Stenopsocus immaculatus (Stephens, 1836)

The identification characters used by New (2005) and Lienhard (1998) to separate S. immaculatus and S. lachlani have been shown to be largely unusable with British specimens (see Saville, 2009). The only character that can be used is the ratio of the distance between the eyes to the longest diameter of an eye (IO/D ratio). The ranges of these ratios for the two species are: S. immaculatus - male (0.8-1.1), female (1.6-2.1); S. lachlani - male (1.3-1.5), female (2.2-2.4).

Summary: has been found on a wide range of deciduous and coniferous/evergreen tree and bush branches (no records from trunks).

Associations:

• Deciduous branches: alder, ash, beech, birch, blackthorn, elder, field maple, hawthorn, hazel, honeysuckle, hornbeam, lilac, lime, oak, plum, rowan, Salix lapponum, sallows and sycamore.
• Conifer/evergreen branches: broom, gorse, holly, larch, pine, sitka spruce and yew.
• Other microhabitats: leaf litter and log pile.

Sampling techniques: beating branches, hand searching and litter sieving.