Lasius emarginatus

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Lasius emarginatus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Lasiini
Genus: Lasius
Species: L. emarginatus
Binomial name
Lasius emarginatus
(Olivier, 1792)

Lasius emarginatus casent0172762 profile 1.jpg

Lasius emarginatus casent0172762 dorsal 1.jpg

Specimen labels


A very common species occurring in central and southern Europe, and from Anatolia to the Caucasus, even in disturbed habitats (Rigato & Toni, 2011).


Distinguished in the worker caste by the distinctly red alitrunk, more sparse, oblique appendage hairs and relatively longer antennal scapes. The queen has the mesoscutum reddish and distinctly flattened. The male has the mesopleurae in part testaceous yellow, sparse scape hairs and a more sculptured frontal triangle than Lasius niger (Collingwood 1979).

As a member of the close-knit and difficult complex, Lasius emarainatus, like niger, must be determined by careful examination of multiple characters. It is easily separable from Lasius niger and Lasius alienus over part of its range on the basis of color and appendage length, but the three species tend to show convergent variation in the Balkans area, Mediterranean perimeter, and southcentral and eastern Asia. (Wilson 1955)

Keys including this Species


This is a Central and South European species that occurs in Poland, and the Channel Islands (Collingwood 1979).

Distribution based on Regional Taxon Lists

Palaearctic Region: Albania, Andorra, Armenia, Austria, Azerbaijan, Balearic Islands, Belarus, Belgium, Bulgaria, Canary Islands, Channel Islands, China, Croatia, Czech Republic, France (type locality), Georgia, Germany, Gibraltar, Greece, Hungary, Iberian Peninsula, Iran, Israel, Italy, Luxembourg, Malta, Monaco, Montenegro, Poland, Portugal, Republic of Macedonia, Republic of Moldova, Romania, Russian Federation, Slovakia, Slovenia, Spain, Switzerland (type locality), Turkey, United Kingdom of Great Britain and Northern Ireland.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


Wilson (1955) - This species nests mostly under rocks in open, dry situations. In Germany Gosswald (1932) found it in orchards, along forest borders, and in wasteland, nesting almost exclusively under rocks and in the crevices of rock walls, and avoiding woodland and moist situations in general. Nowotny (1931) found it uncommon in southwestern Poland, inhabiting dry areas under rocks and in walls. It was found in the same general type of habitat by Scherdlin (1909) in Alsace, by Donisthorpe (1928) in Italy, by Zimmermann (1934) in Yugoslavia, and by Goetsch (1937) in Italy, Switzerland, and Germany. Zimmermann found one colony in the wood of a pine stump on Campo Marzio in the Quarnerian Islands. Gosswald and Goetsch both report that the species occasionally enters houses.

Ecological data accompanying the Lebanon series previously mentioned are of interest because of the peripheral origin of these series (see under distribution). Dr. Christiansen collected the Wadi Jahhnam workers in a valley bottom well shaded by mixed conifers and maples. The ants were foraging above ground along a stream bank. The Kammouha Plain workers were taken well up on a mountainside (1900 meters) under rocks in spruce woods.

Food habits, pastoral activities, and colony founding in this species have been treated briefly by Goetsch (1937). They do not appear to differ fundamentally from Lasius niger and are not worth bringing into the discussion here.

Guiliani et al. (2019) observed this species foraging on extrafloral nectaries of the invasive Reynoutria x bohemica (Polygonaceae) in Tuscany. The habitats examined were river banks and disturbed habitats.

This species is a host for the ant Lasius umbratus (a temporary parasite).



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

  • emarginatus. Formica emarginata Olivier, 1792: 494 (w.q.m.) FRANCE. Hauschteck, 1962: 219 (k.). Combination in Lasius: Fabricius, 1804: 416; in Formicina (Donisthorpea): Emery, 1916b: 240; in Lasius: Menozzi, 1921: 32; Müller, 1923: 123; in L. (Lasius): Wilson, 1955a: 89. Subspecies of niger: Forel, 1874: 46; Emery & Forel, 1879: 452; Ruzsky, 1905b: 302; Bondroit, 1910: 486; Stitz, 1914: 85. Status as species: André, 1882b: 193; Nasonov, 1889: 23; Ruzsky, 1902d: 16; Forel, 1915d: 53; Emery, 1916b: 240; Bondroit, 1918: 24; Müller, 1923: 123; Finzi, 1924a: 14; Karavaiev, 1927c: 279; Stitz, 1939: 283; Stärcke, 1944a: 155; Wilson, 1955a: 89; Bernard, 1967: 357; Kutter, 1977c: 228; Atanassov & Dlussky, 1992: 239; Seifert, 1992b: 34. Senior synonym of brunneoemarginatus, brunneoides, nigroemarginatus: Wilson, 1955a: 89; of illyricus, pontica: Seifert, 1992b: 34.
  • brunneoemarginatus. Lasius emarginatus var. brunneoemarginatus Forel, 1874: 47 (w.) SWITZERLAND. Junior synonym of emarginatus: Wilson, 1955a: 89.
  • brunneoides. Lasius niger var. brunneoides Forel, 1874: 47 (w.) SWITZERLAND. Junior synonym of emarginatus: Wilson, 1955a: 89.
  • pontica. Lasius alienus var. pontica Stärcke, 1944a: 157 (w.) CAUCASUS. Junior synonym of alienus: Wilson, 1955a: 78 [repeat of this synonymy in Arakelian, 1994: 117, is ignored]; of emarginatus: Seifert, 1992b: 34.

