type species, Rhagadotarsus . The Trepobatinae are the most diverse subfamily, comprising 11 genera and 35 species.

  • Gerridae (Heteroptera)

  • Gerridae (Heteroptera)

  • Limnogonus fossarum gilguy