Rhyncogonus caudatus Van Dyke

Tailed Rhyncogonus Weevil (Rhyncogonus caudatus)

This species is endemic to the island of Huahine, where it can be found on the leaves of several non-native and native plants, including nahe (Angiopteris evecta (G. Forst.) Hoffm.).

The animals are black in colour and bear some larger, white scales on the sides of the head, the body, and above all, the abdomen, where they build some kind of a short process.

The males reach a length of about 1,15 cm, the females, with 1,4 cm, are distinctly larger. [1]

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References:

[1] Edwin C. Van Dyke: Rhyncogonus of the Mangarevan Expedition. Bishop Museum Occasional Papers 13(11): 89-129. 1937

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Rhyncogonus submetallicus Van Dyke

Tahitian Metallic Rhyncogonus Weevil (Rhyncogonus submetallicus)

The Tahitian Metallic Rhyncogonus Weevil was described in 1933.

The species reaches a length of about 1,3 cm, the upper side is glossy black with metallic greenish bronze shining elytra, it is covered with gray to very light fulvous hair. [1]

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References:

[1] Edwin C. Van Dyke: Rhyncogonus submetallicus, new species, from Tahiti. Bishop Museum Bulletin 113: 51-52. 1933

Dryophthorus distinguendus Perkins

Hawaiian Driftwood Weevil (Dryophthorus distinguendus)

The Hawaiian Driftwood Weevil was described in the year 1900.

The species was found first on the island of Laysan, namely in wooden boxes that came from the main islands. It was subsequently found also on nearly all of the other Hawaiian Islands (Hawai’i, Kure, Lana’i, Maui, Midway, Moloka’i, and O’ahu), but appears in lists of extinct species, which, in my opinion, is quite strange.

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References:

[1] R. C. L. Perkins: Coleoptera, Weevils. Bishop Museum Bulletin 31: 53-66. 1926

Lyperobius carinatus Broun

Keeled Lyperobius Weevil (Lyperobius carinatus)

The Keeled Lyperobius Weevil, described in 1881, is endemic to the alpine regions of New Zealand’s South Island.

The quite large, flightless beetle reaches a length of about 2 to 2,5 cm, the body is reddish-brown to black and covered with white or yellowish white scales, which form keel-like longitudinal stripes on the elytra.

Nesotocus giffardi Perkins

Giffard’s Nesotocus Weevil (Nesotocus giffardi)

Giffard’s Nesotocus Weevil is found on the islands of Hawai’i, Kaua’i, Maui, and O’ahu.

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The genus Nesotocus, which contains four species, is now placed within the subfamily Molytinae, with the most closely related species living in Australia and New Zealand.

The males of all species can easily be distinguished from the females by their longer legs, and especially by the position of their antennae, these are placed in the anterior third of the rostrum, while in the females the antennae are placed further towards the posterior third.

The larvae of all species bore in the wood of dead olapa trees (Cheirodendron trigynum (Gaudich.) Heller) on which they feed upon, the pupation takes place inside a chamber (pupal cell), which can be detected by a distinct hole on the outside of the wood.

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References:

[1] John Colburn Bridwell: Notes on Nesotocus Giffardi Perkins (Coleoptera). Proceedings of the Hawaiian Entomological Society 4(1): 250-256. 1918
[2] Sadie A. Solomon: Systematics of the Hawaiian endemic weevil genus Nesotocus Perkins 1900 (Coleoptera: Curculionidae). Student Competition Display Presentations, Section A. Systematics, Morphology, and Evolution 2003

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Photo: Hank L. Oppenheimer
http://hear.smugmug.com

(under creative commons license (3.0))
http://creativecommons.org/licenses/by-nc/3.0

Oclandius vestitus (Broun)

Snares Oclandius Weevil (Oclandius vestitus)

The Snares Oclandius Weevil was described in the year 1909.

The flightless species reaches a body length of only 0,12 cm, it occurs exclusively on some of the Snares Islands.

The beetles are nocturnal and obviously feed mainly on the leaves of the Snares Islands Anisotome (Anisotome acutifolia (Kirk) Cockayne) and Lyall’s Tree Daisy (Olearia lyallii Hook. f.).

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Depiction from: ‘Chas. Chilton: The Subantarctic Islands of New Zealand. Reports on the Geo-Physics, Geology, Zoology, and Botany of the Islands lying to the south of New Zealand, based mainly on observations and collections made during an Expedition in the Government Steamer “Hinemoa” (Captain J. Bollons) in November 1907. Wellington, N.Z., printed by J. Mackay, Government Printer 1909′

(public domain)

Elytrurus niuei Zimmerman

Niue Coconut Weevil (Elytrurus niuei)

This species was described in the year 1956, it reaches a length of about 1 cm, the females are slightly larger than males.

The larvae seem to feed on the bark or wood of coconut palm trunks (Cocos nucifera L.). [1]

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References:

[1] Elwood C. Zimmerman: Description of a new species of Elytrurus and a catalogue of the known species (Colepotera: Curculionidae: Otiorhynchinae). Pacific Science 10: 286-295. 1956

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elytrurus-niuei-padil-ch

Photo: Caroline Harding
http://www.padil.gov.au

(under creative commons license (3.0))
http://creativecommons.org/licenses/by/3.0

Rhyncogonus brevis Van Dyke

Short Rhyncogonus Weevil (Rhyncogonus brevis)

The Short Rhyncogonus Weevil was first discovered in the year 1930, when an individual was found on a puatoatoa shrub (Vaccinium cereum (L. f.) G. Forst.).

It is a small species, about 1 cm long, with an short, robust, sparsely haired, black coloured thorax. [1]

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References:

[1] Edwin C. Van Dyke: Microgonus, new genus, and Rhyncogonus, from the Marquesas. Bishop Museum Occasional Papers 98: 23-52. 1932

Rhyncogonus fulvus Van Dyke

Fulvous Rhyncogonus Weevil (Rhyncogonus fulvus)

The Fulvous Rhyncogonus Weevil is a large (about 1,4 cm long), broadly fusiform, black colored species, densely clothed above with ochraceous hair-like scales.

The species was discovered in the year 1934, when the holotype, a female, was found on a cultivated yams plant (Dioscorea spp.). [1]

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References:

[1] Edwin C. Van Dyke: Rhyncogonus of the Mangarevan Expedition. Bishop Museum Occasional Papers 13(11): 89-129. 1937

Rhyncogonus blackburni Sharp

Blackburn’s Rhyncogonus Weevil (Rhyncogonus blackburni)

This weevil is endemic to the island of O’ahu, where it can be found at several places within the Ko’olau Range, for example the Kahana, the Papali-Ma’akua, the Wai’alae Iki, and the Wailupe Ridges. This species may once have been far more common, as the first specimens were collected in the vicinity of Honolulu.

Blackburn’s Rhyncogonus Weevil is a pitch black coloured beetle with the females being much larger than the males (they are about 1,7 cm long, while the males are only about 1,2 cm long).

The food plants of the leaf-feading adult beetles include koa (Acacia koa A. Gray), kalia (Elaeocarpus bifidus Hook. & Arn.), and naupaka kuahiwi (Scaevola gaudichaudiana Cham.).

The beetles lay their eggs onto the phyllodes of the Koa Acacia, where they are glued together, forming a protective envelope.

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A wasp species, the Rhyncogonus Wasp (Eupelmus rhyncogoni Perkins), is known as a brood parasite of this beetle species. [1]

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References:

[1] G. A. Samuelson: Review of Rhyncogonus of the Hawaiian Islands (Coleoptera: Curculionidae). Bishop Museum in Entomology 11: 1-107. 2003