Geotrupes stercorarius (Linnaeus, 1758)
This is probably the most widespread Palaearctic member of the family, it is generally common throughout Europe to the far north of Fennoscandia although in some southern regions it occurs only locally and mostly in mountain regions, up to 2300m, and to the east extending through Asia Minor and Russia to the far east of Asia. It is the most common and widespread of our U.K. geotrupids although in the south G. spiniger (Marsham, 1802) is often equally common and the two frequently occur together; it occurs throughout England, Wales and Scotland, including most of the islands. They show a preference for horse dung but are not uncommon in cattle dung and have also been recorded from other species as well as at rotting fungi. Adults appear a little later in the year than spiniger, generally from April or May, and might occur wherever suitable host material is abundant; cattle pasture but also woodland, moorland and hillsides, they are mostly crepuscular or nocturnal and may be seen in flight, often around cattle as they lie in fields, or attracted to light in large numbers. Mating occurs in the spring and both sexes participate in digging a vertical burrow directly beneath the host material, this may be up to 50cm deep, depending on the substrate, and when finished the female will begin at the base and dig a series of horizontal brood chambers off the main burrow, each will be provisioned with dung and a single egg before being sealed with soil from the next chamber. Larvae development proceeds through the summer and some will pupate and produce adults in the autumn that will feed and then overwinter in the burrows, while others will remain within the brood chambers and pupate in the spring to produce slightly later adults. Adults fly over pasture etc. on warm spring and summer evenings but they may aslo fly considerable distances and occur far from apparently suitable habitats, sometimes in gardens or on roadsides, no doubt disorientated by lights, and by late spring most are heavily infested with phoretic mites.
16-26mm. Similar to G. spiniger but with the pronotum less closely punctured laterally, the abdominal sternites evenly punctured and pubescent throughout and the innermost transverse ridge on the outer face of the hind tibia extending only half way between the teeth. Among the largest of our species; elongate with almost parallel-sided elytra, the upper surface black with a green or blue reflection and often with brighter and more strongly metallic borders to the pronotum and elytra, underside metallic blue, violet, green or a mixture of these colours and with rather dense black hairs evenly distributed across the abdomen.