Competition between Formica cinerea Mayr [Hymenoptera: Formicidae] and co-occurring ant species, with special reference to Formica rufa L.: direct and indirect interferences

Formica cinerea Mayr is supposed to be the top dominant of ant communities in successional sandy habitats, whereas wood ant species, e.g. F. rufa L., play this role in forests. These species often co-occur in overlapping habitats. The aim of the study was to recognize competitive interrelations between them in the broad ecological aspect of relations with local subordinate species, including F. fusca L., Tetramorium caespitum (L.) and Myrmica schencki Viereck. Study area was a sand dune slope surrounded by pine forest at Tvärminne, S Finland, where F. cinerea nest complexes were encircled by F. rufa colonies. Baiting experiments, preceded by ‘nudum’ observations were carried out. The presumption that F. rufa would influence the activity of F. cinerea was not supported by the results. No-ant zones separated the territories of these two species almost through the total length of the boundary of the F. cinerea range. The outcome of interspecific interactions within the multi-species community studied corresponded with the species competitive status generally. The results are discussed in the context of interspecific competition hierarchy in ants and succession of ant communities.