Lasius alienus

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

Lasius alienus casent0005401 profile 1.jpg

Lasius alienus casent0005401 dorsal 1.jpg

Specimen labels


Common in Europe and Asia, where its preferred habitats are open areas such as agricultural fields. In North America, it is also commonly collected and widespread but is found primarily in forests and occasionally in bogs and other wetlands. It nests in soil, in and under rotten logs and stumps, and sometimes in deep leaf litter. (Ellison et al., 2012).

Photo Gallery

  • Worker. Photo by Tom Murray.
  • Worker. Photo by Tom Murray.


Greyish yellow to brownish black. Pubescence adpressed, moderately thick over whole body and appendages. Short erect hairs scattered over dorsum and round whole occipital margin of head. Back of head convex. Ocelli indistinct or invisible; frontal furrow indistinct. Erect hairs absent on scape and front tibiae, sometimes present on hind tibiae. Length: 3.0-4.2 mm (Collingwood 1979).

Mackay and Mackay (2002) - This is a small, dark brown or black species with relatively large eyes (12-14 ommatidia in maximum diameter). The scape has few (less than 5) or no erect hairs (except at apex). The penultimate tooth is about the same size as the adjacent teeth (other 2 basal teeth).

Ellison et al., (2012) - In New England, the large-eyed Lasius alienus can be confused with either of the other three species in the niger group: Lasius pallitarsis, Lasius neoniger, or Lasius niger. The key feature is that L. alienus lacks erect hairs on its scape and hind tibiae, and is more common in forested habitats. The other three species all have erect hairs on their scapes and hind tibiae, and are more common in open habitats.

Keys including this Species


This species as currently understood has a Holarctic distribution: it occurs throughout the Northern Hemisphere. In North America, it nests from southern British Columbia west to Nova Scotia, south to northern Florida and in the mountains of the southwestern United States and Mexico. It also occurs throughout Europe and Asia, from the British Isles and Scandinavia south to Morocco and Tunisia, east into Lebanon, northern Iraq, and southern China, and north into Russia, Central Asia, China, and Japan. (Ellison et al., 2012)

Distribution based on Regional Taxon Lists

Nearctic Region: Canada, Canada, United States.
Neotropical Region: Mexico.
Oriental Region: India, Pakistan.
Palaearctic Region: Albania, Andorra, Armenia, Austria, Belarus, Belgium, Bulgaria, Channel Islands, China, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany (type locality), Greece, Hungary, Iberian Peninsula, Iran, Israel, Italy, Japan, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Malta, Mongolia, Montenegro, Netherlands, Poland, Portugal, Republic of Korea, Republic of Macedonia, Republic of Moldova, Romania, Russian Federation, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Turkmenistan, United Kingdom of Great Britain and Northern Ireland.
Lasius alienus Distribution.png

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Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Lasius alienus for further details


Wilson (1955) - The Eurasian and North American populations differ markedly from one another in habitat preference. In North Africa and France (Bernard, 1950; Scherdlin, 1909), Ireland (O’Rourke, 1950), England (Diver, 1940), Germany (Gosswald, 1932), East Prussia (Skwarra, 1929), and Daghestan (Kuznetzov-Ugamskij, 1929), Lasius alienus typically inhabits open dry situations, nesting under stones and occasionally constructing crater entrances in open soil. It shows much less latitude in nesting sites than its sister species Lasius niger, but is more successful in cultivated areas. Bernard notes that in France it is able to replace niger entirely in pastures, even at high elevations, but tends to give way in turn to Tapinoma simrothi and Tapinoma nigerrimum. Diver, in an intensive study of the comparative ecology of alienus and niger in a local area in Dorset, found alienus restricted mostly to dry heath, whereas niger occurred in every major habitat studied. In Daghestan, Kutznezov-Ugamskij found alienus to have more southern affinities than niger. Where the two occur together, alienus is limited mostly to the steppes and mountain meadows (up to 11,000 feet), while niger occurs mostly in the forests.