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



Wilson (1955) - (1) Scape and other appendages longer relative to body size than in all other members of the genus except Lasius productus. Eliminating the largest workers (HW 1.10 mm, or greater), the SI exceeds 103 in more than 95 per cent of nest series examined (Fig. 5); 95 per cent or more of Lasius niger and Lasius alienus in the same size range have an SI of less than 103, with the following exceptions: niger from the Balearics, North Africa, Canaries, and eastern Asia; and alienus from the Balkans and eastern Asia.

(2) As a corollary of (1), ML exceeding EW.

(3) Thoracic dorsum low and flattened with respect to the propodeum; if the heights of the propodeum and mesonotum are measured in profile from a base line drawn from the lowest point of the prosternum (anterior to the coxal insertion) to the lowest point of the mesosternum, the propodeum is usually about 1.05 X higher than the mesonotum; the two points are usually of equal height in niger and alienus.

(4) Scape with abundant standing hairs predominantly or entirely subdecumbent and tending to be concentrated on the distal third (Pl. 1, Fig. 8). Rarely the standing hairs may be predominantly suberect-erect or altogether lacking (see under further description below). niger, especially from eastern Asia, occasionally approaches this typical emarginatus condition.

(5) Coloration of medium and large workers (i.e. workers with PW about 0.53 mm. or greater) usually distinctive. Alitrunk and petiole yellowish red, contrasting with both the head, which is medium to dark brownish red, and the gaster, which is dark brownish red. The alitrunk and petiole occasionally darken to approach the niger-alienus coloration; this divergent condition appears to preponderate in the Balkans population.

In a sample of 75, with no more than 2 per nest series, PW range 0.48-0.78 mm., mean with standard error 0.633 -l- 0.006 mm., standard deviation 0.050 mm. Total range of SI 103-122, a strongly allometric character with highest values in the minimas. Head tends to be narrower than in niger and alienus, but considerable overlap occurs; in a limited series with HW range of 0.94-1.05 mm., CI varied between 84 and 91. Mandibular dentition similar to niger, with three or four basal teeth present, but differing statistically in two ways; (1) the four-toothed condition is more common, (2) the second tooth from the basal margin is often bifurcate, a condition rare in niger. Forty individuals each representing a different nest series were examined especially for dentition: 16 had three whole basal teeth, 16 had four whole basal teeth, and 8 had a bifurcate second tooth in a set of three. This variation is not allometric, since minimas may have four basal teeth, and it does not appear to have a rigid genetic control, since two adjacent conditions can occur in the same nest series and even on different mandibles of the same individual. The petiole is less variable in outline than in other species of the complex; in all series examined the dorsal margin was shallowly and angularly impressed.

Scape pilosity as described in the diagnosis with the following three exceptions: a series from Dalmatia (H. Kutter leg.; Oxford University Museum) has a preponderance of suberect-erect hairs along the plane of the seta count; two series from Lebanon (Kammouha Plain and Wadi Jahhnam; K. Christiansen leg.; MCZ) lack standing hairs altogether.


Wilson (1955) - (1) Within a HW range of 1.61-1.70 mm. in a limited number of series measured, SI ranged 76-86. If this is a general condition it allows a 90 per cent separation from sympatric series of niger, exclusive of the southern European and North African populations previously described.

(2) ML in this sample ranged 0.23-0.26 mm.

(3) Scape densely clothed with preponderantly subdecumbent and occasional decumbent hairs one-third to one-half as long as the maximum scape width.

(4) Alitrunk medium reddish brown, the head and gaster somewhat darker and tending to contrast against the alitrunk, but never so much as in the worker. This same coloration is closely approached by callow niger queens, so that separation on this character alone is difficult.

Several interesting character trends have been noted which are, however, of less than diagnostic value. The scutum in profile tends to be more flattened than in other members of the subgenus. The posterior 5/6 of the scutum may be perfectly flat, whereas in niger the anterior third or more is usually involved in the anterior declivity. The posterior scutal border (transscutal suture) was found to be markedly sinuate in five out of six specimens examined; in niger and other Lasius s. s. this border is rarely more than feebly sinuate and often perfectly straight. The punctures of the scutum tend to be deeper and more distinctive in emarginattts than in and alienus.


Wilson (1955) - (1) Within a HW range of 0.92-1.07 mm. in a limited number of series measured, SI ranged 70-76.

(2) ML in this sample ranged 0.24-0.28 mm.

(3) Scape with numerous decumbent hairs one-fourth to one-half as long as the maximum scape width, and few or no suberect or erect hairs.

(4) Subgenital plate typically similar in outline to that of Lasius pallitarsis, but larger (in five nest series measured, maximum transverse length ranged 0.59-0.73 mm.), and more arc-shaped: the posterior border tends to be evenly concave, sweeping back evenly to the prominent posterolateral flanges, while the anterior border is correspondingly convex (one exception noted, see further description below).

