Threatened wetapunga, New Zealand’s largest insect, have been released on Tiritiri Matangi Island to help secure the survival of this giant insect.
Twenty five wetapunga were released on the pest free island in the Hauraki Gulf Marine Park, near the Whangapaora Peninsula, on Saturday 10 December.
Wetapunga are New Zealand's largest insect“These are big insects. An adult female body can measure 10 cm long and with its legs it covers your whole hand,” says Department of Conservation scientific adviser Dr Chris Green.
Wetapunga are also recognised as one of the heaviest insects in the world. Adult female wetapunga grow to a weight of 35 grams, five grams heavier than a house sparrow. Some female wetapunga can weigh as much as 50 grams.
“Despite their size and fearsome appearance wetapunga are quite docile and are a threatened species,” says Dr Green.
Before the arrival of pests such as rats and stoats, wetapunga lived throughout Northland, Auckland, on Great Barrier Island and other islands in the Hauraki Gulf.
“Due to animal pests, and the destruction of native forests, they’ve been wiped out on the mainland and all the Hauraki islands with the exception of Little Barrier Island or Hauturu,” says Chris Green.
“Making Hauturu pest free by eradicating kiore rats ensured wetapunga were able to survive on the island. We’ve seen wetapunga double in numbers on Little Barrier since we removed the rats. But it’s very risky having the entire population of a species in one location.”
“To protect wetapunga from the risk of extinction we’ve taken adults from Little Barrier and successfully bred them in captivity. We’re now moving captive bred wetapunga to new pest free island homes,” says Dr Green.
Wetapunga released on Tiritiri Matangi The 25 wetapunga being released on pest free Tiritiri Matangi Island have been bred at Butterfly Creek near Auckland International Airport. They were bred from 18 adult wetapunga captured on Little Barrier Island in December 2008 and May 2009. In September last year the first group of wetapunga raised at Butterfly Creek were released onto pest free Motuora Island, about 12 km northwest of Tiritiri Matangi.
“The wetapunga have grown slowly but steadily, are in good shape and are ready for release on Tiritiri Matangi,“ says Butterfly Creek wetapunga expert Paul Barrett.
“They’re feeding well, eating the leaves of a range of native plants. They’re bigger than the wetapunga released on Motuora. Some are adults, some are close to adulthood. We hope they’ll start mating and laying eggs on Tiritiri Matangi in late summer around March.”
The aim is to establish self-sustaining populations of wetapunga on Tiritiri Matangi and Motuora. It’s planned to move more than 100 wetapunga bred at Butterfly Creek onto each island over the next five years. In addition 20 wetapunga will be transferred to each island direct from Hauturu to increase the genetic diversity of the two new populations.
“It will take a number of years to build self-sustaining populations of wetapunga on Tiritiri Matangi and Motuora because these giant insects have long life cycles,” says Dr Green.
“It can take up to two years for them to reach adulthood and their eggs have to be in the ground for 10 months before they hatch. We need to be patient but we believe these special giants will survive and thrive on their new pest free homes.”
A ferry service carries more than 30,000 people a year to Tiritiri Matangi. Motuora has a campsite and bach run by DOC and is popular with people boating in the Hauraki Gulf Marine Park. “Having wetapunga on Tiritiri Matangi and Motuora will give more people a chance to learn more about this remarkable insect,” says Dr Green.
Supporters of Tiritiri Matangi chairperson, Peter Lee, says the volunteer organisation welcomes the wetapunga release on the island it manages in a partnership with DOC.
“It’s fantastic to add wetapunga to the kiwi, takahë, kokako, tuatara and other threatened native species living in the wild on Tiritiri Matangi. The release is a milestone in the restoration of the natural heritage of the island. Having wetapunga on Tiritiri Matangi enhances the island's reputation as a sanctuary for a wide range of our rare and magnificent wildlife close to our biggest city," says Peter Lee.
- Wetapunga are the largest of the 11 species of giant weta found in New Zealand. There are over 70 species of weta unique to New Zealand. In Te Reo Maori wetapunga means ‘god of ugly things.’
- Female wetapunga are larger than the male. Most female wetapunga reach a weight of 35 grams. Male wetapunga can reach a weight of 20 grams.
- Weta are one of the world’s most ancient types of land animals. They are virtually unchanged in design from fossil weta found in Queensland that date back 190 million years. This was when New Zealand and Australian were part of the same land mass.
- Wetapunga feed on fresh leaves and prefer native plants with large leaves such as karaka, karamu, mamangi, mahoe, and kohekohe.
- They are nocturnal and live in trees. They hide during the day and are well camouflaged under foliage such as dead hanging silver fern fronds. They come out at night to feed on tree leaves.
- Butterfly Creek is near Auckland International Airport. It features a tropical butterfly house with over 700 free-flying exotic butterflies. Visitors can also see giant crocodiles and alligators, reptiles, fish, birds and a variety of other invertebrates such as tarantula, cockroaches and locusts.
- The wetapunga are housed in purpose-built facilities at Butterfly Creek with the breeding programme sponsored by Greenfingers Garden Bags Ltd.
Tirirtiri Matangi Island
- Tiritiri Matangi is an island sanctuary that lies off the coast of Auckland's Whangaparaoa Peninsula. It became pest-free with the eradication of kiore rats in 1993 and provides a safe home for threatened native wildlife including kiwi, takahë, kokako, tïeke, hihi, riflemen, tuatara, native geckos and skinks.
- The island is managed by the Department of Conservation in partnership with the Supporters of Tiritiri Matangi. The volunteer group has planted between 250,000 and 300,000 native trees providing a home for the native wildlife moved onto the island.