Saprinus semistriatus (Scriba, 1790)
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POLYPHAGA Emery, 1886
HYDROPHILOIDEA Latreille, 1802
SAPRININAE Blanchard, 1845
Saprinus Erichson, 1834
Among the commonest and most widespread members of the genus this species occurs from lowlands to middle mountain altitudes throughout Europe from the Mediterranean north to the UK and above the Arctic Circle in Scandinavia, it is present on most of the Mediterranean and Atlantic islands but mostly absent from North Africa; to the east it extends into Asia Minor and Russia and may include the whole Palaearctic region although here there may be confusion with a similar species. In the UK it is locally common in Wales and England north to Nottingham and more sporadic and scarce further north to the Scottish Highlands and it is by far the most frequently recorded UK member of the genus. Adults are present year-round; they are active from April until October and may be found in most fairly dry habitats, including open grassland and woodland, and on most soil types. They are strongly attracted to carrion and are often among the first beetles to arrive, they are very strong and agile fliers and will often arrive in numbers at fresh carrion; they usually occur at small mammal and birds, less frequently at larger carrion and only rarely at dung or decaying vegetation. Both adults and larvae predate other insects and mites etc but more usually diptera larvae, at fresh carrion adults may mate and even oviposit but they usually leave soon afterwards, at larger carcasses or where smaller carcasses host large populations of fly larvae they may remain for several weeks and large populations may build up as new adults arrive. Larvae develop among the carrion and are fully-grown within a few weeks, they pupate in the ground below the host and adults emerge within a week or so. New generation adults emerge and disperse but probably do not reproduce until the following spring. Sampling adults usually involves searching through carrion or placing pitfall traps near to samples, but they tend to remain on the ground beneath smaller cadavers and so are easily to find although they can quickly vanish into the ground when disturbed, they almost always occur in numbers and they mostly disperse by flight during the evening and so sometimes occur in flight-interception traps.
3.5-5.5 mm. Broadly oval and entirely shiny black, distinguished from other superficially similar genera by the form of the head and anterior prosternal margin being simple i.e. not produced forward into a lobe. Head transverse, frons with a raised border adjacent to prominent and convex eyes that covers the antennal insertions from above, surface with a mix of fine and very fine punctures, frontoclypeal suture without a raised keel. Antennae 11-segmented, the basal segment massively dilated internally and the last three segments forming a fused club, inserted towards the base of the eyes in a small scrobe between the frons and the gena. Pronotum transverse, widest across slightly acute posterior angles and curved laterally to rounded and projecting anterior angles, apical margin straight, basal margin widely curved and produced medially. Pronotal surface smooth and only very finely punctured across the disc and towards the apical margin, variably but strongly and usually quite densely punctured towards the lateral and basal margins. Mesosternum strongly punctured (important identification feature). Elytra Transverse, as broad across the base as the base of the pronotum and curved laterally to separately rounded apical margins, with four strongly-punctured striae that extend beyond the basal third and shorter stria below the shoulder, in the apical half a more-or-less complete sutural stria extends to the apex where it joins an apical stria, apical half strongly punctured; these usually extend from the apical margin to the base of the sutural striae and the apices of the dorsal striae. Legs long and robust, the femora excavate posteriorly (at least towards the apex) to accommodate the tibiae in repose, all tibiae strongly broadened to the apex and with strong external spines, the front tibiae excavate to receive the tarsi. All tarsi with five simple segments.