Nebria brevicollis (Fabricius, 1792)
This is a common and generally abundant ground beetle occurring throughout Europe and Asia Minor east to the Caspian Sea, extending to high latitudes, and it has recently become established in parts of Canada and the northern United states, it is abundant throughout the U.K. including the Western Islands, Orkney and Shetland, and is our most common larger carabid. It occurs in a wide range of moist but not wet habitats, primarily woodland but also parkland, wasteland and gardens etc. and may be very abundant on heaths and dense heather moorland; it occurs commonly in coastal areas but is generally absent from dry-dune and saline areas. Adults may be found year-round, the new generation appears from late winter or early spring and is abundant by the end of March, they are nocturnal and predatory, feeding on other insects and larvae, and worms etc. they may also be found at carrion but are unable to deal with the slime produced by slugs. They remain active and feeding until July or early August when they enter a resting phase for the summer, here they will usually aggregate under logs or debris in damp, shady situations. Feeding activity resumes in late summer and mating begins in September or October, the majority of adults then die off by the end of November and only a few survive into the winter. The predatory larvae appear during October and November and they will develop through the winter, hunting on the soil surface in all but the coldest conditions, and roaming far from the oviposition site; first instars are known to travel 10-15m while third instars travel tens of metres and it is thought the species disperses, at least partly, by this means. The majority of adults are macropterous but most have only poorly developed flight muscles and are incapable of flight, some specimens can fly and do so but this is rare, they are known to travel long distances walking and running and, along with the larval movements, it is thought that dispersal is entirely terrestrial. Adults are readily recorded nocturnally e.g. on pathways or low down on trunks in woodland, or diurnally under logs or debris in shaded and damp situations. At night they will often be recorded alongside other carabids and staphs etc. and may occur in such unlikely situations as reed beds or in houses.
10-14mm Glabrous and uniformly dark when mature although in many the extreme edges of the pronotum and elytra are translucent and pale, and pale immature specimens are common early in the year. Head smooth with large convex eyes, parallel temples and a single supra-orbital puncture, palps brown with the terminal segment truncate, antennae pale, pubescent from the fourth segment. Pronotum transverse, strongly rounded and cordate, lateral margins explanate with a setiferous puncture in the middle and at the posterior angles, punctured along the base and lateral and anterior margins. Posterior angles sharply acute, the base with a wide oblique fovea either side of the middle and the basal margin sinuate. Elytra elongate, smoothly rounded and narrowly explanate, each with eight well-impressed and punctured striae, the third with three to six larger, somewhat foveate, punctures. Interstices with transverse microsculpture visible at X50. Legs long and slender; dark with the tibiae and tarsi variously pale. Meso- and meta-tarsomeres each with several transverse pairs of fine setae which may need to be looked for very carefully (X50), in the closely similar N. salina Fairmaire & Laboulbéne, 1854 these are missing. Claws smooth.