Agrypnus murinus (Linnaeus, 1758)
This widely distributed and generally common species occurs throughout Europe, except in the far north, from lowlands to mountains in a wide range of habitats including open forest areas, parkland, domestic gardens and all types of grassland. In the U.K. it is generally distributed though local through England and Wales with most records from western coastal regions, especially around Wales and Cumbria, inland records are scattered with many from the Thames and Severn basins, becoming progressively rarer further north. The typical habitats in the U.K. are open scrubland, grassland and dune slacks. Adults appear early in the year, from April or May and remain active into June or July; they may be swept, often in numbers, from grass etc. in suitable situations and can often be seen in flight low over grassland in the late afternoon or evening. Eggs are deposited in the soil where the larvae will develop, feeding upon the roots of grasses etc. and occasionally woody plants such as oak saplings etc. In some European countries they have occurred in large numbers and have become pests of commercially grown plants and crops. Larval development takes two years and pupation occurs in the soil in late summer, adults eclose in the autumn and overwinter in their pupal cells, emerging in the spring.
This large elaterid, 10-17mm in length, is distinctive among the U.K. fauna due to the dense scale-like pubescence which almost covers the dorsal surface. This comprises brown or red to grey or silver groups which may be mixed to varying extents and which lie at oblique angles to the longitudinal axis so giving the appearance of vague, differently-coloured maculae although in some specimens a single colour may predominate. The antennae are pale with one or, rarely, two basal segments darkened, the second and third segments are almost quadrate and the third segment is only slightly shorter and narrower than the second. The pronotum is transverse and convex with dense and evenly spaced punctures, the lateral margins are sinuate and the anterior margin much narrower than the basal margin. The hind angles are broad, laterally produced and truncate. Scutellum pentagonal and concave, without a central ridge. The elytral striae are well-impressed and punctured, the interstices densely and finely punctured. The legs are dark with pale tarsi.