Pollinators play a crucial role in ecosystems globally, ensuring the seed production of most flowering plants. They are threatened by global changes and knowledge of their distribution at the national and continental levels is needed to implement efficient conservation actions, but this knowledge is still fragmented and/or difficult to access. As a step forward, we provide an updated list of around 3000 European bee and hoverfly species, reflecting their current distributional status at the national level (in the form of present, absent, regionally extinct, possibly extinct or non‐native). This work was attainable by incorporating both published and unpublished data, as well as knowledge from a large set of taxonomists and ecologists in both groups. After providing the first National species lists for bees and hoverflies for many countries, we examine the current distributional patterns of these species and designate the countries with highest levels of species richness. We also show that many species are recorded in a single European country, highlighting the importance of articulating European and national conservation strategies. Finally, we discuss how the data provided here can be combined with future trait and Red List data to implement research that will further advance pollinator conservation.

The nanus group of the genus Merodon Meigen (Diptera, Syrphidae) is revised, yielding an illustrated key, a discussion of taxonomic characters and morphological diagnosis for the five species of this group. Three new cryptic species are described, Merodon kopensis Vujić et Hayat sp. n., M. neonanus Vujić et Taylor sp. n. and M. rasicus Vujić et Radenković sp. n. New diagnostic characters are given for M. nanus Sack and M. telmateia Hurkmans. In addition, environmental profiles for each investigated species have been defined and compared, and maps of distribution and richness created. Niche dissimilarity was found for each species. Eastern Anatolia and the southern Aegean region of Turkey are reported as the most species rich regions for the nanus group.

Summary A list of 25 species of the genus Eumerus Meigen (Diptera: Syrphidae) from the eastern Mediterranean islands is presented. Descriptions are given for three new species: Eumerus aurofinis Grković, Vujić & Radenković n. sp. from Lesvos, Samos, Rhodes islands (Greece) and Bozdağ mountain (Turkey), E. torsicus Grković & Vujić n. sp. from Chios Island (Greece) and Cyprus; E. crassus Grković, Vujić & Radenković n. sp. from Lesvos Island (Greece). In addition to classical morphological characters, mitochondrial COI barcode sequences were generated for several specimens of two available taxa. The status of Eumerus alpinus Rondani, 1857 is revised, and the taxon is resurrected from synonymy of E. olivaceus Loew, 1848. The zoogeographical significance of the described endemic taxa to the biodiversity of the Aegean islands is discussed.

Dehesas are typical Mediterranean habitats for extensive livestock raising. Hoverflies (Diptera: Syrphidae) may act as bioindicators in dehesas, but they are still poorly known in this habitat type. With the purpose of the present study, hoverfly diversity was surveyed in Campanarios de Azaba, a typical oak dehesa in Salamanca province, Spain. A total of 41 species were recorded, including Eumerus azabense sp. nov. This new species was found to belong to the Eumerus tricolor group, both in morphological and genetic terms, and clearly separated (DNA characters) from the similar Eumerus niveitibia, which is redescribed here. Genetic monophyly of the E. tricolor group is confirmed in the present paper. An updated hoverfly checklist of Salamanca province is provided (152 sp.) with indication of the 56 species recorded in Campanarios de Azaba. Obtained results address the importance of dehesa biodiversity, which includes species new to science.

The diversity in the Eumerus tricolor group, the largest group within the genus in Southeast Europe, is investigated. Two new, locally distributed species are described, E. crispus Vuji? & Grkovi?, sp. n. from Serbia and E. nigrorufus Grkovi? & Vuji?, sp. n. from Montenegro. In addition to Southeast European members, one related species E. arctus van Steenis, sp. n. is described from Switzerland. We designate lectotypes for E. ovatus Loew, 1848, E. tarsalis Loew, 1848, E. tricolor (Fabricius, 1798) and E. varius Meigen, 1822. A map of the distribution of members of the E. tricolor group in Southeast Europe is provided. In addition, records from other parts of Europe are listed and an illustrated identification key to the SE European species of the E. tricolor group provided. We also study and discuss the significance of small habitat patches for the preservation of species of Eumerus, because the three species described in this paper are currently known from such patches.

Eumerus Meigen (Diptera, Syrphidae) is one of the most speciose hoverfly genera in Europe, with several species groups recognized within. As part of the tricolor group of species, a subgroup of long-legged representatives stands out. We name it Eumerusbinominatus subgroup and provide descriptions for two new European species which belong to this subgroup: E.grallatorsp. nov. from mainland Spain and E.tenuitarsissp. nov. from Lesvos and Evros, Greece. A key for all five recognized species of the binominatus subgroup is provided.