In North America Lasius alienus reverses this habitat preference. Over its entire range on this continent, it shows a strong predilection for well shaded woodland, where it nests in rotting logs and stumps and under stones. Among the hundreds of colonies I have encountered in the field in the eastern United States, nearly all conformed to this ecological character. It may happen, however, that at high elevations or at the northern periphery of its range, the species occasionally nests in open situations. At the summit of Grandfather Mountain in North Carolina, for instance, I found a small but vigorous population living under stones in an open blueberry-and-heath "bald". The elevation was 5800 feet, higher by 700 feet than any other collection of the genus made in the course of several field trips in the southern Appalachians.

I would like to venture the suggestion that the difference in habitat preferences between the Eurasian and North American populations may be a reflection of competition with various other members of the genus. In Eurasia alienus is replaced in most habitats, including woodland, by its extremely successful and abundant sister species Lasius niger. In North America it is replaced in nearly every available habitat except woodland by the equally successful and abundant members of the Lasius neoniger complex. As previously indicated in the description of the ecology of that species, Lasius pallitarsis occupies the same types of nesting sites as alienus and probably limits its northward spread. In general, one gains the impression that in Eurasia and North America alienus has been squeezed into relatively narrow ecological ranges by its congeneric competitors, but is nevertheless eminently successful within those ranges.

Lasius alienus probably does not differ much from niger in food habits and ethology. Several Europeans, including Gosswald and O'Rourke have independently observed that alienus tends to be the more secretive of the two species. This is possibly correlated with the preference of this species in Eurasia for more exposed situations.

Records of nuptial flights in this species are too sparse to allow a rigorous comparison with niger. In Europe winged forms are found in nido during about the same period as for niger. I have records ranging from June (Trieste, MCZ; no further date) to October 28 (Italy, MCZ) without evident preponderance during any part of this period; a single pair were preserved in copula in October (Trieste; MCZ; no further date). In North America records range from May 30 (Decatur Co., Ga.) to December 4 (Alachua Co., Fla.). Both of these are very exceptional dates, however; the majority of the other records fall in August.

Regional Notes


Collingwood (1979) - This wide ranging species nests in the soil on sandy lowland heaths, dry open pasture, sea cliffs and rocky outcrops in North Europe. Its habits are mainly subterranean, feeding on the exudates of root aphids but also by scavenging and predating small insects. Workers are generally unobtrusive and non aggressive compared with Lasius niger. Nests are single queened founded by solitary fertilised queens. Mating swarms occur in August.

New England

Ellison et al. (2012) - This omnivorous species collects elaiosomes from seeds, live insects and carcasses of dead ones, and tends a wide variety of aphids, scales, and treehoppers, and coccids that feed on plant roots. The colonies can be very large and have many queens, but individual queens disperse and found colonies independently.

Associations with other Organisms

Other Insects

This ant has been associated with the butterflies Glaucopsyche alexis and a species that has recently been split into two species: Polyommatus icarus and Polyommatus celin (Obregon et al. 2015).


This species is a host for the ectoparastic fungus Laboulbenia formicarum (Espadaler & Santamaria, 2012).






