Amara familiaris (Duftschmid, 1812)
This is a generally common and often locally abundant species throughout Europe extending north to Southern Scandinavia, south to North Africa and east through temperate Siberia to Mongolia. Following early 20th century introductions it is now widespread in the northern United States and much of Canada. In the U.K. it is common throughout England and Wales, and more local and scattered in Scotland to the far north including the Western Isles. Typical habitats are open and dry situations, usually exposed to the sun, on well-drained soil with patchy vegetation e.g. roadsides, dunes, agricultural land, wooded margins and gardens etc. On the continent it is especially abundant, and undergoes occasional population explosions, on agricultural land. Adults are active from March to November and most abundant in the spring and autumn; they are primarily nocturnal although may often be seen running on pathways etc. in bright sun. They overwinter under debris, among litter or in the soil and emerge early in the year when they may be seen on the soil surface running among weed etc. at night, they soon begin mating and dispersing to open situations with abundant weed growth; they are fully-winged and fly well and so may disperse over wide areas. They are omnivorous and feed on a range of small insects and larvae as well as seeds, more especially those of chickweeds, Cerastium sp. and Stellaria media (L.), the females do not reproduce until they have fed upon seeds and their fecundity is linked to seed consumption. Eggs are laid in the soil among suitable vegetation and the larvae emerge from early April, these are also omnivorous and are active on the soil surface at night, remaining hidden in crevices or under leaf rosettes etc. by day. They pass through 3 instars and are fully grown by mid-June when they will pupate just below the soil surface. New generation adults appear from July and may be found by searching among weedy areas at night, they may also be swept as they climb vegetation in search of seeds although in the warmest parts of the summer they may enter the soil and become inactive in order to avoid the heat. September and October is usually another period of activity and now they may appear to be abundant; often being among the most frequent carabids in suitably placed pitfall traps.
This species is usually obvious in the field; the entirely pale legs and the metallic lustre, which is generally weaker than in other common species of the genus, are distinctive.
5.5-7.2mm Head and pronotum shiny, without microsculpture, elytra a little less shiny, with microsculpture evident at X20. Frons with 2 supra-orbital punctures beside weakly convex eyes. Antennae dark with segments 1-3 and the base of 4 yellow, the third segment sometimes infuscated, palpi with the basal segments yellow. Pronotum weakly curved in the basal half, the lateral margins bordered, this border continues onto the anterior and posterior margins but becomes obsolete towards the middle. The basal fovea is represented by weak depressions or an indistinct streak among a few punctures, and the seta inside the posterior angle is close to the margin. Anterior angles protruding and distinctly angled; in the closely similar A. lucida (Duftschmid, 1812) they hardly project and are rounded. Elytra with a small and sharp shoulder tooth, distinct and well-impressed striae that become deeper towards the apex so that the interstices appear distinctly convex, and a scutellary stria that lacks a pore at the base. The seventh stria bears 2 preapical punctures, the posterior of which may be indistinct among the convoluted stria, and there is a single puncture at the apex of the first or second stria. Elytral epipleurs crossed. The terminal spur of the pro-tibia is simple i.e. not tridentate as in the common A. plebeja (Gyllenhal, 1810). Male with the basal pro-tarsal segments dilated.