Lasius emarginatus (Olivier, 1792)

Description and notes

Lasius emarginatus is a fairly common warmth-loving ant found in much of Europe including the Channel Isles but only recently discovered in mainland Britian. It looks similar to the common black ant L. niger (Linnaeus) except for its distinctive orange/red alitrunk contrasting with its dark brown head and gaster. It could, possibly be confused with L. brunneus (Latreille), which is also bi-coloured, but it is a much bolder species. Unlike the furtive L. brunneus, L. emarginatus can be found running around on open ground. Under the microscope the antennal scapes of L. emarginatus can be seen to have outstanding hairs unlike the scapes of L. brunneus.



There is a record of a single worker from the Isle of Wight in 1979 and another from Dorset in 2011 and a colony in Islington, Middlesex, was found in 2008 (Smith & Williams, 2008). A colony in Islington, Middlesex, was found in 2008 (Smith & Williams, 2008) and since then it has been found nesting at several other sites in North London. A colony was found in 2017 on the Norfolk/Cambridgeshire border. As a native species it is found throughout the Channel Isles.

Found throughout central and southern Europe and around the Mediterranean.

Status (in Britain only)

The Channel Islands are, for a number of reasons, excluded from the geographical coverage of the British Red Data book (Shirt, 1987) and the subsequent review (Falk, 1991). If the species becomes established in Britain then its status will need to be assessed.


It requires a warm open site and its natural habitat is warm sparsely vegetated rocky areas. The colony in Middlesex is nesting in a south facing brick wall.

Flight period

Mid July to late August

Foraging behaviour

On warm days workers run around quickly in search of prey or scavenging. They mainly feed on honeydew from aphids and other plant sucking insects.

Nesting biology

Nests are made under stones, amongst rocks or in brickwork.

Author of profile

M G Fox

Year profile last updated