Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz

Scarabaeidae

Including Aclopidae, Aphodiidae, Cetoniidae, etc.

Chafers, Dung-beetles, etc.

General appearance. 2.6–30 mm long (in Britain, but the family worldwide encompasses the largest known insects, with the tropical American Dynastes hercules and the African Goliathus goliatus reaching 16 cm and 11 cm respectively). Body length/maximum body width 0.9–3.6. Elytral length/pronotal length 0.45–5.55. 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 (the prothorax relatively wide in Aphodiinae). Beetles oval to elongate-oval; dorsally somewhat convex to dorsally strongly convex; not necked; somewhat waisted to conspicuously waisted; 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. Inclination of the head slight to very strong (the labrum and mouthparts often visible from above, but concealed beneath the fronto-clypeus in Aphodiinae and Scarabaeinae). Eyes two, entire; strongly protuberant, or not strongly protuberant; bristly (often), or without bristles (e.g., Aphodiinae); finely facetted. The labrum at least partly visible in antero-dorsal view, or concealed beneath the clypeus (commonly); labrum where recorded, mostly moderately to heavily sclerotized. Mandibles absent or vestigial (in some Cetoniini), or present; with a well developed mola (mostly), or with a reduced mola to without a mola (some Rutelinae); with well developed prosthecae to without prosthecae. The mandibular apices simple, or bidentate or bilobed, or multidentate or multilobed (some Aegialiini). The incisor edges of the mandibles simple (mostly), or with a single tooth (some Aegialiini). The maxillae with distinct galea and lacinia apically to the palp, or with a single apical structure additional to the palp (quite commonly). The maxillary palps not especially elongated; apical segment of the maxillary palps cylindrical to fusiform (mostly), or securiform to cultriform (some Aegialiini). Antennae very short to short; strongly asymmetric; not elbowed; (7–)9 segmented, or 10 segmented; without a much-elongated scape; clubbed. Antennal clubs tightly lamellate (but with the capacity to open fan-like); 3–7 segmented. Antennal insertions visible from above, or hidden from above (e.g., in Aphodiinae); not in fossae.

Cervical sclerites present. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.3–3.08. The pronotum with lateral keels (pronotal carinae) (mostly), or without lateral keels (some Scarabaeinae); keels when present, complete, or incomplete (some Cetoniini and Scarabaeinae only). Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Scutellum conspicuous, or highly reduced to absent (Scarabaeinae); 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; variously interrupted, or entire; when not interrupted, complete; rather consistently slightly overlapping the mesoventrite, or 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; strongly transverse, or slightly transverse; without lateral extensions; internally open, or broadly closed internally (Hopliin1). 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 contiguous or narrowly separated; 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. The front tarsi present and well developed (e.g., Aphodiinae), or reduced or absent (Scarabaeinae); front tarsi when not reduced or absent (i.e., usually), with as many segments as the mid-tarsi; front tarsi when present, 5-segmented. Mid-leg tarsi 5-segmented; pentamerous; the penultimate segment not distinctly shorter than the antepenultimate one (mostly), or distinctly shorter than the antepenultimate one (some Scarabaeinae). 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 sometimes with three or more setae, but no more than two in Aphodiinae), or without an associated empodium. Hind tarsi with as many segments as the mid-tarsi; 5-segmented (and the hind tibiae with two spurs in Aphodiinae, only one in Scarabaeinae).

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, or entirely concealed by the ends of the elytra even when viewed from behind (a more or less concealed pygidium being the supposedly defining feature of Aphodiinae). 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 (always, in British representatives). Wings variously with an anal lobe, or without an anal lobe. Wings with a medial fleck, or without a medial fleck; the medial fleck when present, not bisected by a vein. Abdominal sternites 5–7 (usually 6); all articulated and moveable to all fused and immoveable (all fused in some Aphodiinae). Basal abdominal sternites immovably joined when present, 2, or 4–6. Abdominal segment 8 with apparently functional spiracles, or apparently without functional spiracles. The male external genitalia bilobate.

Adult habitat, ecology. On living vegetation, or in decaying plant material, or associated with dung; phytophagous, or consuming decaying plant material, or coprophagous (Melolonthinae, Hopliinae and Rutelinae feeding on foliage, Cetoniinae on leaves and nectar, Scarabaeinae and most Aphodiinae 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 (mostly), or not C-shaped (e.g., in Cetoniinae). 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; 2 segmented, or 3 segmented, or 5 segmented; 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 living vegetation, or in decaying plant material, or in dung, or in the soil; phytophagous (Melolonthinae, Hopliinae and Rutelinae notably feeding on roots), or consuming decaying plant material (Cetoniinae), or boring into dead wood, or coprophagous (most Aphodiinae, Scarabaeinae).

Mostly curved, C-shaped ‘curl-grubs’, with brownish head, three pairs of well-developed legs and mostly 4-segmented antennae; the anus V- or Y-shaped in Melolonthinae and Hopliinae but transverse in Cetoniinae and Rutelinae.

Classification. Suborder Polyphaga; Infraorder Scarabaeiformia; Superfamily Scarabaeoidea.

