Wild bees (Hymenoptera: Anthophila) and hoverflies (Diptera: Syrphidae), the two major groups of insect pollinators, are undergoing alarming declines worldwide, including Europe. The lack of accessible and verified spatial and temporal occurrence records currently challenges efforts to understand and mitigate this decline. Here, we compiled datasets from diverse sources, including taxonomists, national experts, public repositories, museum collections, published literature, verified open-access platforms, and aggregated datasets from previous European projects. The collected data were standardised, cleaned and validated by taxonomists and national experts. This collective effort resulted in two databases comprising more than 4.34 million and 1.04 million records for wild bees and hoverflies, respectively. The databases cover 97% of the European bee fauna (2,083 species out of 2,138 recorded in Europe) and 97% of the European hoverfly fauna (886 species out of 913 recorded in Europe). These standardised databases constitute essential resources for future assessments of status and trends, habitat associations, and other research and conservation initiatives to protect and understand wild pollinators on the European continent.

Fire is a major global disturbance affecting the evolution of organisms and shaping plant and animal diversity, especially in fire‐prone regions like the Mediterranean. Yet its impacts on insect‐pollinator communities remain poorly understood. We conducted a 3‐year study on a Greek island, examining spatial and temporal impacts of fire on bee communities and species' functional traits. We compared bee diversity and population sizes in burnt and unburnt sites, by including in our analysis fire severity metrics using dNBR (differenced Normalized Burn Ratio) derived from satellite imaging. We show that fire initially led to increased bee abundance despite having a strong negative impact on floral resources. Burnt and unburnt communities differed significantly in species composition revealing that specific bee taxa drove post‐fire recovery. In post‐fire year 1, the population spike in burnt sites was driven by an increased abundance of below‐ground nesters, excavators and trophic generalists (polylectic); in contrast, the populations of trophic specialists (oligolectic) were negatively affected. By year 3, most differences between burnt and unburnt sites had been alleviated. Multivariate models incorporating fire severity, plant diversity and floral resources revealed that the heterogeneity of fire severity, even within small spatial scales, drove most of the variation in bee populations, followed by flower numbers. Our findings highlight the role of fire as an environmental filter, selecting species with specific traits and shaping distinct post‐fire communities. Notably, within 3 years, burnt bee communities started converging with the unburnt sites, suggesting a relatively rapid recovery of functional composition.

