Ctenicera cuprea (Fabricius, 1775)
A predominantly northern insect with few records south of a line from the Wash to the Severn estuary although there are 10 or so from the west country. Virtually absent south of the Thames. Widespread throughout Scotland to the far north and western isles (NBN website). On the continent a common species of mountain and subalpine meadows. Larvae live in soils of open mesophilus habitats. Pupation occurs at the end of summer or in early autumn and adults hibernate (Hurka). Adults appear from May or June and may be found by sweeping grass or low vegetation.

Our single record is a male from open grassland between extensive mixed woodland (Whippendell wood) and pine plantations (Lees wood) during August 2004, the insect was attracted to M.V. light on a horizontal sheet around midnight.

12-15mm. Antennae black, in male pectinate,flagellum on segment 3 shorter than length of segment, in female serrate and shorter than male. Insertions wider than length of segment 1. Head and pronotum distinctly punctured (X20) and with dense erect setae, shiny black with obvious violet or red lustre. Pronotum with median longitudinal furrow and strong ridges laterally at base continuing onto backwardly projecting hind angles. Elytra glabrous with well impressed and punctate striae, 5 and 6 on distinct humeral prominence, interstices finely punctate. Brown with apical third or so , suture and humeral prominence dark with violet lustre which becomes obvious when lit from behind. Var. aeruginosus Fab. is entirely metallic coppery red or green and not uncommon in populations. Legs entirely black, claws red. Femora and tibiae without teeth or spines. Tarsal segments not lobed. Claws smooth with small basal tooth. Pronotum and elytra in female are very distinctly broader than in male.

Description from 5 Watford specimen at X20

Update Nov 2008
The genus Ctenicera (no species given) is quoted by Gratwick as a pest of arable crops in some upland areas. A general description of the various stages and of the life cycle is given and summarised here. Eggs are laid in May and June in grassy or weedy soil, they are more likely to dry up and die in bare soil. Larvae hatch after a month or so and grow very slowly, young larvae feed on both living and dead plant material in the soil while older larvae feed on the underground parts of living plants. Feeding rates vary through the year, being most intense from March to May and in September and October. They will generally grow for four or five years in the soil before reaching maturity, generally during July or August. Mature larvae burrow deeper into the soil where, at a depth between 10-25cm, they hollow out small cells in which to pupate. Adults hatch within three or four weeks of pupation and remain to hibernate in the cell although if disturbed they will climb up through the soil and hibernate elsewhere. With the exception of potatoes, most serious damage is caused to young arable crop plants in spring and early summer

On June 1st 2008 this species was found swarming over open grassland in Cassiobury park. We found the swarm active in bright sunshine around 11am and observed, at any given time, an estimated two hundred specimens. The swarm covered an area 20mx30m flanked by mature beech, birch and oak, the grass was very sparse and growing through a spongy, dry layer of moss. The few cow-parsley flowers nearby were ignored by the beetles. A few beetles were seen to emerge from the moss, ascend grass stems and sit for a few minutes before taking flight. Many specimens were removed from grass flowers and examined; all specimens seen that day were males. Despite following many specimens in flight and seeing them alight on grass stems or flowers, and despite searching the soil and moss, no females were observed. When we left at 1pm they were still swarming. Outside this area only a few specimens were seen, mostly among long grass towards the A412. The majority of specimens were of the bicoloured variety but many entirely metallic violet or black individuals were seen (f aeruginosa Fab.). Returning on the 3rd June (11am) only a few specimens were seen, and none outside this swarming area. Beyond this time only one further specimen was seen, on 25/07/08 (male). As well as more weekend searches, the area was inspected more-or-less daily by Conall Murray to and from school. Considering the protracted life cycle it might be interesting to see whether adults occur in 2009.

f aeruginosa Fab.

f aeruginosa Fab.