Lasius bicornis

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Lasius bicornis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Lasiini
Genus: Lasius
Species: L. bicornis
Binomial name
Lasius bicornis
(Foerster, 1850)

Lasius bicornis casent0280461 p 1 high.jpg

Lasius bicornis casent0280461 d 1 high.jpg

Specimen Labels


This species exhibits temporary social parasitism (although its host is currently unknown). Queens found new colonies by infiltrating an established nest of another Lasius species, killing the queen and using host workers to care for her initial brood.

At a Glance • Temporary parasite  



A rare Eurasian species somewhat similar in habitus to North American species Lasius minutus but showing profound differences in the petiolar outline and pilosity. (Wilson 1955)

Worker clear citron yellow. Funiculus segments not longer than broad; scape distinctly flattened. Outline of petiole characteristic: high, tapering dorsally with a deep emargination. Body hairs long, longest hairs nearly as long as maximum hind tibial width, sparse on dorsum of gaster where restricted to posterior borders of tergites; genal hairs sparse, scapes and tibiae bare. Length: 4.0-4.5 mm (Collingwood 1979).

Keys including this Species


Central and South Europe from Pyrenees and Caucasus but also recorded from Himalayas (Kashmir), South Italy to Netherlands; uncommon (Collingwood 1979).

Distribution based on Regional Taxon Lists

Oriental Region: India.
Palaearctic Region: Armenia, Austria, Belgium, Bulgaria, Croatia, Czech Republic, France, Georgia, Germany (type locality), Greece, Hungary, Iberian Peninsula, Italy, Netherlands, Norway, Poland, Romania, Russian Federation, Slovenia, Spain, Sweden, Switzerland, Turkey.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


This species nests in rotten logs. Alatae have been taken in September (Poldi, 1962).



The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • bicornis. Formica bicornis Foerster, 1850a: 41 (q.) GERMANY. Forel, 1874: 47 (w.); Forel, 1915d: 56 (m.). Combination in Lasius: Mayr, 1861: 51; in Formicina: Emery, 1916b: 242; Menozzi, 1918: 87; in Acanthomyops: Ruzsky, 1925b: 45; in Lasius (Chthonolasius): Ruzsky, 1914a: 61; Emery, 1925b: 232; Wilson, 1955a: 183. Subspecies of umbratus: Forel, 1874: 47; Emery & Forel, 1879: 453; Mayr, 1886d: 430; Forel, 1886f: 208; Forel, 1904b: 387; Bondroit, 1910: 485. Status as species: André, 1882b: 196; Ruzsky, 1902d: 15; Bondroit, 1912: 352; Emery, 1916b: 242; Bondroit, 1918: 34; Emery, 1922b: 13; Karavaiev, 1927c: 279; Stärcke, 1937: 55; Stitz, 1939: 302; Wilson, 1955a: 183; Bernard, 1967: 365; Kutter, 1977c: 231; Collingwood, 1982: 293; Seifert, 1988: 161; Atanassov & Dlussky, 1992: 251. Senior synonym of incisa: Smith, F. 1858b: 8; Emery, 1922b: 13; Seifert, 1988: 161; of microgyna: Vandel, 1926: 197; Wilson, 1955a: 183; of kashmirensis, neapolitana, oertzeni: Wilson, 1955a: 183.
  • incisa. Formica incisa Schenck, 1852: 63 (w.) GERMANY. Junior synonym of bicornis: Smith, F. 1858b: 8; Emery, 1922b: 13; Seifert, 1988: 161.
  • oertzeni. Lasius bicornis subsp. oertzeni Forel, 1910a: 26 (w.q.m.) GREECE. Combination in L. (Chthonolasius): Emery, 1925b: 233. Raised to species: Stärcke, 1937: 56. Junior synonym of bicornis: Wilson, 1955a: 183.
  • microgyna. Formicina microgyna Bondroit, 1918: 33, figs. 16, 17 (q.m.) FRANCE. Combination in Lasius (Chthonolasius): Emery, 1925b: 233. Subspecies of bicornis: Emery, 1925b: 233; Stärcke, 1937: 56. Junior synonym of bicornis: Vandel, 1926: 197; Wilson, 1955a: 183.
  • neapolitana. Lasius bicornis var. neapolitana Emery, 1922b: 13 (q.) ITALY. Junior synonym of bicornis: Wilson, 1955a: 183.
  • kashmirensis. Acanthomyops (Chthonolasius) bicornis subsp. kashmirensis Donisthorpe, 1930a: 225 (q.m.) INDIA. Junior synonym of bicornis: Wilson, 1955a: 183.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



