Cercyon quisquilius (Linnaeus, 1761)

Quoted by Joy simply as common (without any regional qualifications), and with records throughout mainland UK (NBN), this species is common and usually abundant in cattle and horse dung throughout our area. Adults are active from early spring, flying to horse dung in just about any situation, at this time they are common in Whippendell wood and on bright days may be swept in flight along the canal near the A412. They soon become abundant and appear on common moor soon after the cattle arrive; when cattle dung forms a crust the beetles are often seen on the surface, when this crust is lifted they are usually present on the undersurface in numbers. They are quick to arrive at fresh dung and may be netted through the summer in flight over Common moor. Although they seem to prefer moist dung they may be found through the autumn under dried samples of cattle dung that have become 'stuck' to the ground, our latest record from the moor is during December. The specie sbreeds in dung and is usually considered coprophagous (Skidmore) and while we have only recorded them from dung they are known to inhabit all kinds of decaying plant matter (Hansen) eg compost heaps, decaying grass cuttings and plant debris around plant buildings.

Although tiny this species is soon recognised by its colouration and rather elongate form. If a sample of horse dung a few hours old is worked through in a tray under hot sunlight the adults may be seen emerging from the dung, unfolding their elytra and taking flight.

1.9-2.6mm (Vogt, 1971). Elongate, convex and rather parallel sided, yellow elytra contrasting with dark forebody make this species distinctive even in the field. Upper surface glabrous, outline of pronotum/elytra more or less continuous. Head shining black, without microsculpture (X50) and with moderately strong puncturation, labrum lighter. Broadest at eyes which are convex and continuous with outline of head. Maxillary palps as long as antennae, testaceous or darker apically. Antennae testaceous with club black. Pronotum black (pale in teneral specimens) with lateral margin, or sometimes only inside of front angles, testaceous. Broadest at base and finely bordered laterally, surface shining and punctured as head. Hind angles obtuse. Scutellum elongate, shining black and finely punctured. Elytra entirely testaceous or (rarely) with a dark mark at scutellum, suture and punctures within striae sometimes darker. Apex rounded. Surface shining becoming dull towards apex, striae well impressed to apex, interstices flat and finely punctate. In side view the pronotum and elytra contribute to single curve. Legs light, as elytra. Protibiae rounded at apex, all tibiae with strong spines along outer edge. Meso and metatibiae with two strong apical spurs on inner edge. Tarsi 5-5-5, basal segment of meso and metatarsi much larger than second.

Vogt Key to Cercyon spp. in Freude, H., Harde, K.W., and Lohse, G.A 1971 Die Kafer Mitteleuropas Vol.3 pp 130-139.