Weta have become icons for invertebrate conservation in New Zealand because many species are threatened or endangered. There are more than 70 species of weta in New Zealand, 16 of which are at risk.
There are five broad groups of weta:
- Tree weta
- Ground weta
- Cave weta
- Giant weta
- Tusked weta
Diet: Weta are mainly herbivorous in the wild, but are also known to eat insects.
Habitat: They are nocturnal and live in a variety of habitats including grassland, shrub land, forests, and caves. They excavate holes under stones, rotting logs, or in trees, or occupy pre-formed burrows.
Many different species
The wetapunga of Little Barrier is the biggest, and the Nelson alpine weta the smallest, at 7 grams. There are tree weta, ground weta, cave weta, and three species of the spectacular looking tusked weta. These males have two tusks which they use to butt other males, or rasp together to warn off competitors.
Species of weta continue to be discovered. One of the three tusked species, the carnivorous "Jaws", was found by lizard expert Tony Whittaker on Middle Mercury Island off the Coromandel Coast 29 years ago; another of them in the Raukumara Ranges on the East Coast of the North Island as recently as 1995.
Many of the giant species now only survive on protected land and many are endangered. The Mahoenui giant weta, long considered extinct on the mainland, was rediscovered in a patch of King Country gorse in 1962. Department of Conservation staff have established a new population of these on Mahurangi Island, off the Coromandel coast. Two hundred have been transferred there and after four years they are showing signs of breeding.
The challenge of classifying weta
One feature of weta conservation is the lack of basic information on their distribution, abundance, and ecology. Furthermore, there can be a great deal of variation within individual species, despite the fact there is little genetic difference between them.
Therefore, the classification and conservation of weta is an evolving process.
A Department of Conservation Recovery Plan is currently in action. It exists as a guide that can be modified as new information and conservation priorities emerge.
Population and range
Little is known about the past distribution of weta.
Several species that were once found on mainland New Zealand are now only found on offshore islands. Very little is known about these offshore island populations.
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