Novgorodova Т.А., Chesnokova S.V. 2024. Quantitative assessment of ant aggressiveness: Formica uralensis Ruzsky, 1895 vs. Formica aquilonia Yarrow, 1955 (Hymenoptera, Formicidae) // Euroasian Entomological Journal. Vol.23. No.5: 252–260 [in English].
Institute of Systematics and Ecology of Animals, Siberian Branch of the Russian Academy of Sciences, Frunze Str. 11, Novosibirsk 630091 Russia. E-mail: tanovg@yandex.ru , tchsvet@mail.ru
doi 10.15298/euroasentj.23.05.03
ABSTRACT. Aggressive behaviour plays an important role in the stability of ant colonies and the success of ant species. To adequately assess the potential capabilities and competitiveness of individual ant species, and to predict their behaviour in different situations, it is important to have a clear understanding of their levels of aggressiveness, assessed on a single, “universal scale”. An easy-to-use and sufficiently effective method for rapid assessment of ant aggressiveness, suitable for both laboratory and field use, has been refined and tested. The method is based on recording the responses of ant workers to a simple artificial stimulus and using a universal 9-point scale to quantify aggression. A comparative analysis of the aggressiveness of two ant species of the genus Formica Linnaeus, 1758 was carried out in the Central Altai (Russia, Altai Republic, Ust-Koksinsky District, Yustik Village) within the territories of large nest complexes of Formica aquilonia Yarrow, 1955 and F. uralensis Ruzsky, 1895. Tests were carried out on ant nest mounds and foraging trails (on tree trunks) for five nests of each ant species. The aggressiveness of F. uralensis workers, even from a large nest complex (more than 120 nests), was significantly lower than that of F. aquilonia, both in general and separately on foraging trails and nest mounds. Similar results were obtained both for the tested ant colonies as a whole and separately for large nests (mound diameter of about 80–100 cm). The results obtained are consistent with the data on the lower competitiveness of F. uralensis compared to representatives of the Formica rufa group. Despite lower aggressiveness compared to red wood ants, it is F. uralensis that usually dominates in mountain-valley forests of the central part of Altai (e.g., in birch-spruce-larch streamside forests), forming huge complexes of more than 200 (sometimes up to 400 or more) nests. In spring, such habitats often have extreme conditions for ants due to the prolonged inundation of the area during floods. We assume that F. uralensis has a sufficient (perhaps even unique) reserve of «physiological strength» to survive in such conditions, and that it is apparently superior to members of the Formica rufa group in this respect. However, this issue requires focused and detailed study.
KEY WORDS: behaviour, aggressiveness, estimation method, ants, universal scale, simple artificial stimulus, red wood ants.