Janet Farr in the field. Image - Parks and Wildlife
Janet Farr in the field. Photo © Parks and Wildlife

Invertebrates are animals without backbones. They include jellyfish, worms, crustaceans, insects, coral, sponges and molluscs and make up more than 95 per cent of all living animal species. Invertebrates occur in almost every terrestrial, marine and freshwater habitat apart from the extreme polar regions and very high mountain peaks.

Invertebrates vary in size, from the very small (flat worms, nematodes, collembolla and ostracods) to the very large (giant squid). To date, scientists have documented 1.7 million invertebrate species, but they estimate numbers could range between 10-30 million. In comparison there are only 40 000 - 50 000 known vertebrate species. Up to 20,000 new invertebrates are documented every year. Unfortunately, species numbers are declining faster than scientists can record their existence.

Australia has 100 000 documented, and an estimated 200 000 undescribed invertebrate species. This compares with 6000 vertebrate species. Most Australian invertebrates do not occur anywhere else in the world.

Invertebrates perform vital roles in every ecological system on earth:

  • Invertebrates are an essential component of most food webs.
  • They both consume and are consumed by plants and other animals.
  • Invertebrates recycle organic matter, putting it back into circulation for use by other parts of the ecosystem.
  • Invertebrates assist in the transmission of disease.
  • Invertebrates cross-pollinate flowers.
  • Invertebrates are instrumental in controlling the numbers of other species.

Parks and Wildlife invertebrate research

Invertebrates make up most of the biodiversity of Western Australian species. Of the documented Western Australian invertebrate species, five are extinct and more than 80 are rare or at risk of extinction. Western Australia has a high diversity of subterranean invertebrates. These are animals that live underground either in air spaces (troglofauna) or in groundwater (stygofauna). Parks and Wildlife’s Pilbara Region Biological Survey has shown that there are more than 350 species of stygofauna in the Pilbara.

Research on invertebrates aims to increase our knowledge about insect habitats and ecology. Much of the focus is on the impact of human activities and fire on the biodiversity of invertebrates. Other research includes monitoring the impact of destructive native pests on our jarrah forests. These pests include the jarrah leafminer (Pertida glyphopa) and the gumleaf skeletonizer (Uraba lugens). Invertebrate research is a component of many of our larger biodiversity monitoring projects. These include FORESTCHECK (Invertebrate component) and the Pilbara Region Biological Survey.

More information

  • Landscope articles
  • BugBase 
    BugBase is a database of the Department's Forest Insect Reference Collection, composed mainly of specimens of beetles, butterflies and moths.
  • Common Butterflies of the South-West
    This Parks and Wildlife bush book describes some of the butterflies found in the south-west of Western Australia.
  • Bugs in the Backyard
    This Parks and Wildlife bush book describes some of the invertebrates found in gardens, homes and other buildings in Western Australia.
  • Walpole Wilderness Invertebrate Fire Research Project
    Following the March 2001 wildfire in the Nuyts Wilderness, a large group of local volunteers from the Walpole Community and Walpole Nornalup National Parks Association have been trapping and inventorying the litter arthropod species of these forest sites, as well as long unburnt sites nearby. This website records their findings.
  • Western Australian Museum 
    Information on the WA museums, entomology research and collection
  • WA Department of Agriculture and Food 
    Information about insect pests in Western Australia


For further information on Parks and Wildlife invertebrate research, contact Dr Janet Farr