Wetapunga: Deinacrida heteracantha



Deinacrida heteracantha, commonly known as Wetapunga in Maori, one of the Giant Weta, is the heaviest insect in the world. The highest recorded weight of this particular species was that of a captive female, weighing in over 71 grams, which is the heaviest weight recorded for an adult insect ever! The Wetapunga, belonging to the order Orthoptera, in the family Anostostomatidae, is an insect endemic to New Zealand but now Deinacrida heteracantha only lives on the Little Barrier Island off the coast of the North Island, which is largely free of mammalian predators. While other giant weta are present elsewhere, those on the Little Barrier Island live longer and are on average much larger. There are 11 species of the Giant Weta but Deinacrida heteracantha is the largest; all 11 are examples of the phenomena island gigantism. Average weight for the Giant Weta is between 35 and 45 grams although the female when filled with eggs can obtain weights up to 70 grams. In general. the Wetapunga can achieve wingspans of up to seven inches and body length up to four inches. All 11 species of Giant Weta are flightless, or apterous, and do not even have wings, characteristic of animals isolated on islands. The Weta are arboreal, spending the majority of their time above ground in the trees, although oviposition does occur on the ground. The Wetapunga are nocturnally active, relatively slow moving, and mainly herbivorous feeding on foliage and vegetation. During the day they retreat to the leaf canopy or squeeze into a gallery in a tree or hole in the ground to avoid predation. There is strong evidence to support that communication between individuals occurs through pheromones however the Wetapunga, when threatened, will create a defensive sound by rubbing the spines present on the hind legs over a “file” on the abdomen. A study found that the majority of Wetapunga are dark brown in coloration in both sexes while a small percentage of them are present as a yellow color morph. Although they are nocturnal, the Weta mate during the day after having paired the pervious night and appear to be monogamous. Giant Weta are hemimetabolous; the egg stage lasts approximately 10 months and is followed by 11 nymphal instars, molting their exoskeleton over 11 times, and taking over a year to reach sexual maturity. Oviposition occurs during the fall months and the eggs hatch about a year later. Female adult Weta can lay 100 to 300 eggs throughout their life.

The diversification of Deinacrida dates back over five million years ago during the Miocene and parallels adaptation to new habitats following mountain uplift in the country. Decline in population numbers was and is in large attributed to introduced pests and mammals, most notably Polynesian rats, which may have been the driving cause in keeping the Weta tree-borne. At one time only a single population of the Wetapunga existed on the Little Barrier Island and the species was considered nationally endangered. Due to conservation efforts of the Department of Conservation in New Zealand, the Weta moved from nationally endangered to reasonably secure.

Gibbs, G.W. 1998. Why are some weta (Orthoptera: Stenopelmatidae) vulnerable yet others are common? Journal of Insect Conservation 2: 161-166.

Hitchmough, R.; Bull, L. and Cromarty, P. 2007 New Zealand threat classification system lists 2005. Department of Conservation, Wellington, New Zealand.

Pratt, R., Morgan-Richards, M., & Trewick, S. (2008). Diversification of New Zealand weta (Orthoptera: Ensifera: Anostostomatidae) and their relationships in Australasia. Philosophical Transactions of the Royal Society B: Biological Sciences, (363), 3427-3437. doi:10.1098/rstb.2008.0112

Sherley, G. H., and L. M. Hayes. 1993. The conservation of a giant weta (Deinacrida n. sp. Orthoptera: Stenopelmatidae) at Mahoenui, King Country: habitat use, and other aspects of its ecology. New Zealand Entomologist 16.

Sherley, G. (n.d.). Threatened Weta Recovery Plan, Threatened species recovery plan No. 25. Retrieved December 1, 2015, from http://www.doc.govt.nz/Documents/science-and-technical/tsrp25.pdf

Watt, J. C. 1963.The rediscovery of a giant weta, Deinacrida heteracantha, on the North Island mainland. New Zealand Entomologist 3: 9-13.

Video on Weta

Video on Weta II

Geographic Distribution of 11 Giant Weta Species

New Zealand Govt’ information on Weta

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