We introduce the initial modification to the most recently issued inventory of European wild bees published by Ghisbain & Rosa et al. in 2023. We report new changes and taxonomic acts including: the description of a new species, Panurginus cypricus Hopfenmüller, 2025 sp. nov.; the lectotype designation of Hylaeussubtilis Förster, 1871; the upgrade or resurrection of five subspecies to species rank: Lasioglossumaeneidorsum (Alfken, 1921) stat. rev., Osmia bulgarica Friese, 1923 stat. rev., Seladonia alpina (Alfken, 1907) stat. rev., Seladonia glacialis (Ebmer, 1979) stat. nov., and Seladonia perkinsi (Blüthgen, 1926) stat. rev.; the resurrection of two species from previous synonymy: Hylaeus subtilis Förster, 1871 spec. resurr. and Protosmiamirabilis (Friese, 1899) spec. resurr.; and Hoplitis taurica (Radoszkowski, 1874) is here considered to be a nomen dubium. Finally, the following six new synonymies are proposed: Anthophoralarvata Giraud, 1863 syn. nov. of Anthophorafulvipes Eversmann, 1846; Protosmiamonstrosa (Pérez, 1895) syn. nov. of Protosmiatiflensis (Morawitz, 1875); the following taxa are all synonyms of Hylaeussubtilis Förster, 1871: Hylaeus nigrifacies Bramson, 1879 syn. nov., Prosopis gracilicornis var. luteifrons Strand, 1909 syn. nov., Prosopis moricella Bischoff, 1954 syn. nov., and Prosopis moricella f. atricallosa Bischoff, 1954 syn. nov. We also report 4 new species for Europe: Andrena immaculata Warncke, 1975, Anthophora bifasciata Fedchenko, 1875, Nomada felici Schwarz, 1977, and Systropha anatolica Warncke, 1977. Ancyla nitida Friese, 1902 replaces the use of the name Ancyla nigricornis Friese, 1902 in Europe. Nomada chrysopyga Morawitz, 1871 replaces the use of the name N. mauritanica Lepeletier, 1841 in Europe. The presence and identity of species belonging to the genus Schmiedeknechtia in Europe is discussed. Seven species were overlooked and are now added to the European list: Andrena pinguis Ariana, Scheuchl, Tadauchi & Gusenleitner, 2009, Clavipanurgus anatolicus (Warncke, 1972), Eucera cressa (Tkalců, 1984), Euceramavromoustakisi (Tkalců, 1984), Icteranthidium floripetum (Eversmann, 1852), Seladonia pici (Pérez, 1895) and Megachile sanguinipes Morawitz, 1875. Conversely, seven species are excluded from the European list: Halictusconstantinensis Strand, 1910, Halictus rufipes (Fabricius, 1793), Hoplitisturcestanica (Dalla Torre, 1896), Hoplitis caucasicola Müller, 2012, Lasioglossum andromeda Ebmer, 1978, Lasioglossumedessae Ebmer, 1974, and Seladonia confusa Smith, 1853. Heriades labiata Pérez, 1895 is confirmed as being described from Europe (Barcelona), and not Algeria as previously thought. We also report taxonomic changes recorded after the publication of the latest European checklist (Ghisbain & Rosa et al. 2023), including: the revaluation of two genera, Acanthonomada Schwarz, 1966 and Eupavlovskia Popov, 1955; the synonymy of the subgenus Royanthidium with the genus Pseudoanthidium, which is the senior synonym; the report of the neotype designation of Tetralonia malvae (Rossi, 1790); 32 new species recently described as new to science; 12 species recently synonymized and ten subspecies upgraded to species rank; seven species recently resurrected from previous synonymy; eight species recently recorded as new for Europe; one species noticed as overlooked in the previous European checklists; six species recently removed from the European list; and other various changes such as transfer of species from one genus or subgenus to another. We provide corrections to 136 names of authors and specific epithets, years of publication, and gender agreements demonstrated to be incorrect for various reasons. Overall, the present work revises the total number of species for Europe sensu IUCN to 2,187.

Plant diversity is critical to ensure the future of humanity, as it provides essential ecosystem services and functioning. As recent estimates showed that animal-mediated pollination is crucial for the reproduction of approximately 90% of flowering plants, playing an essential role in maintaining biodiversity and agricultural productivity, effort to preserve plants cannot be disjoined from pollinator conservation initiatives. Despite their importance, pollinators have experienced alarming declines. The LIFE 4 Pollinators project was launched to involve people protecting wild bees and other pollinators in the Mediterranean. This study presents data collected through the project's web-platform, where users uploaded over 2,000 photographs of plant-pollinator interactions between 2021 and 2024. The dataset focuses on the identification of flower-visiting insects and plants, and the current study gives emphasis to citizen scientists' ability to identify plants and pollinators. 1,407 photo-records were analysed, revealing that bees and beetles were the most frequent pollinators, with plants of the Asteraceae and Cistaceae families being the most recorded. Users correctly identified 93.7% of insect taxonomic aggregations and 74.2% of plant species. The study also highlights the recording of threatened, alien, and invasive species, including the vulnerable Callicera spinolae and the invasive Vespa velutina. The plant-pollinator network analysis supports the floral syndrome concept, with floral morphologies like 'Head' and 'Disk' attracting a wide range of pollinators. The results indicate that citizen science contributes to the identification and monitoring of pollinators, generating knowledge that may be key to the conservation of these organisms and to better understand plant-pollinator interactions. Data collection through citizen-generated photographs allows to significantly expand the geographic area and the magnitude of studies, facilitating large-scale analyses that would be difficult to achieve with traditional monitoring methods. These findings provide a useful basis for future conservation initiatives and the development of policies aimed at mitigating pollinator decline.

