Mecodema howittii
| Mecodema howittii | |
|---|---|
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Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Coleoptera |
| Suborder: | Adephaga |
| Family: | Carabidae |
| Genus: | Mecodema |
| Species: | M. howitti
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| Binomial name | |
| Mecodema howitti Laporte de Castelnau, 1867
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| Synonyms | |
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Mecodema howitti, termed the large Banks Peninsula ground beetle, is a carnivorous forest ground beetle in the genus Mecodema. It is endemic to Banks Peninsula, Canterbury, New Zealand, and is the largest of the 10 endemic carabids found in the area.[1]
There are very limited records, and in general there is little ecological knowledge about this species. M. howitti is listed as threatened, range-restricted, and sparse within Banks Peninsula,[2] however the Department of Conservation has been prevented from ranking this species as a priority threatened species due to the lack of ecological information available.[3]
Taxonomy
This species was originally described in 1867 by Francis de Castelnau from a specimen collected in Christchurch. The specific name refers to the collector "Dr Howitt".[4] The type specimen is stored in the Genoa Museum.[5] The species was described again just a year later as Mecodema rectolineatum and then again as Mecodema walkeri in 1904 by Thomas Broun.[6][7] These species names were later synonymised in 1874 and 1949 respectively.[8][5] The species was most recently given an updated description in 1949, in which it was assigned to the costellum species group.[5]
Description
They are the largest of the 10 endemic ground beetle species that can be found in Banks Peninsula, measuring 26-31mm (1.02-1.2 in) in length.[1] They are similar to other Mecodema and can be distinguished by the structure of the elytra and the presence or absence of setiferous punctures (depressions in the body with a hair in them).[5]
The overall colour of the body is black. The vertex of the head has a smooth texture with a depression and faint (or in some cases absent) punctures. The basal section of the labium has three punctures on either side. The margins of the pronotum have ten to twelve punctures on the lateral margins. The third and fifth elytral intervals are flattened. The second, fourth, sixth and eighth intervals are shiny (except for where they have punctures). The first, third and seventh intervals are also shining.[5]
Distribution and habitat
M. howitti is endemic to Banks Peninsula in the Canterbury region of the South Island. They are only known to occur in the central and eastern parts of the peninsula, although historical records indicate they used to occur as far west as the Port Hills. It is possible that this reduction is distribution is due to habitat loss and predation by introduced mammals. They can be found at both lowland and higher altitudes.[1]
They are known to occur in forest and grassland habitats (and are apparently most common in the latter), but can also be found in human modified habitat such as pastures.[1][9] The distribution of the species is linked with the presence of fallen logs to hide under (although they live in burrows).[1][3]
Life history
They are most active during spring and summer months (when they appear to be breeding), being most common in November. Gravid females have been observed from December to January.[3]
Behaviour
The beetles are nocturnal, but can be seen during the day in some conditions.[9][3] They are known to be active predators. There are observations of them preying on the larvae of Holcaspis suteri , crane flies and Tenebrio molitor (in captivity).[10] They are thought to be less active when soil temperatures are below 6.5°C and are also known to be slow runners.[3][9]
Predators and parasites
Native predators are presumed to include the morepork, large species of spider and weka (although this species is no longer present on the peninsula).[10] They are also assumed to be preyed upon by introduced mammalian predators.[1] An undescribed species of mite from the Micromegistus genus has been associated with M. howitti. The mites primarily latch onto the pronotal and metasternum areas and are most common around the coxae.[10]
Conservation status
Under the New Zealand Threat Classification System, this species is listed as "Declining" with the qualifiers of "Range Restricted" and "Sparse".[2]
External links
iNaturalist observations of M. howitti
References
- ^ a b c d e f Anderson, Susan J.; Emberson, Rowan M.; Brown, Barbara (2003). "Distribution and conservation requirements of Mecodema howitti Castelnau (Coleoptera: Carabidae: Broscini)". New Zealand Entomologist. 26 (1): 45–52. doi:10.1080/00779962.2003.9722107. ISSN 0077-9962.
- ^ a b Leschen, R. A.B.; Marris, J. W.M.; Emberson, R. M.; Nunn, J.; Hitchmough, R. A.; Stringer, I. A.N. (2012-07-01). "The conservation status of New Zealand Coleoptera". New Zealand Entomologist. 35 (2): 91–98. doi:10.1080/00779962.2012.686311. ISSN 0077-9962.
- ^ a b c d e Anderson, S. J.; Brown, B.; Emberson, R. M. (2004). "Seasonal activity and habitat associations of Mecodema howitti and Megadromus guerinii, two endemic New Zealand ground beetles (Coleoptera: Carabidae)". New Zealand Journal of Zoology. 31 (4): 305–312. doi:10.1080/03014223.2004.9518383. S2CID 84551722.
- ^ Laporte de Castelnau, F L (1867). "Notes on Australian Coleoptera Part II". Transactions and Proceedings of the Royal Society of Victoria. 8: 159–160.
- ^ a b c d e Britton, E.B. (1949). "The Carabidae (Coleoptera) of New Zealand Part III - A revision of the Broscini". Transactions of the Royal Society of New Zealand. 77 (4): 533–581.
- ^ Putzeys, J (1868). "Les broscides". Stettiner Entomologische Zeitung. 29: 317–318.
- ^ Broun, T (1904). "Descriptions of new genera and species of New Zealand Coleoptera". Annals and Magazine of Natural History. 12: 43–44.
- ^ Bates, H W (1874). "On the geodephagous Coleoptera of New Zealand". Annals and Magazine of Natural History. 4: 236.
- ^ a b c Larochelle, A; Larivière, M-C (2001). "Carabidae (Insecta: Coleoptera): catalogue". Fauna of New Zealand. 43. doi:10.7931/J2/FNZ.43. ISSN 1179-7193.
- ^ a b c Anderson, S. J. (2000). Distribution, Habitat Associations, and Activity Patterns of Two Endemic Banks Peninsula Carabid Beetles, Mecodema howitti and Megadromus guerinii (Phd). Lincoln University.