Anagotus stephenensis

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Ngaio weevil
Ngaio Weevil.JPG
Status NZTCS NC.svg
Nationally Critical (NZ TCS)
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Curculionidae
Genus: Anagotus
Species:
A. stephenensis
Binomial name
Anagotus stephenensis
G. Kuschel, 1982
Synonyms [1]
  • Phaeophanus o'connori Broun, 1921

Anagotus stephenensis, commonly known as the ngaio weevil, is a large flightless weevil that is only found on Stephens Island in New Zealand. The ngaio weevil was discovered in 1916 by A.C. O'Connor on Stephens Island. Thomas Broun described it in 1921 as Phaeophanus oconnori after its collector. The weevils were observed at the time to be 'feeding on tall fescue and the leaves of trees'. [2]

Contents

Description

This large weevil has a dark exoskeleton, covered in small hair-like coppery-brown scales. On the sides and posterior, the colouration is lighter with a prominent white streak along the centre of its thorax. It has obvious prominences on its sides and posterior. Its rostrum is as long as its thorax with a wide channel in the centre. Including the rostrum, its size ranges from 23 to 27 mm. [1] This weevil is nocturnal and flightless. It is similar in colouration and size and closely related to the Turbott's weevil. [3]

Distribution

The ngaio weevil has a historic range as far away as South Canterbury. The collection of elytra, heads and other body parts in seven cave deposits produced by the extinct laughing owl show it was once widespread and common. It has a relict population on Stephens Island. [2]

Habitat

The weevil is known to live on ngaio trees (Myoporum laetum), feeding on leaves, where it produces a characteristic feeding notch. The adults have also been found on the karaka tree (Corynocarpus laevigatus). [2] Larvae are thought to be woodborers of the same host tree. [4] Larvae of other members of the Aterpini tribe are mostly associated with live wood, boring into stems, leaf bases and roots. [5]

Conservation

This species had its conservation status upgraded to nationally critical in 2012 due to it being found in low numbers in one location. [6] Fifteen specimens were collected by the original expedition in 1916 by A.C. O'Connor. There have not been any specimens collected since 1971 and a devoted search in 1995 found one or two specimens over five nights. This indicates a reduction in population since 1916. [2] The cause of this is likely to be the forest clearance on Stephens Island which caused a reduction in weevil habitat, when a lighthouse was built there in 1892. [7] It is possible that the side-effect of an increase in tuatara population after the removal of feral cats in 1925 [8] may have been to reduce the population of the ngaio weevil. [9] The chances of a large, flightless and nocturnal beetle moving from one ngaio tree to another past numerous tuatara and surviving predation is low. [2] It is protected under Schedule 7 of The 1953 Wildlife Act, making it an offense to collect, possess or harm a specimen. [10]

Related Research Articles

Weevil Superfamily of beetles

Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than 6 mm in length, and herbivorous. About 97,000 species of weevils are known. They belong to several families, with most of them in the family Curculionidae. Some other beetles, although not closely related, bear the name "weevil", such as the biscuit weevil, which belongs to the family Ptinidae.

New Zealand giraffe weevil Species of beetle

The New Zealand giraffe weevil, Lasiorhynchus barbicornis, is a distinctive straight-snouted weevil in the subfamily Brentinae, endemic to New Zealand. L. barbicornis is New Zealand's longest beetle, and shows extreme sexual dimorphism: males measure up to 90 mm, and females 50 mm, although there is an extreme range of body sizes in both sexes. In males the elongated snout can be nearly as long as the body. Male giraffe weevils use this long rostrum to battle over females, although small males can avoid conflict and 'sneak' in to mate with females, sometimes under the noses of large males. The larval weevils tunnel into wood for at least two years before emerging, and live for only a few weeks as adults.

<i>Hadramphus tuberculatus</i> Species of beetle

Hadramphus tuberculatus is a rare weevil endemic to Canterbury in the South Island of New Zealand. It was thought to be extinct in 1922 but was rediscovered in 2004.

<i>Hadramphus</i> Genus of beetles

Hadramphus, commonly known as knobbled weevils, is a genus of flightless molytine weevils from the family Curculionidae. It is endemic to New Zealand and consists of four species.

Flax weevil Species of weevil endemic to New Zealand

Anagotus fairburni or flax weevil is a large flightless weevil. It feeds on leaves of New Zealand flax species where it produces a characteristic feeding notch. It is found on islands and in alpine areas of New Zealand.

<i>Peristoreus flavitarsis</i> Species of beetle

Peristoreus flavitarsis is a species of true weevil. It is endemic to New Zealand. The larvae are leaf miners of Podocarpus totara. Similar leaf mines have also been found on Podocarpus acutifolius and Podocarpus cunninghamii.

<i>Peristoreus stramineus</i> Species of beetle

Peristoreus stramineus is a species of true weevil. It is endemic to New Zealand. The larvae develop in flower buds of Hoheria populnea.

Turbotts weevil Species of beetle

Turbott's weevil is a weevil that is endemic to New Zealand. It has been found on the Hen and Chicken Islands, the Poor Knights Islands and the Three Kings Islands.

<i>Blosyropus spinosus</i> Species of beetle

Blosyropus spinosus, also known as the spiny longhorn or spiny silver-pine borer, is a rare species of longhorn beetle endemic to New Zealand. It has no specific Māori name, but the term for large longhorns of this type are howaka and kapapa.

<i>Didymus metrosideri</i> Species of beetle

Didymus metrosideri is an endemic weevil from the Kermadec Islands in New Zealand. This species was discovered by W. L. Wallace during the 1908 Kermedec Islands expedition.

