Some Peninsula ants
Glenda M. Orledge, BWARS Ant Recorder.
Whether as the objects of casual observations, or as the subjects of more serious study, ants are undeniably fascinating. Despite the substantial attention they receive from amateur and professional myrmecologists worldwide, and the impressive and continuously growing body of knowledge that has resulted from this work, there is a great deal still to be discovered. Close to home, for instance, it remains unclear how many ant species are represented in Britain, and there is considerable scope for improving our understanding of the distributions and abundances of British species at local, regional and national levels.
Much of our knowledge of ant distributions in southwest England comes from records generated during the second half of the twentieth century. The majority of these come from G.M. Spooner, one-time National Ant Recorder who lived at Yelverton, South Devon, K.N.A. Alexander, who has surveyed many National Trust properties in the southwest with the National Trust Biological Survey team, A.J. Prince from Somerset, and the Mellor family from Falmouth, Cornwall, who were active during the early 1990’s. Despite the recent upsurge of interest in British ant recording under the umbrella of BWARS (the Bees Wasps and Ants Recording Society), no-one has emerged to take the place of these recorders – so there is plenty of opportunity for anyone who wishes to contribute to our knowledge of Peninsula ants.
The southwest Peninsula is a rewarding area in which to look for ants. From Dorset westwards, representatives of all fourteen of the native British ant genera listed by Bolton (2005) have been recorded, as well as the apparently long-established exotic, Hypoponera punctatissima (Roger). The warm southern coasts are especially species rich, whilst the heaths and moors support additional species. Several Peninsula ants are of conservation concern, including Formica exsecta Nylander (the Narrow-headed Ant, see Carroll, 2004), Ponera coarctata (Latreille), Solenopsis fugax (Latreille), Temnothorax albipennis (Curtis) (formerly misidentified in Britain as Leptothorax tuberum (Fabricius), see Orledge, 1998, and recently moved from Leptothorax to Temnothorax by Bolton, 2003), and two permanent social parasites of Tetramorium caespitum (Linnaeus), Anergates atratulus (Schenck) and Strongylognathus testaceus (Schenck).
Both A. atratulus and S. testaceus have been recorded from Bolt Head and Bolberry Down on the South Devon coast. Other British records for these species are few, and restricted to the extreme south of England (Barrett, 1979: Roberts & Hoy, 2002). Unlike the workerless A. atratulus that occurs only in host nests which have lost their original queen, S. testaceus produces workers as well as sexuals within the host nest, which retains its original queen. However, the production of the host’s sexuals is suppressed when S. testaceus is present. Strongylognathus is a genus of obligate slave-makers, and it is thought that S. testaceus workers, in company with workers from their host nest, may raid neighbouring T. caespitum nests for brood (Bolton & Collingwood, 1975; Collingwood, 1979).
Hypoponera punctatissima is a cosmopolitan species of tropical origin (Czechowski et al. 2002). The majority of British records for this ant come from heated buildings, but it has been found in the open on a few occasions. The single Peninsula record for the species is reported by Timmins & Stradling (1993), who found many workers in an old fermenting horse dung heap at St. Thomas Hall, University of Exeter in 1992. They also found H. punctatissima in similar heaps in Staffordshire and Warwickshire, and suggest that the apparently long-term survival of this ant in Britain may owe much to the presence of warm fermenting matter associated with human activity.
Ants to look out for in the southwest
Formicoxenus nitidulus (Nylander)
This small, shining, reddish-yellow to brown ant is a ‘guest ant’, living within the nest mounds of its ant hosts. Known hosts in Britain are the ‘wood ants’, Formica aquilonia Yarrow, F. lugubris Zetterstedt and Formica rufa Linnaeus, of which only the latter occurs in southern Britain. Peninsula records for F. nitidulus come from just two 10km squares in Devon, SX78 (Lustleigh) and SX88 (near Dunsford). However, this ant can be difficult to find, and since its F. rufa host is known from several other Peninsula sites (Hoy & Roberts, 1997), it is likely that F. nitidulus is more widely distributed in the southwest than records suggest.
Formicoxenus nitidulus nests within the host nest mound, in hollow twigs and stems, wood fragments, or the earth floor. A single Formica mound may contain several Formicoxenus nests, each typically with less than one hundred workers and with one egg-laying queen. Workers forage singly within the host nest, obtaining food from host workers, either by intercepting regurgitated food being passed between them, or by direct soliciting. Although they seldom leave the mound interior, both workers and the wingless, worker-like males can sometimes be seen running on the surface of the mound on warm, dull, humid days. So the surfaces of F. rufa mounds are always worth a few minutes of careful observation in such weather.
