Invertebrates
Spiny Leaf Insect
Extatosoma tiaratum · also called spiny leaf insects, Macleay's spectre
A newly hatched spiny leaf insect scurries across a eucalyptus branch moving convincingly like a stinging ant, a disguise it will eventually outgrow in favour of looking, quite simply, like an ordinary curled leaf.
Overview
The spiny leaf insect, Extatosoma tiaratum, also known as Macleay’s spectre, is a large, dramatically camouflaged insect native to rainforest and eucalyptus forest habitat across eastern Australia. Its ant-mimicking nymphs, scorpion-like defensive bluff, and striking size difference between the sexes make it one of the more behaviourally fascinating and visually memorable stick and leaf insects in the world.
A costume change built into its life cycle
The spiny leaf insect doesn’t settle on one disguise for life, starting out mimicking an ant as a vulnerable nymph before growing into an adult that instead convincingly impersonates a dead leaf.
Status
Least Concern — widespread and common across suitable rainforest and eucalyptus forest habitat throughout eastern Australia.
Spiny Leaf Insect: common questions
Why do young spiny leaf insects act like ants?
A newly hatched nymph moves and curls its body to resemble a stinging ant, a defensive mimicry strategy that likely deters predators wary of a genuine ant's bite or sting, and this ant-like behaviour fades as the insect grows larger and shifts toward leaf-like camouflage instead.
Can a spiny leaf insect actually sting like a scorpion?
No, despite curling its spiny abdomen up and over its body in a pose that closely resembles a scorpion's raised tail when threatened, this species has no sting or comparable weapon at all, relying entirely on the visual bluff to deter predators.
How different do male and female spiny leaf insects look?
Quite dramatically — adult females are large, heavily spined, and flightless, closely resembling a curled leaf, while males are considerably smaller, slimmer, and capable of flight, one of the more pronounced examples of sexual dimorphism among stick and leaf insects.
Where does the spiny leaf insect live?
This species is native to rainforest and eucalyptus forest habitat across eastern Australia, where it feeds on eucalyptus, bramble, and related plant leaves while relying on its leaf-like camouflage to avoid predators.