In the small islands of New Zealand, world’s heaviest insect lives: The Giant weta. There are 70 types of species of weta in the genus Deinacrida of the family Anostostomatidae. Giant weta is endemic to New Zealand and is an example of island gigantism: which is a biological phenomenon leading to a larger size than their mainland relatives because of their isolation and lack of large predators. A female giant weta filled with eggs can reach up to 70 grams or more!
There are eleven species of giant weta, most of which are larger than another weta, despite the latter already being large by insect standards. The largest species is the Little Barrier Island giant weta. Large species can be up to 10 centimeters (4 in) not inclusive of legs and antennae, with body mass usually no more than 35 grams. But rarely, a female filled with eggs can reach up to 70 grams or more: one captive female reached a mass of about 70 grams (2.5 oz.), making it one of the heaviest documented insects in the world and even heavier than a sparrow. The largest species of giant weta is the Little Barrier Island giant weta, also known as the wētāpunga, which means the “god of ugly things” in the Maori language. One example reported in 2011 weighed 71 grams, and a 72 grams specimen has been recorded.
Most populations of this amazing insect have been in decline since humans began modifying the New Zealand environment. All but one giant weta species is protected by law because they are considered at risk of extinction. When humans arrived in New Zealand hundreds of years ago, they inadvertently brought weta predators along with them, like rats and cats, which ate the insects.
To help safeguard this threatened species, an experimental breeding project was successfully undertaken by the staff at Butterfly Creek in South Auckland under the guidance of the Weta Recovery Group. Auckland Zoo was extremely successful at breeding hundreds of wētāpunga.
Little Barrier Island (Hauturu in Māori language), lies off the northeastern coast of New Zealand’s North Island. Located 80 kilometers (50 mi) to the north of Auckland, the island is separated from the mainland to the west by Jellicoe Channel, and from the larger Great Barrier Island to the east by Cradock Channel. It is an extinct andesitic volcanic cone, roughly circular in shape, about 6 km (3.7 mi) across, with an area of 28 km2.
The giant weta is usually less social and more passive than other weta species. Their genus name, Deinacrida, is Greek for “fierce grasshopper”. Its diet consists of plants (even carrot!), other small insects and fruit.
Another amazing fact about the wētāpunga: many species are alpine specialists. Five species are only found at high elevation in South Island. The scree weta D. connectens lives about ~1200 meters above the sea level and freezes solid when temperatures drop below -5°C.
- Giant weta on Wikipedia
- “10 Intense Facts About the Giant Weta” on Mental Floss
- Wētāpunga on New Zealand Government Department of Conversation webpage