One of the large formica species commonly known as wood ants. This species is very similar in appearance, size and nesting habits to Formica fusca but was firmly described and keyed by Yarrow in 1954. Workers differ from those of F. fusca by the presence of short stubby hairs on the promesonotal dorsum which is usually bare in F. fusca, and there are good diagnostic differences in males and queens. Greyish to brownish black with paler legs. Adult workers are typically 5 to 7 mm in length.
Short stout hairs present on promesonotum normally numerous but occasionally abraded or few. Underside of mid and hind femora normally with one or more hairs at mid length. Frons coarsely sculptured to that punctures readily seen under ordinary magnification.
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Formica lemani is abundant on high moorland in south-west England - Bodmin, Dartmoor, Exmoor, Mendips and Blackdown and on uncultivated land throughout Wales, northern England and Scotland as far as Hoy in Orkney. Nests are sited in open woodland, woodland verges, heaths and moorland. The ants nest under stones and in tree stumps under loose bark, but F. lemani may sometimes nest in turfy banks.
Mating flights typically occur between in July and August. Adult workers can be seen from early spring through to autumn.
Workers forage individually. They are predators on other insects. In Yorkshire an experiment on biological control of bracken was ruined by F. lemani workers destroying an introduced population of bracken-feeding caterpillars! This species also seeks out aphid honey dew.
It appears to be absent from the counties of south-east England - Hampshire and the Isle of Wight to Kent, Bedford and Northampton. There is no decline in this species which continues to do well in its known locations.
Uncommon in Leicestershire and Rutland where it is at the edge of its range, overlapping with Formica fusca. The last VC55 record was in 2017 taken from pitfalls traps at Charnwood Lodge.
Leicestershire & Rutland Map
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Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015