Stick insects

Most stick insects are tropical insects. Some species are quite large – more than 15 cm long! They do not bite, but large stick insects can inflict wounds with the sharp spines on their legs.

The eggs of some stick insects are collected by ants. The ants hide the eggs in their underground nest, away from parasites. In exchange for this service, the ants feed on an edible substance that covers the eggs.

In addition to their protective camouflage, some stick insects are able to spray a noxious chemical on birds that attack them. The chemical’s composition and effects are similar to tear gas.

Young stick insects have another useful method of defence. If one of their legs is caught by an enemy, they leave it and escape. Their leg grows back the next time they moult. Adult insects can’t do this because they no longer moult.