New Zealand Journal of Ecology (2014) 38(1): 132- 138

Factors influencing occupancy of modified artificial refuges for monitoring the range-restricted Banks Peninsula tree weta Hemideina ricta (Anostostomatidae)

Research Article
Mike H. Bowie 1*
Warwick J. Allen 1
Jill McCaw 1
Rachel van Heugten 2
  1. Ecology Department, Agriculture and Life Sciences Division, PO Box 85084, Lincoln University, Lincoln 7647, New Zealand
  2. School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
*  Corresponding author

The use of non-destructive and non-invasive monitoring methods is often necessary for species of high conservation status. Developing monitoring methods to maximise numbers of individuals found is important, given that rare species can be difficult to locate. Artificial refuges called ‘weta motels’ have been used for monitoring tree weta (Orthoptera: Anostostomatidae) since 1992, but poor occupancy for Hemideina ricta and H. femorata necessitated an improved design and assessment of placement to encourage tree weta use. Modification to a basic design of weta motel was tested on New Zealand’s rarest tree weta, H. ricta, on Banks Peninsula, Canterbury, New Zealand. Possible lures such as peanut butter or frass from male and female H. ricta were placed in motels in an attempt to improve occupancy. We recorded high occupancy rates with an improved weta motel design and found that motels containing female frass had significantly higher levels of occupancy than controls, with the former reaching 80% occupation after 6 months. Weta motels were more likely to be used by tree weta in areas with low subcanopy density and patchy or little canopy cover, with H. ricta found to prefer higher altitude sites. Occupation of weta motels was compared with results from a previous hand search survey, finding very similar distributions of tree weta species with the two survey methods. We conclude that this modified refuge is effective for monitoring tree weta, including the range-restricted Banks Peninsula tree weta H. ricta.