Wilson (1955) – Based on a single oertzeni syntype and an unlabeled worker in the Mayr Collection.

(1) PW of oertzeni syntype 0.68 mm., Mayr specimen 0.79 mm., well within range of Lasius umbratus size variation.

(2) Body hair longer than in umbratus-rabaudi but shorter and finer than in minutus. In both available specimens the dorsal gastric hairs average about 0.09 mm, and do not exceed 0.14 mm,; the maximum width of the hind tibia at its midlength commonly used in the present study as a reference measurement, is 0.16 mm, The cephalic and gastric hairs of these specimens are sparser than in minutus. The number of hairs extending beyond the profile of the first gastric segment anterior to the extreme posterior strip and seen in perfect side view is 17 in the oertzeni syntype and only 6 in the Mayr specimen; 30 or more is usual for minutus, umbratus-rabaudi, and subumbratus.

(3) Petiolar outline in the oertzeni syntype similar to that described for the queen (Pl. 2, Fig. 3); emargination somewhat more shallow in the Mayr specimen.

(4) Scape flattened to the extent seen in extreme rabaudi workers. oertzeni syntype: maximum width at scape midlength 0.11 mm., minimum width 0.06 mm. Mayr specimen; maximum width 0.12 mm., minimum width 0.07 mm.


Wilson (1955) - (1) Smaller than umbratus but considerably larger than minutus. HW of oertzeni lectotype 1.34 mm.; microgyna lectotype 1.25 mm., syntopotypes 1.24 and 1.26 mm., Saint Sever "syntypes" 1.22 and 1.29 mm. ; a queen from the Taurus Mountains, Turkey (Berlin Museum), 1.34 mm. (measured by H. Bischoff).

(2) Long standing hairs abundant over the alitrunk, approaching the minutus condition, but sparser on the head and gastric tergites. In full face, the number of hairs projecting beyond the occipital contour is 4 in the oertzeni lectotype, 6 in the microgyna lectotype, 5 and 7 in the microgyna syntopotypes, and 6 and 7 in the Saint Sever specimens; the number in minutus is commonly 30 or more. In perfect side view, the first gastric tergite of the oertzeni lectotype shows only 15 standing hairs projecting beyond its profile, the microgyna lectotype 12, and microgyna syntopotypes 10 and 14, the St. Sever specimens 13 and 15, and a specimen from Hanau (Berlin Museum) 7; the typical number for minutus is 25 or more. In bicornis the pilosity of the first gastric tergite is limited mostly to the anterior slope and extreme posterior strip; in minutus it is evenly distributed over all of the tergital surface except for the anteriormost part of the anterior slope. The body hairs are proportionately shorter than in minutus. The longest hairs of the first and second gastric segments shorter than the maximum width of the hind tibia at its midlength (in the oertzeni lectotype, for instance, maximum hair length is 0.17 mm., tibia width is 0.21 mm.). At the same time, bicornis resembles minutus in having the scapes and legs completely bare of hairs except for a few scattered along the flexor margins of the femora.

(3) The petiole in frontal view slender, tapering dorsally; deeply emarginate, so that the depth of the emargination measured from the level of the bicornuate dorsal crest to the bottom of the emargination is distinctly greater than the width of the emargination taken across the midpoint of the depth measurement (Pl. 2, Fig. 2).

