Agathidium laevigatum Erichson, 1845

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POLYPHAGA Emery, 1886

STAPHYLINOIDEA Latreille, 1802

LEIODIDAE Fleming, 1821

LEIODINAE Fleming, 1821

AGATHIDIINI Westwood, 1838

Agathidium Panzer, 1797

A Palaearctic species also known from the Oriental region; the nominate subspecies occurs throughout the range and is locally common throughout central and northern Europe, reaching to the far north of Fennoscandia, less so to the south where it extends from Portugal to Greece and is present on most of the Mediterranean islands. A further subspecies, meridianum Hlisnikovsky, 1964 is known from North Africa and the Canary Islands. There are scattered records throughout mainland UK and Northern Ireland and the species is present on Anglesey, Man, Orkney and the Western Isles; it is generally very local and scarce and there seems to have been a gradual decline over recent decades but it remains locally common in Kent, East Anglia and parts of the English midlands, and across North Wales and Anglesey. Typical habitats are damp woodland, Carr, fens and wooded parkland and grassland from lowland to alpine altitudes where the species is associated with a wide range of both broadleaf and coniferous trees, in lowland forests often on Birch (Betula L.)and Oak (Quercus L.), and at higher altitudes often on Spruce (Picea Mill.) and Pine (Pinus L.). Adults are present year-round; they overwinter among litter or under damaged bark and are active from March until September or October, peaking in abundance during May and June. Little is known of the biology but adults are nocturnal and usually appear on trunks etc. in the vicinity of fungal sporocarps or mould-infested wood, and larvae (typical of the genus) probably develop through the summer among slime moulds (Eumycetozoa). Adults may be found by nocturnal searching but they are generally more common among mosses and damp leaf-litter in wooded areas and though they sometimes appear in decaying fungi in the autumn they do not seem to be generally associated with terrestrial sporocarps, they disperse by flight on warm spring and summer evenings and so may appear in flight-interception traps.

Agathidium laevigatum

Agathidium laevigatum

2.2-2.7 mm. Broadly-oval and strongly discontinuous in outline although they can roll up into an almost spherical shape in life, body glabrous and entirely shiny black or with the pronotal margins obscurely reddish or brown, antennae brown with darker clubs, legs entirely brown, Head transverse, broadest across weakly convex eyes and with long converging temples, surface smoothly convex, finely punctured and with fine mesh-like microsculpture. Antennae 11-segmented; segment 3 about 1.5X longer than 2, segments 7 & 8 short and transverse, segments 9 & 10 broader and longer, and segment 11 elongate-oval. Pronotum transverse, from above continuously rounded from the base to rounded and slightly projecting anterior angles, anterior margin rather strongly curved, surface evenly convex and finely but distinctly punctured and microsculptured. Mesosternum finely keeled, metasternum with distinct femoral lines. Elytra almost circular in outline from above, humeral angle widely obtuse (about 30 degrees from the basal margin in side view) Surface punctured and microsculptured much as the pronotum; without longitudinal series of punctures or an impressed sutural stria towards the apex. Femora simple and not visible in normal setting, tibiae narrow and hardly thickened from the base; each with longitudinal series of fine spines and a pair of tiny apical spurs. Tarsi 5-5-4 in males, 5-4-4 in females, all segments simple, basal segments of front tarsi weakly dilated in males.