Scolopterus tetracanthus explained

Scolopterus tetracanthus, more commonly known as the four-spined weevil, is a beetle of the genus Scolopterus. First described by A. White in 1846, it is endemic to New Zealand.

Taxonomy

The species was described by Scottish zoologist Adam White in 1846, who based his description on specimens collected during the Ross expedition. Thomas Broun designated S. tetracanthus as the type species of the genus Scolopterus in 1880.

Physical characteristics

White's original text (the type description) reads as follows:

The four-spined weevil is highly distinct in appearance, with knobs and spines common on its physical form.^{[1] [2]} The shoulder of each elytron forms into an acute cone,^[3] with a sharp spine at the summit of the hind slope, distinguishing them from their less pointed and spiny cousin, Scolopterus penicillatus.

It is about long, usually shiny black with bronze or red reflections.^[4] Metallic and bright colours are not common in this family.

It has a smooth head and thorax, with elytra very deeply punctured in lines. One major feature of an elytra in Coleoptera is the striae, and in the case of Scoplopterus tetracanthus, they have very deeply prominent punctures.

Individuals within the genus of Scolopterus tend to have large, longitudinally oval eyes that are not convexed, and sit on the upper surface either side of their narrow head.^[5]

Behaviour

The four-spined weevil is a pollinator of an endemic tree to New Zealand, Schefflera digitata, of the family Araliacaea, known also as patē, seven-finger, or umbrella tree.^[6]

Distribution and habitat

Distribution

They are naturally uncommon,^[7] but distributed in forest throughout North Island of New Zealand, with very few observations recorded in South Island

Habitat

Four-spined weevils are known to breed in dead and rotting timber.^[8] The larvae of Scoplopterus require dead wood to eat and grow.^[9] Adults can be found in spring, summer and autumn.^[10]

Notes and References

1. Book: Walker, J.J. . The president's address. - The fringes of butterfly life. . 1920 . Transactions of the Entomological Society of London . 1919: XCI-CXIII.
2. Book: Walker, J.J. . Antipodean field notes. 2 - A year's insect hunting in New Zealand . 1904 . Entomologist's monthly magazine . 40:68-77.
3. Cawthra, E.M. . 1966 . A redefinition of the subfamily Eugnominae to include the Meriphinae. . Transactions of the Royal Society of New Zealand: Zoology . 7 . 12 . 171–178.
4. Book: Hudson, G.V . New Zealand beetles and their larvae: an elementary introduction to the study of our native Coleoptera. . 1934 . FERGUSON & OSBORN LTD, WELLINGTON: 236 PP.
5. Broun, T. . 1893 . Manual of the New Zealand Coleoptera. . Government Printer, Wellington . 5, 6 & 7 . V-XVII . 975–1504.
6. Heine, E.M. . 1937 . Observations on the pollination of New Zealand flowering plants. . Transactions and Proceedings of the Royal Society of New Zealand . 67 . 133–148.
7. Moeed . Abdul . Meads . M. J. . 1983 . Invertebrate Fauna of Four Tree Species in Orongorongo Valley, New Zealand, as Revealed by Trunk Traps . New Zealand Journal of Ecology . 6 . 39–53 . 24052727 . 0110-6465.
8. Book: Anon . Forest insect survey and life, Forest insect survey newsletter. . 1957 . Forest research institute, N.Z. . Forest Service: 6:1-32.
9. Book: May, Brenda M. . Larvae of Curculionoidea (Insecta: Coleoptera): a systematic overview. Fauna of New Zealand, Ko te Aitanga Pepeke o Aotearoa, Number / Nama 28 . 1993 . Manaaki Whenua Press . Lincoln, Canterbury, New Zealand.
10. Moeed . Abdul . Meads . M. J. . 1987 . Seasonality of arthropods caught in a Malaise trap in mixed lowland forest of the Orongorongo Valley, New Zealand . New Zealand Journal of Zoology . en . 14 . 2 . 197–208 . 10.1080/03014223.1987.10422990 . 0301-4223.