Extatosoma tiaratum

Extatosoma tiaratum

Spiny leaf insect, Giant prickly stick insect, Macleay's spectre, Australian walking stick

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SPECIES
Extatosoma tiaratum

Extatosoma tiaratum, commonly known as the spiny leaf insect, the giant prickly stick insect, Macleay's spectre, or the Australian walking stick, is a large species of Australian stick insect. The species has the Phasmid Study Group number PSG9.

Appearance

Female adult E. tiaratum are covered with thorn-like spikes for defense and camouflage. Their long, rounded bodies grow to about 20 cm (8 in) long. The females are further described as "heavy-bodied, brachypterous and having numerous spines and integumental expansions on the face and legs, including a tuft of spines on the conical occiput of the hypognathous head". As mentioned, the wings of the female are too small for flying, especially when she is gravid.

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Exhibiting the sexual dimorphism of many similar insects (particularly other phasmids as well as mantises), males are small and thinner, growing only about 11 cm (4.5 in) in length and have three ocelli. Males lack the thorny growths except for spikes around their faces. They have long wings and are good flyers who readily take to the air if disturbed or in search of females.

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Distribution

Geography

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E. tiaratum is endemic to rainforests in Australia, with most of its range in eastern New South Wales and eastern Queensland, but it is also found in eastern Victoria (one old record) and South Australia (possibly introduced). The closely related and similar E. popa is from New Guinea.

Habits and Lifestyle

Both sexes, when threatened, adopt a threat pose, standing on the front and middle legs, pointing their abdomen up or to the side in a sort of "scorpion" pose. They fold back their legs to defend themselves if anything comes in contact with their abdomen; the pincer movement with the sharp spines on the rear legs can puncture human skin. Adults make clicking sounds and can release a defensive odor reminiscent of toffee. Males may attempt to startle predators by flashing their wings open.

Seasonal behavior

Diet and Nutrition

E. tiaratum are herbivores and although they thrive on Eucalyptus which is their native food, breeders abroad recommend feeding them bayberry, bramble, hawthorn, hazel, oak, photinia, raspberry, rose, and salmon berry (red or yellow) and guava.

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Although they survive well on non-eucalypt leaves, they don't always grow as large or retain the same natural colour.

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Mating Habits

E. tiaratum typically reproduce through sexual reproduction and produce eggs that hatch four months later. When no males are present in the population, this stick insect exhibits parthenogenesis instead. Eggs laid without fertilization take up to nine months to hatch and produce only females. In either cases, the female "flicks" her eggs, swinging her tail, up to several feet to land on the forest floor. These eggs must be kept relatively cool - under 25 °C - or they are unlikely to hatch.

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The outside material of E. tiaratum eggs consists of lipids and other organic compounds that ants identify as food. They carry these eggs to their colony, consume the edible outer portion, and dump the intact eggs into their waste piles. Luckily for captive breeding, the ants eating the edible outer layer is not crucial to development, so they will hatch just as healthy without the need for any removal of the outer layer, which is not easily visible.

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Population

References

1. Extatosoma tiaratum Wikipedia article - https://en.wikipedia.org/wiki/Extatosoma_tiaratum
2. Extatosoma tiaratum on The IUCN Red List site - https://www.iucnredlist.org/species/80201037/104413678

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