The commonest of our four small, metallic-green/torquiose Lasioglossum species. Both sexes are most easily distinguished from the others by the densely punctate, dull scutum which has obvious microsculpture between the punctures. Some females of L.leucopus can difficult to separate, but morio has a duller thorax, duller hind margins to the upper part of the propodeum, and minute transverse ridges on the apical depression of tergite 2.
This is a widespread and often abundant species found in a wide range of habitats, where it exploits various flowers. It can sometimes be found nesting in the soft mortar walls.
It is a host of the cleptoparastic bee Sphecodes niger and possibly S. geoffrellus and Nomada sheppardana; also the conopid fly Thecophora atra.