Image: Stick insect

Stick insect

Stick insect, line drawing. Stick and leaf insects, often called phasmids, are insects that eat leaves and resemble sticks or leaves. They are usually green or brown but may reveal brightly coloured underwings when they fly. They have developed many unusual shapes to camouflage themselves to avoid detection by predators. The Order Phasmatodea includes the longest insects in the world.

Creator:
Andrew Howells
Rights:
© Australian Museum

Notes

What do stick insects look like?

Size:
  • 30 mm - 300 mm in length.
Body:
  • Commonly stick-like or cigar-shaped while other varieties include leaf-shaped and grass-like.
  • Many bear spines or outgrowths.
  • Appears hard.
Antennae:
  • Thread-like.
  • Length variable but never longer than body.

Eyes:

  • Small but prominent and well separated.
Mouthparts:
  • For chewing or munching.
  • Held downward at rest.
Wings:
  • Two pairs if present.
  • Forewings hardened and leathery, partially see-through or cloudy.
  • Hindwing visible much larger than forewing and folds like a hand fan; folded region of wing membranous and clear
  • Both wings have numerous cross-veins forming many cells.
  • At rest wings are held flat or rolled around body, overlapping and much shorter than the abdomen.
Limbs:
  • Six legs.
  • Usually long and slender.
  • Groove at base of forelegs in which the head rests when the legs are held in front outstretched.
  • Tarsi (toes) with five segments.
Abdomen tip:
  • Two moderate to long cerci (tails), unsegmented.
  • In males the tip may be modified as clasping organs.

Where are stick insects found?

  • On the foliage of trees and shrubs, on herbs, grass tussocks or in leaf litter.

What do stick insects do?

  • They are solitary and are infrequently encountered due to their secretive nature.
  • When disturbed they commonly remain still, sway or if really stressed act dead by dropping to the ground like a fallen branch. Alternatively some rapidly raise brightly coloured wings, which in turn creates a fluttering or hissing sound.
  • They are weak clumsy fliers, usually flying for short bursts.
  • They are experts at camouflage. They may behave in a particular way and use colourations, patterning or special body forms to blend in with their surroundings. They are also capable of remaining motionless for long periods of time.
  • They are plant feeders.
  • Most are only active at night.

What looks similar?

  • Some species of grasshoppers greatly resemble stick insects in behaviour and appearance. They differ from stick insects by their pronotum (segment behind head), which appears to �drape over the sides. Additionally their tarsi never have more than four segments and when they have wings the hindwing is hidden and both wings tend to be longer than the abdomen.
  • True bugs can be distinguished from stick insects by having tube-like mouthparts, and membranous wings.
  • Praying mantids can be distinguished from stick insects by having raptorial forelegs and a triangular head.

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Tags stick insects, leaf insects, phasmids, invertebrates, identification, BugWise,