Leistus fulvibarbis Dejean, 1826
This is a generally common species throughout lowland Europe, including the Canaries and most of the Mediterranean Islands, from Portugal to Greece and Turkey and extending north into the Netherlands and the UK, it is widespread across North Africa and a single subspecies, ssp. danieli Reitter, 1905, occurs in Italy. In the U.K. it is locally common throughout England, Wales and Ireland and less so to the far north of Scotland including the Western Isles and Orkney. Typical habitats are open and fairly dry woodland, dunes, parkland, hedgerows and scrubland on all types of soil where the adults hide during the day under logs or among litter etc. and become active at night , hunting springtails etc. on the surface of trunks and logs. Adults occur year round, peaking in abundance during early spring and again in the autumn, they spend the winter in the soil under logs or among litter or bark etc. and are active from February or March, these overwintered adults persist into the spring but die off before the next generation emerges during May and June. Soft-bodied and pale teneral specimens may be found under stones and logs etc, they begin feeding and are active until late June or July when they will aestivate in the soil, often in groups, during the warmest part of the summer, and emerge to breed in the autumn. Larvae develop through the winter and pupate in the spring. After breeding most adults will die off during the autumn and winter but many will persist until the following spring. Adults may be found under debris or among litter during the day but they are mainly nocturnal and should be searched for on pathways, lawns and around logs and the base of trees, they are very active and most have fully-developed wings although flight capacity is not known and functional flight muscles have been found in only a small percentage of specimens. As with other members of the genus, both adults and larvae are specialist springtail predators.
6.5-8.5 mm. When fully-developed the body is entirely dark brown or black but teneral specimens may be very pale and might be confused with ferrugineus or terminatus but there is always a faint metallic reflection to the elytra and the pronotal margins are distinctly punctured. Dorsal surface black to dark brown with a weak metallic blue reflection, pronotum sometimes with narrow pale lateral margins, appendages and mouth parts pale reddish-brown. Frons indistinctly wrinkled and punctured beside the eyes but otherwise the head is smooth, antennae very long and slender, densely pubescent from the fifth segment. Pronotum broadest in front of the middle, strongly narrowed to a sub-basal constriction, then slightly protruding before perpendicular hind angles; the explanate margin is narrow and distinctly punctured throughout and the posterior angle lacks a setiferous pore (this is present in rufomarginatus, spinibarbis and montanus). The elytra vary but are typically narrow and rather parallel with prominent shoulders that lack a lateral tooth. Male with basal segments of the front tarsi dilated.