Lasius illyricus

Information on the ecology and biology of this species is very scarce. Ecological segregation from Lasius emarginatus due to slightly different habitat preferences is witnessed in Greece (Borowiec & Salata, 2013), but no information is available from regions in which L. emarginatus is probably absent (Schifani & Massa, 2020). Lasius illyricus is common in mainland Greece and Ionian Islands, rare in Aegean Islands and Crete, and so far not recorded from Cyclades and Dodecanese. It prefers warm deciduous forests and mediterranean bushes, but in Achaia and Aetolia-Acarnania, it was noted also from mountain pastures and fir forests (Borowiec & Salata, 2021).

Identification
Seifert (2020) - In north Iran, L. illyricus occurs in synoptic sympatry with Lasius persicus. The two species have very similar pigmentation but strongly deviating structural characters; L. persicus has longer setae, much higher setae numbers (on the scape and hind tibia in particular), shorter scapes and terminal segments of the maxillary palps, and smaller eyes.

Borowiec and Salata (2013) - L. illyricus is most similar to Lasius emarginatus. Both occur in similar habitat and appear superficially similar in morphology. Lasius illyricus is easily distinguished from L. emarginatus by pubescence and setation of scapes and external margin of hind tibiae. In L. illyricus the scape in frontal view on dorsal apical 1/3 length has only erect hairs and 2-3erect setae while in the same area in L. emarginatus erect setae predominate. In the same view on the ventral side of the scape suberect hairs with some setae only slightly longer than hairs predominate in L. illyricus while in L. emarginatus setae distinctly longer than adjacent hairs predominate. The difference in chaetotaxy is more clearly visible on the anterior surface of the scape in dorsal view of antenna. In L. illyricus the surface has no to 3-4 erect setae, occasionally to 11 setae in large specimens while in L. emarginatus the setation is more clear with several long erect setae (usually 15-20, up to 34) and only occasionally in small specimens with only 9-10 setae. L. illyricus has sparser setation oh external edge of hind tibia with 6-18 erect setae (mean 13 ± 3), while in L. emarginatus there are 13-27 erect setae (mean 20.8 ± 3.9).

L. illyricus specimens in comparison to southern populations of L. emarginatus are slightly larger (ML 1352 ± 115.9 vs. 1213.7 ± 94.7; HL 1020 ± 72 vs. 1002.3 ± 78.2, HW 981.1±99.5 vs. 952.8±97.6), and more contrastingly coloured with a reddish thorax that is distinctly paler than the head and abdomen. Lasius illyricus is more similar in coloration to northern populations of L. emarginatus than to populations from Greece. The latter are typically dark, with a reddish-brown to brown thorax.

Distribution
Seifert (2020) - From the Balkans (42.65°N, 18.07°E) over the southern Ukraine, the southern Caucasus and entire Asia Minor east to the eastern Elburs Mountains (36.867°N, 54.933°E). The altitudinal distribution ranges from sea level up to 1900 m.

This is species common in northern Greece and the Ionian Islands, rare in Crete and the southern Aegean islands (Borowiec et al., 2022).

Distribution based on Regional Taxon Lists
Palaearctic Region: Armenia, Austria, Azerbaijan, Croatia, Greece, Montenegro, North Macedonia, Russian Federation, Serbia, Turkey, Ukraine.

Biology
Borowiec and Salata (2013) - Prefers broadleaved forests, especially oak and platanus forests, but L. illyricus prefers more open and drier localities and on Korfu it is common in urban areas, gardens and olive plantations (on Korfu olive plantations are different than in other parts of Greece, more like natural-growth forests with extremely high unclipped trees overgrown by epiphytic mosses). On Peloponnese L. illyricus prefers forest margins.

Near Agridi (N Peloponnese, Aroania Mts.) we found nests of both typical L. emarginatus and the L. illyricus form. This was the only locality where we observed sympatric occurrence of both taxa. In Ionian Islands and Central Peloponnese we observed only L. illyricus while in central and northern Greece only L. emarginatus. Halkidiki is an exception where in an extremely warm locality on the Sithona Peninsula near Parthenonas we found only L. lyrics and in Holomontas mountains only L. emarginatus.

Seifert (2020) – Habitat selection by  Lasius illyricus is only marginally different from L. emarginatus. In a sympatric area on the Balkans, both species prefer broadleaved forests, especially Quercus and Platanus forests, but there is some trend of L. illyricus to select more open and drier localities. It may occur in urban areas, in gardens and olive plantations. In regions with dryer macroclimate it is found in very shady woods along streams. In north Iran it typically occurs in humid broad-leafed Caspian forest. Reproduction: A mating flight was observed shortly after sunset. Nesting: Nests are in soil, under stones or in rotten logs. Chemistry: Zimmermann wrote in the original description of L. illyricus”...auch fehlt ihnen der L. emarginatus eigentümliche Geruch...“ [”...even so, the peculiar odor of L. emarginatus is lacking...“]. It remains to be checked if this is a constant character or only an ephemeral impression due to the circumstances of observation.

