| | Insects of Britain and Ireland: Coleoptera-Scarabaeoidea (dung beetles and chafers) |
General appearance. 4.5–11 mm long (Onthophagus spp.), or 16–21 mm long (Copris lunaris). Body length/maximum body width 1.81–2.1. Elytral length/pronotal length 1–2.4. Base of prothorax not or scarcely narrower than the combined elytral bases to distinctly narrower than the combined elytral bases. Greatest prothoracic width not narrower or only slightly narrower than the greatest elytral width. Body noticeably widest immediately behind the thorax, or not noticeably widest either behind the thorax, or at the rear. Beetles oval to elongate-oval; dorsally somewhat convex to dorsally strongly convex; conspicuously necked, or not necked; somewhat waisted to conspicuously waisted; neither particularly long- nor short-legged to decidedly short-legged; exhibiting bright ‘warning colours’, or without ‘warning colouration’. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.
Detailed morphology. Beetles not prognathous. Inclination of the head slight. Eyes strongly protuberant, or not strongly protuberant; without bristles; finely facetted. Ocelli absent. The labrum concealed beneath the clypeus (the labrum and mouthparts concealed beneath the fronto-clypeus). Mandibles present; with a well developed mola; with well developed prosthecae to without prosthecae. The mandibular apices simple, or bidentate or bilobed. The incisor edges of the mandibles simple. The maxillae with distinct galea and lacinia apically to the palp, or with a single apical structure additional to the palp. The maxillary palps normal, flexible; apical segment of the maxillary palps cylindrical to fusiform. The apical segment of the labial palps not expanded apically. Antennae very short; strongly asymmetric; not elbowed; (7–)9 segmented, or 10 segmented; clubbed. Antennal clubs tightly lamellate (but with the capacity to open fan-like); 3 segmented. Antennal insertions visible from above; not in fossae.
Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.3–3.08. The pronotum with lateral keels (pronotal carinae), or without lateral keels; keels when present, complete, or incomplete. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Scutellum highly reduced to absent; when applicable, elevated above the mesoscutum in lateral view, or not elevated; anteriorly simple; posteriorly narrowly rounded or acute, or broadly rounded or obtusely angulate. The prosternal process present. The prosternal process interrupted, or entire. The prosternal process when entire, slightly overlapping the mesoventrite to moderately or strongly overlapping the mesoventrite. Metaventrite without a transverse groove. The fore-leg coxae countersunk in ‘procoxal cavities’. The fore-leg coxal cavities closed behind externally; narrowly closed, or broadly closed; medianly confluent, or narrowly separated; medianly confluent, or narrowly separated; strongly transverse, or slightly transverse; without lateral extensions; internally open. The front tibiae with three lateral teeth. The mid-leg coxae countersunk in ‘mesocoxal cavities’; separated by less than the shortest diameter of the cavity, or more than the shortest diameter of the cavity. The mid-leg coxal cavities narrowly separated, or moderately to widely separated; not or scarcely oblique, or markedly oblique; open laterally. Hind-leg coxae extending laterally to meet the elytra. Tarsal segmentation formula 0, 5, 5 (occasionally), or 5, 5, 5. The tarsi without bilobed segments; always? without ‘hidden’ segments. Tarsal claws two; equal (the claws without lateral teeth). The front tarsi reduced or absent. Mid-leg tarsi 5-segmented; pentamerous; the penultimate segment not distinctly shorter than the antepenultimate one, or distinctly shorter than the antepenultimate one (sometimes). The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple; with an empodium between them, or without an associated empodium. The hind tibiae with one apical spur. Hind tarsi with as many segments as the mid-tarsi; 5-segmented (and the hind tibiae with only one spur).
Elytral length/maximum width across the elytra 0.6–2.1. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite to at least one but fewer than three complete abdominal tergites. The pygidium at least partly exposed beyond the long elytra. Elytra glossy, or dull. Elytra with six or more longitudinal lines of punctures, or with six or more impressed striae, or apunctate, irregularly punctate, or each with fewer than 6 longitudinal lines of punctures or impressed striae; the lines per elytron when more than five, 6–7, or 8 to 12 or more. Scutellary striole absent. Wings well developed. Wings without an anal lobe. Wings without a medial fleck. Abdominal sternites 6; comprising both fused and moveable components, or all fused and immoveable. Basal abdominal sternites immovably joined 4–6. Abdominal segment 8 with apparently functional spiracles, or apparently without functional spiracles. The male external genitalia bilobate.
Adult habitat, ecology. Associated with dung; coprophagous (feeding on dung like their larvae).
Larvae. Mature larvae minute (less than 3 mm long) (rarely), or small to medium-sized to relatively large. The larvae elongate and more or less parallel-sided; C-shaped in lateral view (with a marked dorsal hump). Body circular in cross-section. Vestiture restricted to fine hairs or setae. The larvae dorsally only very lightly pigmented or sclerotized; ventrally only very lightly pigmented. The antennae 4 segmented, or 5 segmented (rarely more?). Stemmata absent (usually), or present; on either side of the larval head when present, 1. The frontoclypeal suture between frons and clypeus distinct. The labrum and head capsule separated by a complete suture. Apices of the mandibles with a single lobe or tooth, or bilobed or bidentate, or trilobed or tridentate. The maxillary palps 4 segmented. The labium without ligula between the palps, or with a short ligula between the palps. Labial palps present and segmented; 2 segmented. Mesothoracic legs present and segmented, or much reduced or absent; 2 segmented, or 3 segmented, or 5 segmented; the tarsi reduced or absent; with 1 moveable claw. Visible abdominal segments 9, or 10. Tergum 9 of the abdomen entirely dorsal. The abdomen having functional spiracles on anterior segments (these cribriform); without spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 without amature. The last abdominal segment without cerci.
Larvae in dung; coprophagous.
Mostly curved, C-shaped ‘curl-grubs’, with brownish head, three pairs of well-developed legs and mostly 4-segmented antennae.
Classification. Suborder Polyphaga; Infraorder Scarabaeiformia; Superfamily Scarabaeoidea.
Worldwide and British representation. About 4500 species worldwide (mostly tropical, with only tribes Coprini and Onthophagini represented in Britain). 9 species in Britain; genera in Britain 2; Copris, Onthophagus.
General comments. The head and/or pronotum often conspicuously horned or tuberculate (especially in males), the powerful legs with thickened, spiny tibiae. Some tropical representatives of the group attain 7 cm in length..
Illustrations. • Copris lunaris (Lunar-headed Dung-beetle: B. Ent. 414). • Copris lunaris: B. Ent. 414, legend+text. • Copris lunaris: B. Ent. 414, text cont.. • Onthophagus taurus (Bull-headed Dung-beetle: B. Ent. 052). • Onthophagus taurus: B. Ent. 052, legend+text. • Onthophagus taurus: B. Ent. 052, text cont.. • Copris lunaris, Onthophagus taurus, O. nutans, O. fracticornis, O. nudicornis: Fowler 4, 99 (1890). SCARABAEIDAE-SCARABAEINAE. 6, Copris lunaris, with (6a) side view of head of the male. 7, Onthophagus taurus; 8, Onthophagus nutans, with (8a) side view of head of male; 9, Onthophagus fracticornis; 10, Onthophagus nudicornis. From Fowler's plate, with the names from the original legend (q.v.) updated. • Fowler 4, 99 (1890): original legend..
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: Coleoptera-Scarabaeoidea (dung beetles and chafers). Version: 27th July 2019. delta-intkey.com’.
