Ancistronycha abdominalis (Fabricius, 1798)
POLYPHAGA Emery, 1886
ELATEROIDEA Leach, 1815
CANTHARINAE Imhoff, 1856
CANTHARINI Imhoff, 1856
Ancistronycha Märkel in Kiesenwetter, 1852
This is a very local and generally scarce species of western, central and southern Europe, extending north into the UK and northern Germany but absent from the Baltic countries, to the east it reaches Poland and has recently been recorded from Slovakia, it occurs along the Mediterranean from Spain to Italy and although generally absent from the Balkans and Greece it has been recorded from Bulgaria and Ukraine; in northern Europe it is most frequently recorded from mountain areas and in the alps is present to about 2700m. In the UK it is very local and has probably declined in recent decades; it still occurs in the Brecon Beacons in south Wales but probably no longer exists in the north, it is absent from southern England and most modern records are from the Pennines, North Yorkshire Moors and the Lake District, in Scotland there are only a very few modern records from the Highlands. Adults occur from late May until July or August, depending on latitude, and the typical habitats are open deciduous woodland and woodland margins where they predate small insects and consume pollen among foliage and flowers, mating has been observed early in the season, in Spain as early as late April, but otherwise little is known of the biology.
11.0-14.5 mm. Easily recognized among our UK fauna by the large size and distinctive colour; the pale pronotum coupled with metallic blue elytra and black legs are diagnostic. Head black above and pale in front of convex and protruding eyes, temples long and converging, surface flat or concave, finely punctured and with fine pale pubescence, maxillary palps variously darkened, and the terminal segment securiform. Antennae filiform with all segments elongate, the second much smaller than the others, entirely black but the basal segments are usually to some extent pale. Pronotum transverse with rounded margins and angles, surface weakly and unevenly convex and widely explanate, in most specimens pale with the anterior margin darkened, sometimes the basal margin is also dark and, rarely, all margins may be dark. In Europe they are much more variable and specimens with a pale-margined dark pronotum or pale brown elytra occur. Scutellum small and triangular, very finely punctured and pubescent and coloured as the elytra. Elytra elongate, sub-parallel and with separately rounded apices, without striae but usually with traces of weak longitudinal ridges, surface densely and smoothly granulate throughout, usually metallic dark blue but the blue may be weak and not obvious. Legs black or sometimes the base of the front femora are obscurely lighter, only the tibial spurs and claws are consistently pale. Fourth segment of all tarsi widely bilobed, terminal segment long and curved. In females both claws on all tarsi have a strong basal tooth; in males both claws are simple.
Ancistronycha abdominalis 1
Ancistronycha abdominalis 2
© Lech Borowiec