Formica cunicularia
As well as Formica rufibarbis Fabricius, 1793, common and abundant throughout the Lower Volga Region in grassland habitats, but occurs in slightly more xerothermic habitats. The question of status and presence in the Lower Volga region of Formica clara Forel, 1886 sensu Seifert and Schultz, 2009, remains unclear. The concept of this species in this article is based on the discriminant analysis of morphometric data of workers, applicable with a non-zero error. Such differences seem to me not reliable enough to distinguish species without other confirmation of their isolation in nature. On the other hand, there is another concept of the species F. clara, defined by G.M. Dlussky (1967), which is based on the features of females and cannot be compared with the concept of Seifert and Schultz (based only on the features of workers). F. clara sensu Dlussky is definitely absent in the Lower Volga region. Thus, I see no possibility to separate F. clara in any of the existing concepts of this species among specimens of F. cuniculara collected in the Lower Volga region until its status will be finally clarified.
Seifert, B.; Schultz, R. 2009B. A taxonomic revision of the Formica rufibarbis Fabricius, 1793 group (Hymenoptera: Formicidae). Myrmecological News 12:255-272.
Dlussky, G. M. 1967. Ants of the genus Formica (Hymenoptera, Formicidae, g. Formica). [In Russian.]. Moskva: Nauka Publishing House, 236 pp.
Some additional data and images of Formica cunicularia in the alternate database are available (new window)