''Isoplectron'' is a genus of cave

wētā Wētā (also spelt weta) is the common name for a group of about 100 insect species in the families Anostostomatidae and Rhaphidophoridae endemic to New Zealand. They are giant flightless crickets, and some are among the heaviest insects in th ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Rhaphidophoridae The orthopteran family Rhaphidophoridae of the suborder Ensifera has a worldwide distribution. Common names for these insects include cave wētā, cave crickets, camelback crickets, camel crickets, Hogan bugs, spider crickets (sometimes shortene ...

with three species currently recognized. The genus is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to New Zealand and distributed throughout the country.

Taxonomy and morphology

The genus ''Isoplectron'' was described by Hutton in 1896. All species in this genus are small in size (10-17mm body length) and are commonly misidentified as a result of increased undescribed species. The fore femora of the ''Isoplectron'' does not contain apical spines, in addition, the hind tibiae models two pairs of apical spines. Adult females have a broad bilobed subgenital plate while males have a triangular shape. Multiple species are undescribed and are not able to reflect the fauna presently however, descriptions relating to ''Isoplectron armatum, Isoplectron calcaratum'' and ''Isoplectron aciculatum'' have been made.

''Isoplectron armatum''

''Isoplectron armatum'' are the most commonly observed species of ''Isoplectron''. They are found across New Zealand but are more concentrated around

Dunedin Dunedin ( ; mi, Ōtepoti) is the second-largest city in the South Island of New Zealand (after Christchurch), and the principal city of the Otago region. Its name comes from , the Scottish Gaelic name for Edinburgh, the capital of Scotland. Th ...

and can be found in dry spaces under bark or in holes of various trees, especially ''Nothofagus cliffortioides'' and Kanuka. They are also caught in pitfall traps in southern North Island forests. Their morphology consists of a body length between 11-17mm, short dorsal and laterals in the hind tibial apical spurs, a very small ventral pair of hind tibial apical spurs and no spinules in the hind tarsal plantulae. This is consistent across males and females.

''Isoplectron calcaratum''

This species overlaps in habitat and morphology with their close relative ''Isoplectron armatum'' and have been observed in the north of the South Island and Wellington.

''Isoplectron/Setasutum pallidum''

Described by

Aola Richards Dr Aola Mary Richards (16 December 1927 – 2 November 2021) was a New Zealand entomologist specialising in the study of New Zealand and Australian cave crickets, or wētā (Rhaphidophoridae), and Australian ladybird beetles ( Coccinellidae). She w ...

in 1972. Limited descriptions and studies have been made on ''Setasutum pallidum'' (which might belong in the genus ''Isoplectron'') however they are claimed to be an alpine species with observations in the South Island occurring.

Species

* ''

Isoplectron aciculatum ''Isoplectron'' is a genus of cave wētā in the family Rhaphidophoridae with three species currently recognized. The genus is endemic to New Zealand and distributed throughout the country. Taxonomy and morphology The genus ''Isoplectron'' was ...

'' Karny, 1937 * ''

Isoplectron armatum ''Isoplectron'' is a genus of cave wētā in the family Rhaphidophoridae with three species currently recognized. The genus is endemic to New Zealand and distributed throughout the country. Taxonomy and morphology The genus ''Isoplectron'' was ...

'' Hutton, 1897 * ''

Isoplectron calcaratum ''Isoplectron'' is a genus of cave wētā in the family Rhaphidophoridae with three species currently recognized. The genus is endemic to New Zealand and distributed throughout the country. Taxonomy and morphology The genus ''Isoplectron'' was ...

'' Hutton, 1897

Predation

A study conducted by Bremner ''et al''. (1989) compared insect response to disturbance (touch) between individuals living with mammalian predators and those on mammal-free islands. Wētā were observed to jump away or leap off tree branches when disturbed in environments with rodents, but were more likely to move away without haste in environments without rodents. The paper concluded that invertebrate populations, specifically the ''Isoplectron'' sp. population in

Fiordland Fiordland is a geographical region of New Zealand in the south-western corner of the South Island, comprising the westernmost third of Southland. Most of Fiordland is dominated by the steep sides of the snow-capped Southern Alps, deep lakes, ...

, altered their behaviour in environments that contained predators such as stoats (''Mustela erminea'') and ship rats (''Rattus rattus'') in comparison to predator free environments. Individuals within the genus ''Isoplectron'' are eaten by endemic reptiles such as the

Tuatara Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language and m ...

(''Sphenodon''), spotted skink (''Leiolopisma infrapunctatum'') and Pacific geckos (''Hoplodactylus pacificus'') as well as avian species such as Riflemen ('' Acanthissitta chloris''), Ruru ('' Ninox novaeseelandiae''), Kākā ('' Nestor meridionalis'') and Tieke (''Philesturnus'').

Conservation

All species within the genus ''Isoplectron'' are considered not threatened and are consequently of little conservation concern.

References

Peripatus

{{DEFAULTSORT:Isoplectron Ensifera genera Cave weta Endemic fauna of New Zealand Endemic insects of New Zealand