Insects of Kangaroo Island
What is an insect?
Insects are an ancient group of animals that have been on earth for at least 360 million years. There are more types of insects than any other type of animal on the planet. This amazingly diverse group of animals live in all types of environments.
All insects have:
- a hard external shell or exoskeleton to protect their soft internal organs
- a body made up of the head, thorax and abdomen
- antennae on their head
- six legs.
Insects tend to be small but can vary in size from 0.1 mm to over 50 cm long. Insects generally hatch from eggs but some give birth to live young. Young insects are called nymphs or larvae. As insects grow they moult or shed their old exoskeleton and grow a new one.
Scientists divide insects into different groups called Orders based on their common physical features. Dragonflies, grasshoppers, stick insects, preying mantids, cockroaches, earwigs, termites, parasitic lice, aphids, thrips, ant lions, beetles, fleas, butterflies and bees all belong to different Orders.
Built for their environment
Insect bodies are extremely diverse but all are divided into three main parts: the head, thorax and abdomen. Insects have six legs, one pair of antennae and one or two pairs of wings.
Most insects have chewing mouthparts for eating plant and animal matter or sucking mouthparts for nectar, blood and plant fluids. Some insects, like flies, have sponge‑like mouthparts for soaking up liquids. Some insects are wingless, such as cockroaches, fleas and silverfish. Some have only one pair of wings, for example flies, and some have tiny wings.
The thorax is divided into three parts (pro, meso and meta-thorax). Each part has a pair of legs. The fore and hind wings attach to the meso and meta-thorax respectively. The abdomen holds vital organs for digestion and breeding and often has chemical secreting glands to mark an insect’s trail or attract a mate.
Insects – essential for life
Without insects life as we know it would not exist. Insects play an essential role in the web of life in every environment. They are the pollinators, undertakers, leaf litter sweepers, garbage collectors, soil conditioners and natural fertilizer producers of nature.
About 80% of all flowering plants on earth are pollinated by insects. Pollinating insects improve the yields of 75% of crops and up to 94% of wild flowering plants depend on insect pollinators to reproduce. Without insects we would not have the fruits, flowers and vegetables we depend on, nor the honey, beeswax, silk and other useful products insects produce. However, some insects are agricultural pests, for example, locusts feeding on crops, and aphids and thrips spreading crop viruses.
Insects, such as termites, are key decomposers of dead wood and plant litter, enabling their nutrients to be recycled. Many insects are parasitic and their consumption of other insect species controls their populations.
Animals, including people, eat insects making them an essential part of the food chain. They are a rich source of protein, vitamins and minerals.
Why is KI important?
Of all agricultural regions in South Australia, Kangaroo Island has the highest percentage of native vegetation. This vegetation is an important refuge for insects, including rare species such as the large eastern bronze azure butterfly and species now extinct elsewhere, for example, the green carpenter bee. New species like the enigma moth are still being discovered on KI. This moth is the only surviving member of a new primitive moth family and is of global scientific importance.
Insect populations are decreasing around the world. By clearing native vegetation the amount of habitat available to insects has diminished. The use of pesticides in agriculture and home gardens and the spread of alien species and diseases have destroyed wild insects too.
You can help insects by:
- Planting native trees, shrubs and flowers in your backyard for insect food and habitat.
- Incorporating organic matter into your garden soil to benefit useful insects.
- Avoiding the use of bug zappers and insect sprays which also destroy beneficial insects.
- Reducing the use of pesticides and buying organic produce and materials.
- Minimising native vegetation clearance, including fallen branches and logs, to save insect habitat.