Insects (Class Insecta)
There are more species of insects, in Australia and the world, than any other group of organisms. Insects are one of evolution's great success stories.
Insects are invertebrates that have a jointed exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.
Insects are found almost everywhere on land, in the air, underground, and in fresh water. A few species live on the surface of the ocean. None, however, regularly live beneath the ocean's surface.
Insects are amongst the economically most important groups of organisms, being both beneficial (by controlling pests, pollinating plants and helping decompose litter) and deleterious (some insects spread disease, and many are pests of crops).
The current best estimate is that there are more than 200,000 species of insects in Australia. Only around 62,000 of these have been named so far. Many more are represented by specimens in insect collections, but have not yet been resolved and named. Many more still are collected for the first time in the field every year.
A Cairns Birdwing (Ornithoptera euphorion). Photo: Bernard Spragg CC0
All Australian museums and many universities have insect collections. There are around 35 active insect taxonomists in Australia, working particularly on groups such as beetles, butterflies and moths, flies, true bugs, dragonflies, wasps and ants.
In 2018, taxonomists described 500 new species of Australian insects.
Some insects are extremely rare and threatened. This hatchling Lord Howe Island stick insect (Dryococelus australis) is part of a breeding program at Zoos Victoria, which aims to protect and reintroduce the species to Lord Howe Island, where it is currently extinct.