INTERACTIONS OF THREE DOMINANT SPECIES, LASIUS EMARGINATUS (OL.), FORMICA RUFA L. AND LASIUS FULIGINOSUS (LATR.) (HYMENOPTERA, FORMICIDAE) AMONG THEMSELVES AND WITH SUBORDINATE SPECIES OF ANTS IN BROADLEAF FORESTS. COMMUNICATION 1
The investigation was carried out in July and August, 2013-2015 in the broadleaf forests of the memorial park of landscape gardening art ‘Feofaniya’ in Kiev (Ukraine). The study was aimed at the structure of forage areas of three dominant species of ants, Formica rufa L., Lasius fuliginosus (Latreille) and L. emarginatus (Olivier), and distribution of the subordinate species within these areas. Thirteen species of ants have been found on the soil surface in the investigation sites in the forest dominated by common oaks (Quercus robur) and European hornbeam (Carpinus betulus) with admixture of Norway maple (Acer platanoides), common ash (Fraxinus excelsior), and littleleaf linden (Tilia cordata). The environmental optimum for ant activity falls on July which is manifested in greater figures of their dynamic density in the experimental sites and in larger amounts on bites as compared to August. Variation of the dynamic density is broader in August than in July which suggests their uneven distribution over forage areas. The dominants prefer protein-rich bites, while influents more frequently visit carbohydrate bites. Dominants’ visiting protein-rich bites is due to their trophobiosis, which is especially true for L. fuliginosus. Subordinate species co-occur on experimental sites with L. emarginatus 1.5-2.0 times more frequently than with c L. fuliginosus, and at least 3.0 times more frequently than with F. rufa. From two (at the forage area of the nest complex) to five (in the territories of single colonies) ant species are found together with F. rufa. Eight ant species are found co-occurring with each L. fuliginosus and L. emarginatus, which is almost the same figure as in the areas without dominants (7 species). Dominants determine the level of the ant biodiversity in their territories and differ in their territoriality which is manifested in different dynamic density of subordinate species in dominants’ forage areas. According to their territoriality, dominants may be arranged in ascending order as follows: L. emarginatus < L. fuliginosus + F. rufa (single colonies) < F. rufa (nest complex). Dominant’s territoriality depends mostly on the biotope resources. In the biotopes with limited food resources, dominant with high nest and workers densities in the territory will decrease species diversity and numbers of subordinate species. In the territory of the F. rufa nest complex, workers of the subordinate species constituted less than 1 % of all ants present. Formica rufa in the broadleaf forests is a territorial dominant, while the other two species are weakly territorial.