Pollinators play a vital role in most terrestrial ecosystems, supporting wild plant communities and enhancing agricultural yields. However, despite their ecological and economic importance, they have been experiencing an alarming decline over the past decades. The Mediterranean region, known for harboring highly diverse communities of plants and pollinators, is particularly vulnerable due to intense anthropogenic pressures. Furthermore, the ecological roles of many floral visitors remain poorly understood, hindering conservation efforts. In response, in recent years, growing attention has been directed toward the contribution that citizens can give in support of pollinator research. An increasing number of projects have adopted a Citizen Science approach to enable large-scale data collection. The LIFE 4 Pollinators project (LIFE18/GIE/IT/000755) “Involving people to protect wild bees and other pollinators in the Mediterranean” aims to promote the conservation of pollinating insects and entomophilous plants across the Mediterranean region by fostering progressive changes in human practices that threaten wild pollinators. In addition to the implementation of several actions to raise awareness, the project launched a web platform to collect photographic records of flower–insect interaction from the public. The platform is expected to remain active for at least ten years, during which we encourage continuing record submissions by interested bodies. With this data paper we are making the current dataset freely accessible to anyone, committing to periodic online updates.

1. Fire is a common worldwide disturbance that affected the evolution of life and shaped plant and animal diversity; this is especially applicable in the Mediterranean.2. In this study, we explore the response to fire of two eusocial bee species of Halictidae, namely, Lasioglossum marginatum (Brulle, 1832) and Lasioglossum malachurum (Kirby, 1802), as to their population number, body size and pollination specialisation.3. The study was carried out on Chios Island, Greece, during the first 3 years after a wildfire (2013-2015). Fire effect was examined from a spatial viewpoint by comparing unburnt with burnt sites and from a temporal one by comparing populations among different postfire years.4. We found that L. malachurum populations increased with time after fire, while they were more abundant in the burnt sites during the second postfire year. In contrast, L. marginatum populations decreased in both burnt and unburnt sites, which suggests that the decline was not an effect of the fire alone.5. Insect body size differed among years for both species, with L. marginatum individuals being smaller in the burnt sites compared to the unburnt, albeit only in the first postfire year. Finally, both species show high partner fidelity but to different plant partners.6. Our results underscore the importance of studies focusing on the effects of a disturbance at the intraspecific level. However long-term monitoring is required, especially in the context of the global pollinator crisis and the more frequent and severe wildfires as an effect of climate change.

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.

1. We studied alpha- and beta-diversity of pollinators, flowering plants and plant-pollinator interactions along the altitudinal gradient of Mt. Olympus, a legendary mountain and biodiversity hotspot in Central Greece.2. We explored 10 study sites located on the north-eastern slope of the mountain, from 327 to 2596 m a.s.l. Insect surveys were conducted once a month using hand netting (years 2013, 2014 and 2016), and they were combined with recordings of flowering plant diversity (species richness and flower cover). We then calculated alpha- and beta-diversity of pollinators, plants in flower and plant-pollinator interactions, and explored their demographic response along the altitudinal gradient.3. Alpha diversity of pollinators, plants and plant-pollinator interactions were altitude dependent; alpha-diversity of all pollinators, bees, non-bumblebee bees, bee flies and butterflies showed linear declines with altitude, whereas those of hoverflies and bumblebees showed unimodal patterns. Beta diversity and its turnover component of all pollinators, hoverflies, bees, bumblebees, non-bumblebee bees, butterflies and plants showed linear increases, whereas those of bee flies and of plant-pollinator interactions varied independently from the pairwise altitudinal difference.4. The high dissimilarity and uniqueness of pollination networks, which is probably a result of the high biodiversity and endemism of Mt. Olympus, is driven by species turnover and the formation of new interactions between new species. Contrasting to the monotonic decline of the remaining groups, the unimodal patterns of hoverfly and bumblebee alpha-diversity are probably the effect of a higher tolerance of these groups to high-altitude environmental conditions. Our findings highlight that the high turnover of species and of pollination interactions along the altitudinal gradient are the mainstay of hyperdiverse mountains, a fact that conveys important historical, ecological and conservational implications.

