Diversity of the caddisflies (Trichoptera) of Bulgaria

Conservation of freshwater environments and assessment of their ecosystem services as a function of biodiversity are key research objectives with global importance. Additionally, the taxonomic composition of aquatic communities, including benthic macroinvertebrates, is crucial for the evaluation of the ecological status of the water bodies they inhabit. Numerous biotic indices and metrics have been developed based on freshwater benthic invertebrates. This contribution focuses on the order Trichoptera, as it includes diverse sensitive taxa with specific requirements to their environment. The aim was to summarise the current knowledge on morpho-taxonomy of adult and larval stages of Bulgarian caddisflies based on published and original data. The only checklist of Bulgarian caddisflies was published in the 1980s by Kumanski 1981 and included 218 species from 76 genera. This checklist was mostly based on adult Trichoptera. It was followed by two monographs (Kumanski 1985, Kumanski 1988) and numerous scientific papers (mostly by the same author, e.g. Kumanski 1993, Kumanski 2007) that by 2007 increased the number of known caddisflies from Bulgaria to 258 species. Based on the literature and on original data, the number of valid species of Trichoptera in Bulgaria is estimated to 255. They are from 78 genera, belonging to 20 families. Worldwide, adult forms are better studied, while not all of the larval stages of caddisflies are currently known or described. More than 100 of the Bulgarian caddisflies (almost 40%) lack larval description. This is likely owing to their limited geographical distribution and insufficient studies on the aquatic stages of Bulgarian Trichoptera over the last decades. Additionally, some of the representatives of the order are endemic for the Balkan Peninsula or Bulgaria.