Onthophagus medius (Kugelann, 1792)
This widespread western Palaearctic species is less thermophilic than many other members of the genus and so while it occurs throughout Europe generally it is absent from warmer Mediterranean areas, occurring mainly at medium and higher altitudes in the south, and extends north to Denmark and the UK, it is known to reach to at least 54 degrees north but is generally absent from Fennoscandia although there are a few records from the south of Finland, to the east it extends into Northern Iran, Turkey, Caucasus and Western Russia. The species has only recently (see HERE) been split from O. vacca, which has a more southerly distribution and does not occur in the UK (though it is present in the Channel Islands), and as they are sympatric over much of Europe the distributions are not fully understood but there seems to have been a general decline in abundance over recent decades. Here it is a very local species of England south of London, adults occur year round but tend to appear later in the year than other Onthophagus species, they are active from April until the autumn, peaking in late May and September, occurring mostly on low-lying pasture and often on alluvial soils and floodplains beside rivers. Here they are associated with horse dung, cattle dung and sheep droppings; adults excavate burrows directly below dung which females provision with brood masses, larvae develop through the summer and pupate within the burrows to produce new generation adults in late summer. These adults may emerge and feed before returning to the soil to overwinter or may remain in place until the following spring.
A medium sized dung beetle with contrasting dark forebody and mottled brown elytra. Distinguished from our other Onthophagus by the combination of continuously curved, i.e. not sinuate, lateral margins to the pronotum and the dark elytral markings which are random and vary in extent bit do not extend to the base. Males are distinguished by the long curved horn at the base of the head, in the female the base is produced either side into a small horn but lacks the long median horn of the male. Head with a curved ridge on the vertex in both sexes, the surface otherwise densely and quite strongly punctured, clypeus more produced and narrower apically in the male. Pronotum transverse and strongly convex, evenly curved laterally to rounded or weakly angled posterior angles, anterior angles strongly produced and anterior margin more convex in the female. Most specimens have a distinct metallic green lustre to the pronotum and often the head as well. Elytra mid to light brown with dark markings that are usually discrete, irregular and arranged along the broad interstices, they may be more extensive and confluent but they do not extend to the base.