Structure of mound-building ant settlements (genus Formica) in Kuzokotsky Peninsula (northern Karelia)

Abstract

The spatial distribution of obligate dominant ant species, which includes four species of the genus Formica: F. exsecta, F. lugubris, F. aquilonia and F. uralensis, and differentiation of multispecies settlements has been studied in the eastern Kuzokotsky Peninsula (northern Karelia, Russia). F. exsecta and F. lugubris were present in remote single colonies, groups of two or three nests, single-species complexes of no more than ten nests, or larger multispecies settlements. F. aquilonia formed a small complex within one of the multispecies settlements. The nests of F. uralensis were single. Significant preference of F. exsecta to aggregate with F. lugubris was revealed in two permanent multispecies settlements; such a preference is atypical for these species in other areas. The nests of F. aquilonia were aggregated only with the nests of their own species. Presumably, the settlement of F. lugubris was facilitated by capturing the active nests of F. exsecta. This is confirmed by the reported case of capture of one F. exsecta nest by an adjacent colony of F. lugubris, as well as by similar cases repeatedly described by other authors. The change of the host species did not violate the spatial structure of the settlement. Thus, a unique structure of settlements of obligate dominant ant species with complicated interactions among them has been described in northern Karelia.