Wētāpunga comeback: the hand-sized insect once confined to one island is now producing new wild generations
After nearly disappearing from New Zealand, more than 11,000 wētāpunga were released and new wild generations are now being found.
The breakthrough was not just spotting giant insects in the dark. It was realizing some of them were far too young to belong to the original releases, meaning the species was breeding on its own in the wild. For an animal that had been pushed back to a single island, that changes the story completely.
The moment the rescue became real
On Motuora and Tiritiri Matangi islands, researchers went out at night and checked tracking tunnels that captured the distinctive footprints of wētāpunga. By 2025, what they found pointed to something bigger than a successful release programme. Some of the insects matched ages that fit fourth and fifth generation descendants of the original animals put back into the wild.
That is the kind of evidence conservation projects are built around. Releasing animals is one thing. Proving they can establish populations that continue without constant human restocking is another.
The species at the centre of this effort is not easy to forget. The wētāpunga is a New Zealand icon and the world’s heaviest known orthopteran, part of the same broader group as crickets and grasshoppers. Its body can reach nearly 10 centimetres, or about 4 inches, while its spiny legs can stretch to roughly twice that. It has no wings and cannot fly.
Adult females typically weigh around 35 to 40 grams, about the weight of a small mouse. One especially large female carrying eggs reached 71 grams, or 2.5 ounces. For all its imposing appearance, this is a nocturnal plant-eater that spends much of its life hidden among leaves.
How it was pushed to the edge
Wētāpunga belong to an ancient insect lineage that has lived in New Zealand for millions of years. They evolved in a place that was largely free of native land mammals, which left them badly exposed when new predators arrived with human settlement.
Habitat loss and introduced predators, especially rats, cats and stoats, hammered their numbers. By the middle of the 20th century, the species had disappeared from its former range across northern New Zealand and survived only on Te Hauturu-o-Toi, also known as Little Barrier Island.
Even that last refuge did not feel secure. Surveys carried out during the 1990s raised concerns that the remaining population was declining. Pacific rats were eradicated from the island in 2004, and later surveys showed signs of improvement, but the population there was still considered too valuable to risk removing large numbers for releases elsewhere.
That forced conservationists toward a different answer. If they wanted to restore the species beyond its final stronghold, they would need to raise it in captivity first.
The effort that followed brought together conservation scientists, zoo keepers, local restoration groups and Ngāti Manuhiri, the Māori iwi for whom wētāpunga are a treasured species. What started as a rescue for a threatened invertebrate would become one of the most ambitious insect conservation programmes attempted in New Zealand.
Breeding a giant insect turned out to be surprisingly complicated
The captive programme began in 2008, when researchers collected a small number of wētāpunga from Little Barrier Island and established a breeding colony at Butterfly Creek near Auckland. Auckland Zoo joined in 2012.
Raising the insects was slow from the start. Their eggs take about nine and a half months to hatch on average, and can take considerably longer. After that, the young pass through 10 moults over about 14 months before they become adults.
They were not simple nursery residents either. Older juveniles sometimes ate smaller ones. Researchers eventually worked out a communal system that usually kept around 20 similarly aged insects together. They were given places to hide and a controlled diet that included fresh foliage, forest leaf litter and fish flakes for protein.
That protein mattered. The youngest wētāpunga appeared to depend heavily on it, and survival improved when the team kept similarly sized juveniles together and made sure their diet contained enough of it. In some breeding groups, survival reached 80 percent by the time the insects were ready for release.
Observations in the wild had hinted that very young wētāpunga were not feeding exactly like the adults. Early-stage juveniles had been seen near fungi, mould and bird droppings, suggesting a more varied diet than the mainly leaf-eating adults.
Once the juveniles were ready, they were moved to selected sites where rats had been removed and where suitable shelter and food plants were available. Some were transported inside bamboo tubes, which also served as temporary refuges when attached to trees.
More than 11,000 released, and now the population is changing course
Across 45 separate transfers between 2010 and 2025, conservationists released 11,214 wētāpunga across eight islands and two fenced mainland sanctuaries.
Chris Green, the lead author of the new study and an honorary research associate at New Zealand’s Department of Conservation, described the programme as an unusually comprehensive example of breeding threatened invertebrates and returning them to the wild.
The strongest outcome has come from the monitoring work on Motuora and Tiritiri Matangi. Researchers used the insects’ developmental stages and the amount of time since the original releases to reconstruct successive generations. On both islands, the evidence now points to self-sustaining populations, which is the central goal of reintroduction work.
That matters beyond a single species. A 2019 review of insect reintroductions found that only 52 percent of conservation-led projects succeeded, and that the number of animals released was an important predictor of whether a programme would work.
The wētāpunga story suggests that numbers alone were not enough. The project combined large-scale releases with captive breeding methods that improved survival, and it placed insects into sites where major predators had already been removed.
The species’ improving outlook has already led conservation authorities to change its threat classification from nationally endangered to nationally increasing.
For an insect that once survived only on one island, that is a striking shift. The real sign of recovery is no longer just that people can raise wētāpunga and set them free. It is that the next generations are already out there, leaving tracks in the night.
