Hemideina ricta

Hemideina ricta Hutton, 1896 is a tree wētā that belongs to the insect order Orthoptera. It was originally described by Frederick Hutton in 1896, based on two male and five female specimens from Banks Peninsula and South Canterbury.{{Cite journal |last=Hutton |first=Frederick Wollaston |date=1897-06-01 |title=The Stenopelmatidae of New Zealand |url=https://www.wikidata.org/wiki/Q74888722 |journal=Transactions and Proceedings of the New Zealand Institute |language=English |volume=29 |pages=208–242}} It is one of seven species in the endemic New Zealand genus Hemideina.{{Cite web|url=https://teara.govt.nz/en/weta/page-2|title=Wētā – Tree Wētā|last=Gibbs|first=George|website=Te Ara, Encyclopedia of New Zealand|language=en|access-date=2019-01-27}}

Adults of the Banks Peninsula tree wētā are red-brown in colour, can weigh 4–6 g, and can reach 40–55 mm in length.{{Citation needed|date=July 2023}} The head of the mature male Banks Peninsula tree wētā is much larger and darker than that of females or juvenile males, with large mandibles used to fight other males.{{Citation needed|date=July 2023}}

Hemideina ricta is similar to H. femorata, which is also found in forest fragments on Banks Peninsula.{{Cite web|url=https://newzealandecology.org/nzje/2011|title=Distribution, habitat and conservation status of Hemideina ricta and H. femorata on Banks Peninsula, New Zealand|last=Townsend|date=1997|website=New Zealand Journal of Ecology (1997) 21(1): 43- 49|language=en|access-date=2019-06-06}} These two species can be differentiated using the number of stridulatory ridges on their abdomen.{{Cite journal|last=Morgan-Richards|first=M|date=1995|title=Hybridisation of tree weta on Banks Peninsula, New Zealand, and colour polymorphism within Hemideina ricta (Orthoptera: Stenopelmatidae)|journal=New Zealand Journal of Zoology|volume=22|issue=4|pages=393–399|doi=10.1080/03014223.1995.9518058|doi-access=free}}{{Cite journal |last=Townsend |first=J. |last2=B |first2=Brown |last3=I.A.N |first3=Stringer |last4=M.A |first4=Potter |date=1997-01-01 |title=Distribution, habitat and conservation status of Hemideina ricta and H. femorata on Banks Peninsula, New Zealand |url=https://www.wikidata.org/wiki/Q120877225 |journal=New Zealand Journal of Ecology |language=English |volume=21 |issue=1 |pages=43–49}} Hemideina ricta has more than 20 ridges in total, whereas H. femorata has fewer than 16 stridulatory ridges. Although these two species will share the same daytime refuge holes, only a few F1 hybrids have been found, and no gene flow has been detected between the two species.{{Citation|last=Van Heugten|first=Rachel A.|title=Data from: Sleeping with the 'enemy' - Hybridization of an endangered tree weta|date=2017|chapter-url=https://datadryad.org/resource/doi:10.5061/dryad.4qn07|publisher=Dryad Digital Repository|doi=10.5061/dryad.4qn07|access-date=2019-06-06|last2=Hale|first2=Roddy J.|last3=Bowie|first3=Mike H.|last4=Hale|first4=Marie L.|chapter=Hybridisation}}

The Banks Peninsula tree wētā is found only on the east side of the Banks Peninsula.{{Cite book |last=Gibbs |first=George W. |url=https://www.wikidata.org/wiki/Q120878175 |title=Weta |date=2003-01-01 |publisher=Reed Publishing |isbn=978-1-86948-604-4 |language=English}} Its range is limited to a roughly 200 km² area between Pigeon Bay and Akaroa Harbour, from about 400-800 m above sea level.

Hemideina ricta live in cavities in trees, wooden posts, crevices, rocks, fallen tree logs, or the ground. Some of the tree species it may occupy include lacebark, kanuka, broadleaf, mahoe and five finger. Hemideina ricta generally does not dig its own cavities, instead occupying those previously made by the larvae of other insects,{{Cite journal |last=Bowie |first=Mike H. |last2=Allen |first2=Warwick J. |last3=McGraw |first3=Jill |last4=Heugten |first4=Rachel van |date=2014-01-01 |title=Factors influencing occupancy of modified artificial refuges for monitoring the range-restricted Banks Peninsula tree weta Hemideina ricta (Anostostomatidae) |url=https://www.wikidata.org/wiki/Q120876770 |journal=New Zealand Journal of Ecology |volume=38 |issue=1 |pages=132–138}} preferably those with a small opening (wide enough for its head to fit through) with a large space inside. There can be several wētā living in a single cavity at any one time, often a single male with several females.{{Citation needed|date=July 2023}}

