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Journal of Insect Conservation

, Volume 13, Issue 3, pp 287–295 | Cite as

Where have all the weta gone? Results after two decades of transferring a threatened New Zealand giant weta, Deinacrida mahoenui

  • Corinne Watts
  • Danny Thornburrow
Original Paper

Abstract

There have been numerous transfers of the large-bodied orthopteran, the Mahoenui giant weta (Family Anostostomatidae: Deinacrida mahoenui), over the past 19 years but there has been limited follow-up monitoring to ascertain establishment and breeding of transferred populations. Recent surveys carried out at all the locations where this weta were transferred, found weta at four of the seven transferred sites. The most important factor determining the success of past transfers is the absence of introduced mammalian predators, particularly rats, at a site. At two sites, Mahurangi Island Scenic Reserve and Warrenheip, weta appeared to be flourishing and have successfully established new populations in the absence of rats. If mammals are present at a site, the occurrence of dense prickly gorse to protect giant weta from predation is another important factor in their survival. Weta were found at very low densities (only single specimens were captured) at Mangaokewa Scenic Reserve and Tikikaru (private land) and it is likely their populations are not viable in the long term. Further efforts to establish Mahoenui giant weta populations should be in mammal-free sanctuaries containing native forest. More intensive post-transfer monitoring using radio-transmitters would enable better understanding of their behaviour after transfer. In addition, long-term regular monitoring of transferred populations is required, particularly those where the likelihood of rat re-invasion is high.

Keywords

Orthoptera Translocation Conservation Predation Rats Monitoring 

Notes

Acknowledgements

Research funds were provided by the Foundation for Research, Science and Technology New Zealand (under contract C09X0508). Particular thanks to Derek Cox, Daniel Rapson and Rob Chappell for providing transport to Mahurangi and Motutapere Islands. Thank you to Robbie Price, Lisa Daglish, Phil Bradfield, Kyle Chambers and Gary Coles for assisting with the weta searches. We thank Arthur Cowan, Phil Bradfield, and Andrew Gaston for access onto their land to search for weta. Greg Sherley, Ian Stringer, Anne Austin, George Gibbs, Henrik Moller and one anonymous reviewer provided useful comments on the draft manuscript. Research was carried out under Department of Conservation—National Permit Number: WK-18670-RES.

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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Landcare ResearchHamiltonNew Zealand

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