Mordellochroa abdominalis (Fabricius, 1775)
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POLYPHAGA Emery, 1886
TENEBRIONOIDEA Latreille, 1802
MORDELLINAE Latreille, 1802
MORDELLISTENINI Ermisch, 1941
Mordellochroa Emery, 1876
This is the most widespread and generally common of the five European members of the genus; with the exception of the Iberian peninsula it occurs throughout Europe north to mid-Fennoscandian latitudes, south to northwest Africa and east into Ukraine and western Russia, in the UK it is locally common across England north to Nottingham and across south and central Wales. Typical habitats are woodland borders, hedgerows, wooded parkland, gardens and wasteland with abundant flowers. Adults appear in May and persist into July or August; early in the season they appear on blossom, mostly Crataegus (hawthorn) and occasionally wild Rosa (roses) but also on other flowers with exposed nectaries, a little later they frequent umbel flowers, especially Anthriscus sylvestris (L.) (cow-parsley), Daucus carota L. (wild carrot) and species of Heracleum L. (hogweeds) but also others. They usually occur in numbers and are readily seen on flowers in warm weather, they are easily beaten or shaken into a net where they jump and tumble around and may be difficult to observe, they otherwise rest on trunks or among long grass and occasionally occur by general sweeping. Little is known of the biology but larvae develop under bark or in dry sapwood of a range of deciduous trees; in the UK they are known from Fraxinus excelsior L. (common ash), in Sweden from Salix caprea L (goat willow) and in Denmark from Fagus L. (beech), Corylus L. (hazel) and Salix L. (willow).
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4.5-6.5mm, readily recognized as a mordellid by the form of the abdominal apex, this species is unmistakeable among our fauna due to the colouration and the form of the maxillary palps. Abdomen and front margin of the head orange in both sexes, female pronotum orange, occasionally with a darker spot on the disc, male pronotum substantially black but usually with the base lighter, entire dorsal surface finely pubescent. Head black and evenly convex, with large weakly-convex eyes and a truncate basal margin, anterior clypeal margin and labrum pale, maxillary palps mostly pale or variously infuscated, terminal segment in the male transverse and with a finely pubescent pad along
the external margin, in the female large and fusiform. Antennae inserted laterally in front of the eyes, 11-segmented with all segments elongate, basal and distal segments pale, middle segments darker. Pronotum widely transverse, widest in front of rounded posterior angles and strongly converging to a very narrow anterior margin, anterior angles absent and basal margin very strongly bisinuate. Elytra entirely dark or obscurely paler laterally, slightly narrower across the base than the base of the pronotum, elongate and gradually narrowed to separately-rounded apical margins, the surface finely punctured throughout and without striae. The pygidium is usually black with a red base in both sexes but may occasionally be extensively pale. Legs mostly brown but front legs usually orange in the female, hind tibiae with a transverse apical ridge and usually two incomplete external ridges towards the apex, front and middle tibiae without obvious spurs, hind tibiae with a single strong spur which is much shorter than the basal tarsomere. Tarsal formula 5-5-4; front and middle tarsi slender, hind tarsi much more robust, the basal segment in all cases much longer than the others.