Aderus populneus (Creutzer, 1796)
This native and locally common western Palaearctic species is now widespread in the northern Nearctic region following introductions first noticed in the 1940’s. In the U.K. it is widespread in southeast England, the midlands and South Wales and is our commonest member of the family. The species is saproxylic, developing in rotten wood in a wide range of deciduous trees e.g. oak, lime, plane and willows; the larvae feed among fungus infested wood and pupate in late summer or autumn. The adults eclose late in the year and overwinter in hollow trees or beneath bark etc. and become active from April or May. The typical habitat is woodland, wooded parkland or pasture but they occur in suitable trees in gardens and other urban situations and have also been recorded at compost, manure and feeding upon cobwebs under bark etc. During the summer we sometimes find them on walls inside during the day. The adults may be found in numbers in decaying wood during spring and autumn while in late spring and summer they may be beaten from suitable foliage in small numbers, they are active and fly nocturnally and are attracted to light on warm summer evenings.
A small species, 1.5-2.3mm which is entirely testaceous but for the dark head and the elytral pattern which with experience will serve to identify it in the field. The entire dorsal surface is densely pubescent, that on the elytra forming a pattern with a dark oblique strip from the shoulders and a transverse strip behind the middle. The head is transverse and at least as wide as the pronotum, with large eyes that occupy the entire lateral as well as part of the basal margin. Antennae thick and densely pubescent from the fourth segment, inserted in front of the eyes and separated by about the length of the basal segment; segments 2 and 3 short, together about as long as the fourth, segments 4-11 distinctly elongate in the male but only slightly so in the female. The terminal segment of the labial palps is broadly triangular. Pronotum pentagonal; subparallel in the basal half, angled near the middle and narrowed anteriorly, the surface is weakly depressed towards the base and the hind angles are sharp and produced. Elytra elongate and completely covering the abdomen; broadest behind the middle, more so in the female, and evenly rounded to the apex. The legs are long and slender and lack any obvious teeth or spines. Tarsi 5-5-4 with the first segment long, on the metatarsi 1.5x the combined length of 2-4, and the third segment is bilobed.