Insects make up 40% of all animal species on earth. They are beautiful and intriguing, and are essential for life.
Without insects there would fewer crops and no honey, and our insect-eating native animals would die out. Insects sit towards the bottom of the food chain, so if there are fewer insects there will be fewer insect-eating native animals like frogs, birds, reptiles and mammals.
How insects keep our gardens healthy
Insects are essential in keeping our world healthy. Not all insects are pests – many are pollinators and nature’s pest controllers:
- bees, flies, moths, butterflies, and beetles pollinate our plants and crops
- ants, cockroaches, flies and earwigs break down decaying matter, returning nutrients into the soil
- wasps, praying mantids, ladybirds, lacewings, dragonflies, hoverflies and damselflies eat other garden pests.
Insects you could see in your garden
Variable ladybird (Coccinellidae sp)
A common visitor to Sydney gardens is the orchard swallowtail butterfly, a large black, white and orange butterfly that lays eggs on citrus trees. Its caterpillars are disguised as bird poo.
You may also glimpse the aqua-coloured blue triangle butterfly. The blue patterns on their wings join to make a triangle.
Night time is the best time to view our beautiful nocturnal moths. They are attracted to light so will often be seen flitting around light bulbs.
Although gardeners do not always encourage caterpillars, they are a vital food source for insects, birds, and other animals.
Find out which butterflies visit your garden with this list of butterflies recorded in the Greater Sydney area.
Visit Moths and Butterflies Australasia and navigate to the Butterflies Australia project. Take part in this citizen scientist project by recording butterfly species you see. You can also download the Butterflies Australia app and use the field guide to help identify butterflies.
Attract butterflies to your garden by building a butterfly box.
Bees play an important role in nature and are the most important animal pollinator in agricultural systems.
There are around 20,000 bee species in the world, 200 of which can be seen in Sydney.
Find out more about native bees you might see in your garden and how to attract them.
Cicadas are sap-suckers, or ‘true bugs’ – 50,000 to 80,000 species of insects belonging to the Hemiptera family that includes cicadas, aphids, planthoppers, leafhoppers, and stink bugs.
Other common garden sap-suckers include scale, aphids, leafhoppers and mealy bugs. They may be considered pests, but they are nutritious food for your garden birds.
Cicadas are one of the largest insects in Sydney. With whimsical names like the double drummer, the green grocer, black prince and cherry nose, they are probably our most loved insect.
Cicadas spend their adult years in trees then lay their eggs in the ground. Their larvae, called nymphs, can stay underground for up to 17 years. When mature, they climb up a tree, shrub or side of a building to emerge as a winged adult.
You can help them by not covering your garden with bricks or concrete, which would entomb the nymphs, and by not using chemicals. You’ll also be providing our birds with a hearty and nutritious meal.
Beetles make up 40% of all insect species and over one-quarter of all known animal species on earth.
Amazingly, there are 8 times as many different types of beetles as species of birds, mammals, fish, amphibians and reptiles put together.
Sydney has around 1,500 species of beetles. In your garden you might see Christmas beetles, weevils and ladybirds. Some are exquisitely beautiful, some are garden pests, others are pollinators and some let us know Christmas is just around the corner.
Ladybirds are a particularly welcome garden visitor because they eat plant pests like aphids, mealy bugs and scale.
If you gathered all insects that exist on earth today and weighed them, ants would make up an impressive 75% of the weight.
Ants are social animals and live in nests. Though not welcome in our houses, they are very important in our gardens.
Ants are nutrient recyclers (detritivores) – they feed on dead plant or animal matter, returning essential nutrients to the environment. Other detritivores include native cockroaches, some beetles, millipedes, worms and slaters. They are busy in our leaf litter and compost bins making rich soil.
As well as improving our soil, detritivores are a food source for echidnas, lizards, frogs and birds.
Help our native insects
Many people, including scientists, are concerned about declining insect numbers. Widespread pesticide use and habitat loss has led to a decline in insect diversity and abundance.
There are a few easy things you can do protect these important animals:
- Let your garden go a bit wild!
- Grow butterfly-friendly native plants like bottlebrushes, grevilleas, lilly pillies and daisies.
- Put in a birdbath or pond – insects need water too.
- Don’t use chemicals – garden pests are food for birds, frogs and lizards, who will become your natural pest controllers.
- Don’t cover your garden with bricks or concrete – use natural groundcovers and mulches.
- Share your garden with caterpillars – the resulting butterflies are not only beautiful but will pollinate your plants.
Endangered giant dragonfly
The endangered giant dragonfly lives in Sydney’s wetlands. One of the largest dragonflies in the world, females have a wingspan up to 12.5 centimetres and males have a wingspan up to 11 centimetres.
Its larvae are slow growing and can live for up to 10 years underground.
Survival of these creatures depends on high moisture in our wetlands to stop the larvae dying out. Our Saving our Species program, in partnership with the Blue Mountains City Council, Local Land Services and the local community, is protecting its habitat.
Giant dragonfly (Petalura gigantea)
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