Conservation status: All species are vulnerable

Appearance

Stick-insectThere are around 3000 species of stick insects, so obviously their appearance is varied. Typically they are mostly shades of brown, but they can be green, gray, black and even blue. Some have cylindrical stick-like bodies while others have a flat shape like a leaf. Just like their name suggests they look like sticks or twigs which is great for their camouflage as they are able to blend in to their surroundings.

As there are so many different species of stick insects there is a wide range of sizes. The smallest is around half an inch long (11.6mms) being the Timema cristinae with the biggest being the Phobaeticus kirbyi at 13 inches long (328mms). The males of the species are generally smaller than the females.

Lifespan

The lifespan of the stick insect is 1-2 years in the wild.

Diet

The stick insect is a herbivore (a plant eater). They feed on leaves and other green plants, and will also sometimes eat berries or fruit. They will usually feed at night as they are mainly nocturnal creatures, which helps them to remain undetected by predators.

Habitat

Due to the large number of species of stick insects they are found all around the world, especially in warmer zones such as the tropics and subtropics. They live in the forests, jungles and rainforests.

Reproduction

The female stick insect can lay her eggs in a few different ways. She can flick the egg onto the ground which spreads the eggs around so that a predator will not eat all the eggs if it comes across them. She can bury them in the soil or she can stick the eggs to the underside of a leaf or the stem of a plant. A female can lay between 100 -1500 eggs after mating and the eggs vary in the time they take to hatch, ranging from 13 to longer than 70 days with the average 20-30 days. Many of the species of stick insects lay eggs which have a fatty knob on the end which attracts ants, the ant then takes the egg into their underground nest where they eat the fatty knob leaving the egg intact. The egg then hatches and the young nymph which looks like an ant leaves the nest and climbs the nearest tree for safety.

One of the most interesting things about the stick insect is that it can reproduce without a male being around. This is know as Parthenogenesis. This type of reproduction however only allows females to be born, if the female mates with a male then some eggs will be female and some male. When the stick insects are hatched they resemble an ant so they blend in for camoflage if they are born in an ant’s nest. After the young insects go through several moults they reach adulthood and will resemble an adult stick insect.

stick insectBehaviour

Some species of stick insects sway from side to side when they are walking so that they look like a twig or a leaf blowing in the breeze.
Some stick insecs will also flap their wings when they are feeling threatened. They have brightly coloured patterns on their wings that are hidden when they are still, the predator gets confused because they are looking for a brightly coloured insect but all they can see is something that looks like bunch of twigs.
Stick insects also have the ability to play dead if they are threatened by a predator. They will drop from the tree that they are in to the ground and stay perfectly still, it will then be hard for the predator to find as they would just look like a stick on the ground.

Quick facts

Stick insects are able to shed their legs to get away from a predator. If a predator grabs their leg the stick insect can break it off and escape, they will then grow a new leg to replace it.

Stick insect eggs look like seeds when they are scattered about on the forest floor. This gives the eggs a better chance of survival as most predators will not be interested in them.

When they have shed their skin after molting they will usually eat the skin to stay hidden from predators and to recycle the protein in it.

Some species of stick insects can release a chemical a bit like tear gas that can save them from being eaten by a predator.