Agriotes obscurus Linnaeus, 1758
Common names: Obscure click beetle, Wireworm Click Beetle, Dusky Wireworm Beetle [En], Taupin obscure [Fr], Donkere akkerkniptor [Nl]
Hamoir, LIEGE ● Belgium
Description: The beetle is 7-10 mm long, and tries to escape in case of danger through “clicking” - true to its name. Is is a uniform mid-brown coloured species with a very dense covering of lighter brown/cream hairs. Its shape is despite being elongated, appears to be stubby, as the margin of its broad thorax runs down beside the shoulder of the elytrae. Its head is convex, with dots, the thorax is also dotted, its side margins are bending towards the ventral side, the elytrae are conical.
Rows of pits form ridges down the length of the elytra that appear in ‘pairs’ and are a darker brown colour to the rest of the elytra. The legs and antennae are slightly darker brown than the rest of the insect. The antennae are slightly longer than the length of the head and pronotum. A. lineatus may look similar, but the stripes along the elytra in that species have a two-tone dark and light appearance. A. sputator is another similar species, but the pronotum, in A. obscurus is much narrower at the front than in the middle and much more strongly contracted towards the front. Conversely, in A. sputator, the pronotum is more nearly parallel-sided and much less strongly contracted to the front.
Biology: Adults move at night, feeding on the leaves of grasses. They lay eggs into the surface soil in April, May and early June. Young larvae hatch in June or July. These larvae, called Wireworms, are long lived (up to four years in this stage of development) and feed on the roots of grasses and other plants. Host plants of the larva include maize, cereals, sunflower, sugarbeet, potatoes, other grasses, and also many other plants, i.e. tomatoes.
Habitat: Meadows and grassy places.
Distribution: Widespread Eastern-Palearctic species, much commoner than A. lineatus. Eurasia from Atlantic to Pacific Ocean, including the Northern Caucasus, Northern Kazakhstan, and Northern Mongolia. The beetle is most numerous and harmful in Europe in the zone of predominance of coniferous forests and podzolic soils of the northern type, and also in forest-steppe districts of Siberia. It has been introduced to Northern America early around 1900, with soils from the ships.
Elateridae of the British Isles
Pheromone traps, Plant Protection Institute, Centre for Agricultural Research, HAS, Budapest
Agro Atlas. Project “Interactive Agricultural Ecological Atlas of Russia and Neighbouring Countries. Economic Plants and their Diseases, Pests and Weeds”, 2003-2009