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| Insects of Britain and Ireland: water beetles |
Including Calendridae, Chapuisidae, Cossonidae, Erirhinidae, Ipidae, Rhynchophoridae, etc.
Weevils and Ambrosia Beetles, True Weevils, Snout Beetles.
Adults. Beetles terrestrial (but often associated with plants of wet places); walking in water or free-swimming by conventional ambulatory motion of the legs, not diving strongly; 1.5–14 mm long; elongate-oval to elongate; not necked; conspicuously waisted; equipped with a rostrum.
Eyes without bristles. Mandibles without a mola; without prosthecae. The mandibular apices simple, or bidentate or bilobed, or multidentate or multilobed. The incisor edges of the mandibles simple, or with a single tooth, or with two or more teeth. The maxillae with a single apical structure additional to the palp; without stylet-like lobes. The maxillary palps if visible, short and rigid. The apical segment of the maxillary palps cylindrical to fusiform. The apical segment of the labial palps not expanded apically. 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 usually channelled for reception of the scape); (1–)11(–12) segmented; with the scape much-elongated; clubbed. Antennal clubs 3 segmented, or 4 segmented.
Prothorax with notopleural sutures, or without notopleural sutures. Metaventrite without a transverse groove. The prosternal process interrupted, or entire; complete, or incomplete; falling short of the mesoventrite to slightly overlapping the mesoventrite. The fore-leg coxal cavities narrowly closed, or broadly closed; medianly confluent, or narrowly separated to quite widely separated; circular to longer than wide; without lateral extensions; broadly closed internally. Tarsal segmentation formula 4, 4, 4.
Elytra present; 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). Wings with an anal lobe, or without an anal lobe; without a medial fleck. Exposed abdominal sternites 5. The male external genitalia curculionoid.
Adults not predacious; phytophagous; in living vegetation. Likely to be found in association with most green plants.
Larvae. The larvae apodous; C-shaped in lateral view.
The larvae not predacious; phytophagous; on living vegetation.
The small, legless larvae with reduced, 1-segmented antennae.
Representation in Britain and Ireland, and worldwide. 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.
Classification. Suborder Polyphaga; Infraorder Cucujiformia; Superfamily Curculionoidea. 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 terrestrial, but ubiquitous, and species associated with plants of wet places commonly found near or struggling in water; variable in shape, usually more or less waisted and often clothed with scales; eaily recognised by the characteristic form of the head and antennae. See the ‘Families of British Coleoptera’ package for a more detailed description.
Miscellaneous. • Phytobius comari (Marsh Cinqfoil Weevil: B. Ent. 558). • Anthonomus pomorum (Pear-and apple Weevil: B. Ent. 562). • Anthonomus pomorum: B. Ent. 562, legend+text. • Anthonomus pomorum: B. Ent. 562, text cont.. • Hypera dauci (Pretty Hypera: B. Ent. 116). • Hypera dauci: B. Ent. 116, legend+text. • Hypera dauci: B. Ent. 116, legend+text. • Miarus graminis: B. Ent. 627. • Miarus graminis: B. Ent. 627, legend+text. • Miarus graminis: B. Ent. 627, text cont.. • Chromoderus, Cleonus, Hylobius, Larinus, Leiosoma, Liparus, Lixus: Fowler 5, 164 (1891). CURCULIONIDAE. Cleonus piger. 2, Chromoderus albidus. 3, Cleonus nebulosus. 4, Lixus paraplecticus; 5, Lixus bicolor; 6, Lixus algirus. 7, Larinus planus. 8, Leiosoma deflexa; 9, L. deflexa var. collaris. 10, Leiosoma pyrenaeum ssp. troglodytes. 11, Liparus coronatus; 12, Liparus germanus. 13, Hylobius abietis. From Fowler's plate, with the names from the original legend (q.v.) updated. • Mouthparts of Pissodes, compared with a non-rostrate type. A. Pissodes strobi (Curculionidae): ventral view of rostrate head, with details of mouthparts and maxillae. B. Dytiscus marginalis (Dytiscidae): ventral view of head, with mandibles and maxillae dissected out.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2012 onwards. Insects of Britain and Ireland: water beetles. Version: 14th April 2022. delta-intkey.com’.
