Stick Insect (order Phasmatodea)

InsectInvertebrateCamouflage

Overview

Stick insects (order Phasmatodea, which also includes the leaf insects) are among nature's greatest masters of disguise. Their long, slender bodies and limbs mimic twigs, stems, and leaves so closely that they seem to disappear against the plants they live on. The order's name comes from a Greek word for “phantom” or “apparition,” reflecting how easily these insects vanish in plain sight. Some species are extraordinarily long — among the longest insects in the world.

Camouflage is only the start: many stick insects add to the illusion by swaying like a twig in the breeze, and they have an array of further defences and unusual reproductive tricks.

Note: there are thousands of stick and leaf insect species; details here cover them broadly. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Stick insects are found mainly in the tropics and subtropics, but also in temperate regions, living among the vegetation they eat — in forests, woodlands, scrub, and gardens. They spend their lives on or among the leaves and stems of their host plants, where their camouflage works best.

Diet

Stick insects are herbivores, feeding on the leaves of trees, shrubs, and other plants — many species specialise on particular host plants. They feed mostly at night, when it is safer to move, and chew foliage with simple mouthparts. In large numbers some species can strip foliage, but most are harmless to their host plants overall.

Behavior

Camouflage and stillness are a stick insect's main defences: by day they stay motionless, looking just like the twigs around them, and many gently rock or sway to mimic a stem moving in the wind. If discovered, different species have backup defences — startling flashes of brightly coloured hindwings, the release of foul-smelling or irritating chemicals, defensive postures, or shedding a leg to escape (it can partly regrow). Reproduction is unusual too: many stick insects can reproduce without males (parthenogenesis), with females laying eggs that develop into more females, and their seed-like eggs are sometimes spread by ants.

Human Interaction & Conservation

Stick insects are harmless to people and are popular, easy-to-keep pets and classroom animals, valued for their gentle nature and remarkable looks. In the wild they are an important part of food webs as plant-eaters and as prey for birds and other animals. Most are common, though some — such as certain island species — are rare and of conservation concern. They should not be released outside their native range. Consult authoritative sources for details.

More photos of the stick insect