Sigaus childi

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Sigaus childi
NZAcrididae1.JPG
Female
NZAcrididae2.JPG
Male
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Orthoptera
Suborder: Caelifera
Family: Acrididae
Genus: Sigaus
Species:
S. childi
Binomial name
Sigaus childi
Jamieson, 1999
NZAcrididae5.png
Distribution of S. childi

Sigaus childi is an endangered protected species of grasshopper known only from the Alexandra district of the South Island of New Zealand. It is one of just two species of grasshopper listed for protection under the New Zealand Wildlife Act 1953 (the other is Brachaspis robustus). [1] It is currently classified as "At Risk, Naturally Uncommon" by the Department of Conservation. The genus Sigaus is endemic to New Zealand.

Contents

Taxonomy

Sigaus childi was described by Colleen Jamieson in 1999, from a male specimen collected on 15 December 1997 at Galloway Station, Otago ( 45°12′35″S169°29′26″E / 45.209820°S 169.490626°E / -45.209820; 169.490626 ). [2] The holotype and paratype are deposited in the Otago Museum, Dunedin. The species was named after the late Peter Child of Alexandra, who first collected it from Graveyard Gully in 1967. [3]

Description

Sigaus childi displaying its cryptic coloration NZAcrididae15.JPG
Sigaus childi displaying its cryptic coloration

Sigaus childi is morphologically cryptic and polymorphic in colour, ranging from pale grey through earthy tones to green and black. Some individuals closely match foliose lichens that grow in rocks in the area, but others more closely resemble gravels or pebbles. They rely on camouflage rather than hopping to evade predators, and their hops are short: 30–40 cm and 15 cm high. Sigaus childi was originally mistaken for Sigaus minutus , a small grasshopper species from lowland McKenzie district (South Island NZ), that it looks very similar to. [4]

The wings on S. childi are very small – between 1–2 millimetres (0.039–0.079 in); like most New Zealand grasshoppers, this species is flightless. Males are 11–13 millimetres (0.43–0.51 in) long; females are twice as large, 21–25 millimetres (0.83–0.98 in). They have no ears, and do not sing.

Distribution and habitat

Typical S. childi habitat (Galloway Station
45deg14'55''S 169deg29'31''E / 45.248474degS 169.491863degE / -45.248474; 169.491863) NZAcrididae3.JPG
Typical S. childi habitat (Galloway Station 45°14′55″S169°29′31″E / 45.248474°S 169.491863°E / -45.248474; 169.491863 )

This species has a patchy distribution in a small area of about 200 square kilometres around the township of Alexandra, 200–500 m above sea level. The current distribution of S. childi is likely to shrink due to climate change, and without human efforts to translocate and protect habitat the species will be extinct by 2070. [5] Searches have been carried out on the northern end of the Knobby Range, North Rough Ridge, and the Rock and Pillar Range: all have failed to locate further populations. [6] [7] Sigaus childi is primarily found on dry, open, sparsely vegetated slopes, usually on north-facing hillsides, but rarely on modified farmland. Most of these sites appear rocky, mainly due to their low growing and sparse vegetation.

Another more widespread species, S. australis , that lives mostly in alpine and subalpine habitat in the mountain ranges nearby, [8] also occurs in this lowland semi-arid habitat. This brings it into close contact and sympatry with S. childi at some locations. Genetic data indicate extensive gene flow between these two species despite maintaining morphological differences. [9] [10] The alpine grasshoppers of New Zealand are sister to alpine species from Tasmania, but the New Zealand clade radiated about 12 million years ago. [11]

Conservation

Threats to S. childi include introduced predators such as cats, rodents, mustelids, and hedgehogs. They are also eaten by native skinks. Rabbits compete with them for food plants (sorrel, hare's-foot clover, viper's bugloss, and Raoulia ). Sigaus grasshoppers are adapted to arid open habitats, so they are threatened by landscape modification like irrigation [12] and climate change. [5] As at 2016 this species was classified as "At Risk, Naturally Uncommon" by the Department of Conservation. [13]

