Goliath Stick Insect – Eurycnema goliath
The Goliath stick insect is a robust, bright green phasmid with yellow patches on the head, legs and thorax. Their bodies can reach up to 25cm in length. The Goliath has two pairs of bright green wings with red markings underneath. The female Goliath is probably our heaviest stick insect in Australia. Goliath stick insects can be found throughout Northern Australia, into New South Wales and Victoria and also in Western Australia.
Female Goliaths are much larger than the males, with huge abdomens full of eggs. The females are so heavy, that despite having large wings, they cannot fly. The males are much shorter, thinner and can fly quite well.
The eggs of the Goliath are brown and are about the same shape and size as a tic-tac. The female flicks her eggs out of a special chute at the end of her abdomen. The eggs drop down to the ground and lay in the leaf litter for around 4 – 6 months before they hatch.
Goliath nymphs are brown and look like little sticks. They shed their skin around five times to grow into an adult. When they shed their skin for the final time, they will grow wings and turn green.
Goliath stick insects love to munch on the leaves of Acacia (Wattle trees) Eucalyptus (Gum trees), Callistemon (Bottle Brush) and will even eat the leaves of Guava plants. They mainly feed at night and spend their day hiding amongst the trees from enemies.
Due to their enormous size, birds love to eat Goliaths. It’s like gobbling down a big juicy sausage! The adults and nymphs are really good at camouflage, which makes it difficult for birds to find them. If they are spotted, they will flash open their wings to reveal their bright red underside (red is a warning colour often used to scare away enemies). They puff out their wings to make them appear larger and make a loud hissing sound. Goliaths will also kick back with their sharp spiny legs, which makes them a very prickly insect to try and catch. And lastly, they have black spots on the underneath of their legs that look like a large pair of eyes – another trick to scare away an enemy.
- The name “Goliath” comes from the warrior giant that battled against David in the Bible. The word “goliath” means colossal, powerful or giant. Lots of large animals are therefore named Goliath such as the Goliath Stick Insect, Goliath Beetle, Goliath Heron and the Goliath Frog.
- Female Goliath stick insects can lay eggs even if they haven’t mated with a male. This process is called parthenogenesis and is a form of cloning.
- Even though the females can’t fly, their wings can act like parachutes if they fall out of a tree. They fill with air so the Goliath can float down to the ground without getting hurt.