Lasius platythorax Seifert
When the ubiquitous blackish brown Lasius niger (Linnaeus) was split into a pair of sibling species, L. niger s. str. and L. platythorax, by Seifert (1991), this not only enabled the addition of L. platythorax to the British list, but also meant that existing records of L. niger were rendered of little use (since they represent both species). Whilst it seems likely that L. niger s. str. is widespead and common in Britain, the situation for L. platythorax is less clear. BWARS records indicate that L. platythorax is widespread in southern England and South Wales, and is common in some parts of southeast England. John Pontin (personal communication) has found specimens of L. platythorax from Cumbria and the Tay Estuary, Scotland, in his collection. However, away from southeast England, records are very few. There are none from Cornwall and only two from Devon, both from Bovey Heath. The ant almost certainly occurs more widely in the Peninsula than the meagre data suggest, and would no doubt repay a targeted search.
The morphological similarity between L. niger s. str. and L. platythorax means that their separation requires care, and reliably identified specimens for comparison. Before settling on a determination, it is always worth seeking a second opinion from someone familiar with both species; and, of course, it is important to retain voucher specimens! In comparison with workers of L. niger s. str., those of L. platythorax have less dense clypeal pubescence, a less domed lateral clypeal profile, and somewhat longer body hairs. The female mesonotum of L. platythorax is noticeably lower that that of L. niger s. str. These characters are figured by Seifert (1991) and Chechowski et al. (2002).
Since there are some general ecological differences between L. niger s. str. and L. platythorax, habitat data may suggest which of the two species has been found. However, because there is habitat overlap between the species in Britain, such data cannot replace morphology as an identifier. For reliable determination morphological characters need to be checked. Lasius niger s. str. occurs most frequently in dry open habitats, including paved areas and urban gardens. Although often found in open habitats, L. platythorax is more tolerant of shade, and is generally found in damper situations, including boggy ground. A nest in rotting wood is more likely to belong to L. platythorax than to L. niger s. str. So, you can be pretty sure that the blackish brown Lasius ants nesting under the slabs of a warm, dry garden patio, or in the greenhouse, are L. niger s. str., whilst rather shinier ants nesting in damp, rotting wood on boggy ground are likely to be L. platythorax. Such specimens are a useful starting point for anyone wishing to get to know these two species.
Myrmica specioides Bondroit
British records for this species date from 1958, when an alate female was collected at Herne bay, Kent, by J.C.Felton. During the next forty years records were added from other localities in Kent, then from sites in Essex (Harvey, 2005), from the coasts of Suffolk and Norfolk (records of Phil Attewell), and from Rye Harbour, Sussex (Grace & Yates, undated). In 2004 M. specioides was found on Hayling Island by Mike Edwards. This pattern of record accumulation might be interpreted as a range expansion. It is, however, also possible that the difficulty in distinguishing between M. specioides and the morphologically similar species, M. scabrinodis Nylander and M. sabuleti Meinert, has caused M. specioides to be overlooked. In the latter case, at least, M. specioides might be present in the Peninsula, and is certainly worth looking for in suitable habitat, particularly on the southern coasts. Although occasionally reported inland on garden lawns, calcareous grassland and sparsely-vegetated brownfield sites (Allen, 2004; Harvey, 2005), M. specioides is known in Britain primarily from warm, sparsely-vegetated coastal sites, including dunes, gravels and grassland. The workers may be separated from those of M. scabrinodis and M. sabuleti (both of which occur widely in the Peninsula) by their more rounded petiole node (figured by Bolton & Collingwood, 1975, Collingwood, 1979, Skinner & Allen, 1996, and Chechowski et al., 2002). But since differences can be slight, it is always worth asking an expert to check any putative M. specioides specimens, and it is important to retain voucher specimens.
Finding out more: the Bees, Wasps and Ants Recording Society
BWARS is an active society, with a growing membership, that extends a warm welcome to beginners and experts, alike, who are interested in the identification and recording of bees, wasps and ants in Britain. The Society produces two newsletters a year, and the AGM weekend in September includes one or more workshops and informal study/identification sessions, also several talks. The membership is currently working on a series of atlases of the aculeate Hymenoptera of Britain and Ireland. The five published volumes (Edwards, 1997, 1998; Edwards & Telfer, 2001, 2002; Edwards & Broad, 2005) cover twenty one ant taxa, and more are to come. Neither L. niger s. str., L. platythorax nor Myrmica specioides have been covered yet. They will be included when more records have been gathered. To help with this a BWARS study of Lasius s. str. ants, including L. niger s. str. and L platythorax, was initiated two years ago, and some of the information in this article is the result of this work.