Related Research Articles

<i>Hemiandrus</i> Genus of orthopteran insects

Hemiandrus is a genus of wētā in the family Anostostomatidae. In New Zealand they are known as ground wētā due to their burrowing lifestyle. Hemiandrus wētā are nocturnal, and reside in these burrows during the day. Ground wētā seal the entrance of their burrow during the day with a soil plug or door so that their burrow is concealed. This genus was originally said to be distributed in Australia and New Zealand, however, with recent molecular genetic methods, this is under debate. Ground wētā adults are smaller than other types of wētā, with the unusual trait of having both long and short ovipositors, depending on the species. The name of this genus is said to come from this trait as hemi- mean half and -andrus means male, as the species where the female has a short ovipositor can sometimes be mistaken for a male. This genus has a diverse diet, depending on the species.

Insulanoplectron is a genus of cave wētā in the family Rhaphidophoridae, with just one species: the Snares Island Wētā. Insulanoplectron spinosum is endemic to the subantartic Snares Island of New Zealand, where it is considered to be naturally uncommon. Wētā are nocturnal crickets found all around the world. During the day on the Snares, wētā can be found hiding in seabird burrows.

<i>Pharmacus</i> Genus of orthopteran insects

Pharmacus is a genus of cave wētā in the family Rhaphidophoridae, endemic to New Zealand. All species are alpine adapted and found at high elevations in the South Island. They live among rocks on high mountain ridges, often well above glaciers and vegetation. Pharmacus has a geographical range that extends from Nelson south to central Otago and Fiordland. They are small insects with a body length of approximately 14-20mm. In this genus, females are larger than males. All species exhibit dark brown to black pigmentation of the body and legs. They have a dense clothing of setae and a serrated ovipositor. When active they are lively jumpers. For example, Pharmacus montanus is known as the Mount Cook flea because of its habit of leaping out of rock crevices on to mountain climbers.

<i>Sigaus homerensis</i> Species of grasshopper

Sigaus homerensis is a grasshopper endemic to the southern South Island of New Zealand. It is known only from three isolated populations in Fiordland.

<i>Brachaspis robustus</i> Species of grasshopper

Brachaspis robustus is a nationally endangered species of grasshopper endemic to the Mackenzie Basin of the South Island of New Zealand. The genus Brachaspis is endemic to the South Island of New Zealand. Although a grasshopper, it is a poor jumper, relying on camouflage to hide from predators. It is threatened by introduced mammals such as stoats, hedgehogs, and rats.

<i>Sigaus villosus</i> Species of grasshopper

Sigaus villosus is New Zealand's largest grasshopper. It is only found in the central mountains of the South Island. The genus Sigaus is endemic to the New Zealand. Like all of New Zealand sub-alpine and alpine grasshoppers S. villosus has a 2 or 3 years life cycle. The eggs must ‘overwinter’ before they will hatch. Hoppers are found throughout the year and adult grasshoppers can be found throughout the New Zealand summer between December and April. Adult S. villosus do not overwinter.

<i>Alpinacris tumidicauda</i> Species of grasshopper

Alpinacris tumidicauda is a species of grasshopper only known from Otago and Southland, New Zealand. The genus Alpinacris is endemic to the South Island of New Zealand. A. tumidicauda was described in 1967 by Robert Sidney Bigelow, with a type locality of Obelisk in the Old Man Range (45°19′22″S169°12′27″E). A male holotype and paratype are deposited in the Canterbury Museum, Christchurch. Like all of New Zealand sub-alpine and alpine grasshoppers, A. tumidicauda has a 2- or 3-year life cycle. The eggs must "overwinter" before they will hatch. Hoppers are found throughout the year, and adult grasshoppers can be found throughout the New Zealand summer between December and April. The adult A. tumidicauda do not overwinter.

