Ischnomera sanguinicollis (Fabricius, 1787)
POLYPHAGA Emery, 1886
TENEBRIONOIDEA Latreille, 1802
OEDEMERINAE Latreille, 1810
ASCLERINI Gistel, 1848
Ischnomera Stephens, 1832
This locally common species occurs from the southern tip of Scandinavia and the south of the U.K. through the middle of Europe to southeast France, Northern Italy, Switzerland and through the Balkans to Greece, and there is a separate population in northeast Spain. In the U.K. it is widespread although of local and sporadic occurrence in the south of England; West Sussex to Dorset, South Essex, Berkshire, Oxfordshire and Gloucestershire etc. There are a few southern coastal records from Wales and two from North Yorkshire. The species is generally associated with old deciduous woodland with plenty of timber in various stages of decay but it also occurs on isolated mature trees on old parkland and pasture etc. Adults have a short season, occurring for a few weeks from April to June, when they may be found on the foliage and flowers of a range of broadleaf trees and shrubs e.g. Crataegus, Acer campestre, A. pseudoplatinus, Sorbus, Ulmus, Tilia and Viburnum opulus. They fly well and frequent umbel flowers etc. on wooded margins where they feed on pollen and mate, thus sweeping suitable situations on hot sunny days is the best way to find them. Larvae develop in moist decaying wood of a range of broadleaf trees e.g. they have been found on Acer, Alnus, Fagus and Ulmus, they are fully grown by late summer when they pupate in the wood and the adults eclose in the autumn but remain in the wood until the following spring, hence they are occasionally found beneath bark during the winter.
7-12mm. characteristically bicoloured and so distinct among the U.K. oedemerids; elongate and narrow with proportionally very long elytra. Head shiny black with a metallic green reflection, densely punctured and distinctly depressed between weakly emarginate eyes, vertex convex, frons and labrum only weakly produced forward. Antennae 11-segmented in both sexes; the third segment almost twice the length of the second, dark with segments 1-3 testaceous beneath. Maxillary palpi dark above and pale below; terminal segment deeply furrowed along the inner margin. Pronotum shiny orange, cordiform, widest in front of the middle and lacking lateral borders, the surface densely punctured and with well-developed basal fovea. Elytra dark metallic
grey with a variable green reflection, densely and rugosely punctured, each with five longitudinal costae from the base to near the apex; the outer forming the lateral margin beyond the basal third. Abdomen entirely dark metallic. Legs long and slender, entirely dark metallic but for the distal tarsal segments which are lighter. All tibiae with two small spurs on the inner apical angle. Tarsi 5-5-4; the penultimate segment in each case strongly bilobed. All claws with a strong basal tooth.
Ischnomera Stephens, 1832
Variously included within the Asclerini Gistel, 1848, Ischnomera Stephens, 1832 is a Palaearctic genus of about 50 species with the greatest diversity in central and eastern Asia. Several Australian species as well as the Madagascan I. atricolor (Pic, 1922) are now thought to belong in other genera, and the Nearctic Asclera Stephens, 1839, which includes 7 species, was formerly included while several European species once included in Asclera are now re-classified within the present genus. Four widespread European species occur in Britain; the bicoloured I. sanguinicollis (Fabricius, 1787) and three unicolourous metallic green to bronze species which have frequently been confused in the past and can be very difficult to separate i.e. I. cinarascens (Pandellé, 1867), I. caerulea (Linnaeus, 1758) and I. cyanea (Fabricius, 1792). All species are medium-sized, generally 6-12mm, elongate and rather parallel-sided although many have the elytra weakly broadened behind the middle, metallic; either entirely green or bronze to almost black, or bicoloured with the pronotum contrasting red or yellow. The dorsal surface is clothed with short recumbent pubescence, the direction, aspect and colour of which is often diagnostic. The head is short and transverse with moderately convex eyes in front of which are the antennal insertions (in some genera these lie within or partly within, the emargination). The antennae are 11-segmented with the second segment half to two-thirds the length of the third. The terminal segment of the maxillary palpi is securiform, sometimes very elongate and broadest towards the base, and the mandibles are bifid. The pronotum is cordiform, strongly constricted towards the base and variously sculptured. Elytra distinctly shouldered; wider at the base than the pronotum, and each has four longitudinal costae which are usually distinct into the apical quarter although they may be variously evanescent, especially the third. The meso-coxae are contiguous, the mes-episterna widely separated medially and the terminal abdominal sternite has a median projection in both sexes. The pro-tibiae have two short spurs on the inner apical angle, and all the claws have a more or less (often strongly developed) obvious basal tooth-a character unique among the European oedemerid fauna.