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

  • alienus. Formica aliena Foerster, 1850a: 36 (w.m.) GERMANY. Foerster, 1850a: 71 (q.); Wheeler, G.C. & Wheeler, J. 1953c: 147 (l.); Hauschteck, 1962: 219 (k.). Combination in Lasius: Mayr, 1861: 49; in Donisthorpea: Donisthorpe, 1915d: 212; in Formicina: Emery, 1916b: 240; in Acanthomyops: Ruzsky, 1925b: 44; in Lasius: Menozzi, 1921: 32; Müller, 1923: 125; Emery, 1925b: 230; Kuznetsov-Ugamsky, 1929a: 27. Subspecies of niger: Forel, 1874: 46; Mayr, 1886d: 429; Forel, 1892i: 307; Forel, 1904b: 386; Wheeler, W.M. 1906c: 322; Forel, 1913d: 438; Forel, 1915d: 53; Emery, 1916b: 240; Santschi, 1925g: 349; Karavaiev, 1927c: 280; Menozzi, 1936d: 305; Menozzi, 1939a: 312. Status as species: Saunders, E. 1880: 209; André, 1882b: 192; Nasonov, 1889: 22; Emery, 1897f: 238; Ruzsky, 1902d: 16; Emery, 1908d: 24; Bondroit, 1911: 11; Donisthorpe, 1915d: 212; Bondroit, 1918: 25; Stitz, 1939: 279; Novak & Sadil, 1941: 101; Röszler, 1942a: 53; Stärcke, 1944a: 153; Wilson, 1955a: 77; Baroni Urbani, 1971c: 200; Kutter, 1977c: 227; Collingwood, 1979: 97; Yamauchi, 1979: 156; Collingwood, 1982: 285; Kupyanskaya, 1990: 218; Atanassov & Dlussky, 1992: 237; Seifert, 1992b: 13. Senior synonym of americanus, pannonica and material of the unavailable names alienoamericanus, flavidus, turkmenus referred here: Wilson, 1955a: 77.
  • americanus. Lasius niger var. americanus Emery, 1893i: 639 (w.q.m.) U.S.A. Wheeler, G.C. & Wheeler, J. 1953c: 147 (l.). Subspecies of niger: Wheeler, W.M. 1904e: 305; Forel, 1900e: 285; Buren, 1944a: 296. Raised to species: Gregg, E.V. 1945: 530. Subspecies of alienus: Creighton, 1950a: 419. Junior synonym of alienus: Wilson, 1955a: 77.

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



Wilson (1955) - Within the PW range of 0.53-0.70 mm., the seta count is always less than 20 and usually less than 10. The seta count is strongly allometric, making it advisable to determine individual specimens by comparing them with the regression zones of Figure 6. In Europe the regression zones of Lasius niger and Lasius alienus are parallel but well segregated; the alienus line is set so that the great majority of workers have seta counts of less than 5, while most niger exceed 20. In eastern Asia, on the other hand, alienus evidently becomes scarcer, and the niger zone shifts down and forward to become contiguous with that of alienus. As a result, a small number of individuals cannot be safely determined to either species.

Size ranging and averaging smaller than in niger. In a sample of 147, with no more than 2 per nest series, mean with standard error 0.56 ± 0.004 mm., standard deviation 0.054 mm, Color averaging lighter than niger, although total variation in both species shows complete overlap.


Wilson (1955) - Seta count never exceeding 10 and usually 0.

Size averaging smaller than niger when the North American populations are included.


Wilson (1955) - Seta count almost always 0.

Size range about the same as in Lasius niger and showing parallel geographic variation. Mandibles typically of niger type, but in two series (Engadin, Switzerland, Kutter leg. and Coll., Hornet, Beltrami Co., Minn., A. Achenbach leg., G. C. Wheeler Coll.) the mandible type is closer to the intermediate type of Lasius brunneus. Subgenital plate showing the same wide variation as in Lasius niger; series from Godinne, Belgium (A. Raignier leg.; MCZ) and the Engadin Valley, Switzerland (Kutter) encompass within themselves the full variation from the unilobed to bilobed condition.

Type Material

Wilson (1955) - Dr. H. Bischoff has informed me that no syntypes of Lasius alienus can be located in the Foerster Collection in the Berlin Museum. What may be part of the type series has been found instead in the Mayr Collection and lent me by Dr. M. Beier. This consists of two pins, one holding two workers and the other a single male, labelled "Aach. Forst/Las. alienus det. Mayr." The workers are identifiable as typical alienus.