Paramore length 0.24-0.27 mm. in all series examined, apparently varying allometrically with respect to head width to about the same degree as in niger. In the total of eight specimens (5 localities) examined for genitalic characters, the setiferous lobes of the subgenital plate showed the same amount and kind of variation as in niger (q.v.). Two males from the same nest series (Lausanne, Switzerland; M. Bibikoff leg. and Coll.) encompassed the total possible variation, one with a single lobe and the other with two lateral lobes. Seven of the specimens showed the diagnostic outline previously described; one from Milan (USNM) was sub quadrate and indistinguishable from sitkaensis except in size.


  • 2n = 30 (Switzerland) (Hauschteck, 1962).


  • 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 193, Status as species)
  • Atanassov, N.; Dlussky, G. M. 1992. Fauna of Bulgaria. Hymenoptera, Formicidae. Fauna Bûlg. 22: 1-310 (page 239, 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 357, Status as species)
  • Bondroit, J. 1910 [1909]. Les fourmis de Belgique. Ann. Soc. Entomol. Belg. 53: 479-500 (page 486, Subspecies/race of niger)
  • Bondroit, J. 1918. Les fourmis de France et de Belgique. Ann. Soc. Entomol. Fr. 87: 1-174 (page 24, Status as species)
  • Collingwood, C. A. 1979. The Formicidae (Hymenoptera) of Fennoscandia and Denmark. Fauna Entomol. Scand. 8:1-174.
  • Emery, C. 1916a [1915]. Fauna entomologica italiana. I. Hymenoptera.-Formicidae. Bull. Soc. Entomol. Ital. 47: 79-275 (page 240, Combination in Formicina (Donisthorpea), Status as species)
  • Emery, C.; Forel, A. 1879. Catalogue des Formicides d'Europe. Mitt. Schweiz. Entomol. Ges. 5: 441-481 (page 452, Subspecies/race of niger)
  • Fabricius, J. C. 1804. Systema Piezatorum secundum ordines, genera, species, adjectis synonymis, locis, observationibus, descriptionibus. Brunswick: C. Reichard, xiv + 15-439 + 30 pp. (page 416, Combination in Lasius)
  • Finzi, B. 1924a. Formiche dell'isola d'Elba e Monte Argentario. Boll. Soc. Entomol. Ital. 56: 12-15 (page 14, Status as species)
  • 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, Subspecies/race 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, Status as species)
  • Giuliani, C., L. Lastrucci, L. Cresti, G. Santini, B. Fogg, and M. M. Lippi. 2019. The morphology and activity of the extrafloral nectaries in Reynoutria x bohemica (Polygonaceae). Plant Biology. 21:975-985. doi:10.1111/plb.13004
  • Hauschteck, E. 1962. Die Chromosomen einiger in der Schweiz vorkommender Ameisenarten. Vierteljahrsschr. Naturforsch. Ges. Zür. 107: 213-220 (page 219, karyotype 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 228, Status as species)
  • 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)
  • Müller, G. 1923b. Le formiche della Venezia Guilia e della Dalmazia. Boll. Soc. Adriat. Sci. Nat. Trieste 28: 11-180 (page 123, Combination in Lasius, Status as species)
  • 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 23, Status as species)
  • Olivier, A. G. 1792. Encyclopédie méthodique. Histoire naturelle. Insectes. Tome 6. (pt. 2). Paris: Panckoucke, pp. 369-704. (page 494, worker, queen, male described)
  • 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.
  • 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. 1905b. The ants of Russia. (Formicariae Imperii Rossici). Systematics, geography and data on the biology of Russian ants. Part I. Tr. Obshch. Estestvoispyt. Imp. Kazan. Univ. 38(4-6 6: 1-800 (page 302, Subspecies/race of niger)
  • Seifert, B. 1992b. A taxonomic revision of the Palaearctic members of the ant subgenus Lasius s.str. (Hymenoptera: Formicidae). Abh. Ber. Naturkundemus. Görlitz 66(5): 1-67 (page 34, Status as species, Senior synonym of illyricus and pontica)
  • Stärcke, A. 1944b. Retouches sur quelques fourmis d'Europe. III. Autres Lasius. Entomol. Ber. (Amst.) 11: 153-158 (page 155, Status as species)
  • Stitz, H. 1914. Die Ameisen (Formicidae) Mitteleuropas, insbesondere Deutschlands. Pp. 1-111 in: Schröder, C. (ed.) Die Insekten Mitteleuropas insbesondere Deutschlands. Band II, Hymenopteren, 2. Teil. Stuttgart: Franckh'sche Verlagshandlung, 256 pp. (page 85, Subspecies/race of niger)
  • 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 283, Status as species)
  • Wilson, E. O. 1955a. A monographic revision of the ant genus Lasius. Bull. Mus. Comp. Zool. 113: 1-201 (page 89, Combination in L. (Lasius), Status as species, Senior synonym of brunneoemarginatus, brunneoides and nigroemarginatus)