Lasius alienus

34. Lasius alienus (Forster, 1850)

Figs. 128-130.

Formica aliena Forster, 1850:36.

Worker. Greyish yellow to brownish black. Pubescence adpressed, moderately thick over whole body and appendages. Short erect hairs scattered over dorsum and round whole occipital margin of head. Back of head convex. Ocelli indistinct or invisible; frontal furrow indistinct. Erect hairs absent on scape and front tibiae, sometimes present on hind tibiae. Length: 3.0-4.2 mm.

Queen. Greyish black to brownish black. Wings hyaline. Head much narrower than broad alitrunk. Pubescence and pilosity as in worker, no erect hairs on scape and front tibiae. Length: 8.0-9.0 mm.

Male. Greyish black. Wings hyaline. No erect hairs on tibiae or scapes. Length: 3.0-3.8 mm.

Distribution. Common in Denmark and South Sweden; in Norway only recorded from. O, HE and VE; in Finland recorded as far north as Ob and Ks. - Common in South Britain, local in Ireland and Southwest Scotland. - Range: Portugal to Japan also Himalayas, North Africa to Finland. Also North America (Wilson, 1955).

Biology. This wide ranging species nests in the soil on sandy lowland heaths, dry open pasture, sea cliffs and rocky outcrops in North Europe. Its habits are mainly subterranean, feeding on the exudates of root aphids but also by scavenging and predating small insects. Workers are generally unobtrusive and non aggressive compared with Lasius niger. Nests are single queened founded by solitary fertilised queens. Mating swarms occur in August.