Effect of urban habitats on colony size of ants (Hymenoptera, Formicidae)In memory of Professor A. A. Zakharov (Russian Academy of Sciences, Moscow)

Abstract

Urbanized ecosystems are suitable for the habitat of only a few species of ants, due to conditions caused by human activities. Invasive species of ants have adapted to urbanized ecosystems most successfully. The study of the ant colonies sizes started in Crimea in 2013-2014. In 2019-2021 it was carried out in Ukraine (the Carpathians, Kyiv city, and Kyiv region), in Russia (Rostov-on-Don city and region, and the Urals), and in Uzbekistan (Tashkent city, and tugai forests). The study covers natural (forest, meadow, steppe), suburban (alleys and tree planting) and urban habitats (tree planting along streets and roads, botanical gardens). Our study covers 21 species of ants with trails on forage areas. Nine species were sampled for interspecific comparison of colony sizes. They were collected in at least 2 habitat types within the same geographic region. According to the activity parameter on the trails, the number of foragers and the population of the colony were calculated (using the formula of A. Zakharov). According to our calculations, the maximum colony sizes are typical for invasive species (Crematogaster subdentata, Lasius neglectus, 100-7500 thousand workers) in the urban habitats. Some native species (Dolichoderus quadripunctatus, Formica cinerea) in the urban areas have colonies with 120-350 thousand workers. These values may exceed those for ant species inhabiting natural habitats (30-250 thousand workers). High rates of colony size in the urbanized habitats can be achieved due to availability of food, nesting resources, and the absence of competing ant species. Key words: Colony size, urban ecology, invasive species, native species, Crematogaster subdentata, Lasius neglectus, Dolichoderus quadripunctatus, Formica cinerea