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Nine Red List, 26 nationally critical

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Home > New Zealand ecology > Gigantism in insects

A striking feature of New Zealand's diverse ecology is the variety of large flightless ground-dwelling insects that are related to species in lands that were once part of Gondwana.  These 'living fossils' made their way to New Zealand before it was an isolated archipelago, and developed very unique habits to fill a place in the mammalian-free environment, but remained physically unchanged for a very long time.

Giant weta  Deinacrida spp

The weta is one of the world's most ancient species still living, with little change in 190 million years.  New Zealand has the world's most diverse weta fauna of 70 endemic species.  Seven Deinacrida species of rat-sized giant weta that have survived on offshore islands reach mammoth insect proportions - up to 150mm (6 inches) in length, taking the place of small rodents in the mammal-free ecology. A Little Barrier giant weta D. heteracantha has weighed 71g (2.5 oz) which is heavier than a thrush.  It is the heaviest insect in the world.  See more

Giant land snails  Powelliphanta spp

There are 21 Powelliphanta species and 51 subspecies that evolved during New Zealand's long isolation, and now occupy small isolated areas.  They vary in size but some are gigantic - up to 90mm across.  The largest is P. superba prouseorum in Kahurangi National Park.  It is the size of a man's fist, and weighs 90g which is as much as a tui.  Powelliphanta snails are living fossils, with an origin about 200 million years ago, and belong to the oldest family of carnivorous land snails on Earth.  See more

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Kauri snail  Paryphanta busbyi
Flax snail  Placostylus hongii

Placostylus snails have coiled shells up to 115 mm (4.5 inches) in diameter. They belong to the oldest land snail family that originated 200 to 300 million years ago in the late Palaeozoic or early Mesozoic. Land snails were once wide-spread in the Northland region, but have suffered from habitat depletion and predation by introduced animals. The Kauri snail Paryphanta busbyi may live more than 20 years, and is carnivorous, eating earthworms, insects, and insect lavae. They are also cannibals, eating other snails.

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Puriri moth  Aenetus virescens

The puriri moth is New Zealand's largest moth, with a wingspan of up to 150 mm.  A. virescens is only found in the North Island, but has related species in Australia, New Caledonia and Papua New Guinea. The caterpillar starts life in a bracket fungus, and then bores a refuge tunnel in the trunk of its favorite puriri tree, or beech or putaputaweta.  They feed on wound tissue around the entrance to the tunnel which is hidden by a silken tent, and grow to 70-80 mm during a 7-year life.  Adult moths have no mouth and cannot feed, living only for a couple of days, just long enough to breed or be eaten by a morepork.

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Stick insect
Argosarchus, Acanthoxyla and Clitarchus spp

There are about 20 species of stick insect in New Zealand.  It is the country's largest insect.  The green common stick insect Clitarchus hookeri (right) and other Acanthoxyla and Clitarchus species are 8 to 10cm long when mature.  The largest is Argosarchus horridus which reaches 15cm in length. Many species are parthenogenic, meaning females are able to lay fertile eggs without mating with a male.  Colour can vary from green to brown, even yellowish, amongst a species, possibly because of the particular habitat.

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Huhu beetle  Prionoplus reticularis

The huhu is a member of the Cerambycidae family of longhorn beetles, and is the largest New Zealand beetle, common throughout the country.  It is 35 mm long with a pair of long, jointed antennae. Huhu are most active at night and can be heard flying into windows, attracted by the lights of the building. It is usually harmless but is capable of a powerful nip with its mandibles if mishandled.  The grub stage is the well-known 70 mm long huhu grub which lives in timber.  It was an edible delicacy of the Maori who say it has a buttery chicken taste.

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Giant pill millipede  Procyliosoma tuberculata

Myriapods also have monsters.  A giant pill millipede can grow up to 5cm long and 2.5cm wide. They feed on decaying vegetation, and are widespread in the North Island and northern South Island. The giants only reach full size on offshore islands free of predators. The endemic pill millipede Procyliosoma striolatum (right) is smaller.  New Zealand's five species of pill millipede belong to the order Sphaerotheriida, a group with a Gondwanan distribution of 100 species in Australasia, South Africa and Madagascar.

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Giant centipede  Cormocephalus rubriceps

A 25cm long giant centipede with armour plating and jointed legs has the appearance of an oversized caterpillar from Hell.  Females carry their young to protect them.  The giant centipede is a predacious carnivore of most earth fauna, capturing insects, spiders, snails, slugs and worms with claw-tipped pincers which inject a lethal poison.  They are also known to kill small lizards.  C. rubriceps can still be found in the North Island, however, the full-sized ones are only on rat-free offshore islands.

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Leaf-veined slug Athoracophorus bitentaculatus

New Zealand has thirty native slugs that are all endemic, many of which are not formerly described.  Unlike the common European slug, they have two tentacles instead of four, and are more attractively colored.  New Zealand slugs are unique in having a pinhole on their backs which, like a whale's blowhole, leads to a highly developed lung found in no other mollusc.  The largest, the giant leaf-veined slug Amphiconophorus gigantea reaches 15cm long.  Some species are widespread, but as with the related giant snails, many have been driven into relic forests and tussock grassland.

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Nelson cave spider  Spelungula cavernicola

Spelungula cavernicola may be the missing link between primitive spiders from 350 million years ago and modern spiders.  It is New Zealand's largest spider with a 3cm long body and a 13cm leg-span.  Its size has scared the living daylights out of many a speleologist in the limestone caves of the Tasman Region where it is found.  It is the only spider protected by the Wildlife Act 1953 and is listed as "Range restricted" in the 2005 New Zealand Threat Classification System.

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Bush giant dragonfly  Uropetala carovei

The bush giant dragonfly is New Zealand's largest dragonfly, with a body length of 80-85 mm and a wingspan reaching 140 mm or more.  It is found throughout both main islands, and is often seen and its loud clattering flight is heard when hovering around forest clearings during the summer. They are voracious predators that can consume 20 flies in an hour, and sometimes catch large cicadas. They are preyed upon by kingfishers, wasps and rats.  The male has large, petal-shaped hind appendages.

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Giraffe weevil  Lasiorhynchus barbicornis

The New Zealand giraffe weevil is the longest weevil in the world, with a length of 80 mm which is mainly taken up by the snout.  In males, the antennae are near the tip of the snout, but in the smaller females, antennae are in the middle.  L. barbicornis is found throughout New Zealand.  Females chew holes in the wood of karaka, houhere, and pigeonwood trees to lay their eggs, and the hatched larvae tunnel further into the wood.

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North Auckland worm  Spenceriella gigantia

New Zealand has an unusual earthworm fauna, including famous giant species a metre long.  The 173 species of native earthworms are another ancient remnant of Gondwana.  The most spectacular, and New Zealand's largest worm is the North Auckland worm Spenceriella gigantia, which reaches 1.4 metres (55 inches) long and 11 mm (0.4 in) in width.  The burrows are up to 20 mm in diameter, reaching a depth of 3.5 metres.  The Maori worm can exceed 300 mm in length.  S. gigantia luminesces so brightly at night that it is possible to read by the light from one worm.  See more