A female wētāpunga, or giant wētā, during a previous release in the Bay of Islands. Photo / Peter de Graaf
Peter de Graaf of RNZ
A gigantic insect absent from New Zealand forests for almost 200 years is making a comeback in the Bay of Islands.
The wētāpunga, the largest of 11 species of giant wētā and one of the world’s largest insects, emerged before the dinosaurs and outlived them by tens of millions of years.
But by 1840, they had been all but wiped out by introduced predators, clinging to survival only on Te Hauturu-o-Toi/ Little Barrier Island in the Hauraki Gulf.
Since 2012, Auckland Zoo has been breeding wētāpunga collected from Hauturu, with the aim of reintroducing these ancient insects to predator-free islands and reserves.
Last Wednesday just over 300 juvenile wētāpunga were released on two islands in the Bay of Islands, where community conservation group Project Island Song has been working for almost 20 years to restore native flora and fauna.
Project Island Song general manager Richard Robbins said the giant wētā was the eighth endangered species returned to the islands since 2012.
“We’re bringing the wētāpunga back because they’re a really important part of the ecosystem, and they’ve been missing for about 200 years.”
Wētāpunga usually grew to about 35g — about the weight of a sparrow — but adult females could tip the scales at a whopping 70g.
“They’re huge, one of the largest insects in the world, and they’ve coexisted with other species here on the islands for millions of years. They were almost lost with just one remnant population left, so being able to be part of a larger programme to bring them back is really special.”
Adult wētāpunga had previously been released onto the islands but last Wednesday’s operation was more delicate because it involved juveniles aged about 4 months.
The insects were carefully liberated at night onto dry ponga fronds to give them plenty of places to hide and the best chance of survival.
Auckland Zoo ectotherm curator Don McFarlane said returning wētāpunga to the Bay of Islands was especially significant because the last specimen recorded on the New Zealand mainland was in Paihia in 1838.
“So it’s amazing to start releasing them back from whence they came. It’s a real homecoming,” he said.
McFarlane said New Zealand’s birds and lizards received a lot of attention because they were obvious and often also colourful and noisy, but the country’s many endangered insects played a more important role in the environment.
“The invertebrates are the underdog in the conservation world. But they are essential to healthy, functioning ecosystems, and without them, nothing works.”
The mostly herbivorous wētāpunga subsisted on leaves and produced droppings that fell to the forest floor, ensuring nutrients in the forest canopy were recycled to the soil.
That role had been missing from New Zealand ecosystems for the past 200 years, McFarlane said.
Another curious fact about wētāpunga was that their faecal pellets — that’s poo in layman’s terms — were among the biggest relative to body size in the natural world.
McFarlane said wētāpunga were unique in many other aspects of their natural history and body form.
“They just capture people’s imagination because they’re so gigantic. I mean, they’re among the largest insects in the world. And, in my view, they are very beautiful.”
McFarlane conceded not everyone would share that view, but said the more we understood something, the more we could see its beauty.
“If most people stop for a moment, resist the recoil you sometimes see with people when they first see a wētāpunga, and just watch them move — the way those feathery antennae waft around looking for the next place to put a foot — I think they’ll see a beauty,” McFarlane said.
Also taking part in the release were members of local hapū Ngāti Kuta and Patukeha, conservation volunteers, and high school students voyaging on the youth sail training ship R. Tucker Thompson.
About 1200 wētāpunga have been released onto Urupukapuka, Moturua and Motuarohia islands in the Bay of Islands since 2020.
Young, island-hatched wētāpunga have been detected since then, which confirmed they were breeding.
The insects live for about three years.
Other locally extinct species reintroduced to the islands by Project Island Song include the toutouwai/North Island robin, tīeke/North Island saddleback, pōpokotea/whitehead, kākāriki/red-crowned parakeet and Duvaucel’s gecko.
In total Auckland Zoo has released about 7000 wētāpunga into the wild, mostly onto islands in the Hauraki Gulf.
The next release in the Bay of Islands is expected to take place in the spring.
“There is also a beauty in the very act of putting something back that was once missing. It’s redressing a balance. So it’s a beautiful animal and this is a beautiful experience. It feels great.”