Diversity and Trophic Relationships of Functional Groups of Bumblebees (Hymenoptera: Apidae, Bombus Latreille, 1802) in Urban Habitats

Species composition, distribution, and trophic relationships of bumblebees are studied in six types of urban habitat: urban parks, botanical gardens, least-disturbed areas within the city, residential areas, and roadsides. Twenty bumblebee species are recorded in the present study. The species composition of bumblebees has changed from 1933 to 2017. Rare species have disappeared from the city—Bombus fragrans, B. cullumanus, and B. jonellus. The core of urban bumblebee communities consists of ecologically plastic species, most of which belong to the functional morphoecological “short-tongued” group (83%). The more specialized “medium-tongued” and “long-tongued” species are less diverse. Their populations make up 14% and 3% of the total bumblebee population. Five most common species, B. lucorum, B. terrestris, B. lapidarius, B. pascuorum, and B. hypnorum, are found at locations of the most noted categories of habitats. One of the main factors affecting the diversity of morphoecological groups of bumblebees in urban conditions is the state of floral resources. The bumblebees are observed feeding on more than 60 plant species of the families Asteraceae, Fabaceae, Lamiaceae, Rosaceae, and Salicaceae in urban environment; however, the insects favored plants of 30 species. The ornamental, ruderal, and some invasive species of plants are significant in bumblebees’ feeding in urban conditions. The resources for bumblebee feeding and sustainable density of nesting sites are rich in quality and quantity only at a few of model urban sites. At these territories, the highest species diversity of bumblebee is recorded, including rare, protected, and vulnerable species. The ecological potential of other studied urban sites is enough to sustain the most ecologically plastic bumblebee species.