(4) Scapes flattened as in rabaudi; in the oertzeni lectotype, the maximum width at the midpoint is 0.14 mm., the minimum width only 0.07 mm. .At the same time, the funicular segments are not elongated as in rabaudi; third funicular segment length in oertzeni lectotype 0.11 mm., width 0.10 mm.

(5) As in minutus, the mandibles more massive relative to the remainder of the head and set farther apart from the midline when compared with umbratus.

Type Material

Wilson (1955) - HOLOTYPE. Dr. Bischoff has informed me that the unique type of bicornis is not with the Foerster Collection in the Berlin Museum, and it has not been found among the Foerster material in the Mayr Collection. Fortunately, the original description adequately covers the essential diagnostic features in petiole shape and pilosity of this distinctive species, and there can be little doubt that the name has been correctly applied in the present study.


  • André, E. 1882c. Les fourmis. [part]. Pp. 153-232 in: André, Edm. 1881-1886. Species des Hyménoptères d'Europe et d'Algérie. Tome Deuxième. Beaune: Edmond André, 919 + 48 pp. (page 196, Status as species)
  • Atanassov, N.; Dlussky, G. M. 1992. Fauna of Bulgaria. Hymenoptera, Formicidae. Fauna Bûlg. 22: 1-310 (page 251, Status as species)
  • Bernard, F. 1967a [1968]. Faune de l'Europe et du Bassin Méditerranéen. 3. Les fourmis (Hymenoptera Formicidae) d'Europe occidentale et septentrionale. Paris: Masson, 411 pp. (page 365, Status as species)
  • Bondroit, J. 1910 [1909]. Les fourmis de Belgique. Ann. Soc. Entomol. Belg. 53: 479-500 (page 485, Race/subspecies of umbratus)
  • Bondroit, J. 1912. Fourmis de Hautes-Fagnes. Ann. Soc. Entomol. Belg. 56: 351-352 (page 352, Status as species)
  • Bondroit, J. 1918. Les fourmis de France et de Belgique. Ann. Soc. Entomol. Fr. 87: 1-174 (page 34, Status as species)
  • Collingwood, C. A. 1982. Himalayan ants of the genus Lasius (Hymenoptera: Formicidae). Syst. Entomol. 7: 283-296 (page 293, Status as species)
  • Emery, C. 1916a [1915]. Fauna entomologica italiana. I. Hymenoptera.-Formicidae. Bull. Soc. Entomol. Ital. 47: 79-275 (page 242, Combination in Formicina, Status as species)
  • Emery, C. 1922b. Il genere Lasius (F.) Mayr e particolarmente le forme mediterranee del gruppo umbratus Nyl. Boll. Soc. Entomol. Ital. 54: 9-15 (page 13, Status as species, Senior synonym of incisa)
  • Emery, C. 1925d. Hymenoptera. Fam. Formicidae. Subfam. Formicinae. Genera Insectorum 183: 1-302 (page 232, Combination in Lasius (Chthonolasius))
  • Emery, C.; Forel, A. 1879. Catalogue des Formicides d'Europe. Mitt. Schweiz. Entomol. Ges. 5: 441-481 (page 453, Race/subspecies of umbratus)
  • Foerster, A. 1850a. Hymenopterologische Studien. 1. Formicariae. Aachen: Ernst Ter Meer, 74 pp. (page 41, queen described)
  • Forel, A. 1874. Les fourmis de la Suisse. Systématique, notices anatomiques et physiologiques, architecture, distribution géographique, nouvelles expériences et observations de moeurs. Neue Denkschr. Allg. Schweiz. Ges. Gesammten Naturwiss. 26: 1-452 (page 47, worker described, Race/subspecies of umbratus)
  • Forel, A. 1886h. Études myrmécologiques en 1886. Ann. Soc. Entomol. Belg. 30: 131-215 (page 208, Race/subspecies of umbratus)
