Selatosomus aeneus (Linnaeus, 1758)

This transpalaearctic species occurs from continuously from the west of Europe to the far east of Russia but is absent from Japan, and over much of its north-western continental range is a pest of various crops and young orchard trees. In the U.K. it is locally common throughout England and Wales with the exception of the southeast, and there are a few scattered records from the Scottish Highlands. It occurs in a wide range of woodland, grassland and agricultural habitats where the adults are active from early spring until mid-summer. European populations are more typical of grassland habitats whereas those further east occur in more forested habitats, in the U.K it is a mostly grassland species which has not become a crop pest. Adults occur under debris or among leaf-litter early in the year, becoming active and dispersing by flight during May and June when they feed upon leaves of grass and shrubs for a while before mating, usually on the soil surface in sparsely vegetated areas. Females are very fecund, producing between 300 and 650 eggs which are laid on emerging grass leaves, among leaf-litter or in cracks in the soil. The eggs develop slowly with larvae emerging after four or five weeks, the young larvae move among the soil or litter seeking out conditions of optimal temperature and humidity before they begin to feed upon roots and young shoots etc. and they are also known to consume small insects and larvae, as they grow they move between plants on the surface or through the soil. Development takes between two and four years, or longer at higher continental latitudes, and winters are spent deeper in the soil, they will moult between eight and twelve times and when fully grown will pupate in a deep subterranean cell from July onwards. The adults eclose from August but remain in the cell until the following spring. In parts of Northern Europe the larvae  may be the most numerous of all pest elaterids and they commonly attack cereals, sunflowers, potatoes and various vegetables, consuming seedlings and young roots of developing plants and causing deterioration of tuber and root crops. Control measures include deep ploughing etc. but the beetles typically maintain healthy populations in marginal habitats among native grasses and so are very difficult to eradicate in the long term.