Priscilla Northe, Auckland Zoo
Thousands of wētāpunga nymphs have hatched at the Zoo to help ensure the species’ survival!
Last year, a team of six from Auckland Zoo travelled to Te Hauturu-o-Toi/Little Barrier Island to continue our conservation project for New Zealand’s largest wētā. With the blessing of mana whenua Ngāti Manuhiri and permits from the Department of Conservation, their mission was to gather 12 adult ‘founder’ wētāpunga for the Zoo’s conservation breeding programme.
Introduced predatory mammals and destruction of native forests led to the near extinction of wētāpunga and their extirpation from on mainland New Zealand. Until conservation measures were implemented they were restricted to just one island - Te Hauturu-o-Toi. Having an entire species confined to one location is extremely risky as extreme weather, disease and predators can so easily bring about a rapid decline and even extinction. Increasing their distribution and numbers across other predator-free island reserves became essential.
Auckland Zoo staff have been breeding wētāpunga for over a decade. Following some early trail-blazing husbandry work by colleagues at Butterfly Creek, the Zoo team scaled-up and soon began breeding and releasing wētāpunga in their thousands…almost 8000 to date across five islands in the Hauraki Gulf and three in Bay of Islands. The offspring of the latest ‘founders’ will add new genetic material to these existing populations and assure their long-term establishment.
As you can imagine, wētāpunga breeding season is a busy time at the Zoo. After mating the adult females are provided with soil-filled containers. The female probes the soil with her ovipositor —a tube-like organ adapted for egg-laying. Testing its texture and moisture before inserting it vertically—sometimes up to 15mm deep. Once she finds a suitable spot, she arches her body and remains still for several minutes as she carefully deposits each egg.
She then shifts slightly before repeating the process, laying between 100 and 300 cigar-shaped eggs. When the tubs are full, keepers can spot tiny "potholes" left behind—clear evidence that eggs have been deposited. The soil is then incubated under controlled conditions to ensure proper development.
Wētāpunga eggs are small (measuring about 6mm long and 1.5mm wide), dark brown, and have a sausage-like shape. They typically take eight months or more to hatch.
Wētāpunga nymphs emerge from their eggs as tiny, pale versions of the adults. Their bodies are almost translucent, with hues of white, green, and pale brown. Fully formed antennae help them navigate their surroundings as they begin feeding on fresh leaves from native trees such as karaka, karamu, māhoe, and kohekohe, which is carefully collected and delivered throughout the week by our browse team. Three times a week, our ectotherm team gets to work—spending up to 4–5 hours at a time feeding the animals and cleaning their habitats.
As they grow, the nymphs undergo 10 developmental stages, known as instars, shedding their exoskeleton with each moult. The entire process from nymph to fully grown adult takes between 15 and 24 months, with wētāpunga reaching their sexual maturity shortly afterwards. Once mature, adult wētāpunga live for between 6-9 months, which means their total lifespan from egg to adult is about three years.
These Zoo-bred wētāpunga will be released onto the predator-free islands where populations have already been established by this technique, adding essential new genetic material to improve the viability of each sub-population and ensure the species survival for generations to come.
