By ANNE BESTON
A rare New Zealand weta is about to leave home for the first time in 80 million years.
The Middle Island tusked weta (Motuweta isolata) was discovered on Middle Mercury Island by a Government scientist in 1970.
The 13ha island, one of the Mercury group off the east coast of
Coromandel Peninsula, is almost untouched by humans and has no introduced predators.
It is home to a number of New Zealand's most unique species, including tuatara.
But the island is also ecologically fragile and the critically endangered weta suffers heavy predation from native lizards, giant centipedes and native birds.
To minimise the threat of extinction, the Department of Conservation decided to establish tusked weta populations on other islands in the group but realised that taking them from Middle Island would put that population at risk.
The department began a captive breeding programme about five years ago but it has taken until now to produce a significant number of offspring because the weta will attack and eat one another if left together for any length of time.
But at the beginning of last year, two females and one male produced 181 hatchlings, 100 of which will make the trip by boat to Double Island and Red Mercury Island this week.
The young weta, which were bred at Landcare Research in Mt Albert and at Auckland Zoo, will be released at least 5 sq m apart to minimise conflict. They are at present about 3cm long but the male, which has the distinctive tusks from which the species gets its name, can grow to 10cm.
Landcare Research technician Chris Winks said the aim was to eventually establish populations of the weta on the larger of the seven islands in the Mercury group.
It will not be easy monitoring how well the settlers take to their new home - the tusked weta is nocturnal and spends about 80 per cent of its time underground.
The head of the zoo's breeding programme, Paul Barrett, is a big fan of what is probably one of New Zealand's least-loved indigenous species.
"It's been a pleasure looking after them," he said. "They might seem to live a relatively boring life underground but they're fascinating, a really remarkable animal."
