Defenses: Birds foraging in grass or in leaves and branches of forest trees prey on the stick insect. Most hunt during the day, so the insect camouflages itself. The stick insects’ slender, mottled brown or green bodies and legs give them a twiglike appearance. A green stick insect blends into a grass stem or leaf by clinging with its tail to a twig and extending its forelimbs above its head. It sways to imitate the effect of wind on vegetation. If disturbed, the insect may drop to the ground like a dead twig. If this does not fool predators, it may then fly away. The extended wings of some species have bright colors. When the insect folds its wings, the color is hidden, making it invisible to hunters.

Food and Feeding: Stick insects only eat the foliage of herbaceous plants, shrubs, and trees, gnawing the leaves with their small but effective jaws. Each species has its own preferred food plants. The stick insect feeds at night while enemies sleep. The insect forages slowly, avoiding abrupt movements that might give away its presence. Most species feed alone, but Didymuria violescens, found in the eucalyptus forests of Australia, gather in swarms and strip leaves from entire trees, causing serious crop damage or failure. The Didymuria violescens found in Australia can devastate eucalyptus trees.

Breeding: Some species have few males. Instead of mating, the female lays eggs that develop without fertilization. Most stick insects reproduce non sexually, but this fact has disadvantages. The young are identical to the female, allowing no random variations that cause a species to evolve. The male genes from other groups are what cause these variations. Stick insects find mates easily in groups, but scattered females attract mates by emitting a pheromone, a seductive scent. The two then mate while clinging to a twig or leaf. The female scatters her eggs. Each egg may stay on the forest floor for up to three years, protected by its seedlike appearance and hard shell. Eventually the young insect emerges from its hinged shell.

Special Adaptation: Some stick insects can expose or conceal pigment granules in their skin cells, making their colors lighter or darker. These pigments can also control body temperature. The tropics can be hot by day and cold at night. The insect remains pale in the sun, reflecting heat. As the temperature drops, it becomes dark to absorb heat.

Key Facts:
Sizes:
Length: 2-13 in. Females larger than male
Mouthparts: Chewing
Wings: When present, one pair folded beneath horny cases formed from modified forewings. Many species are wingless

Breeding:
Breeding season: In temperate areas the eggs are laid in summer, but in the tropics they may be laid at any time of year
Eggs: 100-1,300, depending on species
Incubation: 3 months to 3 years

Lifestyle:
Habit: Nocturnal, slow moving
Diet: Foliage

Related Species: The leaf insect, a flattened leaflike creature, is in the same order. Both are closely related to grasshoppers and mantises.
Distribution: Widespread throughout the tropics, but also found in warm and temperate regions.
Conservation: Most stick insects live in poorly documented areas, so their numbers are not known. The deforestation of the rainforests affects many species who rely on single food plants.

Species of the Stick Insect:
Giant prickly stick insect: Extatosoma tiaratum, also known as Maclean’s specter. Subfamily Tropidoderinae. Found in Australia.
Defense: The giant prickly stick insect curls up its abdomen to mimic the scorpion attacking with its tail.
Indian stick insect: Carausius merosus. Subfamily Lonchodinae. Found in India. Green color camouflages it against foliage.
Pink winged stick insect: Sipyloidea sipylus. Subfamily Necriclimae. Found in Madagascar.

Did You Know: 
The Southeast Asian stick insect, Pharnacia serratipes, is, at 13 inches, the longest insect in the world.
The males of some stick insect species have never been found in the wild.
If a young stick insect loses a leg, it grows another to replace it. The non molting adult loses this ability.
Some stick insects will discourage their attackers by regurgitating their food at them or squirting them with poison.

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