Walking Sticks
Order: Phasmida
Status: Not Listed
Classification: Invertebrate
Description
Walking sticks, or stick insects, are a group of highly camouflaged insects. They escape predation by blending into plant material. As their name suggests, they look just like sticks, and may even sway back and forth to more closely resemble a twig moving in the wind.
Depending on the species, walking sticks can grow from 1 to 12 inches (2.5 to 30 centimeters) long, with females usually growing bigger than the males. Stick insects are the biggest insects in the world—one species measures over 20 inches (51 centimeters) long with its legs outstretched.
Range
Walking sticks are found on every continent except Antarctica. They mostly live in temperate and tropical regions. Within these areas, the stick insect usually inhabits woodlands and tropical forests, where it hides on trees in plain sight. Walking sticks 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 sticklike appearance.
Diet
All walking sticks are herbivores. They use their strong mandibles to consume leaves, the primary food in their diet.
Behavior
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 foes. Others drop their legs when a predator attacks, but can regrow the appendages. Some species are winged and flash brightly colored patches under their wings to confuse predators.
Life History
Walking sticks are one of many species that can reproduce parthenogenetically, meaning the females can produce unfertilized eggs that hatch and grow into new females. Females lay eggs that look like seeds, and they have numerous egg-laying mechanisms to keep predators away. Some females lay eggs in places that are hidden or hard to get to. Others drop eggs one by one on the ground so they’re not all in one place for a predator to find. Newly hatched walking sticks reach adult size once they’ve undergone several molts. They reach maturity between three months and one year, and usually live up to two years.
Conservation
More than 3,000 species of stick insect exist, many of which are susceptible to habitat destruction, pesticide use, and collection for the pet trade.
Fun Fact
Walking sticks are members of the same order as leaf insects, which are also fantastically camouflaged.
Sources
National Geographic
San Diego Zoo
