Wetas back from the brink and breeding

Two threatened species of weta – found only in tiny pockets of the Tusked WetaCoromandel and King Country – have recently been discovered breeding outside their traditional habitats, thrilling conservationists involved in their plight.  The ferocious-looking Middle Island Tusked weta and the Mahoenui Giant weta were once feared extinct, but the latest findings have given renewed hope to their long-term survival.

Giant WetaSince then Doc has carried out extensive investigations and feasibility studies aimed at increasing the number of Tusked wetas and moving them.That is due to Conservation Department (Doc) recovery programmes, which date back 10 years.
The Tusked weta was discovered on Middle Island, part of Coromandel’s Mercury group of islands, less than 30 years ago.
  It was hailed as one of the most exciting insect finds of the century.

Jason Roxburgh of Doc’s Hauraki office told The Waikato Times this week there had been a breakthrough… Tusked weta had been recently identified on nearby Red Island.

“It’s an amazing achievement given that translocation (shifting) of other invertebrates to other islands hasn’t been overly successful.  It was a really steep learning curve… taking in a species we didn’t know anything about. Its behaviour is so different. It lives underground most of the time, which makes things difficult.”

The captive breeding programmed that had operated since 1993 was done in conjunction with Chris Winks of Landscape Research.  In 2000, Mr. Winks and Doc staff had released 150 weta on Double Island and Red Island, said Mr. Roxburgh.

Signs of breeding were first discovered in April this year.

“When they come above ground the females have egg spikes, which they poke into the ground, so we’d seen where they had been.”

The only way to confirm offspring was by constructing an inside enclosure.

“The guys found some eggs in them, then found some tiny weta,” said Mr. Roxburgh.  “It’s like a safety net. We’ve got two populations living separately, so we’ve got an insurance policy.”

The real celebrations were being saved for next year, however, when it was hoped a further generation of Tusked weta would be produced.

“That’ll be the true beginning of a new population,” Mr. Roxburgh said.

The Tusked weta would then be protected from being wiped out by an environmental disaster, such as fire.

Although the relocation programme for the King Country’s giant Mahoenui Weta on Mahurangi Island in Coromandel had shown no evidence of success, there was still hope. About 200 were set free on Mahurangi in 1996.

But Tertia Thurley of Doc’s Maniapote office said some Mahoenui giant weta had been successfully moved from the Mahoenui scientific reserve to a small block of gorse on private land.

That had proved the weta was capable of being moved.

 

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