<i>Deinacrida connectens</i> Species of orthopteran insect

Deinacrida connectens, often referred to as the alpine scree wētā, is one of New Zealand's largest alpine invertebrates and is a member of the Anostostomatidae family. Deinacrida connectens is a flightless nocturnal insect that lives under rocks at high elevation. Mountain populations vary in colour. This species is the most widespread of the eleven species of giant wētā (Deinacrida).

<i>Sigaus</i> Genus of grasshoppers

Sigaus of grasshoppers in the tribe Catantopini that isendemic to New Zealand, and all but one species is endemic to the South Island: Sigaus piliferus is the only North Island representative and is the type species. There are eight species in the genus; all are flightless, and many are coloured for camouflage against rocky ground. Sigaus minutus and S. childi are threatened with extinction.

<i>Sigaus australis</i> Species of grasshopper

Sigaus australis is the most common alpine grasshopper found in New Zealand. It can be found in the southern half of the South Island above the tree line. Sigaus australis was described in 1897 by Frederick Hutton. Like all of New Zealand sub-alpine and alpine grasshoppers S. australis has a 2 or 3 years life cycle. Individuals can survive the cold by freezing solid at any life stage, at any time of the year. Sigaus australis adults are relatively large grasshoppers. The genus Sigaus is endemic to New Zealand.

<i>Phaulacridium marginale</i> Species of grasshopper

Phaulacridium marginale is a small species of short-horned grasshopper in the family Acrididae. It is endemic to New Zealand where it is found in low elevation open habitat throughout North Island, South Island, Stewart Island and on many smaller islands.

<i>Phaulacridium otagoense</i> Species of grasshopper

Phaulacridium otagoense is an endemic New Zealand grasshopper found at low elevation throughout the central South Island.

<i>Phaulacridium</i> Genus of grasshoppers

Phaulacridium is a genus of grasshoppers in the tribe Catantopini from Australia and New Zealand. These short-horned grasshoppers have a single generation each year

<i>Hemideina thoracica</i> Species of orthopteran insect

Hemideina thoracica, commonly known as the Auckland tree wētā or tokoriro is a cricket-like insect. It is endemic to New Zealand and is found over most of the North Island, except for the Wellington region and regions 900 metres above sea level. This species is an arboreal, herbivorous generalist however, it is also thought to be polyphagous and is found in all wooded habitats, including forest, scrub and suburban gardens.

<span class="mw-page-title-main">Mary Morgan-Richards</span> New Zealand academic

Mary Morgan-Richards is a New Zealand biologist, and as of 2019 is a full professor at Massey University.

<i>Sigaus minutus</i> Species of grasshopper

Sigaus minutus is a species of short-horned grasshopper in the family Acrididae. It is one of the smallest and rarest species of grasshopper in New Zealand, found only in the Mackenzie district of South Island. There are nine species within the genus Sigaus described by Bigelow (1967), all endemic to New Zealand. The population status of Sigaus minutus is declining according to threat assessments made by orthopteran experts in 2010.

<i>Brachaspis nivalis</i> Species of insect

Brachaspis nivalis, is an alpine short-horned grasshopper, endemic to the South Island of New Zealand. Brachaspis nivalis is brachypterous and flightless, therefore they travel by hopping. They bask during the day so need open habitat.

<span class="mw-page-title-main">Wētā</span> Informal group of orthopteran insects

Wētā 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 the world. Generally nocturnal, most small species are carnivores and scavengers while the larger species are herbivorous. Although some endemic birds likely prey on them, wētā are disproportionately preyed upon by introduced mammals, and some species are now critically endangered.

<i>Hemiandrus focalis</i> Species of orthopteran insect

Hemiandrus focalis is a species of ground wētā endemic to New Zealand. This flightless Orthoptera lives in the mountains of the South Island, New Zealand. This species can be distinguished from other ground wētā by their three superior retrolateral spines on their mid tibia and females have relatively long ovipositors. This omnivorous ground wētā species is listed as "not threatened" by the New Zealand Department of Conservation.

