Otophorus haemorrhoidalis (Linnaeus, 1758)
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POLYPHAGA Emery, 1886
SCARABAEOIDEA Latreille, 1802
APHODIINI Leach, 1815
OTOPHORUS Mulsant, 1842
Formerly included in the now extensively revised genus Aphodius Illiger, 1798 this is now the only member of Otophorus Mulsant, 1842. Native to the Palaearctic region it is now Holarctic since becoming establishes widely through Canada and the United States. It occurs from North Africa to middle Scandinavian latitudes and from Portugal to the far east of Asia including Japan, from lowland to subalpine altitudes and is rarely absent from montane dung beetle communities on the continent. Here it is widespread and common throughout southern England and Wales, becoming rarer in the north and absent from Scotland. The species is a general surface feeding dung beetle and its typical habitat is open dung pasture where it occurs in the dung of a wide range of species, usually cattle, sheep or horse but commonly in goat dung in mountain areas, and only rarely do they occur in other habitats e.g. compost or decaying fungi. Adults have a long season, they are active from April to September or October, peaking in abundance from June to August and then becoming much less common, they spend most of their time in dung and may often be found just below the crust of older and partly dried pats, usually in company with other dung beetle species, they fly well and are quick to establish in new habitats. Eggs are laid singly directly in dung where the coprophagous larvae will develop through the spring and summer, new generation adults occur from late May or June and it is suspected there may be two generation each year as the species overwinters mostly as a third-instar larva, but at least some adults also overwinter as they have been recorded from flood-refuse in the winter. In Watford this was often a super abundant species but in recent years numbers seem to have declined; it remains common but our feeling is not as common as it was only fifteen years ago. Adults are readily sampled by pulling apart crusty dung pats, they will also be found by sweeping insects flying over dung pasture or by using dung-baited traps, but the best way to appreciate how abundant they are is to drop pieces of dung into water and wait for the beetles to float to the surface, in this way a large and representative sample of the local fauna will be obtained.
The combination of small size, 3-5.5mm, and elongate scutellum, around a fifth of the elytral length, will identify this species; in the field it is usually obvious from the size and colour; entirely black with red humeri and elytral apices. Head finely punctured, with three variously developed tubercles on the posterior margin of the clypeus, anterior margin of the clypeus rounded and strongly bordered, laterally only weakly expanded in front of the eyes, often more obviously so in the male. Pronotum strongly bordered laterally and across the base, with anterior angles produced, and a mixture of large and small punctures on the disc, all visible at X20. Scutellum elongate-triangular; at least a fifth the elytral length, and densely punctured. Elytra finely punctured and rather shiny between broad and strongly punctured striae, typically black with red humeri and apical areas but variable, and several aberrations have been named e.g. humeralis Mulsant, 1842, elytra black with red shoulders, sanguinolentus Herbst, 1793, black with apex and shoulders red, and circumdatus Dellscasa, 1983 black with red shoulders, side margins and apex. In general the extent of the red markings varies.