The membership fee is modest, and includes a copy of the new BWARS Members Handbook. Members also receive complimentary copies of any of the Society’s atlases that are produced during the course of their membership. The membership secretary is David Baldock, Nightingales, Haslemere Road, Milford, Surrey GU8 5BN; telephone no. (01483) 421154.
If you are interested in any of the aculeate Hymenoptera, then do join us. You will be assured of a warm welcome!
References
Allen, G.A. 2004. Records of scarce and interesting aculeates from southern Britain in 2004. BWARS Newsletter, Autumn 2004: 19-22.
Barrett, K.E.J. (ed.) 1979. Provisional Atlas of the Insects of the British Isles. Part 5. Hymenoptera: Formicidae. Ants. 2nd. edition. Huntingdon: Biological Records Centre.
Bolton, B. 2003. Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute, 71: 1-370.
Bolton, B. 2005. Checklist of British Hymenoptera Aculeata: Formicidae. In, Bees, Wasps and Ants Recording Society Members Handbook. Revised by M. Archer. Centre for Ecology and Hydrology. pp. 117-118.
Bolton, B. Collingwood, C.A. 1975. Hymenoptera: Formicidae. Handbooks for the identification of British Insects, 6, part 3c. London: Royal Entomological Society.
Carroll, S. 2004. Bovey Heath back from the brink. Bulletin of the Devon Invertebrate Forum, No. 11: 12-13.
Collingwood, C.A. 1979. The Formicidae (Hymenoptera) of Fennoscandia and Denmark. Fauna Entomologica Scandinavica, 8. Klampenborg, Denmark: Scandinavian Science Press Ltd.
Czechowski, W., Radchenko, A. & Czechowska, W. 2002. The Ants (Hymenoptera, Formicidae) of Poland. Warsaw: Museum and Institute of Zoology PAS.
Edwards, R. (ed.) 1997. Provisional atlas of the aculeate Hymenoptera of Britain and Ireland. Part 1. Huntingdon: Biological Records Centre.
Edwards, R. (ed.) 1998. Provisional atlas of the aculeate Hymenoptera of Britain and Ireland. Part 2. Huntingdon: Biological Records Centre.
Edwards, R. & Telfer, M. (eds.) 2001. Provisional atlas of the aculeate Hymenoptera of Britain and Ireland. Part 3. Huntingdon: Biological Records Centre.
Edwards, R. & Telfer, M. (eds.) 2002. Provisional atlas of the aculeate Hymenoptera of Britain and Ireland. Part 4. Huntingdon: Biological Records Centre.
Edwards, R. & Broad, G. (eds.) 2005. Provisional atlas of the aculeate Hymenoptera of Britain and Ireland. Part 5. Huntingdon: Biological Records Centre.
Grace, A. & Yates, B.J. Undated. The Aculeate Hymenoptera of Rye Bay. Report to East Sussex County Council.
Hoy, S. & Roberts, S.P.M. 1997. Provisional distribution map for Formica rufa Linnaeus. In Edwards, R. (ed.) Provisional atlas of the aculeate Hymenoptera of Britain and Ireland. Part 1. Huntingdon: Biological Records Centre. p. 21.
Harvey, P. 2005. Myrmica specioides in Essex. BWARS Newsletter, Spring 2005: 10.
Orledge, G.M. 1998. The identity of Leptothorax albipennis (Curtis) (Hymenoptera: Formicidae) and its presence in Great Britain. Systematic Entomology, 23: 25-33.
Roberts, S.P.M. & Hoy, S. 2002. Provisional distribution map for Anergates atratulus (Schenck). In Edwards, R. & Telfer, M. (eds.) Provisional atlas of the aculeate Hymenoptera of Britain and Ireland. Part 4. Huntingdon: Biological Records Centre. p. 25.
Seifert, B. 1991. Lasius platythorax n. sp., a widespread sibling species of Lasius niger (Hymenoptera: Formicidae). Entomologia Generalis, 16: 69-81.
Skinner, G.J. & Allen, G.W. 1996. Ants. Naturalists’ Handbooks 24. Slough: Richmond Publishing Co. Ltd.
Timmins, C.J. & Stradling, D.J. 1993. Horse dung: a new or old habitat for Hypoponera punctatissima (Roger) (Hymenoptera: Formicidae)? The Entomologist, 112: 217-218.