  • 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 192, Status as species)
  • Atanassov, N.; Dlussky, G. M. 1992. Fauna of Bulgaria. Hymenoptera, Formicidae. Fauna Bûlg. 22: 1-310 (page 237, Status as species)
  • Baroni Urbani, C. 1971c. Catalogo delle specie di Formicidae d'Italia (Studi sulla mirmecofauna d'Italia X). Mem. Soc. Entomol. Ital. 50: 5-287 (page 200, Status as species)
  • Bondroit, J. 1911a. Contribution à la faune de Belgique. Notes diverses. Ann. Soc. Entomol. Belg. 55: 8-13 (page 11, Status as species)
  • Bondroit, J. 1918. Les fourmis de France et de Belgique. Ann. Soc. Entomol. Fr. 87: 1-174 (page 25, Status as species)
  • Collingwood, C. A. 1979. The Formicidae (Hymenoptera) of Fennoscandia and Denmark. Fauna Entomol. Scand. 8: 1-174 (page 97, Status as species)
  • Collingwood, C. A. 1982. Himalayan ants of the genus Lasius (Hymenoptera: Formicidae). Syst. Entomol. 7: 283-296 (page 285, Status as species)
  • Donisthorpe, H. 1915f. British ants, their life-history and classification. Plymouth: Brendon & Son Ltd., xv + 379 pp. (page 212, Combination in Donisthorpea, Status as species)
  • Ellison, A.M., Gotelli, N.J., Farnsworht, E.J., Alpert, G.D. 2012. A Field Guide to the Ants of New England. Yale University Press, 256 pp.
  • Emery, C. 1897g. Anhang. Verzeichniss der auf der zweiten Reise nach Kleinasien (1897) gesammelten Ameisen, mit einer Neubeschreibung. P. 239 in: Escherich, K. Zur Kenntniss der Myrmecophilen Kleinasiens. I. Coleoptera. Wien. Entomol. Ztg. 16:229-239. (page 238, Status as species)
  • Emery, C. 1908e. [Untitled. Descriptions of new taxa: Tetramorium caespitum var. diomedea Emery, nova varietas; Strongylognathus huberi For., subsp. rehbinderi For., var. cecconii Emery, nova varietas.]. P. 24 in: Cecconi, G. Contributo alla fauna delle Isole Tremiti. Boll. Mus. Zool. Anat. Comp. R. Univ. Torino 583:1-53. (page 24, status as species)
  • Emery, C. 1916a [1915]. Fauna entomologica italiana. I. Hymenoptera.-Formicidae. Bull. Soc. Entomol. Ital. 47: 79-275 (page 240, Combination in Formicina, Variety/race/subspecies of niger)
  • Emery, C. 1925d. Hymenoptera. Fam. Formicidae. Subfam. Formicinae. Genera Insectorum 183: 1-302 (page 230, Combination in Lasius)
  • Espadaler, X., Santamaria, S. 2012. Ecto- and Endoparasitic Fungi on Ants from the Holarctic Region. Psyche Article ID 168478, 10 pages (doi:10.1155/2012/168478).
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  • 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 46, Variety/race/subspecies of niger)
  • Forel, A. 1892j. Die Ameisenfauna Bulgariens. (Nebst biologischen Beobachtungen.). Verh. K-K. Zool.-Bot. Ges. Wien 42: 305-318 (page 307, Variety/race/subspecies of niger)
  • 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 386, Variety/race/subspecies of niger)
  • Forel, A. 1913d. Fourmis de la faune méditerranéenne récoltées par MM. U. et J. Sahlberg. Rev. Suisse Zool. 21: 427-438 (page 438, Variety/race/subspecies of niger)
  • Forel, A. 1915d. Fauna insectorum helvetiae. Hymenoptera. Formicidae. Die Ameisen der Schweiz. Mitt. Schweiz. Entomol. Ges. 12(B Beilage: 1-77 (page 53, Variety/race/subspecies of niger)
  • Hauschteck, E. 1962. Die Chromosomen einiger in der Schweiz vorkommender Ameisenarten. Vierteljahrsschr. Naturforsch. Ges. Zür. 107: 213-220 (page 219, karyotype described)
