Formica truncorum

Identification
Large workers with head, alitrunk and base of first gaster tergite bright yellowish red, gaster greyish brown covered with long pubescence; smaller workers are usually darker but never with clearly marked black patches as in Formica pratensis. Eyes, occiput, genae, gula, scapes and tibiae as well as whole body covered in short erect hairs. Frons with large shallow punctures; frontal triangle shining without punctures or sculpture. Funiculus in larger workers slender with segments two and three twice as long as wide. Lateral clypeal pits deep and rounded. Length: 3.5-9.0 mm (Collingwood 1979).

Distribution
Jura Alps to North Japan, Italy to North Norway (Collingwood 1979).

Distribution based on Regional Taxon Lists
Oriental Region: India. Palaearctic Region: Austria, Belarus, Belgium, Bulgaria, China, Croatia, Czech Republic, Democratic Peoples Republic of Korea, Denmark, Estonia, Finland , Germany , Hungary, Japan, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Mongolia, Netherlands, Norway, Poland, Republic of Korea, Republic of Moldova, Romania, Russian Federation , Slovakia, Slovenia, Sweden, Switzerland , Turkey, Ukraine.

Biology
Collingwood (1979) - This species has large spreading colonies among stones or in tree stumps with loose surface leaf litter sometimes built into a shallow loose mound. This is an aggressive acid squirting species found at the borders of woodland and in stony banks and often particularly abundant on offshore islands. F. truncorum is normally polygynous, sometimes with many small dark headed queens. New colonies may be formed by nest splitting or by the adoption of single large red headed queens by Formica fusca and allied species. Males and queens occur in July and August, latter than with most members of the F. rufa group.

Nesting Biology
Rybnikova and Kuznetsov (2015) studied nest complexes of wood ants in the Darwin Nature Reserve (Rybinsk Reservoir basin, Vologda and Yaroslavl Provinces, Russia). Their work assessed, in part, how wild boars and seasonal flooding may influence the survival and viability of wood ant colonies.

Silon Island is a tall ridge of glacial origin. The ant communities of the island were studied in the late 1990s (Rybnikova and Kuznetsov, 1998). The greatest part of the island is occupied by a lichen pine forest which provides little food for red wood ants; therefore, foraging mostly takes place in the riparian zone.

The complex of Silon Island—North. A complex of F. truncorum exists in the northern part of the island. In 1997–1998 it comprised 7–8 living nests and 12–15 foraging ones. The living nests of this species concentrated around the inner drainless depression filled with snowmelt water, with hydrophilic vegetation on its periphery. During the low-water periods, when the exposed inundation zone of the reservoir was overgrown with riparian vegetation, the ants built small foraging nests in the shoreline part of the island, at the edge of the precipice. As many as 15 such nests were present on the shore in some years. The foragers traveled down the precipice into the inundation zone, where aphid colonies developed on the riparian and periaquatic vegetation. After the long sequence of high-water years, four living nests remained on the shore, in the willow shrubs at the edge of the inundation zone. Five more living nests remained on the shores of the inner drainless depression. The mean nest size increased due to the disappearance of more than half of the small, mostly foraging nests. Every year, nests of this complex are destroyed by the bear which migrates to the island in the second half of summer. In some years, occasional wild boars also visit the island.

Fungi
This species is a host for the ectoparastic fungus Aegeritella superficialis (Espadaler & Santamaria, 2012).

Nomenclature

 *  truncorum. Formica truncorum Fabricius, 1804: 403 (q.) CZECHOSLOVAKIA. Subspecies of rufa: Emery & Forel, 1879: 450; Santschi, 1925g: 351; Karavaiev, 1936: 247. Status as species: Bondroit, 1917a: 174; Stitz, 1939: 344; Novak & Sadil, 1941: 105; Holgersen, 1942: 13; Dlussky, 1967a: 81; Tarbinsky, 1976: 192; Kutter, 1977c: 274; Gösswald, 1989: 21; Kupyanskaya, 1990: 192; Atanassov & Dlussky, 1992: 270. Senior synonym of truncicola: Roger, 1863b: 13; Bondroit, 1918: 60; Dlussky, 1967a: 81; Radchenko, 2007: 36; of truncicolopratensis: Dlussky, 1967a: 81; Bernard, 1967: 307; of menozzii, rufotruncicola, staegeri and material of the unavailable name stitzi referred here: Dlussky, 1967a: 81. Current subspecies: nominal plus finzii, frontalis.
 * truncicola. Formica truncicola Nylander, 1846a: 907 (w.q.) FINLAND. Nylander, 1849: 29 (m.). Subspecies of rufa: Forel, 1874: 52; André, 1903: 128; Ruzsky, 1905b: 330; Wheeler, W.M. 1908g: 406; Emery, 1909b: 187; Forel, 1915d: 57; Emery, 1916b: 256; Santschi, 1925f: 96. Status as species: Bingham, 1903: 334; Wheeler, W.M. 1913f: 434. Senior synonym of simulata: Forel, 1894c: 403. Junior synonym of truncorum: Roger, 1863b: 13; Bondroit, 1918: 60; Emery, 1925b: 255; Bernard, 1967: 307; Dlussky, 1967a: 81; Dlussky & Pisarski, 1971: 174; Tarbinsky, 1976: 192; Kutter, 1977c: 274; Radchenko, 2007: 36.
 * truncicolopratensis. Formica rufa var. truncicolopratensis Forel, 1874: 53 (w.q.m.) SWITZERLAND. Subspecies of pratensis: Dalla Torre, 1893: 205; of rufa: Karavaiev, 1912b: 589; of truncorum: Stitz, 1939: 346; Holgersen, 1942: 14. Raised to species: Bondroit, 1918: 61. Junior synonym of truncorum: Bernard, 1967: 307; Dlussky, 1967a: 81; Dlussky & Pisarski, 1971: 174.
 * simulata. Formica simulata Smith, F. 1878b: 10 (w.) CHINA. Junior synonym of truncicola: Forel, 1894c: 403.
 * rufotruncicola. Formica rufa var. rufotruncicola Ruzsky, 1896: 68 (w.) RUSSIA. [First available use of Formica rufa subsp. pratensis form. rufotruncicola Ruzsky, 1895: 11; unavailable name.] Junior synonym of truncorum: Dlussky, 1967a: 81.
 * menozzii. Formica truncorum var. menozzii Stitz, 1939: 347 (w.) GERMANY. [First available use of Formica rufa subsp. truncicola var. menozzii Krausse, 1926c: 336; unavailable name. Note: truncicola is misspelled aruncicola in this paper.] Junior synonym of truncorum: Dlussky, 1967a: 81.
 * staegeri. Formica truncorum var. staegeri Stitz, 1939: 347 (w.) GERMANY. [First available use of Formica rufa subsp. truncicola ab. staegeri Krausse, 1926d: 264; unavailable name.] Subspecies of truncorum: Betrem, 1960b: 76. Junior synonym of truncorum: Dlussky, 1967a: 81; Dlussky & Pisarski, 1971: 174.