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

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The backswimmers are a predacious group of freshwater bugs, the Australian fauna comprising 6 genera and approximately 40 species. They bear a superficial resemblance to the Corixidae and novices can often confuse the two families.

Backswimmers (so called because they swim upside down) favour still water such as ponds and lakes, or slow moving streams. Their diet consists mainly of other invertebrates but will attack fish fry and other small aquatic vertebrates if presented with the opportunity. Notonectids must surface occasionally to replenish their air supply, which they take in through specialised organs in the abdomen.

Eggs are attached underwater to the substrate, rocks and on or in the stem of water plants. Juveniles are wingless, but the adults are capable of taking flight and will disperse to new water bodies. Notonectids have often been captured by entomologists after being attracted to light traps while flying.


Two subfamilies are recognised from Australia: the Anisopinae and the Notonectinae. The Anisopinae contains the genus Anisops (28spp.), and the endemic monotypic genera Paranisops (1 sp.) and Walambianisops (1 sp.). The Notonectinae is divided into two tribes: Nychiini, containing the single species Nychia sappho and the Notonectini, containing the genera Notnecta (2 spp.) and Enithares (5 spp.).

  • Notonectidae (Heteroptera)