Anotylus rugosus (Fabricius, 1775)
This is one of the most common of the oxyteline staphs throughout central and northern Europe; it occurs from lowland to subalpine altitudes from North Africa to the far north of Scandinavia and Iceland, extending east through Turkey, Caucasus and into central Mongolia. Adventive and now widely established in Canada and the United States. Here it is generally abundant throughout the UK, including the Western Scottish Isles, Orkney and Shetland. Adults occur year-round, peaking in abundance from March to May, in a very wide range of habitats; they may be present in large numbers, generally along with other oxyteline staphs, in any kind of dung in any situation, and they develop in decaying organic matter generally; compost, leaf-litter and fungi etc. They fly in warm weather, generally during the afternoon or evening, are quick to appear in new habitats and will be swept from vegetation in any situation, they are common in wetland marginal situations e.g. among reed-litter, at carrion, among debris under bark or in mammal and bird nests, they occur among foliage or under debris in salt marshes and have been found under decaying seaweed on the strandline. During the spring and summer they are among the most numerous beetles among arable crops and, being predatory on a wide range of insects and their early stages, are thought to have a significant impact on aphid pests etc. Adults are readily sampled during the warmer months by sweeping and pitfall trapping, they will come to light and throughout the year are often present in extraction samples, and they overwinter among moss, in leaf-litter under hedges or in marginal environments, under bark or in the ground beneath dried-out dung. Some idea of their abundance can be appreciated by extracting beetles from dung by immersion, something we did indoors during April a few years ago. They take flight immediately and accumulate around window and door frames, in our case in their thousands which is interesting for a coleopterist but less so for others.
Adults are distinguished from other staphs by the crenulate pronotal margins, dark antennae and dull, strongly microsculptured clypeus. 4.5-5.5mm, entirely shiny black or with the elytra variously reddish and pale appendages. Head broad with small but strongly convex eyes and long rounded temples; vertex with strong longitudinal striations and punctures, clypeus produced in front of the lateral antennal insertions and contrastingly matt. Antennae 11-segmented; the basal segment very long and not contrastingly paler than the others, 2-4 narrow and 5-11 broadening slightly towards the apex. Pronotum transverse and only a little broader than the head; evenly curved and strongly crenulate laterally, disc with 3 variously complete longitudinal furrows and strong but usually discrete punctures. Scutellum cordate with a median longitudinal keel, often hidden beneath the pronotal margin. Elytra transverse and broadest behind the middle; shiny, strongly and randomly punctured, and with poorly-defined, often obscure longitudinal impressions. Abdomen with strongly raised lateral margins, segments rather dull from strong microsculpture and each with the basal border curved posteriorly before the lateral margin. Male with a strong and prominent tubercle on the sixth abdominal tergite, easily seen in lateral aspect.