Nomenclature

 * . Lasius alienus subsp. illyricus Zimmermann, 1935: 50 (w.q.m.) CROATIA.
 * Combination in L. (Lasius): Borowiec, L. & Salata, 2013: 353.
 * Junior synonym of alienus: Wilson, 1955a: 78; Smith, D.R. 1979: 1435.
 * Junior synonym of emarginatus: Seifert, 1992b: 34; Bolton, 1995b: 223; Radchenko, 2016: 367; Karaman, M.G. 2011: 89.
 * Senior synonym of pontica: Seifert, 2020: 71.
 * Status as species: Borowiec, L. & Salata, 2013: 353 (redescription); Borowiec, L. 2014: 86; Salata & Borowiec, 2018b: 157 (in key); Salata & Borowiec, 2018c: 46.
 * pontica. Lasius alienus var. pontica Stärcke, 1944a: 157 (w.) GEORGIA (Abkhazia).
 * Junior synonym of alienus: Wilson, 1955a: 78; Smith, D.R. 1979: 1435; Arakelian, 1994: 117 (error).
 * Junior synonym of emarginatus: Seifert, 1992b: 34; Bolton, 1995b: 225; Radchenko, 2016: 367.
 * Junior synonym of illyricus: Seifert, 2020: 71.

Worker
Seifert (2020) - Absolute size large (CS 991 µm). Head and scape length indices large (CL/CW900 1.082, SL/CS900 1.073); postocular distance small, eye and torulo-clypeal distance large (PoOc/CL900 0.223, EYE/CS900 0.250, dClAn900 5.45); terminal segment of maxillary palp long (MP6/ CS900 0.217). Number of mandibular dents large (MaDe900 8.58). Pubescence on clypeus very dilute (sqPDCL900 5.71); frontal pubescence short (PLF900 22.9). All body parts with much fewer setae than in Lasius emarginatus but in length very similar (PnHL/CS900 0.137, GuHL/ CS900 0.124, nOcc900 7.8, nGen900 4.1, nGu900 4.1, nSc900 2.1, nHT900 7.4). Coloration: similar to the light morph of Lasius emarginatus. Dark morphs have yet to be observed – the darker, more concolorous pigmentation of the small-sized type specimens is probably due to the positive allometry of yellowish or reddish pigments usually observed in Lasius s.str. species.

See table 6 in Seifert 2020 for additional morphometrics. The abbreviated names of various quantitative data shown above are defined here: Seifert 2020 Lasius characters.

Type Material
Seifert (2020) - Lectotype worker labelled ”Mt. Petka Dubrovnik YUGOSLAVIA V-1928 S.Zimmerman“, ”type series Lasius alienus illyricus Zimmermann“ (upperside 2nd label), ”unlabelled type Le Tenrant 7.90“(underside 2nd label), ”M.C.Z. CoType 30116“, ”LECTOTYPE desig. by E.O.Wilson“, ”Jan-Jun.2001 MCZ Image Database“; 3 paralectoype workers labelled ”Mt. Petka Dubrovnik YUGOSLAVIA V-1928 S.Zimmerman“, ”Lasius alienus illyricus Zimmermann COTYPE“, ”M.C.Z. CoType 30116“; depository:.

References based on Global Ant Biodiversity Informatics

 * Borowiec L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
 * Borowiec L., and S. Salata. 2013. Ants of Greece  additions and corrections (Hymenoptera: Formicidae). Genus (Wroclaw) 24(3-4): 335-401.
 * Borowiec L., and S. Salata. 2017. Ants of the Peloponnese, Greece (Hymenoptera: Formicidae). Polish Journal of Entomology 86: 193-236.
 * Bracko G., K. Kiran, C. Karaman, S. Salata, and L. Borowiec. 2016. Survey of the ants (Hymenoptera: Formicidae) of the Greek Thrace. Biodiversity Data Journal 4: e7945. doi: 10.3897/BDJ.4.e7945
 * Salata S., L. Borowiec, and A.Trichas. 2018. Taxonomic Revision of the Cretan Fauna of the Genus Temnothorax Mayr, 1861 (Hymenoptera: Formicidae), with Notes on the Endemism of Ant Fauna of Crete. Annales Zoologici (Warsaw) 68(4): 769-808.
 * Salata S., and L Borowiec. 2017. Species of Tetramorium semilaeve complex from Balkans and western Turkey, with description of two new species of (Hymenoptera: Formicidae: Myrmicinae). Annales Zoologici (Warsaw) 62:279–313.
 * Salata S., and L. Borowiec. 2018. Taxonomic and faunistic notes on Greek ants (Hymenoptera: Formicidae). Annals of the Upper Silesian Museum in Bytom Entomology 27: 1-51.
 * Salata S., and L. Borowiec. 2019. Preliminary division of not socially parasitic Greek Temnothorax Mayr, 1861 (Hymenoptera, Formicidae) with a description of three new species. ZooKeys 877: 81-131.