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Luminary Oddities · Natural history & art

Spiny Leaf Insect

Extatosoma tiaratum

Phasmatodea / Phasmatidae

Extatosoma tiaratum is an Australian leaf-mimicking stick insect with a spiny body and pronounced differences between the sexes. Its seed-like eggs have an edible cap that can induce ants to carry them into their nests.

Read the species account
Extatosoma tiaratum, dorsal view
Spiny Leaf InsectDorsal view.Illustration adapted from EO 400800 Giant Prickly Stick Insect Extatosoma tiaratum 001 by Smithsonian Institution, National Museum of Natural History. Public domain (Smithsonian Open Access).

At a glance

Family ↘
A stick insect in Phasmatidae. [1]
Food ↘
Eucalyptus leaves are a documented food. [2]
Egg structure ↘
The capitulum attracts some ant species. [3]

Identity and classification

Extatosoma tiaratum (MacLeay, 1826) belongs to Phasmatidae in Phasmatodea. The female holotype is held in the Macleay Museum at the University of Sydney. [1]

Morphology and identification

The adult female is robust and leaf-like, whereas the male is slender. Their irregular outlines and projecting spines resemble dry vegetation. Hatchlings have a contrasting red head and dark body and behave like ants before adopting the slower movements of older nymphs. [2]

Distribution and habitat

The species occurs in Queensland and New South Wales, Australia, where it lives on trees and bushes. Its natural habitat includes the coastal forests of eastern Australia. [5][3]

Life cycle

The egg carries a knob called the capitulum. Ants can remove and consume this cap while leaving the rest of the egg intact in the nest. The nymph emerges from the surviving egg and climbs toward foliage. [2]

Feeding and host plants

The species feeds on eucalyptus foliage. Rose and raspberry leaves have also supported captive insects. [2]

Behaviour

In controlled drop trials, first-instar nymphs steered toward vertical targets with sharp contrasting edges. They preferentially landed on narrow dark surfaces, with brightness contrast providing stronger guidance than colour differences. [4]

Distinctive biology

In one-hour trials comparing five Australian ant species, Iridomyrmex purpureus removed the most stick-insect eggs. Rhytidoponera metallica carried more Acacia seeds than eggs; the other three species removed no eggs during the trials. [3]

Artistic interpretation

Display and care

Keep the enclosure closed and display it in indirect light, away from heat and damp conditions. Handle the frame by its edges and clean only its exterior according to the maker’s instructions.

Sources and further reading

  1. Extatosoma tiaratum (MacLeay, 1826) ↗

    Phasmida Species File · Accessed 2026-10-11

  2. Care of Stick Insects ↗

    Australian Museum · Accessed 2026-10-11

  3. Ant mediated dispersal of spiny stick insect eggs and Acacia longifolia seeds is ant-species dependent ↗

    Smart, Andrew and O’Hanlon; Australian Journal of Zoology 70(4), 105–114 (2023) · Accessed 2026-10-11

  4. Visual ecology of directed aerial descent in first-instar nymphs of the stick insect Extatosoma tiaratum ↗

    Zeng, Lin, Abundo and Dudley; Journal of Experimental Biology 218, 2305–2314 (2015) · Accessed 2026-10-11

  5. Spiny Leaf Insect ↗

    Perth Zoo, Government of Western Australia · Accessed 2026-10-11

Sources checked 2026-10-11. Illustrations · Luminary Oddities.

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