Abstract
BACKGROUND: The singing cicadas (Hemiptera: Cicadidae) of Bulgaria were poorly known. There are published records for 14 species: Cicada orni, Lyristes plebejus, Cicadatra atra, Cicadatra hyalina, Cicadatra persica, Cicadetta montana, Cicadetta mediterranea, Dimissalna dimissa, Oligoglena tibialis, Tympanistalna gastrica, Pagiphora annulata, Saticula coriaria, Tibicina haematodes and Tibicina steveni. NEW INFORMATION: Two species from this list were doubtful in the beginning of our study, since Tympanistalna gastrica is distributed in central and southern Portugal and Saticula coriaria is a north African species.We checked three major institutional collections housed in Sofia, Bulgaria: the National Museum of Natural History (SOFM), the Institute of Zoology (ZISB) and the Biology Faculty of Sofia University "St. Kliment Ohridski" (BFUS). We confirmed 11 of the species mentioned in literature, except Cicadetta mediterranea and found two additional species: Cicadatra platyptera and Cicadetta macedonica (the specimens in BFUS were bioacoustically confirmed).Based on this knowledge, we further investigated the singing cicadas of Bulgaria with the use of morphological and bioacoustic methods in the years 2008, 2009, 2010, 2012, 2016, 2018 and 2019. We were not able to confirm the presence of Cicadatra persica and Cicadetta mediterranea, but found three additional species: Cicadetta brevipennis s. lat., Cicadetta cantilatrix and Tettigettula pygmea. Using the bioacoustic methods, we also detected unknown singing patterns, which could belong to three or four additional taxa, which need to be described.The Bulgarian fauna of singing cicadas at the moment consists of 16 confirmed and 3-4 potential species.