<i>Amychus granulatus</i> Species of beetle

Amychus granulatus, commonly known as the Cook Strait click beetle, is a large flightless click beetle in the family Elateridae.

Cerius otagensis is a species of flightless fungus weevil that is endemic to New Zealand. It has been found in only two locations in the Central Otago region.

<i>Hadramphus spinipennis</i> Species of beetle

Hadramphus spinipennis, commonly called the coxella weevil, is a large, nocturnal, flightless weevil only found on Mangere and Rangatira Islands in the Chatham Islands, New Zealand.

<i>Geodorcus alsobius</i> Species of beetle

Geodorcus alsobius, or Moehau stag beetle, is a large flightless species of stag beetle in the family Lucanidae. It is found only on Mt Moehau, the highest mountain in the Moehau Range on the Coromandel Peninsula in New Zealand.

<i>Geodorcus auriculatus</i> Species of beetle

Geodorcus auriculatus is a large flightless stag beetle that is found in the southern part of the Coromandel Peninsula and on Mount Te Aroha in the Kaimai range of New Zealand.

<i>Geodorcus ithaginis</i> Species of beetle

Geodorcus ithaginis, the Mokohinau stag beetle, is a large flightless species of stag beetle in the family Lucanidae. It was described by Thomas Broun in 1893 after being discovered in the Mokohinau Islands by Andreas Stewart Sandager, a lighthouse keeper on the islands. The species survives only on the small unnamed island "Stack H", in an patch of vegetation the size of a living room, and is in extreme danger of extinction.

<i>Lyperobius huttoni</i> Species of beetle

Lyperobius huttoni is a New Zealand weevil found in alpine areas of the South Island and at sea level around the Wellington coast. It feeds only on speargrass (Aciphylla). Weevils from the endangered Wellington population have been translocated to predator-free Mana Island.

<i>Lyperobius hudsoni</i> Species of beetle

Lyperobius hudsoni is a flightless weevil found in alpine areas of Central Otago and Otago Lakes in the South Island of New Zealand.

<i>Amychus manawatawhi</i> Species of beetle

Amychus manawatawhi, commonly known as the Three Kings click beetle, is a large flightless click beetle in the family Elateridae, found only on the Three Kings Islands of New Zealand.

Brenda Mabel May was a New Zealand speleological entomologist known for her contributions to the understanding of weevil larvae biology. Between 1956 and 1980, she worked in the Entomology Division of the Department of Scientific and Industrial Research (DSIR). Afterwards, she became a research associate at Landcare Research, where she completed a systematic overview of New Zealand Curculionoidea, published in 1993. In 1998, May was elected as a Fellow of the Entomological Society of New Zealand in recognition of her contributions.

References

  1. 1 2 Broun, Thomas (30 August 1910). Descriptions of new genera and species of coleoptera. Wellington, New Zealand: New Zealand Institute. p. 631. Retrieved 28 November 2016.
  2. 1 2 3 4 5 Kuschel, G; Worthy, TH (1996). "Past distribution of large weevils (Coleoptera: Curculionidae) in the South Island, New Zealand, based on Holocene fossil remains title" (PDF). New Zealand Entomologist. 19: 15–19. doi:10.1080/00779962.1996.9722016. Archived from the original (PDF) on 2016-01-24.
  3. ↑ Marris, John (2001). Beetles of Conservation Interest from the Three Kings Islands. Department of Conservation. p. 14. hdl:10182/2996.
  4. ↑ Kuschel, G (1982). "Apionidae and Curculionidae (Coleoptera) from the Poor Knights Islands, New Zealand". Journal of the Royal Society of New Zealand. 12 (3): 281. doi: 10.1080/03036758.1982.10415349 .
  5. ↑ May, Brenda (1993). "Larvae of Curculionoidea (Insecta: Coleoptera): a systematic overview" (PDF). Fauna of New Zealand. 28: 62. Retrieved 19 July 2017.
  6. ↑ Stringer, I.A.N; Hitchmough, R.A.; Leschen, R.A.B.; Marris, J.W.M.; Emberson, R.M.; Nunn, J. (2012). "The conservation status of New Zealand Coleoptera". New Zealand Entomologist. 35 (2): 91–98. doi:10.1080/00779962.2012.686311. S2CID   219566068.
  7. ↑ Miskelly, Colin (2015-02-15). "Birds and mammals of Takapourewa / Stephens Island". Museum of New Zealand, Te Papa. Retrieved 19 July 2017.
  8. ↑ Bellingham, Peter J.; Towns, David R.; Cameron, Ewen K.; Davis, Joe J.; Wardle, David A.; Wilmshurst, Janet M.; Mulder, Christa P.H. (2010). "New Zealand island restoration: seabirds, predators, and the importance of history" (PDF). New Zealand Journal of Ecology. 34 (1): 116. Retrieved 19 July 2017.
  9. ↑ Motala, Saoud; Krell, Frank-Thorsten; Mungroo, Yacoob; Donovan, Sarah E. (2007). "The terrestrial arthropods of Mauritius: a neglected conservation target" (PDF). Biodivers Conserv. 16 (10): 2876. doi:10.1007/s10531-006-9050-9. S2CID   42116131. Archived from the original (PDF) on 15 September 2012. Retrieved 19 July 2017.
  10. ↑ "Wildlife Act 1953". New Zealand Legislation. Parliamentary Counsel Office. Retrieved 28 November 2016.
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