  • Forel, A. 1904c [1903]. Note sur les fourmis du Musée Zoologique de l'Académie Impériale des Sciences à St. Pétersbourg. Ezheg. Zool. Muz. 8: 368-388 (page 387, Race/subspecies of umbratus)
  • Forel, A. 1915d. Fauna insectorum helvetiae. Hymenoptera. Formicidae. Die Ameisen der Schweiz. Mitt. Schweiz. Entomol. Ges. 12(B Beilage: 1-77 (page 56, male described)
  • Karavaiev, V. 1927d. The ant fauna of Ukraine. Zb. Prats Zool. Muz. 2:1-52 [= Tr. Ukr. Akad. Nauk Fiz.-Mat. Vidd. 4:247-296] (page 279, Status as species)
  • Kutter, H. 1977c. Hymenoptera, Formicidae. Insecta Helv. Fauna 6: 1-298 (page 231, Status as species)
  • Mayr, G. 1861. Die europäischen Formiciden. Nach der analytischen Methode bearbeitet. Wien: C. Gerolds Sohn, 80 pp. (page 51, Combination in Lasius)
  • Mayr, G. 1886d. Die Formiciden der Vereinigten Staaten von Nordamerika. Verh. K-K. Zool.-Bot. Ges. Wien 36: 419-464 (page 430, Race/subspecies of umbratus)
  • Menozzi, C. 1918. Primo contributo alla conoscenza della fauna mirmecologica del Modenese. Atti Soc. Nat. Mat. Modena (5) 4: 81-88 (page 87, Combination in formicina)
  • Ruzsky, M. 1902d. Material on the ant fauna of the Caucasus and the Crimea. Protok. Obshch. Estestvoispyt. Imp. Kazan. Univ. 206(su suppl: 1-33 (page 15, Status as species)
  • Ruzsky, M. 1914a [1913]. Myrmekologische Notizen. Arch. Naturgesch. (A)79(9 9: 58-63 (page 61, Combination in Lasius (Chthonolasius))
  • Ruzsky, M. 1925b. New data on the ant fauna of Siberia. Rus. Entomol. Obozr. 19: 41-46 (page 45, Combination in Acanthomyops)
  • Schlick-Steiner, B. C.; Steiner, F. M.; Bracko, G.; Paill, W.; Seifert, B. 2003. The temporary social parasite Lasius bicornis (Fórster, 1850) new to Slovenia, and Myrmica bessarabica Nassonov, 1889 corrected into M. specioides Bondroit, 1918 (Hymenoptera: Formicidae). Acta Entomol. Slov. 11: 159-162 (page 159, new record Slovenia)
  • Seifert, B. 1988a. A revision of the European species of the ant subgenus Chthonolasius (Insecta, Hymenoptera, Formicidae). Entomol. Abh. Staatl. Mus. Tierkd. Dres. 51: 143-180 (page 161, Status as species, Senior synonym of incisa)
  • Smith, F. 1858a. Catalogue of hymenopterous insects in the collection of the British Museum. Part VI. Formicidae. London: British Museum, 216 pp. (page 8, Senior synonym of incisa)
  • Stärcke, A. 1937. Retouches sur quelques fourmis d'Europe. II. Lasius groupe umbratus Nylander. Tijdschr. Entomol. 80: 38-72 (page 55, Status as species)
  • Stitz, H. 1939. Die Tierwelt Deutschlands und der angrenzenden Meersteile nach ihren Merkmalen und nach ihrer Lebensweise. 37. Theil. Hautflüger oder Hymenoptera. I: Ameisen oder Formicidae. Jena: G. Fischer, 428 pp. (page 302, Status as species)
  • Vandel, A. 1926. Fourmis françaises rares ou peu connues. Bull. Soc. Entomol. Fr. 1926: 196-198 (page 197, Senior synonym of microgyna)
  • Wilson, E. O. 1955a. A monographic revision of the ant genus Lasius. Bull. Mus. Comp. Zool. 113: 1-201 (page 183, Combination in Lasius (Chthonolasius), Status as species, Senior synonym of microgyna, Senior synonym of kashmirensis, neapolitana and oertzeni)