British insects: the families of Coleoptera

L. Watson and M. J. Dallwitz

Curculionidae

Including Calendridae, Chapuisidae, Cossonidae, Erirhinidae, Ipidae, Rhynchophoridae, etc.

Weevils and Ambrosia Beetles, True Weevils, Snout Beetles.

General appearance. 1.5–14 mm long. Body length/maximum body width 1.2–5.7. Elytral length/pronotal length 0.9–4.6. Base of prothorax not or scarcely narrower than the combined elytral bases, or distinctly narrower than the combined elytral bases. Greatest prothoracic width not narrower or only slightly narrower than the greatest elytral width, or distinctly narrower than greatest elytral width. Beetles oval to elongate; not necked; conspicuously waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; exhibiting stiff, erect, dark bristles, or not bristly; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.

Detailed morphology. Beetles equipped with a rostrum (see illustration of Pissodes, exemplifying morphological details). Inclination of the head slight to very strong. Eyes strongly protuberant, or not strongly protuberant; without bristles. The maxillary palps if visible, short and rigid. Antennae short to about half the insect's head to tail length; usually conspicuously elbowed (inserted on the rostrum in front of the eyes, the rostrum often chanelled for reception of the scape); (1–)11(–12) segmented; with the scape much-elongated. Antennal scape not swollen. Antennae clubbed. Antennal clubs 3 segmented, or 4 segmented. Antennal insertions visible from above, or hidden from above; ‘countersunk’ within saucer-like fossae, or not in fossae. Mandibular prosthecae absent. Pronotal length/maximum pronotal width 0.42–5.7. Prothorax with notopleural sutures (usually), or without notopleural sutures (?). Metaventrite without a transverse groove. Hind coxae not shaped posteriorly to receive the femur. Tarsal segmentation formula 4, 4, 4. The tarsi exhibiting bilobed segments (usually), or without bilobed segments (rarely); with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth (usually), or without ‘hidden’ segments (rarely, then the third segment is not not bilobed and the claw segment is missing). Front tarsi with as many segments as the mid-tarsi; 4-segmented (usually), or 5-segmented. Mid-leg tarsi 4-segmented (rarely), or 5-segmented (usually); pseudotetramerous (nearly always), or tetramerous (rarely, when the third segment lacks the lobes, and the claw segment is missing). The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple, or one-toothed or bifid, or serrate, denticulate or pectinate; with an empodium between them (this with no more than two setae), or without an associated empodium. Hind tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented. Elytral length/maximum width across the elytra 0.7–4.2. Elytra exposing no more than part of the terminal tergite to at least one but fewer than three complete abdominal tergites; hard (strongly sclerotized, often clothed with scales). Scutellary striole absent. Wings well developed, or absent or much reduced; fringed with long hairs on the hind margin, or not fringed. Exposed abdominal sternites 5; all articulated and movable, or comprising both fused and movable components; immovably joined when present, 2–3 (usually the first two). Abdominal segment 8 apparently without functional spiracles.

Adult habitat, ecology. Not predacious; phytophagous (including numerous pests); in living vegetation.

Larvae. Larvae not predacious; phytophagous; on living vegetation. The larvae C-shaped, without legs, with small 1-segmented antennae.

Classification. Suborder Polyphaga; Superfamily Curculionoidea.

Worldwide and British representation. About 40000 species worldwide; genera about 400. 416 species in Britain; genera in Britain 102; Acalles, Anthonomus, Diaperis, Hypera, Lasiorhynchites, Lixus, Magdalis, Mesites, Mononychus, Notaris, Phytobius, Polydrusus, Zacladus, etc. E.g., Acalles roboris (Oak Achalles Weevil); Anthonomus pomorum (Pear-and-apple Weevil); Mesites tardii (Irish Cossonus Weevil); Diaperis boleti (Orange-spotted Diaperis); Lasiorhynchites ophthalmicus; Lixus angustatus (Narrowed Lixus Weevil, illustrated by Curtis, but probably adventive); Magdalis carbonaria (Long-nosed Magdalis Weevil); Mononychus punctumalbum (Single-clawed Weevil); Notaris aethiops; Phytobius comari (Marsh Cinqfoil Weevil); Hypera dauci (Pretty Hypera); Polydrusus sericeus (Kimpton Weevil); Zacladus geranii.

General comments. Reputed to be largest family in the animal Kingdom. Beetles variable in shape, usually more or less waisted and often clothed with scales; antennae of characteristic form.

To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: the families of Coleoptera. Version: 2nd January 2012. http://delta-intkey.com’.

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