Stick and Leaf Insects

Australia is home to an extraordinarily diverse phasmid fauna, with over 150 described species found in habitats ranging from tropical rainforests and dry sclerophyll forest to suburban gardens and coastal heathland. Australian stick and leaf insects occupy almost every vegetation zone on the continent.

Spiny leaf insects (Extatosoma tiaratum) are native to the tropical and subtropical forests of Queensland and New South Wales, where it feeds on a wide range of eucalyptus species. It is one of the largest and most spectacular stick insects in the world, reaching up to 20 cm in females. Titan and Strong stick insects inhabit eastern Australian forests and are among the longest stick insects in Australia. Children's stick insects are found across eastern Queensland and northern New South Wales and is notable for the vivid sexual dimorphism between males and females. Australian Leaf Insects (Phyllium monteithi), one of Australia's only true leaf insects, is restricted to the wet tropical rainforests of far north Queensland and is a significantly more challenging species to maintain in captivity.

Most Australian phasmid species are available as captive-bred animals. Many are parthenogenetic — females can reproduce without males — making colony management straightforward. All are herbivores and, despite their sometimes dramatic appearance, are entirely harmless.

Height is the most critical enclosure dimension for stick and leaf insects — they need to hang freely when moulting, which they do by suspending from the enclosure ceiling or upper foliage. As a rule of thumb, the minimum enclosure height should be at least three times the length of the adult animal. For large species such as spiny leaf and titan stick insects, a minimum enclosure height of 60 cm is required; 90 cm is preferable.

Mesh or net enclosures — such as purpose-made butterfly or phasmid cages — are ideal as they provide maximum airflow, allow animals to cling naturally to all surfaces, and make feeding and maintenance straightforward. Glass enclosures can be used but must have very good ventilation; stagnant humid air causes disease. Minimum footprint for most species is 30 × 30 cm; larger species and colonies will benefit from wider enclosures.

Foliage should be presented in water-filled jars or vases placed on the enclosure floor, with the water opening sealed with cotton wool to prevent drowning of nymphs. Replace foliage every two to three days or when it becomes dry or heavily consumed. A layer of paper towel, coconut fibre or leaf litter substrate on the enclosure floor catches frass and falling eggs — many phasmid species drop their eggs freely and these can be collected from the substrate for incubation if desired.

Temperature of 22–28°C suits most Australian species. No basking heat or UVB is required, though ambient natural light on a 12-hour cycle supports normal activity. For tropical species such as Australian leaf insects, higher temperatures (26–30°C) and elevated humidity (70–80%) are required.

All Australian stick and leaf insects are herbivores and require a continuous supply of fresh foliage from their accepted host plants. Accepted plant species vary between phasmid species and it is important to research the specific requirements of the species being kept before acquiring animals.

Spiny leaf insects are the most generalist feeders and accept a wide range of eucalyptus species, as well as rose, raspberry, bramble (Rubus species) and wattle — making it the most practical species for keepers without access to specific native plants. Titan and strong stick insects also accept eucalyptus and wattle. Children's stick insects accept eucalyptus, willow and rose. Australian leaf insects require specific rainforest plant species, such as Lilly pilly, and are significantly more demanding to feed.

Foliage should be fresh, pesticide-free and presented in water — stem cuttings placed in a jar of water keep leaves fresh for several days and are the most practical feeding method. Pack the water jar opening with cotton wool or tissue to prevent small nymphs from falling in and drowning. Replace foliage as it dries or is consumed. Provide foliage generously — phasmids have high food requirements relative to their body size and should never run out of fresh leaves.

Stick and leaf insects can be handled gently, though they are primarily observation animals and do not require or seek interaction. Allow insects to walk freely onto the hand rather than picking them up — many will walk confidently onto an outstretched hand when given the opportunity. Never grab or restrain an insect that is resisting — legs can detach (autotomy) and, unlike lizard tails, they do not always regenerate cleanly in adults.

Handle close to a surface or over the enclosure to minimise the risk of a fall. Nymphs are more fragile than adults and should be handled with particular care, if at all. Always wash hands before and after handling. Children should be supervised and reminded to move slowly and gently — stick insects respond poorly to sudden movements.

The most important enrichment for stick and leaf insects is a generous, varied supply of fresh foliage that allows them to browse, select feeding positions and move through a naturalistic three-dimensional environment. Providing a mix of foliage types where the species' dietary range allows — different eucalyptus species, wattle and rose for Extatosoma tiaratum, for example — adds environmental complexity and allows the animal to select preferred leaf types.

A taller enclosure with foliage at multiple levels allows natural movement between resting and feeding positions. For species with wings, providing enough space to extend and occasionally use wings, even briefly, supports normal physical function. Allowing the enclosure to have direct access to ambient natural light (not direct sun) supports normal circadian rhythms. For colony keepers, observing the complete lifecycle — egg, multiple nymph instars, adult — and successfully hatching eggs is a deeply satisfying and educational experience.

Failed moults (dysecdysis) are the most serious and common cause of death in captive phasmids. They almost always result from inadequate enclosure height preventing the animal from hanging freely, insufficient humidity, or disturbance during the moulting process. Prevention requires correct enclosure height, appropriate humidity for the species and a strict no-disturbance policy during moulting. Dehydration can occur in dry conditions — ensure foliage is always fresh and lightly mist the enclosure for tropical species.

Mould and bacterial disease can develop when dead foliage is not removed promptly, frass accumulates excessively or enclosure ventilation is inadequate — maintain cleanliness and airflow to prevent these conditions. Parasitic flies (particularly tachinid flies) can be introduced into a collection via wild-caught foliage — if possible, source foliage from your own garden or a trusted supplier to minimise this risk. Any animal that fails to moult successfully, loses multiple limbs, refuses food for an extended period, or appears to become progressively thinner should be assessed and conditions carefully reviewed.