Fauna, distribution, and DNA barcoding data of caddisflies (Insecta, Trichoptera) in Croatia

Abstract

This study presents a thorough overview of the diversity of the Trichoptera fauna in Croatia, encompassing several key aspects. First, it offers a historical overview of Trichoptera research conducted within the country, tracing the development and major milestones of this field. Second, it provides a detailed analysis of the distribution and species diversity of caddisflies across Croatia’s three geographical regions, the Continental, Alpine, and Mediterranean, as well as within two ecoregions (ER5 – Dinaric Western Balkan and ER11 – Pannonian Lowlands) and two major river basins (AS – Adriatic Sea basin and BS – Black Sea basin). This biogeographic assessment is based on comprehensive records of adult specimens and, in certain cases, on DNA barcoding data obtained from larval stages. Third, the study includes a thorough examination of species synonyms and a critical review of the existing literature. Finally, it delivers a faunistic and taxonomic review of selected species and subspecies. A total of 225 species belonging to 18 families and 74 genera have been identified. Two of these species are represented by two and three subspecies, respectively, bringing the total number of recorded Trichoptera taxa in Croatia to 228. The presence of 223 species was confirmed in the adult stage. Only two species were identified by DNA barcoding as larvae. In the Continental region 170 species were recorded, in the Alpine region 155, and in the Mediterranean part 131 species. The Black Sea basin contains 203, and the Adriatic basin 141 species. In the Pannonian Lowland region (Ecoregion 11) we determined 152 and in the Dinaric Western Balkan (Ecoregion 5) 197 species. The BOLD Systems database currently contains about 593 DNA barcoded Trichoptera specimens from Croatia comprising 176 species, identifying 211 BINs, covering 78% of Croatian Trichoptera fauna.