Tetramorium caespitum

The taxonomy of T. caespitum s.l. is under investigation. It is common throughout Europe; however, the presence of a complex of morphologically nearly indistinguishable species is hypothesized, especially on the basis of biomolecular data (Schlick- Steiner et al. 2006) (Rigato & Toni, 2011).

Identification
Blackish brown, sometimes paler; head including clypeus and alitrunk regularly longitidinally striate. Petiole and postpetiole with shallow punctures and sculpture but smooth in centre. Propodeal spines very short, broadly denticulate, petiole and postpetiole about as broad as long. Length: 2.5-4 mm (Collingwood 1979).

Distribution
Holarctic: America to Japan, North Africa to N. Europe including British Isles (Collingwood 1979).

This taxon was described from Europe. It is also found in United States, United Kingdom of Great Britain and Northern Ireland.

Europe
The species tends to be coastal in North Europe but also inland on heath and on the open borders of woodland, nesting in the earth and also under stones. Colonies are normally single queened, but populous with up to 10,000 or more workers. This species is moderately aggressive, living by predation on other arthropods, scavenging and also from root aphid honeydew. Seeds of various herbs and grasses are often collected into the nest. The alatae are conspicuously large compared with the workers; they are developed in the early summer and fly in late June and July.

North America
This species is a common indoor pest in eastern North America, especially near the coast. Nests are frequently located under building foundations and workers forage for food inside. Once a food source is located, mass recruitment occurs along a well defined odor trail. Commonly known as "pavement" ants this species is often seen in late spring and early summer out on sidewalks in huge battles with neighboring colonies. Baits can be very effective in eliminating colonies within structures. In nature, colonies are often found nesting in soil under stones and the eastern subterranean termite is a common prey.

Other Ants
This ant is parasitized by Anergates atratulus, a workerless species that infiltrates queenless colonies.

Nomenclature

 *  caespitum. Formica caespitum Linnaeus, 1758: 581 (w.) EUROPE. Latreille, 1798: 50 (q.m.); Mayr, 1861: 62 (q.m.); Wheeler, G.C. & Wheeler, J. 1954d: 445 (l.); Hauschteck, 1961: 221 (k.); Imai, 1966: 119 (k.). Combination Manica: Jurine, 1807: 279; in Tetramorium: Mayr, 1855: 426. Senior synonym of fuscula: Smith, F. 1851: 118, Radchenko, 2007: 31; of modesta Foerster: Curtis, 1854: 215; Mayr, 1855: 426; of fusca: Dalla Torre, 1893: 132; of transversinodis: Brown, 1949a: 47; of immigrans: Bolton, 1979: 171; of himalayanum, indocile, transbaicalense: Radchenko, 1992b: 50; of hammi: Bolton, 1995b: 405; of jiangxiense: Wu & Wang, 1995: 82; of fusciclavum: Sanetra, Güsten & Schulz, 1999: 320. Current subspecies: nominal plus barabense, caespitomoravicum, flavidulum, japonicum, pallidum, typicum. See also: Emery, 1909d: 697; Bondroit, 1918: 107; Emery, 1925c: 177; Baroni Urbani, 1971c: 135; Kutter, 1977c: 157; Arnol'di & Dlussky, 1978: 544; Smith, D.R. 1979: 1400; Collingwood, 1979: 84; Cammaerts, Pasteels et al. 1985: 109; Kupyanskaya, 1990: 151; López, 1991a: 31; López, 1991b: 73; López, et al. 1992: 169; Radchenko, Czechowski & Czechowska, 1998: 108.
 * fusca. Formica fusca Leach, 1825: 290 (q.m.) FRANCE. [Unresolved junior primary homonym of Formica fusca Linnaeus, 1758: 580.] Junior synonym of caespitum: Dalla Torre, 1893: 132.
 * fuscula. Myrmica fuscula Nylander, 1846a: 935, pl. 18, figs. 34, 36 (w.q.m.) FINLAND. Junior synonym of caespitum: Smith, F. 1851: 118; Radchenko, 2007: 31.
 * modesta. Myrmica modesta Foerster, 1850a: 49 (w.) GERMANY. Junior synonym of caespitum: Curtis, 1854: 215; Mayr, 1855: 426.
 * himalayanum. Tetramorium caespitum subsp. himalayanum Viehmeyer, 1914b: 38 (w.q.m.) INDIA. Junior synonym of caespitum: Radchenko, 1992b: 50.
 * hammi. Tetramorium caespitum var. hammi Donisthorpe, 1915d: 178 (w.) GREAT BRITAIN. Junior synonym of caespitum: Bolton, 1995b: 408.
 * immigrans. Tetramorium caespitum var. immigrans Santschi, 1927a: 54 (w.) CHILE. Junior synonym of caespitum: Bolton, 1979: 171.
 * indocile. Tetramorium caespitum var. indocile Santschi, 1927a: 53 (w.q.m.) KAZAKHSTAN. Subspecies of caespitum: Pisarski, 1967: 402. Raised to species: Pisarski, 1969b: 304. Junior synonym of caespitum: Radchenko, 1992b: 50.
 * transbaicalense. Tetramorium semilaeve subsp. transbaicalense Ruzsky, 1936: 93 (w.) KAZAKHSTAN. Junior synonym of caespitum: Radchenko, 1992b: 50.
 * transversinodis. Myrmica (Myrmica) brevinodis var. transversinodis Enzmann, J. 1946b: 47, figs. 1,2 (w.) U.S.A. Junior synonym of caespitum: Brown, 1949a: 47.
 * fusciclavum. Tetramorium caespitum var. fusciclavum Consani & Zangheri, 1952: 42 (w.) ITALY. [First available use of Tetramorium caespitum subsp. caespitum var. fusciclava Emery, 1925c: 187; unavailable name (Bolton, 1995b: 408).] Junior synonym of caespitum: Sanetra, Güsten & Schulz, 1999: 320.
 * jiangxiense. Tetramorium jiangxiense Wang & Xiao, in Wang, M., Xiao & Wu, 1988: 269, figs. 24, 25 (w.) CHINA. Junior synonym of caespitum: Wu & Wang, 1995: 82.

Additional References

 * Rigato, F.; Toni, I. 2011. Short notes 21. Hymenoptera, Formicidae. Pp. 873-882 in: Nardi, G.; Whitmore, D.; Bardiani, M.; Birtele, D.; Mason, F.; Spada, L.; Cerretti, P. (eds.) 2011. Biodiversity of Marganai and Montimannu (Sardinia). Research in the framework of the ICP Forests network. Conservazione Habitat Invertebrati, 5. Sommacampagna, Verona: Cierre Edizioni, 896 pp.