There are few suitable monitoring tools for assessing the effectiveness of management for threatened insect taxa. This is especially true for cryptic arboreal species of nocturnal flightless orthopterans in the genus Deinacrida from New Zealand. Systematic searching of habitat during the day was compared with footprint tracking tunnels baited with peanut butter as methods for monitoring the arboreal giant weta Deinacrida heteracantha and Deinacrida mahoenui (Orthoptera: Anostostomatidae). Searching by day required more time (3h per transect) than operating tracking tunnels (1.4h). Lines of 30–35 tracking tunnels spaced 30 m apart could be quickly set to sample large areas. Searching may provide additional information including the species, age class, and sex, whereas tracking tunnels yield presence/absence data for giant weta that were larger than other anostostomatid present. Both methods provide indices of relative abundance: it is impractical in tall forest to accurately estimate absolute density whereas tracking tunnel results are related to the activity of weta. Weta activity may depend on vapour pressure deficit modulated by the temperature. For conservation and monitoring purposes, we recommend that tracking tunnels be used first to detect giant weta and only then search for them if further data is required.
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1 December 2013
Effective Monitoring of Arboreal Giant Weta (Deinacrida heteracantha and D. mahoenui; Orthoptera: Anostostomatidae) using Footprint Tracking Tunnels
Corinne Watts,
Danny Thornburrow,
Maheswaran Rohan,
Ian Stringer
Journal of Orthoptera Research
Vol. 22 • No. 2
December 2013
Vol. 22 • No. 2
December 2013
conservation
footprint tracking tunnels
monitoring tool
threatened taxa