Middle Island Tusked Weta
Updated: Jul 10, 2020
Have you heard about the Middle Island tusked wētā? They’re a little terrifying, but are an oddball creature worth reading about.
What is the Middle Island tusked wētā?
The tusked wētā can grow to over 6 cm and are a slow moving, flightless relative of grasshoppers, locusts, and crickets. They look strikingly similar to the ground wētā (Hemiandrus pallitarsis), however, as Middle Island tusked wētā grow much larger, they can be easily identified when larger than 30 mm.
What do they do all day?
‘Wētā’ is the root of the Māori word ‘wētāpunga’ which means ‘God of ugly things’. This is unsurprising considering the fearful morphology of most wētā; in the case of tusked wētā, their tusks are truly the fuel of nightmares. The tusked wētā is one of three native tusked wētā. The tusk is an extremely unusual trait for insects so it probably arose due to mate competition. Tusks are considerably longer in males because males use tusks as weapons in territorial sparring competitions. However, despite seeming aggressive, there are actually few cases of tusked wētā biting humans.
These nocturnal creatures burrow into the forest floor and use saliva to smooth the walls and seal the entrance. The tusked wētā is extremely shy and only exits these chambers on nights with perfect weather, soil and temperature conditions.
Where do they live?
Native populations of tusked wētā are now confined to 13 ha on Atiu island in the Mercury archipelago off the coast of the Coromandel Peninsula (Te Tara-o-te-Ika a Māui). However, there is speculation that tusked wētā once existed on neighbouring islands but perished due to the kiore (Polynesian rats) that never made it to Atiu. Due to their limited dispersal, they are extremely vulnerable to the effects of climate change, human disturbance, and invasive predators. In order to maintain Aotearoa's biodiversity, and ensure the survival of the tusked wētā and other vulnerable species, it is imperative that we consider our impacts, even on creatures as small as the Middle Island tusked wētā.
Pratt, R. C., Morgan-Richards, M., & Trewick, S. A. (2008). Diversification of New Zealand weta (Orthoptera: Ensifera: Anostostomatidae) and their relationships in Australasia. Philosophical Transactions: Biological Sciences, 363(1508), 3427—3437. Retrieved from http://doi.org/10.1098/rstb.2008.0112
Sherley, G. H. (1998). Threatened Weta Recovery Plan. Department of Conservation Science & Research Unit, Wellington.
Stringer, I. A. N. Chappell, R. (2008). Possible rescue from extinction: transfer of a rare New Zealand tusked weta to islands in the Mercury group. Journal of Insect Conservation, 12,(3), 371—382. Retrieved from https://doi.org/10.1007/s10841-008-9149-2
Stringer, I. A. N. (2006). Distinguishing Mercury Islands tusked weta, Motuweta isolata, from a ground weta, Hemiandrus pallitarsis (Orthoptera: Anostostomatidae) in the field, with observations of their activity. Department of Conservation Research & Development Series 258. Department of Conservation, Wellington.
Gibbs, W. (2002). A new species of tusked weta from the Raukumara Range, North Island, New Zealand (Orthoptera: Anostostomatidae: Motuweta). New Zealand Journal of Zoology, 29(4), 293—301. Retrieved from https://doi.org/10.1080/03014223.2002.9518313
Johns, P. M. (1997). The Gondwanaland Weta: Family Anostostomatidae (Formerly in Stenopelmatidae, Henicidae or Mimnermidae): Nomenclatural Problems, World Checklist, New Genera and Species. Journal of Orthoptera Research, 6, 125—138. Retrieved from https://doi.org/10.2307/3503546
Stringer, I. A. N. (2005). Translocation of the Middle Island tusked weta Motuweta isolata, The Mercury Islands, New Zealand. Conservation Evidence, 2, 83—85. Retrieved from https://www.conservationevidence.com/individual-study/2169
Danielle is a student at Auckland University of Technology studying a double major in Environmental Science and Applied Conservation. She is a keen hiker that tries to identify every plant along the way. She has been known to make up the names of birds or trees if someone asks and she doesn’t know.