Onthophagus coenobita (Herbst, 1783)
This is a generally common species of lowlands and foothills throughout southern and central Europe extending north to the south of the UK and Fennoscandia and east through Asia Minor and Russia to Mongolia, here it is locally common in southeast England and across Wales, becoming more sporadic in the West Country and further north to Norfolk and Isle of Man. The typical habitat is among horse or cattle dung on pasture but they also occur in a variety of habitats such as woodland and parkland and in other types of dung as well as decaying fungi and occasionally among carrion. Adults occur year-round, they are active through the spring and summer, peaking in June and again later in the summer, mating occurs in the spring after they have overwintered and fed and eggs are laid in buried host material. Both sexes excavate vertical brood burrows below or near to host material and unlike most Onthophagus burrows they consist only of a single burrow with no side tunnels or brood chambers, balls of host material are stacked from the base of the burrow and a single egg is laid in each. Larvae develop and pupate within the brood ball and new-generation adults appear from late August. The new generation will feed for a while before entering the ground, usually near to host material, to overwinter and appear from the first warm days in March or April. Adults are easily collected by searching through dung or may be netted in flight over dung pasture, they usually occur in numbers but may need to be looked for carefully as they may remain still for a while or begin to burrow rapidly into soil or host material when disturbed. From South Hertfordshire we have recorded them in large numbers from decaying fungi beside a path in a local park and from beneath a dead rat along with numerous histerids and staphs.
Adults are readily recognized by the overall colour and the form of the pronotal margins. 6.0-10.0mm, females tend to be larger than males. Head and pronotum with fine erect pubescence; metallic green, coppery or red, elytra yellow to pale brown with scattered small darker markings, epipleura pale (view in strong light to eliminate shadows). Pronotum finely and densely punctured throughout, evenly rounded and distinctly sinuate before protruding anterior angles. Elytra with weakly-impressed striae and finely punctured interstices, typically pale with small and poorly defined dark markings but specimens with almost entirely pale elytra are not uncommon. Sexes are distinguished by the strongly dimorphic head; with a backwardly produced horn in the male and a transverse ridge in the female.