Stick insects are part of the order Phasmatodea (also known as phasmids and walking sticks) and are most often found in subtropical tropical habitats—when you can find them, that is. These amazing bugs are hard to spot because they look so much like twigs—until those twigs get up and walk away, that is.
Should a bird or other predator grab hold of its leg, a stick insect can still make an easy escape. Using a special muscle to break it off at a weak joint, the imperiled insect simply sheds the leg in a defensive strategy is known as autotomy. Juvenile stick insects regenerate the missing limb the next time they molt. In some cases, adult stick insects can even force themselves to molt in order to regain a lost leg.
Stick insects are a nation of Amazonians, able to reproduce almost entirely without males, using a process known as parthenogenesis. Unmated females produce eggs that when mature, become female stick insects. When a male does manage to mate with a female, there’s only a 50/50 chance that the offspring of that union will be male. A captive female stick insect can produce hundreds of all-female offspring without ever mating. In fact, there are species of stick insects for which scientists have never found any males.
3. Stick Insects Even Act Like Sticks
Stick insects are so named for their effective camouflage among the woody plants where they feed. They’re typically brown, black, or green, with thin, stick-shaped bodies that help them blend in as they perch on twigs and branches. Some stick insects exhibit lichen-like markings to make their camouflage more authentic but to make the disguise complete, stick insects imitate twigs swaying in the wind by rocking back and forth as they move.
Stick insect mothers aren’t the most maternal. While some stick insects females actually make an effort to hide their eggs—sticking them to leaves or bark or placing them in the soil—they typically drop eggs randomly on the forest floor, leaving the youngsters to whatever fate befalls them. Don’t be so quick to judge mama stick insect, though. By spreading her eggs out, she lessens the chance of predators finding and eating all of her offspring at once. It’s also helpful that the eggs resemble seeds, so carnivorous predators are less likely to take a closer look.
5. Nymphs Eat Their Molted Skin
After a nymph has molted, it’s vulnerable to predators until its new cuticle darkens and hardens. The castoff skin nearby is a dead giveaway to enemies so the nymph quickly consumes the shriveled exoskeleton to get rid of the evidence, simultaneously recycling the protein it took to create the discarded layer at the same time.
Stick insects aren’t venomous but if threatened, one will use whatever means necessary to thwart its attacker. Some will regurgitate a nasty substance to put a bad taste in a hungry predator’s mouth. Others reflex bleed, oozing a foul-smelling hemolymph from joints in their body. Some of the large, tropical stick insects may use their leg spines, which help them climb, to inflict some pain on an enemy. Stick insects may even direct a chemical spray, much like tear gas, at the offender.
7. Their Eggs May Attract Ants
Stick insect eggs that resemble hard seeds have a special, fatty capsule called a capitulum at one end. Ants enjoy the nutritional boost provided by the capitulum and carry the stick insect eggs back to their nests for a meal. After the ants feed on the fats and nutrients, they toss the eggs onto their garbage heap, where the eggs continue to incubate, safe from predators. As the nymphs hatch, they make their way out of the ant nest.
8. Not All Stick Insects Stay Brown
Some stick insects can change color, like a chameleon, depending on the background where they’re at rest. Stick insects may also wear bright colors on their wings but keep these flamboyant features tucked away. When a bird or other predator approaches, the stick insect flashes its vibrant wings, then hides them again, leaving the predator confused and unable to relocate its target.
9. Stick Insects Can Play Dead
When all else fails, play dead, right? A threatened stick insect will abruptly drop from wherever it’s perched, fall to the ground, and stay very still. This behavior, called thanatosis, can successfully discourage predators. A bird or mouse may be unable to find the immobile insect on the ground or prefer living prey and move on.
10. Stick Insects Are the World’s Longest
In 2008, a newly discovered stick insect species from Borneo broke the record for longest insect (which had previously been held by another stick insect, Pharnacia serratipes). The Chan’s Megastick, Phobaeticus chani, measures an incredible 22 inches with legs extended, with a body length of 14 inches.