<i>Brachaspis collinus</i> Species of grasshopper

The Green Rock-hopper grasshopper, Brachaspis collinus is an alpine species of short-horned grasshopper in the family Acrididae. It is found in New Zealand in the mountains of northern South Island, above the tree line and as high as 2000 m asl. In New Zealand alpine grasshoppers can freeze solid at any time of the year and are alive when they thaw out when temperatures rise.

References

  1. "Schedule 7 Terrestrial and freshwater invertebrates declared to be animals". Parliamentary Counsel Office/Te Tari Tohutohu Pāremata. Retrieved 23 December 2010.
  2. Jamieson, Colleen D. (1999). "A new species of Sigaus from Alexandra, New Zealand (Orthoptera: Acrididae)". New Zealand Journal of Zoology. 26 (1): 43–48. doi: 10.1080/03014223.1999.9518176 .
  3. Bigelow, R.S. The Grasshoppers of New Zealand, Their Taxonomy and Distribution. University of Canterbury, Christchurch. 1967. p.60.
  4. Jamieson, C. D; New Zealand; Department of Conservation (1996). The grasshopper Sigaus minutus in Central Otago: a pilot study. Wellington, N.Z.: Dept. of Conservation. ISBN   978-0-478-01842-4. OCLC   53018797.
  5. 1 2 Koot, Emily M.; Morgan-Richards, Mary; Trewick, Steven A. (2022). "Climate change and alpine-adapted insects: modelling environmental envelopes of a grasshopper radiation". Royal Society Open Science. 9 (3): 211596. doi:10.1098/rsos.211596. PMC   8889178 . PMID   35316945.
  6. Morris, S.J. Grasshopper Identification Sheet – Sigaus childi. Department of Conservation, Alexandra.
  7. Morris, S.J. 2003. Distribution and Taxonomic status of New Zealand endangered grasshoppers (Orthoptera: Acrididae). Department of Conservation, Wellington.
  8. Carmelet‐Rescan, David; Morgan‐Richards, Mary; Koot, Emily M.; Trewick, Steven A. (2021). "Climate and ice in the last glacial maximum explain patterns of isolation by distance inferred for alpine grasshoppers". Insect Conservation and Diversity. 14 (5): 568–581. doi:10.1111/icad.12488. ISSN   1752-458X. S2CID   233647314.
  9. Dowle, Eddy J; Morgan-Richards, Mary; Trewick, Steven A (2014). "Morphological differentiation despite gene flow in an endangered grasshopper". BMC Evolutionary Biology. 14 (1): 216. doi: 10.1186/s12862-014-0216-x . ISSN   1471-2148. PMC   4219001 . PMID   25318347.
  10. Trewick, Steven A. (2007). "DNA Barcoding is not enough: mismatch of taxonomy and genealogy in New Zealand grasshoppers (Orthoptera: Acrididae)". Cladistics. 24 (2): 240–254. doi: 10.1111/j.1096-0031.2007.00174.x . S2CID   85151482.
  11. Koot, Emily M.; Morgan-Richards, Mary; Trewick, Steven A. (2020). "An alpine grasshopper radiation older than the mountains, on Kā Tiritiri o te Moana (Southern Alps) of Aotearoa (New Zealand)". Molecular Phylogenetics and Evolution. 147: 106783. doi:10.1016/j.ympev.2020.106783. ISSN   1055-7903. PMID   32135305. S2CID   212567788.
  12. Toki, Nicola; Mulligan, Jesse (3 March 2017). "Critter of the Week: the Sigaus Grasshopper". RNZ. Retrieved 3 March 2017.
  13. Trewick, S.; Johns, P.; Hitchmough, Rod; Rolfe, J.; Stringer, I. (2016-09-01). "Conservation status of New Zealand Orthoptera, 2014" (PDF). New Zealand Threat Classification Series. 16: 1–19.