Bembidion doris (Panzer, 1796)
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ADEPHAGA Clairville, 1806
BEMBIDIINI Stephens, 1827
Trepanedoris Netolitzky, 1918
In Europe this is a mostly central and northern species, reaching northern Spain, central Italy and Bosnia to the south and extending north to the UK and far above the Arctic Circle in Fennoscandia, to the east it extends through Russia and into Siberia as far as Lake Baikal. In the UK it is widespread and generally abundant across south east England and the midlands and more local though often common throughout the mainland north to the Scottish Highlands and much of Ireland, it is present on Anglesey and the Isle of Wight but appears to be absent from the other islands. Adults are present year round and are active over a long season from early in the spring although they may aestivate during the warmest parts of the summer, they are associated exclusively with marginal wetland situations and are very eurytopic, occurring at stagnant and flowing waters on a variety of substrates, and they may be common on dry pond and ditch beds during the summer, they are generally associated with shaded and patchily-vegetated areas with plenty of moss or algae covering the ground, hence they may be found around woodland pools and marshes where they spend much of their time among moss or leaf-litter, often with other small carabids such as other Bembidion species or, often, with Pterostichus diligens (Sturm, 1824). Breeding occurs in the spring and larvae develop over the following months to produce new-generation adults from July or August, these will go on to overwinter among marginal litter etc. they may be active during mild winter spells but become common from March or April, they fly well and tend to disperse from drying habitats and so may suddenly appear in new situations during spring and early summer. Adults are easily sampled by pitfall trapping or searching through litter etc. but they are mostly nocturnal and may be seen active on the surface at night in suitable situations; populations tend to be stable over many years and so they will often be seen in very large numbers over a wide area.
3.1-3.8mm. Adults may be recognized by the combination of deep furrows inside the eyes that converge strongly towards the front of the head, the base of the pronotum lacking large punctures and the elytra which may be indistinctly pale towards the apex but are otherwise entirely dark. Body shiny black with a variable metallic reflection, legs pale brown and antennae variously darkened but always with the basal segments pale. Vertex and frons smoothly convex; with at most only very fine punctures, eyes large and convex, each with two setiferous punctures beside single and well-impressed frontal furrows. Pronotum slightly transverse, broadest in front of the middle and rounded laterally before a sinuate margin in front of near-perpendicular posterior angles, basal margin deeply impressed laterally and often raised medially, otherwise variously wrinkled or depressed but without a series of four well-defined and deep fovea. Elytra widest behind the middle and smoothly rounded from the shoulders to the apex, each with six or seven punctured striae that fade in the apical half or third, interstices smooth and unpunctured; the third with two or three large punctures joining, or almost joining, the third stria, usually entirely dark with an indistinct pale macula near the lateral margin towards the apex, but this is very variable and the apical area may be extensively pale; lifting an elytron will usually reveal these markings in apparently dark specimens. The basal half of the elytra is always entirely dark.