Heteropteryx dilatata

Common name: Jungle Nymph / Malaysian Stick Insect / Malayan Jungle Nymph Origin: Peninsular Malaysia, Sumatra, Borneo, Thailand and Singapore, where it lives in humid lowland and hill rainforest. One of the heaviest stick insects in the world and a long established species in the hobby. Diet: Bramble is the staple and is taken all year round. Oak, hazel, raspberry, hawthorn, guava, rose and salal are also accepted well. Nymphs can be slow to settle on a new foodplant, so introduce changes gradually and leave the old plant in place until they have switched over. Avoid anything from garden centres or treated gardens, as pesticide residue remains lethal to phasmids long after application. Stand cut stems in a bottle of water with the neck plugged so nymphs cannot fall in. Temperature: 22 to 28 degrees, with a slight night drop being beneficial. This species handles normal room temperature well but grows very slowly below 20 degrees. Avoid sustained temperatures above 30 degrees. Humidity: 70 to 85 percent, misted daily. Consistent humidity is essential for successful moulting, and this is the single most common failure point in keeping the species. Underweight or dehydrated animals frequently die during a moult or lose limbs. Keep the enclosure humid but never stagnant, as poor airflow leads to mould and respiratory problems. Size: One of the bulkiest insects kept in captivity. Adult females reach 15 to 16cm body length and can weigh over 50 grams, bright leaf green, heavily built, and covered in short spines across the body and legs. They have small non functional wings. Adult males are entirely different in appearance, around 9 to 10cm, slender, mottled brown, with full functional wings and the ability to fly. Nymphs of both sexes start out brown and spiny, with females turning green after several moults. Lifespan: Females live around 18 to 24 months in total, one of the longest lived phasmids in the hobby. Males are shorter lived at roughly 12 to 14 months. Females take around 12 to 14 months to reach adulthood, males considerably less at around 8 to 10 months, which means males often mature long before the females in the same batch. Defense: Females are strongly defensive and will not simply play dead. When threatened they raise and open the hind legs, which are lined with sharp spines, and snap them shut on whatever touches them. A large female can draw blood and the grip is genuinely painful. They also produce an audible hissing sound by rubbing the wings against the abdomen, and may rear up in a threat posture with the wings flared. Males are far more docile and generally take flight or drop instead. Handle females by supporting the body from below and never place fingers between the hind legs. Despite this the species is not aggressive and calm handling is usually uneventful. Breeding: Not parthenogenetic, both sexes are required for fertile eggs. Because males mature far earlier than females, timing is the main challenge and it is worth staggering hatch batches or keeping males cool to extend their lifespan until females are ready. Females begin laying around 4 to 6 weeks after their final moult and bury their eggs in the substrate using the ovipositor, producing roughly 100 to 150 over their lifetime. Eggs are large, around 8mm, brown and barrel shaped with a distinct ridge. Incubation is very long, typically 8 to 14 months on damp sand or vermiculite kept slightly moist but never wet. Patience is essential, as eggs that look inactive will often still hatch well past the first year. Housing: Space and especially height are critical given the size of the adults. A minimum of 45x45x60cm suits a pair or trio of adults, and larger is better for a group. The enclosure must be at least three times the adult body length in height to allow safe moulting, as a female that touches the floor mid moult will end up deformed or dead. Provide a deep substrate layer of at least 5cm of coconut fibre or sand for egg laying, plenty of sturdy branches capable of holding a heavy female, and mesh or textured surfaces for grip. Combine mesh and glass to keep humidity up while maintaining airflow.