Abdera flexuosa (Paykull, 1799)
POLYPHAGA Emery, 1886
TENEBRIONOIDEA Latreille, 1802
MELANDRYINAE Leach, 1815
Abdera Stephens, 1832
A widespread Western Palaearctic species known from the Pyrenees to Italy and Ukraine in the south, and extending north into the UK, Denmark and the Baltic countries where it reaches far above the Arctic Circle in Norway and Sweden and extends east into parts of Russia. It is locally common from lowlands to lower mountain altitudes in central and northern regions but otherwise very local and rather scarce. In the UK it is widespread but local throughout England and Wales, and very local and generally uncommon in the Scottish Highlands and in Northern Ireland. The typical habitat is damp woodland, carr and heathland where both adults are associated with fungi on a range of deciduous trees, mostly Alder (Alnus glutinosa L.) but also oaks (Quercus L.), Birch (Betula pendula Roth.) and willows (Salix L.) among others. Adults are present year-round; they overwinter under bar or among decaying wood and are active from March until September or October and they peak in abundance during May and June. Reproduction occurs in spring and early summer and larvae develop in a range of sporocarps including Inonotus radiatus (Sowerby) (Alder Bracket). I. dryadeus (Pers.: Fr.) (Oak Bracket), Fomes fomentarius (L.) Fr. (Hoof Fungus), Fistulina hepatica (Schaeff.) Ex Fr. (Beefsteak Fungus) and much more rarely in Phellinus pini (Brot.) on pine. Adults are nocturnal, they may be found on bar low down on trunks or on fallen branches on damp ground, and they often sit for extended periods on the surface of sporocarps, they usually occur in numbers and mating pairs are usually present in spring or early summer. They fly well and so may occur in flight interception traps, when alarmed they can run very fast or may take flight or drop to the ground, in which case they can be very difficult to find.
Abdera flexuosa 1
3-4 mm. Elongate and discontinuous in outline, body finely pubescent, pale brown with the head, pronotal disc and two wavy transverse bands on the elytra dark grey, underside black with very fine pale pubescence, palps yellow, antennae dark with several basal and apical segments pale, legs pale or with darkened femora. Head usually substantially hidden from above, smoothly convex and finely punctured between large transverse eyes that almost follow the outline, clypeus parallel-sided beyond the antennal insertions then narrowed to a widely emarginate anterior margin. Terminal maxillary palpomere elongate and at most only slightly broader than the penultimate segment. Antennae inserted dorsally beside the eyes, 11-segmented and filiform, the third segment much longer than the second segment and only slightly longer than the fourth. Pronotum transverse, broadest behind the middle and narrowed to rounded posterior angles and a rounded apical margin, lateral margins not bordered, basal margin widely produced medially and finely bordered throughout, surface finely punctured and microsculptured, slightly uneven and with a variable median furrow towards the base but without basal fovea. Scutellum short and widely transverse. Elytra parallel-sided or slightly dilated from rounded shoulders to separately-rounded apical margins, surface evenly convex or with vague longitudinal impressions, especially towards the apex, without striae, punctured and microsculptured as the pronotum. Legs long and slender, tibiae hardly broadened from the base and with tiny apical spurs. Tarsi 5-5-4; basal segment of the middle and hind tarsi much longer than the others, penultimate segment of all tarsi weakly bilobed. Front tarsi of males much broader compared to females.