Lyperobius huttoni
Lyperobius huttoni | |
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Illustration by Des Helmore | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Infraorder: | Cucujiformia |
Family: | Curculionidae |
Genus: | Lyperobius |
Species: | L. huttoni
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Binomial name | |
Lyperobius huttoni Pascoe, 1876
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Synonyms | |
Lyperobius huttoni (known as Hutton's speargrass weevil, or simply speargrass weevil) 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.
Taxonomy
This species was first described by Francis Pascoe in 1876.[1] Pascoe based his description on material collected in Tarndale, near Nelson, by Frederick Hutton, and named the species in his honour.[2] Hutton collected it on Aciphylla colensoi.[2] The lectotype specimen is held at the Natural History Museum, London.[3]
Description
This weevil is dark-coloured and about 2 cm long, with a short thick rostrum.[3][4] Males and females are difficult to distinguish externally; females are slightly larger, and have a larger and more rounded fifth abdominal ventrite.[3] George Hudson, comparing this species with Lyperobius hudsoni, described the species as follows:
(25–26 mm) Larger with relatively shorter and broader rostrum; the elytra have six rows of deep punctiform impressions; general colour is black slightly tinged with reddish, almost without clothing.[5]
Distribution and habitat
Lyperobius huttoni lives in subalpine and high country
Behaviour and host species
L. huttoni feeds on the speargrass species Aciphylla squarrosa, A. colensoi, and A. aurea.[3] Adults are active during the day, and are most easily found on foliage on calm, warm, sunny days, feeding on leaves and flower stalks. The weevils leave notches on the leaf edges of their host plant and sometimes eat leaves completely through.[8] Larvae burrow into the soil and feed on the Aciphylla taproot, and can be found in the surrounding dead and decomposing foliage at ground level. Evidence of their presence are dead or dying speargrass plants or deep oval notches on leaf petioles.[9] The weevil spends a year as a larva before constructing a chamber in which it pupates for two weeks.[3] After emerging, the teneral adult weevils can stay in the chamber for eight months before emerging, and live for over two years.[3][4]
Disease
During research into the captive breeding of L. huttoni it was discovered that the weevil is susceptible to a species of fungus in the genus Beauvaria. This was one of the main causes of mortality in the study.[9]
Conservation
The species is one of the invertebrates "declared to be animals" in the 1980 amendment of the Wildlife Act 1953, and thus legally protected.[10] They are flightless, slow-moving beetles, vulnerable to being eaten by mice and rats, and their host plants are susceptible to browsing by mammals such as sheep, pigs, and goats.[6] One population at Ōwhiro Bay on the Wellington coast was destroyed when their entire habitat was turned into a quarry.[3]
The population of this species found in Marlborough is regarded as stable, but in Canterbury the combined effects of predation by rodents and habitat destruction have caused the population of this species to decline.[11]
The Wellington population once extended from
References
- ^ "Lyperobius huttoni Pascoe, 1876". www.nzor.org.nz. Landcare Research New Zealand Ltd. Retrieved 2018-06-08.
- ^ .
- ^ ISBN 0-478-09325-X.
- ^ a b c Bull, R.M. (1967). A study of the large New Zealand weevil, Lyperobius huttoni Pascoe 1876. (Coleoptera: Curculionidae, Molytinae) (Master of Science Thesis). Victoria University, Wellington. Retrieved 8 June 2018.
- ^ Hudson, George Vernon (1934). New Zealand beetles and their larvae: an elementary introduction to the study of our native Coleoptera. Wellington: Ferguson & Osborne. p. 133. Retrieved 8 June 2018.
- ^ a b c d Miskelly, Colin (20 November 2015). "Speargrass weevils thriving on Mana Island". Te Papa blog. Retrieved 8 June 2018.
- ^ a b Department of Conservation (31 March 2006). "Weevil rescue underway". Scoop. Retrieved 8 June 2018.
- S2CID 18904197. Retrieved 8 June 2018.
- ^ hdl:10182/685.
- ^ "Schedule 7: Terrestrial and freshwater invertebrates declared to be animals". New Zealand Legislation. 7 May 2018. Retrieved 8 June 2018.
- ISSN 1171-9834.
External links
- Speargrass weevil discussed on RNZ Critter of the Week, 8 June 2018