Insects fact sheet | Field of Mars EEC

What are insects?

Insects are invertebrates, which means they do not have a backbone. They belong to a larger group of animals called arthropods. Arthropods have jointed legs, segmented bodies and a hard outer covering called an exoskeleton.

Adult insects have three main body parts: a head, thorax and abdomen. They have six true legs, one pair of antennae and may have one or two pairs of wings. Some adult insects are wingless. Ants, bees, butterflies, moths, beetles, flies, cicadas, dragonflies, grasshoppers, crickets, katydids, termites, cockroaches, phasmids and praying mantids are all insects.

Around Field of Mars Reserve, insects can be found in soil, leaf litter, logs, bark, trees, shrubs, flowers, wetlands, creeks, gardens and school grounds.

Insects have three main body parts: head, thorax and abdomen.

Fiddler beetles are colourful flower visitors found in NSW bushland.

How do you know it is an insect?

Adult insects have three main body parts, six true legs, antennae and an exoskeleton. The legs and wings are attached to the thorax. Antennae help insects sense their surroundings.

Many adult insects have wings, but not all insects fly. Some insects are wingless, while others only have wings for part of their life cycle.

Spiders, ticks and mites are not insects because they have eight legs. Centipedes and millipedes are not insects because they have many body segments and more than six legs. Slaters, crabs, snails and worms are not insects. Springtails have six legs, but they are not true insects.

Many adult insects have wings, but not all insects fly.

Insect groups

Pollinators and flower visitors

Many insects visit flowers to feed on nectar or pollen. Bees are important pollinators, but butterflies, moths, flies and beetles can also move pollen between flowers. This helps many plants produce seeds and fruit.

Pollinating insects may have hairy bodies, long mouthparts or feeding behaviours that help them collect nectar and pollen from flowers.

Teddy bear bees visit flowers for nectar and can help move pollen between flowers.

Plant feeders

Many insects feed on plants. Some chew leaves, flowers, stems, seeds or roots. Others use piercing-sucking mouthparts to drink plant sap.

Plant-feeding insects include caterpillars, grasshoppers, katydids, phasmids, cicadas, plant hoppers and true bugs. They move energy from plants into food webs and become food for many birds, spiders, reptiles and predatory insects.

Katydids and other plant-feeding insects move energy from plants into food webs.

Predators

Some insects hunt other animals. Dragonflies and damselflies catch prey in flight. Praying mantids use grasping front legs to catch insects. Green lacewing larvae and lady beetles feed on smaller invertebrates such as aphids.

Predatory insects help keep other invertebrate populations in balance. They are an important part of healthy gardens, wetlands and bushland food webs.

Damselflies are predators that hunt smaller animals.

Recyclers

Some insects break down dead plants, wood, dung, dead animals and other natural material. This returns nutrients to the soil and helps new plants grow.

Termites, beetles, bush cockroaches, flies and some insect larvae are important recyclers. Many live in leaf litter, soil, logs, bark or other damp places where dead material collects.

Termites help recycle dead wood and return nutrients to the soil.

Social insects

Some insects live in organised groups called colonies. Ants, many bees, termites and some wasps are social insects.

In a colony, different insects may have different jobs. Some collect food, some protect the nest and others care for the young. This teamwork helps the colony survive.

Meat ants are social insects that live and work together in colonies.

What is the life cycle of insects?

Insects hatch from eggs and grow by moulting. Moulting happens because an insect’s exoskeleton does not stretch as the insect grows.

Some insects go through complete metamorphosis. This life cycle has four stages: egg, larva, pupa and adult. Butterflies, moths, beetles, flies, bees, ants and wasps grow this way.

Other insects go through incomplete metamorphosis. This life cycle has three stages: egg, nymph and adult. Grasshoppers, crickets, katydids, cicadas, dragonflies, damselflies, cockroaches and termites grow this way.

Caterpillars are the larval stage of butterflies and moths.

What adaptations do insects have to help them survive?

Insects have many adaptations. Their exoskeleton protects the body and helps reduce water loss. Antennae help them sense the world. Compound eyes help many insects detect movement.

Different insects have different mouthparts and legs. Butterflies sip nectar, cicadas drink sap, grasshoppers chew leaves, mole crickets dig, mantids catch prey and bees collect pollen.

Many insects use camouflage to hide. Phasmids may look like sticks or leaves, while katydids can blend in with green foliage. Other insects use warning colours, stings, strong jaws or group behaviour for protection.

Stick insects use camouflage to blend in with branches and leaves.

Why are insects important?

Insects are essential in healthy ecosystems. They pollinate flowers, recycle nutrients, improve soil and help control other invertebrates.

They are also food for many animals, including birds, frogs, lizards, spiders, fish, bats and other insects. Without insects, many food webs would not work properly.

Insects can also tell us about the health of an environment. Changes in insect numbers or diversity may show that a habitat is changing.

Insects are an important food source for many birds and other animals.

How can you help insects?

You can help insects by protecting habitat. Leave leaf litter, logs, bark, sticks and dead wood where it is safe to do so. These places provide shelter, food and nesting sites for many species.

Plant local native plants to provide nectar, pollen, leaves, seeds and shelter across the year. A mix of trees, shrubs, grasses and groundcovers supports more insects than a simple lawn.

Avoid unnecessary pesticide use, especially around flowering plants. Pesticides can harm helpful insects as well as pest species.

Flowering native plants provide food and shelter for many insects.

Explore more

Use the fact sheet links on this page to learn more about invertebrates found in bushland, gardens, wetlands and school grounds.

You can also compare insects with other invertebrate groups such as arachnids, crustaceans, myriapods, worms, molluscs and springtails.

Learn with us