The Highland Biological Recording Group

The HBRG Atlas of Highland Ants
Formica aquilonia F. lugubris F. exsecta F. sanguinea Formicoxenus nitidulus HBRG Atlas Recording
There are in Scotland four species of ant of conservation concern which are or have been included in the UK Biodiversity Action Plan. In addition, the Blood-red Slave-making Ant (the name explains a lot - it raids the nests of other ant species to capture slave workers for its own nests) is, although it has not been rated as a priority, giving cause for concern in England. The Shining Guest Ant, which lives with wood ants, is also a UKBAP species. The Forestry Commission, Scottish Natural Heritage, the Scottish Wildlife Trust and other organisations such as the Woodland Trust Scotland are involved in implementing Action Plans for these species. The identification of the group as a whole is not difficult even for the non-specialist, as they are the largest ants in Scotland, up to 10mm in length and distinctively reddish-brown and black in colour. Telling the species apart is much more difficult, and requires expert examination. Some confusion has probably occurred between the first two species. A useful document is here. The species: Formica aquilonia F. lugubris F. exsecta F. sanguinea Formicoxenus nitidulus
The Scottish Wood Ant (Formica aquilonia) is the most widespread of the four species, and is found patchily in forests throughout the Highlands, north to Sutherland and south to Arran. It builds relatively large nest mounds which can reach 1.5 m in height and contain over 100,000 individuals. Yellow dots <1980 in all maps; green dots >=1980; orange dots are still to be checked. This species and Formica lugubris have been confused. This ant was removed from the UKBAP priority list at the review in June 2007, but is still important as the host for the Shining Guest Ant. Back to top.
	The Hairy Wood Ant (Formica lugubris) is similar in size and distribution to the Scottish Wood Ant within Scotland, but is also known to occur as far south as Derbyshire and mid-Wales. It is relatively less common in the high rainfall areas of the west Highlands. This species and Formica aquilonia have been confused. This ant was removed from the UKBAP priority list at the review in June 2007, but is still important as the host for the Shining Guest Ant. Back to top.
The Narrow-headed Ant (Formica exsecta) is a rare species with its stronghold in the open parts of the Scots pine dominated forests of Abernethy, Glenmore and Rothiemurchus. It is 6-8 mm long, slightly smaller than the true wood ants, with a small notch on the top of its head, though one needs a hand lens and some practice to see this. Its nests are also smaller (usually only about 30 cm across at the base and up to 25 cm high), out in the open away from the shade of trees, and are made up of pieces of dried grass and small fragments of heather, etc. Strangely, this ant turns up again in the very south of England, where there are a few small and vulnerable colonies, with no locations in between. An information sheet can be downloaded here (.pdf file, 111kB). UK BAP page. Back to top.
A nest of Formica exsecta, showing scale. Photo © Murdo Macdonald	Typical habitat of Formica exsecta. Photo © Murdo Macdonald
	The Blood-red Slave-making Ant (Formica sanguinea) is similar in appearance to a wood ant. It is more vivid red than the other wood ants, and tends to be very aggressive when disturbed, biting rather than spraying formic acid as the others do. It is a lot commoner than previously thought in Scotland, and may be found in south-facing open forest and clearings. A guide to recognition is here. Back to top. .
Look out also for the tiny, 2-3mm long Shining Guest Ant Formicoxenus nitidulus, an ant which lives in wood ant nests. It is probably seriously under-recorded. The males can be found on the nest surface in late summer, but workers may be found at any time in warm still weather. A guide to finding the ant is here. UK BAP page. Back to top.
The HBRG Ant Atlas Scheme: HBRG is mapping all ants in Highland from 2006-2010. We have a number of other ant species in Highland, and we know little about some of them. Provisional maps can be downloaded here (Adobe Acrobat file, 260Kb, to be updated at intervals). There are 4 small black ants (Formica lemani, F. fusca, Lasius niger, L. platythorax), six species of small red ants (Myrmica rubra, M. ruginodis, M. sabuleti, M. scabrinodis, M. sulcinodis, M. lobicornis), the yellow Lasius flavus , and the tiny red and black Leptothorax acervorum. Two other species have old records from Highland and may still be present.
Recording: As is often the case, the distribution of ants is not well documented in Highland, and for species that are so important nationally we should try to change this. The current known distribution in Highland is shown in the maps above. It is not necessary to report wood ant nests from Strathspey, as the wood ants are very common and well studied there, but from anywhere else in the area please do let us know. Many species can readily be found foraging at picnic crumbs or under stones. Others will be less easily encountered. Please collect specimens and report sightings, especially from remote sites, Lochaber, Caithness, the islands, and at altitude. Scarcer species are most likely to be encountered in warm dry sandy places (e.g. sand pits, dunes, riverbanks, areas of alluvial sandy soils). Because of the difficulty of identification, I will need specimens. If you find ants, please either a) collect 5 workers from a single nest, kill them in the freezer, and send them to me with the usual supplementary data; or (for wood ants or other mound-builders only) b) send me a grid reference (6 figure minimum) with a description of the location of the nest, and I will endeavour to visit the site myself. Specimens can be protected from damage by preserving them in alcohol, but take care if posting tubes containing liquid. Please send details or specimens to Murdo Macdonald, 'Tigh nam Beithe', Strathpeffer, Ross & Cromarty IV14 9ET. Alternatively, email locations to . Back to top. Wood ants do not sting, but spray formic acid when annoyed. People with unusually sensitive skin should be aware of this, and use gloves if appropriate. It is unwise to place the face close to nest of disturbed ants as the spray can travel several cm to the eyes. The small red ants can sting, but in my experience they cannot pierce the skin. Those with allergies should take precautions. A useful introductory guide to ants is: Skinner, G. & Allen, G.W. 1996. Ants. Naturalists' Handbooks 24. Richmond, Slough. ISBN 0 85546 305 8. Some of this article is based by permission on the SWT leaflet ‘Wood ants in Scotland’ available for download here (.pdf file, 95kB).
Formica aquilonia F. lugubris F. exsecta F. sanguinea Formicoxenus nitidulus HBRG Atlas Recording