Ctenicera cuprea (Fabricius, 1775)
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POLYPHAGA Emery, 1886
ELATEROIDEA Leach, 1815
DENTICOLLINAE Stein & Weise, 1877
CTENICERINI Fleutiaux, 1936
Ctenicera Latreille, 1829
This is a generally common elaterid throughout the Palaearctic and east to Mongolia occurring from lowland to mountain and subalpine elevations. In the U.K. it is a locally common and predominantly northern insect with very few records below the Wash and the Severn estuary; in Scotland it occurs to the far north including the Western Isles. Adults are active from May until July in open grassland, heathland and upland moorland habitats and can sometimes be found swarming in large numbers, they are diurnal and as well as nocturnal and occasionally arrive at light. In the spring they fly over long grass or settle high up on stems and fence posts etc. but later on the majority of specimens will be male as the females remain low down among grass or under stones etc. Eggs are laid during May and June in open and lightly vegetated soils and the larvae emerge after about a month; initially they feed upon living and dead plant material but as they age they move deeper into the soil and feed upon roots, feeding rates vary through the year and are most intense in the spring and autumn. They develop for several years before burrowing deeper into the soil, 10-25cm, to pupate in an earthen cell. Adults eclose after a few weeks but remain in the cells to overwinter. Throughout its range it has been an occasional and serious pest of cereals and other crops, especially in upland agricultural areas, as well as ornamental lawns where its presence may be detected by open, mossy areas in otherwise healthy grass.
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12-17mm. This large and very distinctive beetle is similar to our other U.K. member of the genus C. pectinicornis (Linnaeus, 1758) but here the antennae are more developed; in male pectinicornis the flagellum of the third segment is as long as the segment and on segments 4-10 it is at least twice the length of the segment, in females they are more obtusely serrate with the second segment about twice as long as wide and the remaining segments more elongate, in female cupreus the second segment is at most 1.5x longer than wide and segments 4-7 are about quadrate.
Body entirely shiny metallic green, bronze or coppery-red (var. aeruginosa (Fabricius, 1798)) or with the elytra pale brown and variously metallic towards the base and apex. These colour variations occur together and, in our experience, in roughly equal numbers, and this may be a good guide to the species as pectinicornis is always entirely metallic green to blue or coppery. Head and pronotum densely punctured and with dense pale and erect setae. Pronotum elongate, with a distinct longitudinal median impression that may continue to the anterior margin, and strong ridges above the obliquely produced and acute hind angles. Scutellum large and generally covered with pale pubescence. Elytra glabrous with well-impressed and punctured striae; 5 and 6 above the prominent shoulders; the interstices convex towards the base and apex and finely punctured. Legs entirely dark and variously metallic, with red claws. Femora and tibiae without obvious teeth or spines. The tarsal segments are not lobed and all are distinct, the claws smooth with a small tooth at the base. The female pronotum and elytra are distinctly broader.