Formica caucasicola

Formica caucasicola is the sister species of Formica forsslundi. It was found in moderately grazed, highly montane to alpine grasslands and constructs mounds of finely cut grass pieces. It seems to be largely monodomous but in one locality the arrangement of nests suggested a polydomous colony structure. In each of the six localities was present and socially parasitic colony foundation in this species is evidenced by the finding of a mixed nest. Three findings of alates in the nests were between 27 July and 1 August.

Identification
Worker (Tab. 3, Figs 19–20): slightly larger than Formica forsslundi, mean and maximum CS 1306 and 1380 µm. Head relatively short, mean CL/CW 1.056. Scape much shorter than in F. forsslundi, mean SL/CS 0.972. 2nd funiculus segment distinctly shorter than 3rd, mean Fu2/Fu3 0.948. Dorsal excision of petiolar scale rather shallow, mean PeINC/CS 3.48 %. Eyes with minute hairs, mean EyeHL 6.5 µm. Standing setae on clypeus in 54 % of specimens only present on the 1st level, mean ClySet 1.46. Pubescence surpassing anterolateral clypeal margin almost always absent, mean ClyPub 0.1. Region of occipital corners with appressed hairs. Setae in the area of the ocellar triangle usually absent, mean nOce 0.20. Frontal face of forecoxae almost always without setae, mean nCox 0.06. Metapleural setae always completely absent, mean nMet 0.0. Setae on posterior margin of gaster tergites usually beginning with the 1st tergite, mean TERG 1.17. Setae on anterior area of 3rd tergite always present. Outer edge of hind tibial flexor side with rather few setae, mean nHTfl 5.7. Pubescence distance in ocellar triangle and dorsum of 1st gaster tergite very high, mean sqPDO 7.15, mean sqPDG 6.65.

Gyne (Tab. 6): only two gynes available; very small size, mean CS 1216 µm. Head moderately long, CL/CW 1.007, Scape much shorter than in any other species, mean SL/CS 0.799. Eyes only with minute setae, mean EyeHL 5.0 µm. Surface of head, mesosoma and gaster brilliantly shining, on gaster tergites sometimes with very weak transverse microripples, mean GLANZ 3.0. Standing setae on clypeus present in one gyne only on anterior margin, in the other gyne an accessory 2nd level seta present, mean ClySet 1.5. Single pubescence hairs surpassing anterolateral clypeal margin absent, mean ClyPub 0.0. Setae in the ocellar area absent. Region of occipital corners with appressed hairs, mean OccHD 0 µm. Setae on posterior margin of gaster tergites beginning with the 1st tergite, mean TERG 1.0. Frontal face of forecoxae without setae, mean nCox 0.0. Setae on outer flexor edge of hind tibia rather few, mean nHTfl 4.5. Pubescence distance in ocellar triangle and on dorsum of 1st gaster tergite very high, mean sqPDO 6.46, mean sqPDG 7.82. Color of head, mesosoma and gaster dark to blackish brown, red color components absent.

Distribution based on Regional Taxon Lists
Palaearctic Region: Azerbaijan, Georgia.

Nomenclature

 * . Formica caucasicola Seifert & Schultz, 2021: 202, figs. 19-20 (w.q.) GEORGIA.

Type Material

 * Holotype: worker labelled “GEO: 42.665°N, 44.620°E, Kazbeg, 2224 m, Weide, am Wegrand, Hügel aus kleinen Grashalmstückchen, J. Trettin 2004.06.10”.
 * Paratypes: 4 workers on three pins (together with holotype), same data as holotype.