The spread of <i>Trithemis annulata</i> (Palisot de Beauvois, 1807) (Odonata: Libellulidae) in the western part of the Balkan Peninsula

Trithemis annulata (Palisot de Beauvois, 1807) is a widespread Afrotropical species that substantially expanded its range in Mediterranean Europe in the second part of 20th century and very recently in the West Balkan region. A field study was carried out from June to September 2024 in the southern parts of Bosnia and Herzegovina and the Neretva River delta in Croatia in order to investigate the species’ presence in this area. During the survey, T. annulata was found at 14 locations, seven in each country. The observations from Bosnia and Herzegovina represent the first record of this species for the country. It was found in a wide variety of habitats, both lentic and lotic, including lakes, reservoirs, rivers, larger ponds and canals. Considering that, at several of these locations, the species was not found during surveys in 2022 and 2023, it most likely spread to this area recently. Additionally, two observations of T. annulata from North Macedonia that were found in the online databases Observation and iNaturalist represent the first documented reports for this country. These findings constitute a substantial increase in species range and abundance in the region. The species’ distribution andspread in the Balkan Peninsula is also outlined and discussed.