Dusky Wireworm

Compared to other Agriotes species, the adult beetles of Agriotes obscurus are of medium size and 7–10 mm long. They can be identified by the following combination of features:

Pronotum clearly wider than long, its sides strongly curved. The whole thorax strongly and densely punctured. Elytra relatively short with narrow longitudinal ridges arranged in pairs, the distal part wedge-shaped. Color dark brown to black with elytra, legs and antennae often lighter. However, the whole insect may also be of the same color. The antennae are slightly longer than head and thorax combined. Agriotes obscurus is similar to A. sputator and to A. lineatus, two other common species in Europe which are also agricultural pests, but in both species the pronotum is slightly longer than wide. Compared to A. obscurus, the pronotum of A. sputator is also wider near the head and has less curved, almost parallel sides. A. lineatus can be easily separated from A. obscurus and A. sputator by its striped elytra. Molecular identification of A. obscurus adults and larvae is also possible. The morphological features of A. obscurus larvae are very similar to those of A. lineatus and it is difficult to separate the larvae of both species. The shape of the abdominal spiracles has been described as most consistently different in both species, being longer than wide and narrowing posteriorly in A. obscurus.

Linnaeus gave "Europe" as habitat when he described Elater obscurus, the basionym of Agriotes obscurus. The type localities given for three other species which are now regarded as synonyms of this species (see the taxobox above) are: Denmark, Germany and Europe. A. obscurus is native to Europe and to parts of Asia. It is most common in central Europe like France, regions in and around the Alps, the U.K., Germany, Poland, Scandinavia and the Baltic states. In Europe, the total distribution range extends from parts of Spain and Italy in the south-west to the U.K., Norway and Finland in the north, to Ukraine and western Russia in the east and to Serbia, Montenegro, Bulgaria and Romania in the south-east. In Asia, it is found in some northern and central parts including Armenia, Azerbaijan, northern Kazakhstan, parts of Siberia, northern Mongolia, northern China and Korea. Around 1900, Agriotes obscurus was accidentally introduced into western Canada, possibly with the soil of hop plants. In the province of British Colombia it is now wide-spread and common on Vancouver Island and in Fraser Valley on the Canadian mainland. It is also spreading into neighboring parts of the U.S.A. During a survey in 1997, A. obscurus was recorded in Washington State, just across the border from British Colombia. Further surveys in 2004 and 2005 indicated that A. …