  • Higgins, R. J. and B. S. Lindgren. 2015. Seral changes in ant (Hymenoptera: Formicidae) assemblages in the sub-boreal forests of British Columbia. Insect Conservation and Diversity. 8:337-347. doi:10.1111/icad.12112
  • 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 280, Variety/race/subspecies of niger)
  • Kupyanskaya, A. N. 1990a. Ants of the Far Eastern USSR. Vladivostok: Akademiya Nauk SSSR, 258 pp. (page 218, Status as species)
  • Kutter, H. 1977c. Hymenoptera, Formicidae. Insecta Helv. Fauna 6: 1-298 (page 227, Status as species)
  • Kuznetsov-Ugamsky, N. N. 1929a. Die Ameisen des Süd-Ussuri-Gebietes. Zool. Anz. 83: 16-34 (page 27, Combination in Lasius)
  • Mackay, W. P. and E. Mackay. 2002. The ants of New Mexico (Hymenoptera: Formicidae). Edwin Mellen Press, Lewiston, NY.
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  • Mayr, G. 1886d. Die Formiciden der Vereinigten Staaten von Nordamerika. Verh. K-K. Zool.-Bot. Ges. Wien 36: 419-464 (page 429, Variety/race/subspecies of niger)
  • Menozzi, C. 1921. Formiche dei dintorni di Sambiase di Calabria. Boll. Lab. Zool. Gen. Agrar. R. Sc. Super. Agric. 15: 24-32 (page 32, Combination in Lasius)
  • Menozzi, C. 1936b. Nuovi contributi alla conoscenza della fauna delle Isole italiane dell'Egeo. VI. Hymenoptera - Formicidae. Boll. Lab. Zool. Gen. Agrar. R. Sc. Super. Agric. 29: 262-311 (page 305, Variety/race/subspecies of niger)
  • Menozzi, C. 1939a. Formiche dell'Himalaya e del Karakorum raccolte dalla Spedizione italiana comandata da S. A. R. il Duca di Spoleto (1929). Atti Soc. Ital. Sci. Nat. Mus. Civ. Stor. Nat. Milano 78: 285-345 (page 312, Variety/race/subspecies of niger)
  • Müller, G. 1923b. Le formiche della Venezia Guilia e della Dalmazia. Boll. Soc. Adriat. Sci. Nat. Trieste 28: 11-180 (page 125, Combination in Lasius)
  • Nasonov, N. V. 1889. Contribution to the natural history of the ants primarily of Russia. 1. Contribution to the ant fauna of Russia. Izv. Imp. Obshch. Lyubit. Estestvozn. Antropol. Etnogr. Imp. Mosk. Univ. 58: 1-78 (page 22, Status as species)
  • Novák, V.; Sadil, J. 1941. Klíc k urcování mravencu strední Evropy se zvlástním zretelem k mravencí zvírene Cech a Moravy. Entomol. Listy 4: 65-115 (page 101, Status as species)
  • Obregon, R., M. R. Shaw, J. Fernandez-Haeger, and D. Jordano. 2015. Parasitoid and ant interactions of some Iberian butterflies (Insecta: Lepidoptera). Shilap-Revista De Lepidopterologia. 43:439-454.
  • Roszler, P. 1942a. Myrmecologisches 1938. Tijdschr. Entomol. 85: 50-71 (page 53, Status as species)
  • 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 16, Status as species)
  • Ruzsky, M. 1925b. New data on the ant fauna of Siberia. Rus. Entomol. Obozr. 19: 41-46 (page 44, Combination in Acanthomyops)
  • Santschi, F. 1925g. Fourmis d'Espagne et autres espèces paléarctiques (Hymenopt.). EOS. Rev. Esp. Entomol. 1: 339-360 (page 349, Variety/race/subspecies of niger)
  • Saunders, E. 1880. Synopsis of the British Heterogyna and fossorial Hymenoptera. Trans. Entomol. Soc. Lond. 1880: 201-304 (page 209, Status as species)
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  • Stärcke, A. 1944b. Retouches sur quelques fourmis d'Europe. III. Autres Lasius. Entomol. Ber. (Amst.) 11: 153-158 (page 153, 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 279, Status as species)
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