The SciComm Spectre

Kelly’s Field Notes

Common Name: Australian stick insect, Spiny leaf insect, giant prickly stick insect, Macleay’s spectre (described by William Sharp Macleay, Australian entomologist, in 1826) (Australian Museum, 2025)

Order: Phasmatodea

Family: Phasmatidae

Genus: Extatosoma

Species: tiaratum (“crowned” in Latin, referring to spines on its head)

General Phasmatidae Description:

Phasmids are found on every continent save Antarctica. They have an incomplete metamorphosis (egg, nymph, adult). They are part of the same super order (Polyneoptera) as roaches, mantids, grasshoppers, and crickets. Their forewings are leathery (like roaches) and the adult males of some species can take short flights. Phasmids are highly sexually dimorphic, with females generally being much larger than males (likely to carry eggs).

Phasmids are masters of disguise! Many phasmids sway back and forth to mimic branches moving in a breeze. Some can even change colors over molts to match their surroundings.

Some can be huge! The longest insect in the world is Phryganistria chinensis, a stick insect that is 62.4 cm (24.6 in) in length, including its legs, 37.1 cm (14.6 in) of only body (Baggley, 2016). This species is fairly newly discovered, as of 2016.

Phasmatodeans are a very old group! We have a trace fossil of a relative of modern phasmatodeans, Phasmichnus radagasti, dating back to the Permian Period (~250-300 million years ago) (Logghe et al, 2021). Trace fossils are imprints, not body fossils, and cannot be precisely placed within a phylogenetic tree (evolutionary relationship of organisms visualized as a branching tree). We do have full body fossils of the leaf insect Eophyllium messelensis, which is ~47 mya during the Paleogene Period (Wedmann et al., 2007). This fossil is our oldest example of a leaf insect.

Scientists are still discovering new species of stick insect. In 2025, for example, Acrophylla alta, was discovered in Australia (Pearson, 2025). 

Australian stick insect Description: 

  The Australian stick insect is endemic to the rainforests of Australia. They are a large species, with females typically 15–20 cm (6–8 inches) long with wide abdomens (Australian Museum, 2025). Males are much smaller and slimmer, usually 10–13 cm (4–5 inches). Females weigh up to 20-30 grams (San Francisco Zoo, 2025). They are a variety of colors (brown, green, grey, mottled) and highly textured, covered with spines, knobs, and thorn-like projections, resembling dead leaves and sticks. Females have broad leaf-like abdomens, often curled downward when resting. Males have a narrower, straighter abdomen.

Male Australian stick insects are decent flyers. Adult females have either no wings or nonfunctioning wing buds. Nymphs can actually glide despite not having wings (Zeng et al, 2020).

General Phasmid Life Cycle:

Some species of phasmids engage in myrmecochory. Phasmid eggs are coated in an edible structure (capitulum) that ants love. The ants take the eggs back to their nest, eat the coating, and allow the phasmid egg to hatch unharmed. This is also a strategy some plants use for seed dispersal (Michaelson, 2024).

Australian stick insect Life Cycle: 

Females can lay a total of 200 to 300 eggs in their lifetime. Females drop or flick the eggs to the ground. The egg stage of the Australian stick insect lasts about 8-12 months (Cambridge Butterfly Sneider, 2024). Eggs have a symbiotic relationship with Leptomyrmex ants, who are attracted to the edible structure covering the eggs. The ants disperse the eggs and keep them safe from predators. When the eggs hatch, nymphal stick insects resemble the ants, this mimicry is a form of protection (Smart, 2023). They even have quick, jerky movements much like ants. This is Batesian mimicry, where a harmless animal mimics a dangerous one. Nymphs go through 5-6 molts (instars). Nymphs, unlike adults, have rapid movements.

When this species molts they hang upside down, the old skin splits down the middle, and the soft vulnerable animal hangs out for 24 hours to harden. Adults live 6-18 months depending on temperature and other environmental factors. Females are usually several months longer lived than males. 

Australian stick insects and Humans:

• Very common pets as they are easy to rear and keep in captivity (they are long live di captivity, up to 2 years)

• Very common in museum and other learning spaces

• The Australian stick insect was in Indiana Jones and the Temple of Doom in 1984, there is a scene where one lands on character Willie Scott’s hand (Australian Museum, 2025).

Super Powers:

• Australian Stick Insect Scorpion Pose - males and females flip up their abdomens in a scorpion pose to scare predators (San Francisco Zoo, 2025)

• Australian Stick Insect Armor - covered in spines, tubercles, and ridges these insects are not easy eats for some predators

• Climbing - these insects are excellent climbers with sticky toes

• Camouflage - stick insects have excellent camouflage that changes when they go from active in the day juveniles to nightlife adults. Australian stick insects resemble leaves and stick to blend in with their surroundings.They can also change color between molts.

• Australian Stick Insect Ant Mimicry - nymphal Australian stick insects resemble Leptomyrmex ants, the ants they tend to attract with their eggs.

• Thanatosis - Many species of stick insect, including the tree lobsters,  play dead when threatened! Much like opossums or hog nosed snakes. 

• Parthenogenesis - stick insects can reproduce without males! Females lay unfertilized eggs that produce clones of the mother.

• Flight - some male phasmids can fly!

• Gliding - nymphs, though wingless, can glide.

• Autotomy - phasmids can drop legs when threatened, then regenerate them on their subsequent molts

• Chemical Spray - some species of Phasmatodea, such as Asceles glaber, can spray a noxious chemical at predators. It can cause temporary blindness in vertebrates.

References:

Australian Museum. “Care of Stick Insects.” The Australian Museum, 2025, australian.museum/learn/animals/insects/care-of-stick-insects/.

“Australian Walking Stick - San Francisco Zoo & Gardens.” San Francisco Zoo & Gardens, 29 Aug. 2025, www.sfzoo.org/australian-walking-stick/.

‌‌Baggley, Kate. “World’s Longest Insect Is Two Feet Long.” Popular Science, May 2016, www.popsci.com/introducing-worlds-longest-insect/. Accessed 3 Jan. 2026.

Logghe, Antoine, et al. "A twig-like insect stuck in the Permian mud indicates early origin of an ecological strategy in Hexapoda evolution." Scientific reports 11.1 (2021): 20774.

Michaelson, Julie. “Myrmecochory: How Ants Shape Plant Communities.” Xerces Society, 11 June 2024, xerces.org/blog/myrmecochory-how-ants-shape-plant-communities. Accessed 3 Jan. 2026.

Pearson, Gwen. “A Huge Stick Insect Has Been Discovered in Australia. Here’s Why That’s Important.” The Guardian, 10 Aug. 2025, www.theguardian.com/commentisfree/2025/aug/10/huge-stick-insects-australia-creatures-ecosystem.

Smart, Hannah R., Nigel R. Andrew, and James C. O’Hanlon. "Ant mediated dispersal of spiny stick insect (Extatosoma tiaratum) eggs and Acacia longifolia seeds is ant-species dependent." Australian Journal of Zoology 70.4 (2023): 105-114.

Snieder, Robin. “Spiny Stick Bug Eggs - Cambridge Butterfly Conservatory.” Cambridge Butterfly Conservatory, 19 Apr. 2024, www.cambridgebutterfly.com/spiny-stick-bug-extatosoma-tiaratum/. Accessed 23 Jan. 2026.

‌‌Zeng, Yu, et al. "Canopy parkour: movement ecology of post-hatch dispersal in a gliding nymphal stick insect, Extatosoma tiaratum." Journal of Experimental Biology 223.19 (2020): jeb226266.