Stick and Leaf Insects, Order Phasmida

Habits and Traits of Stick Insects and Leaf Insects

Stick insect.
A stick insect resting on a dead branch. Getty Images/RooM/kuritafsheen

The order Phasmida includes some of the best camouflage artists in the insect world - the stick and leaf insects. In fact, the order name comes from the Greek word phasma, meaning apparition. Some entomologists call this order Phasmatodea.

Description:

Perhaps no other group of insects is better named or easier to recognize than the order Phasmida. Phasmids use their unique camouflage to fool predators.

With long legs and antennae, walkingsticks look much like the twiggy shrubs and tree branches where they spend their lives. Leaf insects, which are usually flatter and more colorful than stick insects, resemble foliage of the plants they eat. 

Most insects in the order Phasmida, including all leaf insects, live in tropical climates. Some stick insects inhabit cooler temperate regions where they overwinter as eggs. Nearly all North American species are wingless. Phasmids are nocturnal feeders, so if you encounter one during the daytime, it will likely be resting.

Stick and leaf insects have leathery, elongate bodies, and long thin legs designed for walking slowly. Leaf insect bodies tend to be flatter, with a horizontal surface that mimics a leaf. Phasmids also have lengthy segmented antennae, with anywhere from 8 to 100 segments depending on the species. Some stick and leaf insects sport elaborate spines or other accessories, to improve their mimicry of plants.

All Phasmids feed on foliage, and possess chewing mouthparts designed for breaking down plant material.

Stick and leaf undergo simple metamorphosis. Eggs are laid, often dropping to the ground, as copulation takes place. In some species, females can produce offspring without fertilization by a male.

These offspring are nearly always female, and males of those species are rare or non-existent.

Habitat and Distribution:

Stick and leaf insects live in forests or shrubby areas, requiring leaves and woody growth for food and protection. Worldwide, over 2,500 species belong to the order Phasmida. Entomologists have described just over 30 species in the United States and Canada.

Major Families in the Order:

  • Family Timemidae -- timema walkingsticks
  • Family Heteronemiidae -- common walkingsticks
  • Family Pseudophasmatidae -- striped walkingsticks
  • Family Phasmatidae -- winged walkingsticks

Phasmids of Interest:

  • The genus Anisomorpha, called devil-riders or musk-mares, squirt terpenes in defense, chemicals which can temporarily blind their attackers.
  • The Lord Howe Island stick insect, an Australian native, is called the rarest insect in the world. It was thought extinct in 1930, but in 2001 a population of less than 30 individuals was discovered.
  • Pharnacia kirbyi, a stick insect of the Bornean rainforest, is the longest insect on record, measuring up to 20 inches in length.
  • Ants collect the seed-like eggs of Macleay's spectre (Extatosoma tiaratum). Newly hatched nymphs mimic the Leptomyrmex ants, even running quickly.

     

    Sources:

    • Order Phasmida, John L. Foltz, University of Florida, Dept of Entomology & Nematology. Accessed online April 7, 2008.
    • Phasmida (web page now unavailable), University of Vermont, Dept. of Entomology. Accessed online April 7, 2008.
    • The Stick Insects (Phasmida), by Gordon Ramel. Accessed online April 7, 2008.