Stick Insects

Photo: CSIRO

Stick Insects

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What do stick insects look like?

Australian stick insects come in all colours, shapes, and sizes. All of these appearances have been developed to make stick insects look like, or to help them blend into, leaves or branches. Some species, like the Spiny Leaf Insect, have reached an expert level in the art of disguise.

Where are stick insects found?

Somewhere amongst the leaves in your backyard is a camouflage master. Even though there are around 150 stick insect species in Australia, it’s still difficult to spot one. Look closely at gum trees, rose bushes or fruit trees for these green or brown buddies. 

Don’t be surprised if you come across these guys when you’re gardening – they’re so well camouflaged that you often don’t see them until they’re almost on you. 

Fast facts:

  1. The stick insect is a Phasmid – insects that eat leaves and resemble leaves or sticks. It is a master of disguise and remains still during the day. The biggest stick insect in Australia is the Ctenomorpha gargantuan. It can grow to a whopping 56 cm.
  2. In the stick insect world, dads aren’t always needed. The female stick insect can reproduce year-round and without fertilisation. This means that she can deposit her eggs and have them grow into normal, healthy nymphs without ever needing to find a mate.

Stick Insects – the full story

Somewhere amongst the leaves in your backyard is a camouflage master. Even though there are around 150 stick insect species in Australia, it’s still difficult to spot one. Look closely at gum trees, rose bushes or fruit trees for these green or brown buddies.

The stick insect is a Phasmid – insects that eat leaves and resemble leaves or sticks. It is a master of disguise and remains still during the day. Look for them at night by torchlight when they’re feeding, or after a storm or a windy day when they may have been blown from their branches.

Stick insect are not aggressive or venomous. These fascinating creatures are simply peace-loving vegetarians who like to keep to themselves.

In fact, stick insects are so private that they don’t like to leave a single trace of their presence. Unlike grasshoppers that leave half eaten leaves in their wake, stick insects eat entire leaves so it’s tough to spot where they’ve been.

Stick insect eggs also look like seeds. Ants carry the eggs of the Spiny Leaf Insect down into their nests and protect them from predators. When they hatch, the babies look and behave like ants until they can escape the nest and climb into a tree.

Stick insects are so good at hiding that they have trouble finding each other. They’ve come up with a crafty solution to this problem – the females can produce young without mating. Mum will lay unfertilised eggs which later hatch into females. If stick insects mate, the eggs will hatch either males or females.

If a male finds a female out of the breeding time, he may latch onto her back and wait until it is time to breed, rather than risk losing her again amongst all the foliage.

When surprised, most stick insects will sway slightly, just like a twig caught in the breeze. Or they will drop to the ground, legs tight to the body, and remain motionless just like a snapped stick.

When very annoyed some varieties will throw open their wings, revealing a bright colour underneath, vibrate noisily and curve angrily toward the attacker.

If you’re lucky enough to spot a stick insect, don’t try to pull it from its branch or it might drop one of its legs. This is a distracting defence mechanism. Young stick insects can regrow legs the next time they moult, but a fully grown adult can’t.

Did you know?

The biggest stick insect in Australia is the Ctenomorpha gargantuan. It can grow to a whopping 56 cm. 

Tip

Look for stick insects when pruning or removing dropped branches from your backyard. As they’re so camouflaged, it’s very easy to toss them out with the garden clippings.

When you want to handle a stick insect, be careful not to place it on your clothes as their claws will catch and tear off. Put your hand or a piece of paper in front of its path and let it crawl aboard. Return it to the branch of a nearby tree.

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