11,000 of the World’s Heaviest Insects, Growing Up to 4 Inches Long, Intentionally Released into the Wild

The wētāpunga, a remarkable giant insect from New Zealand, is experiencing an encouraging resurgence, following extensive conservation efforts. Once teetering on the brink of extinction, this robust relative of crickets and grasshoppers, which can weigh as much as a chicken egg, has seen its population expand across multiple islands due to a dedicated breeding programme.

Recent research published in the New Zealand Journal of Zoology, along with an announcement from the Department of Conservation (DOC) on 2nd October, reveals that the population of wētāpunga has grown significantly after approximately 15 years of intensive breeding initiatives. At least 11,000 individuals have been successfully released into the wild, supporting the recovery of this species once restricted to a single island.

Chris Green, an Honorary Research Associate at the Department of Conservation, described the regeneration of the wētāpunga population as an extraordinary success story in conservation. By documenting their findings, the research team hopes to share vital lessons on breeding techniques, release procedures, and methods for ensuring population sustainability.

Initially, breeding and release techniques for the wētāpunga were pioneered by Butterfly Creek, a wildlife facility that laid the groundwork for these efforts. Auckland Zoo later expanded upon this foundation, successfully rearing large numbers of young insects in communal environments, effectively referred to as “creches”. Throughout the process, the conservation efforts enjoyed the backing of Ngāti Manuhiri, the Māori tribe responsible for overseeing the species.

The population of wētāpunga, which can reach lengths of up to 10 centimetres and a leg span of around 20 centimetres, once thrived across various locations in New Zealand’s North Island. Unfortunately, habitat destruction due to European settlement, coupled with the introduction of invasive predators such as rats and stoats, decimated their numbers to the point that only a single population remained on Te Hauturu-o-Toi, also known as Little Barrier Island.

Surveys conducted between 2005 and 2009 revealed that the numbers on Little Barrier Island were too few to facilitate direct relocations to other sites. Consequently, a small group of insects was captured to establish a breeding colony at Butterfly Creek, which led to the initial releases on Motuora and Tiritiri Matangi Islands in 2010 and 2011. By 2014, Auckland Zoo had added a second colony, resulting in the release of nearly 8,900 wētāpunga between 2014 and 2025.

These insects, known as nymphs during their juvenile stage, are nurtured on a diet that includes fresh foliage, leaf litter, and fish flake protein. This protein source is deemed essential for the young nymphs’ growth before they are introduced back into their natural habitat.

The programme has successfully executed 45 translocations to eight predator-free islands as well as two fenced sanctuaries on the mainland. Green noted that this number is particularly high in the context of species recovery efforts. “Releasing 11,000 individuals is remarkable,” he remarked, underscoring the scale of the operation.

Monitoring efforts on Motuora and Tiritiri Matangi have confirmed the successful birth of at least four generations of wētāpunga since their introduction. This achievement has allowed the species to shift from being classified as Nationally Endangered in 2004 to a status of Nationally Increasing by 2022, a milestone not often reached by many threatened species in New Zealand.

Green expressed his excitement regarding these developments, noting that such positive reports are infrequent when it comes to other endangered species. The methodologies and insights gained from this initiative are now being applied to the conservation of the Māhoenui giant wētā at Ōtorohanga Kiwi House, while similar principles may also extend to other vulnerable invertebrate species, such as the Canterbury knobbled weevil and various native stag beetle species.

As conservationists continue to advocate for critically endangered invertebrates, the prospects for the wētāpunga suggest a hopeful future. The collaborative efforts of various organisations highlight the importance of community involvement, expertise, and commitment in the ongoing struggle to preserve New Zealand’s unique biodiversity. The comeback of the wētāpunga serves as an inspiring reminder of what dedicated conservation efforts can achieve.