Stick insects, or walking sticks, are a group of highly camouflaged insects. They escape predation by blending into plant material. As their name implies, they look just like sticks with legs, and even sway back and forth to more closely resemble a twig moving in the wind. When camouflage isn't enough, some species have evolved the ability to release foul-smelling chemicals to deter predators, and others can secrete a liquid that temporarily blinds their foe. Others drop their legs when a predator attacks but can re-grow the appendages. Some species are winged and flash bright color patches under the wings to confuse predators.
Depending on the species, stick insects can grow from 1 to 12 inches long, with males usually bigger than the females. The biggest insects in the world are stick insects—one species measures over 20 inches long with its legs outstretched. Stick insects are herbivores that eat leaves. They reach maturity between three months and one year and usually live up to two years. Stick insects live in woodlands and tropical forests. Found on every continent except Antarctica, mostly in temperate and tropical regions.
Stick insects are a favorite food of many animals, but perhaps their most effective predators are bats. Most bats hunt by echolocation rather than sight, so they aren't fooled by the insect’s stick-like appearance. Stick insects are one of many species that can reproduce, meaning that the females can produce unfertilized eggs that hatch and grow into new females. Females lay eggs that are seed-like in appearance, and they have numerous egg-laying mechanisms to keep predators away.
Some lay eggs in places that are hidden or hard to get to. Others drop eggs one by one on the ground so that they’re not all in one place for a predator to find. Newly hatched stick insects reach adult size once they've undergone several molts, whereby they shed their old exoskeleton. Stick insects are found in the same group as leaf insects, which also display fantastic camouflage.
Here are over 3,000 species of stick insect, many of which are susceptible to habitat destruction, pesticide use, and collection for the pet trade!