False Garden Mantis - Pseudomantis albofimbriata

Insects

Discover the abundance and diversity of insects in Queensland through our images and fact sheets that explore life cycles, identification and biology.

Overview

Insects are among the most abundant and diverse groups of organisms on Earth. They live everywhere, from pristine bushland to the concreted heart of a city’s CBD. Parks and gardens support hundreds if not thousands of different species.

Insects are vital to the function of ecosystems. They decompose organic matter, recycle nutrients, contribute to soil formation and pollinate the flowers and spread the seeds of many plants. They are also food for many other groups of animals. Only a very small percentage of insect species are troublesome or destructive pests.

An insect's body consists of three parts: a head, thorax and abdomen. In adult insects the head has a pair of compound eyes, a pair of antennae and a set of mouthparts. The thorax is made up of three segments, each with a pair of legs. Most adult insects also have two pairs of wings on the thorax, although some have only one pair, or have lost their wings altogether. Some primitive insects, such as silverfish, have never possessed wings as part of their evolutionary history. The abdomen, the largest and softest of the three body parts, houses the organs for digestion and reproduction.

The diversity of insects is bewildering; it is estimated that there are around 5 million different species of insects on Earth. These myriads are classified into 27 different orders, many of which correspond to familiar groups of insects. For example, beetles belong to the order Coleoptera, moths and butterflies to the order Lepidoptera, and wasps, bees and ants to the order Hymenoptera.

Common questions

We just don’t know the exact number of different insect species in Queensland. There are more than 70,000 named insect species known from the whole of Australia, but this probably represents only around a quarter of the true number. Most of Australia’s insect species are yet to be named. Queensland probably has more insect species than any other Australian state or territory so our insect fauna will number in the tens, if not hundreds of thousands of species.

Queensland’s and Australia’s largest, or at least the longest insect, is easily the Gargantuan Stick Insect, Ctenomorpha gargantua. Females can be in the order of 30 cm long from the head to the tip of the abdomen. To date, this enormous insect has only been found in the rainforests of the Wet Tropics region in north Queensland.

Most insects begin life as an egg, although a few give birth to live young. Insects can be divided into two groups based on their metamorphosis, the way that the immature stages transform into the adult.

In one group, metamorphosis is gradual. The immatures, called nymphs, closely resemble the adults except that they lack wings and reproductive structures. They generally live in the same places and eat the same food as the adults. As they grow the nymphs periodically shed their exoskeleton, a process called moulting. The fully grown nymph sheds its skin one last time to become a fully winged adult.

Insects in the second group have abrupt metamorphosis. They have grub-like immatures called larvae. Larvae do not resemble the adults and differ in their habitat and food requirements. The larvae also moult several times as they grow. In order to make the transformation to an adult they undergo an intermediate stage, the pupa, which does not feed.

Fact sheets

Images

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