Onthophagus verticicornis (Laicharting, 1781)
This widespread western Palaearctic species occurs throughout southern and central Europe from Portugal east to western parts of Russia, it is generally thermophilic and common only in the south of its range, around the Mediterranean and the Balkan peninsula, to the north it extends sporadically to northern France, Germany, Poland and Belarus though it is generally rare and is absent from many areas e.g. Belgium, the Netherlands and Denmark as well as coastal areas generally. It was formerly recorded from a few widespread localities in Wales and the south of England but was last recorded from Dorset in 1926 and is now presumed to be long extinct. On the continent it occurs on dung pasture as well as a wider variety of habitats, generally on light sandy or chalky soils, including grassland, forest margins and clearings and roadsides etc. while UK records are from sheep dung on open pasture. Adults occur from April to July although UK records are from May, and they have been recorded from a variety of droppings including cattle, sheep, horse, goat and badger. The life cycle is typical of the group with adults burrowing beneath the host material and females provisioning the burrow and ovipositing in buried brood masses. Larvae develop during the summer, they pass through three instars and pupate within the burrow after six to eight weeks from hatching, adults eclose from mid-summer and may emerge to feed or remain in the burrow to overwinter.
Adults vary widely in size from 6 to 11mm, the females generally larger, and are readily identified from the combination of entirely dull black colouration and sinuate lateral margins behind the anterior pronotal angles. Habitus elongate with the pronotum and elytra strongly and separately rounded, dorsal surface with very fine and short pubescence throughout. Males have the posterior margin of the head produced into a long horn which is angled forward towards the apex and which is accommodated into an anterior pronotal depression when the head is raised, the female head bears two arcuate transverse ridges, the anterior weaker and spanning only the median area, the posterior much more raised and continued almost to the lateral margins behind the eyes. Head broadened and obtusely angled in front of small transverse eyes, widely rounded anteriorly and densely and quite strongly punctured throughout. Pronotum continuously rounded or with indistinct posterior angles, anterior angles slightly produced in front of the sinuate lateral margin, in males convex and variously depressed or concave anteriorly, in females convex almost to the anterior margin, the surface densely and quite finely punctured throughout in both sexes. Elytra transverse, each angled posteriorly from the shoulder to the suture, rounded laterally and continuously rounded apically, each with seven narrow and punctured striae complete almost to the apex, interstices wide and flat across the disc, finely punctured and rugose.