Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

FNZ 39 - Molytini (Insecta: Coleoptera: Curculionidae: Molytinae) - Taxonomic Definition

Craw, RC 1999. Molytini (Insecta: Coleoptera: Curculionidae: Molytinae). Fauna of New Zealand 39, 68 pages.
( ISSN 0111-5383 (print), ; no. 39. ISBN 0-478-09325-X (print), ). Published 4 Feb 1999

Taxonomic Definition of N.Z. Molytini

Weevils belonging to the tribe Molytini of the curculionid subfamily Molytinae can be recognised in the New Zealand fauna, and distinguished from offshore Molytini by the following combination of characters.

Adults. Length (excluding rostrum) 11.5-28 mm, greatest width (across elytra) 5.9-12.5 mm. Large, brachypterous, flightless molytine curculionids. Wings rudimentary, narrowly laminate, 0.2-0.65x as long as elytra. Antennae geniculate; funicle with 7 segments, the 7th free from club; club with 3 segments, the 1st longer than remainder of club, the 3rd with a transverse line; sutures straight, oblique. Prothorax with ocular lobes prominent to obsolete, prosternum emarginate. Procoxae contiguous, metacoxae transverse. Tibial apex with uncus and premucro, the uncus arising from a low corbel carina (Fig. 35); distal protibial comb rounded, meso- and metatibial combs obliquely sinuate. Tarsi spongy beneath; 1st segment elongate; 3rd segment much broader than the 2nd, bilobed; 4th segment concealed; 5th segment longer than the 3rd; claws symmetric, free.

Male. Tergite 8 not concealed by tergite 7. Sternite 8 composed of 2 separate sclerotised plates, posteriorly emarginate, with short latero-apical setae. Sternite 9 with asymmetric arms and a sclerotised lobe (Fig. 44, 46). Tegmen complete; parameres well developed, with a short manubrium (Fig. 45, 47). Aedeagus: median lobe weakly sclerotised along dorsal median line (Fig. 58); pedal portion divided laterally by a greatly distensible membrane (Fig. 64). Endophallus non-eversible, attached to apical margin of aedeagus. Ejaculatory duct inserted dorsally inside proximal arms of heavily sclerotized basal sclerite.

Female. Sternite 8 with 2 sclerotised arms, sometimes fused apically, and bearing short latero-apical setae (Fig. 70-76). Hemisternites long, divided into distinct proximal and distal portions, the distal portion with numerous short setae; short to long membranous hemisternal pouches present. Vagina not extending past hemisternal bases. Bursa copulatrix large, long; spermathecal duct inserted on base of bursa near junction with median oviduct, dilated at insertion point. Spermatheca falciform, much shorter than large spermathecal gland (Fig. 77-83).

Larvae (see, e.g., May 1993, fig. 830-839). Length 17.5-32 mm, width 6.5-10 mm. Body large, robust, dense creamy white; head dark red-brown to black, partially retracted. Frontal suture narrow, not angulate before apex. Dorsoepicranial setae 3 not in contact with frontal suture. Frontal setae 5 well developed. Thoracic segments with a V-shaped pocket medially between the 2 ventral folds. Abdominal segment VIII without prodorsal setae. Spiracles conspicuous, elongate-ovate or subcircular; airtubes conspicuous, with fine, pigmented annuli, directed dorsad (thoracic) or caudad (abdominal); AbdVIII spiracle on dorsum, as large as thoracic spiracle.

Pupae. Maximum length 17-20 mm. Cuticle glabrous; setae dark, tapering, mounted on small tubercles, strongest on head and pronotum, finer on abdomen. Elbows with subequal setae. Pseudocerci on abdominal segment IX short, dark, curved, without associated setae. Antennal club smooth. Primary protheca bullate (Hadramphus) or striate (Lyperobius), with spinules on dorsal margin and ridges; secondary pterotheca shorter than the primary.

[Descriptions of larvae and pupae from May 1971, 1981, 1987a, 1993.]

Host plants. Apiaceae (Aciphylla and Anisotome), Araliaceae (Stilbocarpa), and Pittosporaceae.

Remarks. Pascoe (1876, 1877) placed Lyperobius huttoni and L. tuberculatus in Lacordaire's (1863) group Molytides, based on Schoenherr's (1823) family-group name for this taxon. The family-group name Liparides (Latreille 1828) - used by Marshall (1932), Solari (1941), Morimoto (1962), and others to refer to a tribe (Liparini) of the subfamily Hylobiinae - is equivalent. An ecophyletic cline from fully flying Hylobinii to flightless Liparini was noted by Morimoto (1982), who associated these two tribes under the family-group name Hylobiini Kirby, 1837; the tribal name Molytini has priority, however. Following Hudson (1934) and Kuschel (1987) this tribe, as represented in New Zealand, is placed in the subfamily Molytinae.

Larvae of Hadramphus and Lyperobius can be separated from the superficially similar large larvae of Anagotus species (Aterpinae) by (a) having dorsoepicranial setae 3 situated on the epicranium and not within the frontal suture or on the frons, and (b) abdominal segment IX having two dorsal setae, one slightly longer than the other. They are unlikely to be confused, though, because of host-plant differences - no Anagotus larvae are found on Apiaceae, Araliaceae, or Pittosporaceae.

Hadramphus and Lyperobius larvae differ from those of the xylophagous Holarctic Hylobius Germar and Nearctic Pachylobius Le Comte mainly in the shape and alignment of the spiracles. They share with Hylobius and its allies conspicuously large airtubes that are often pigmented. Larvae of the European molytine Liparus germanus Linnaeus are very similar also to those of the New Zealand Molytini, having elongate-ovate spiracles in common with Hadramphus larvae (cf. Scherf 1964 and May 1971, 1981, 1987a, 1993).

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