Phasmids are an amazing group of insects from the Phasmatodea order. They are commonly known as stick and leaf insects. They have incredible camouflage and can be found living on most Australian native plants including trees, shrubs and grasses.
How many types of phasmids are there?
Australia is home to around 150 species of phasmids. Worldwide there are over 3000 species!
Some Australian phasmids include spiney leaf insects, strong stick insects, goliath stick insects and spur-legged leaf insects.
Males and females
Male phasmids are usually smaller than females. They have longer antennae, large wings and can fly. In comparison, females are larger, heavier, have smaller wings and cannot fly.
What do phasmids eat?
Phasmids are herbivores. This means they eat plants. Most phasmids eat leaves from a variety of plants such as eucalyptus and lilly pilly trees. Some phasmids are very fussy and will only eat one type of plant.
Phasmid life cycle
All phasmids begin their life cycle as an egg. Phasmids grow through a process called incomplete metamorphosis. This means the young resemble adults. Each time they moult their body changes to look more like an adult.
Each stage of growth between moults is called an instar. Most phasmids have 5 or 6 instar stages before they become an adult.
All phasmids lay eggs. The eggs are camouflaged to blend in with the leaf litter on the forest floor. The eggs can take one to two years to hatch.
Baby phasmids are called nymphs. They are small and fast. Many phasmid nymphs look like ants.
To grow or change shape, phasmids shed their exoskeleton. Each stage of growth between moults is called an instar. Most phasmids have 5 or 6 instar stages before they become an adult.
Most female phasmids can live for 18 months, however males have a much shorter lifespan of only 6 to 8 months.
Female phasmids can produce eggs without a male. This form of reproduction is known as parthenogenesis and results in all the eggs hatching into females. Fertilised eggs hatch into both males and females.
Phasmids can lay thousands of eggs in their lifetime. They lay one egg at a time and flick their abdomen to catapult the egg into the forest. Some will stick their eggs to the underside of leaves.
Many phasmid eggs look similar to seeds and have a bump on top called a capitulum. The capitulum resembles a similar bump found on some seeds. Thinking they are seeds, many ants carry phasmid eggs to their underground nest to store for food. The ants do not harm the eggs and whilst underground the eggs stay safe from predators. Once the nymph hatches it leaves the nest to find a tree.