Representation in Britain and Ireland, and worldwide. About 30000 species worldwide. About 90 species in Britain; genera in Britain about 28 (this predominantly tropical family being relatively poorly representative in Britain); Subfamily Aphodiinae: Aegialia, Aphodius, Euheptaulacus, Heptaulacus, Oxyomus, Saprosites, Brindalus, Diastictus, Psammodius (sic), Tesarius, Pleurophorus, Rhyssemus. Cetoniinae: Cetonia, Gnorimus, Oxythyrea, Trichius. Hopliinae: Hoplia. Melolonthinae: Melolontha, Polyphylla, Amphimallon, Omaloplia, Serica. Rutelinae: Anomala, Phyllopertha. Scarabaeinae: Copris, Onthophagus. E.g., Aphodius villosus (Hairy Aphodius); Aphodius distinctus; Melolontha melolontha (Common Cockchafer); Cetonia aurata (Rose Chafer); Phyllopertha horticola (Sutherland Bracken-clock); Copris lunaris (Lunar-headed Dung-beetle); Gnoremus variabilis (8-spotted Oak-beetle); Onthophagus taurus (Bull-headed Dung-beetle); Phyllopertha horticola; Psammodius asper (Channel-necked Psammodius); Typhaeus typhoeus. Curtis also illustrated the spectacular mainland-European Polyphylla fullo.

General comments. The scarab beetles constitute a taxonomically difficult group, and a satisfactory classification at world level has yet to be achieved. Of the fairly distinct series that have long been recognised, six are represented in Britain. Of these, Geotrupidae, Trogidae and (by some authorities) Aphodiidae are now treated as distinct families, with the rest - Scarabaeinae (dung beetles), Melolonthinae ('chafers') and Cetoniinae - awarded subfamily status. This sensu lato description is not taxonomically judgemental, but seems appropriate in the present context.

A few spectacular exotic forms are illustrated here, including several from the subfamily Dynastinae (1,400 species worldwide), which is not represented at all in Britain.

Illustrations. • Aphodius villosus (Hairy Aphodius: B. Ent. 027). • Aphodius villosus: B. Ent. 027, legend+text. • Aphodius villosus: B. Ent. 027, text cont.. • Psammodius asper (Channel-necked Psammodius: B. Ent. 258). • Psammodius asper (details, B. Ent. 258). • Psammodius asper: B. Ent. 258, legend+text. • Aphodius (10 spp.), Colobopterus (3 spp.): Fowler 4, 100 (1890). • Fowler 4, 100 (1890): original legend.. • Aphodius (12 spp.), Euheptaulacus, Oxyomus sylvestris (as O. porcatus): Fowler 4, 101 (1890). • Fowler 4, 101 (1890): original legend.. • Aphodius distinctus (Rye & Fowler VIII3). • Phyllopertha horticola (Sutherland Bracken-clock: B. Ent. 526). • Phyllopertha horticola (B. Ent. 526, legend+text). • Phyllopertha horticola (B. Ent. 526, text cont.). • Cetonia stictica (Spotted Chafer: B. Ent. 374. Adventive). • Cetonia stictica: B. Ent. 374, legend+text. • Cetonia stictica: B. Ent. 374, text cont.. • Cetonia aurata (Rose Chafer, May-bug: Giles Watson). • Copris lunaris (Lunar-headed Dung-beetle: B. Ent. 414). • Copris lunaris: B. Ent. 414, legend+text. • Copris lunaris: B. Ent. 414, text cont.. • Polyphylla fullo (Kent Cockchafer: B. Ent. 406. Mainland-European). • Polyphylla fullo (details, B. Ent. 406). • Polyphylla fullo : B. Ent. 406, legend+text. • Polyphylla fullo : B. Ent. 406, 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.. • Gnoremus variabilis (8-spotted Oak-beetle): B. Ent. 286. • Gnoremus variabilis: B. Ent. 286, legend+text. • Gnoremus variabilis: B. Ent. 286, text cont.. • Copris lunaris, Onthophagus taurus, O. nutans, O. fracticornis, O. nudicornis: Fowler 4, 99 (1890). • Fowler 4, 99 (1890): original legend.. • Hoplia, Omaloplia (as Homoloplia), Serica, Melolontha, Amphimallon (as Rhizotragus), Phyllopertha, Anomala, Cetonia, Gnorimus: Fowler 4, 103 (1890). • Fowler 4, 103 (1890): original legend.. • Aegialia (3 spp.), Pleurophorus caesus, Psammodius asper, Pammobius porcicollis (with Geotrupidae and Trogidae: Fowler 4, 102 (1890). • Fowler 5, 102 (1890): original legend.. • Trichius fasciatus (with Buprestidae, Throscidae, etc.): Fowler 4, 104 (1890). • Fowler 4, 104 (1890): original legend. • Aphodius nemoralis, with unrelated taxa: Fowler Suppl. 14, 1913. • Fowler 6, 14 (1913): original legend.. • Amphimallon ochraceus and Diastictus vulneratus (with unrelated taxa): Fowler Suppl. 15, 1913. • Fowler Suppl. 15, 1913: original legend. • Phyllopertha horticola (Rye & Fowler VIII1). • Typhaeus typhoeus (Rye & Fowler VIII2).


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. Insects of Britain and Ireland: the families of Coleoptera. Version: 16th May 2016. delta-intkey.com’.

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