The species is listed as At Risk - Naturally Uncommon in the most recent assessment (2022) of the New Zealand Threatened Classification for insects. It also has the qualifiers "STABLE" and "RR" (Range Restricted).{{Cite journal |last=Trewick |first=Steven A. |last2=Hegg |first2=Danilo |last3=Morgan-Richards |first3=Mary |last4=Murray |first4=Tara J. |last5=Watts |first5=Corinne |last6=Johns |first6=Peter M. |last7=Michel |first7=Pascale |date=2022-01-01 |title=Conservation status of Orthoptera (wētā, crickets and grasshoppers) in Aotearoa New Zealand, 2022 |url=https://www.wikidata.org/wiki/Q120876117 |journal=New Zealand Threat Classification Series |volume=39 |issn=2324-1713}}

In captivity mating has been reported during the months of April, May and November. Mating generally occurs within cavities at night, as this is where large groups of females gather to seek out shelter. Adult males fight over ownership of cavities and therefore the females within those cavities, males with larger mandible gapes often come out on top in these battles.{{sfn|Field|2000|p=?}}

After mating the female needs to leave the safety of the tree cavity in order to descend to the ground to lay her eggs. Oviposition, the process of egg laying, typically takes place at night. The female first examines the ground before laying her eggs by placing her ovipositor into it, she then moves on to a nearby patch of land and repeats this process laying more eggs. This procedure takes around 10–15 minutes. The eggs are around 5.9 mm in length, weigh around 16.8 mg and are black, brown or white in color. The eggs can take several months to mature ,{{sfn|Field|2000|p=?}} generally hatching during spring.

When eggs hatch they often do not do so all at once, a single batch of eggs may take up to two weeks to all hatch.{{sfn|Field|2000|p=?}} A female wētā can lay up to 200 eggs in her lifetime. It can take up to two years for juvenile wētā to mature and reach adulthood, during this time the young wētā must moult several times as it grows. It does this by anchoring itself to a tree branch using its hind legs and hanging upside down. The thorax is the first part of the body to emerge, followed by the abdomen, then the head, next the front and hind legs are pulled out and the antennae emerge last. The Banks Peninsula tree wētā goes into a period of inactivity for a few days before moulting and lightens in colour.{{sfn|Field|2000|p=?}} After moulting the wētā consumes its exuviae, the shed skin, as this is made up of valuable proteins.

Adults live for several months and in some cases up to a year.

The Banks peninsula tree wētā is a nocturnal omnivore that eats small insects, as well as the leaves of trees, shrubs, and in some cases, pasture species.{{Cite book |last=Crowe |first=Andrew |url=https://www.wikidata.org/wiki/Q120878300 |title=Which New Zealand Insect? |date=2002-01-01 |publisher=Penguin Books |language=English}}

The main predators of Hemideina ricta are non-native mammal rodents, specifically rats and possums, which are pests throughout mainland New Zealand and some offshore islands.{{sfn|Field|2000|p=?}} Native predators include diurnal birds such as kākā and weka, and nocturnal birds such as kiwi and owls. Other less common predators include tuatara and short-tailed bats.

File:Hemideina ricta 105370854 Mike Bowie.jpg

File:Hemideina ricta 36025923 Mike Bowie.jpg

File:Hemideina ricta 36026022 Mike Bowie.jpg

File:Hemideina ricta 106203304 Mike Bowie.jpg

{{Reflist}}

• {{cite book|last1=Field |first1=L|title=Biology of Wetas, King Crickets and their Allies|date=2000|publisher=CABI|location=Wallingford, United Kingdom}}

• {{cite journal|last1=Gibbs|first1=G|last2=Refuat|first2=C|title=Response of a tree weta population (Hemideina crassidens) after eradication of the polynesian rat from a New Zealand island|journal=Restoration Ecology|date=2003|volume=11|issue=1|pages=13–19|doi=10.1046/j.1526-100X.2003.00058.x}}
• {{Cite journal | ref={{sfnRef|Watts et al|2008}} |last=Watts |first=Corinne |last2=Stringer |first2=Ian |last3=Sherley |first3=Greg |last4=Gibbs |first4=George|last5=Green|first5=Chris|date=1 July 2008|title=History of weta (Orthoptera: Anostostomatidae) translocation in New Zealand: lessons learned, islands as sanctuaries and the future|journal=Journal of Insect Conservation |volume=12|issue=3–4|pages=359–370|doi=10.1007/s10841-008-9154-5|issn=1366-638X}}
• {{CiteQ|Q112911045}}
• {{CiteQ|https://www.wikidata.org/wiki/Q112854540}}
• Troup, Tina and Mike Bowie. ‘Banks Peninsula Tree Wētā brochure’, Lincoln University.

{{Wikicommons}}

• Hemideina ricta discussed on RNZ Critter of the Week, [https://www.rnz.co.nz/national/programmes/afternoons/audio/2018899433/critter-of-the-week-banks-peninsula-tree-weta 21 July 2023]

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Category:Wētā

Category:Banks Peninsula

Category:Insects described in 1896

Category:Anostostomatidae