Wetas are large insects belonging to the genus Deinacrida. Found throughout most parts of New Zealand, they range from the tiny tree wetas, about twice the size of a cricket, all the way up to the so-called South Island sheep-eating weta which, as the name implies, is rumoured to be able to bring down sheep (although this is probably untrue). Wetas are representatives of a very ancient group of insects, with fossil records in New Zealand going back over 270 million years. New Zealands isolation from the rest of the world probably accounts for the large number of endemic species and the large size of most members of the species.

A ground weta found in the upper North Island.

Wetas were first recorded in 1838 when a specimen was collected at Paihia. This specimen is still on display in the Auckland Museum. The perfect preservation of the body is a testament to the almost indestructible nature of the insects. In 1871 the naturalist Sir Walter Buller described attempts to obtain specimens of tree wetas from the Whangarei district. His brother-in-law tried to drown a weta by submerging it in water for four days, without success. He also boiled a specimen without apparently harming it. Buller himself imprisoned two captured specimens in wooden packing crates and left them near his campsite, only to find the crates shredded and the wetas gone when he returned that evening.

A juvenile Poor Knights Islands weta. Note the heavy protective clothing.

Wetas are omnivorous and also carnivorous, eating their own kind if no other food is available. Ferocious predators, they have been known to break the bones of smaller animals when attacking them. Fortunately they always hunt alone, so they pose little threat to larger prey. The only real danger is presented by the females during the mating season, who are venomous over a period of a few months, with the venom causing partial paralysis of the affected limb which usually wears off in a few days. The females can be easily distinguished by the scimitar-like ovipositor shown in the photo of the ground weta below.

A group of South Island sheep-eating weta crossing a country road.

The so-called South Island sheep-eating weta got its name from 19th century farmers who blamed the creatures for the loss of sheep in high country pastures. Recent research has shown that this was extremely unlikely, since the wetas are solitary creatures who never hunt in groups and therefore wouldn't, as individuals, be able to bring down anything larger than a small lamb. However this wasn't known earlier this century, when the government paid farmers a bounty of tuppence for each weta carapace brought in. This lead to the weta being practically wiped out in some areas.

Today the occasional appearance of mutilated rabbit carcasses on high-country sheep runs are still explained away as the result of weta attacks. This may occur when rabbits seek refuge in burrows inhabited by wetas; further study is needed before any conclusions can be drawn. In an extraordinary incident which took place in the South Island in 1964, a woman claimed her baby had been carried off by wetas. No trace of the baby was ever found, and despite widespread speculation that the woman had killed the baby herself, the disappearance was ruled as death by misadventure.

A Maori woman prepares weta carapaces outside her whare in the 1940's.

Even before the government set a bounty on them, weta carapaces were prized by the Maori, who used them as food pouches when going on long journeys. Although incredibly tough, they could be softened by boiling them for several days in the acidic water of volcanic springs, creating a leathery container which could be used to store food and other items. Weta flesh was regarded as a delicacy by the Maori, as shown by the above photograph.

A ground weta, relative of the so-called sheep-eating weta.

Today, wetas are a protected species. Driven into smaller and smaller pockets by human settlement of the land, and in some cases completely wiped out by government-sponsored initiatives, urgent steps were taked in the 1970's to try to preserve the species. In the late 1980's the Minister of Tourism Mike Moore briefly toyed with the idea of commercially farming wetas for food. This attempt failed because of the extreme difficulty encountered in containing the insects, and was lampooned by satirists McPhail and Gadsby in a famous "WetaBurger" sketch, a parody of Moores (relatively) successful LambBurger intiative aimed at bringing NZ lamb to new markets. Currently the use of sheep-eating wetas to control the rabbit problem in the South Island is being investigated. The use of an indigenous species to control an imported pest is attractive, but whether the wetas will cooperate remains to be seen.

This page prepared by Peter Gutmann in cooperation with the School of Biological Science's Eketehuna Research Unit.