The genus Pygopleurus includes some of the most important beetle pollinators of the Eastern Mediterranean islands, showing a particular affinity to red-guild flowers. Focussing on the Aegean Archipelago, 75 individuals belonging to five Pygopleurus species were sampled and screened for two mtDNA loci (COI and 16S). The phylogenetic analysis implemented both by Bayesian and Maximum Likelihood approaches, showed a deep and robust structure for three species, mostly reflecting the palaeogeographic history of the islands. Interspecific divergence among them appears to have emerged at the beginning of the Messinian Salinity Crisis (5.99-5.33 Mya), with differentiation dating back to the eustatic sea level changes of the Pleistocene (2.56-0.0117 Mya). For P. foina, the most abundant species in the Aegean Archipelago, a finer sampling (121 individuals from 8 islands) and analysis of COI locus showed a distinct separation between northern and southern islands of East Aegean that disconnected non-simultaneously from the continent during the Pleistocene. A strong geographic structure was also evident at smaller taxonomic scales, with island populations exhibiting unique haplotypes. Thus, we concluded that the major palaeogeographic events of the region are reflected in the observed patterns of inter- and intraspecific divergence among and within Pygopleurus species in the Aegean Archipelago, something that is facilitated by this genus' low dispersal ability.

Maintaining the diversity of wild bees is a priority for preserving ecosystem function and promoting stability and productivity of agroecosystems. However, wild bee communities face many threats and beekeeping could be one of them, because honey bees may have a strong potential to outcompete wild pollinators when placed at high densities. Yet, we still know little about how beekeeping intensity affects wild bee diversity and their pollinator interactions. Here, we explore how honey bee density relates to wild bee diversity and the structure of their pollination networks in 41 sites on 13 Cycladic Islands (Greece) with similar landscapes but differing in beekeeping intensity. Our large-scale study shows that increasing honey bee visitation rate had a negative effect on wild bee species richness and abundance, although the latter effect was relatively weak compared to the effect of other landscape variables. Competition for flowering resources (as indicated by a resource sharing index) increased with the abundance of honey bees, but the effect was more moderate for wild bees in family Apidae than for bees in other families, suggesting a stronger niche segregation in Apidae in response to honey bees. Honey bees also influenced the structure of wild bee pollination networks indirectly, through changes in wild bee richness. Low richness of wild bees in sites with high honey bee abundance resulted in wild bee networks with fewer links and lower linkage density. Our results warn against beekeeping intensification in these islands and similar hotspots of bee diversity, and shed light on how benefits to pollination services of introducing honey bees may be counterbalanced by detriments to wild bees and their ecosystem services.

Cyprus, the third largest island in the Mediterranean, constitutes a biodiversity hotspot with high rates of plant endemism. The wild bees of the island were studied extensively by the native George Mavromoustakis, a world-renowned bee taxonomist, who collected extensively on the island from 1916 to 1957 and summarised his results in a series of eight Cyprus-specific papers published from 1949 ["1948"] to 1957. The current work represents the first modern checklist of the wild bees of Cyprus, based on a compilation of previous publications, museum specimens and authors' recent collections. Overall, 369 verified wild bee species have been recorded on the island, with eleven species reported from Cyprus for the first time. The island hosts all six of the globally widespread bee families, with Apidae represented by 110 species, Megachilidae with 91, Andrenidae with 76, Halictidae with 72, Colletidae with 19, and Melittidae with 1. Twenty-one of the recorded bee species are endemic (i.e., 5.7 % endemism rate) and Cyprus ranks third after Lesvos and Sicily in known bee species richness among the Mediterranean islands. Previously unpublished records from various locations on Cyprus for 156 previously reported bee species are also provided in the study. The current work provides a baseline for future studies of wild bee diversity on the island of Cyprus and neighbouring regions.

Aim We studied bumblebee diversity and bumblebee pollination networks along the altitudinal gradient of Mt. Olympus, a legendary mountain in Central Greece, also known for its exceptional flora. Location Mt. Olympus, Central Greece. Taxon Bombus(Latreille, 1802). Methods We explored 10 study sites located on the north-eastern slope of the mountain, from 327 to 2,596 m a. s. l. Bumblebee surveys were carried out on a monthly basis using pan traps (years 2013 and 2014) and random transect observations assisted by hand netting (years 2013, 2014, and 2016); visited flowering plants and their diversity were recorded during the transect observations. Results With a total of 22 recorded bumblebee species and one species complex, Mt. Olympus is one of the richest mountains in Mediterranean Europe regarding bumblebee diversity.Bombus quadricolorwas recorded as a new species for Greece, whereas four species were recorded at their southernmost distribution limit, therefore possibly vulnerable to climate change. Species richness of both bumblebees and plants in flower followed a unimodal pattern along the altitudinal gradient, the former peaking at high altitudes (1,900-2,200 m a.s.l.), the latter at lower to intermediate altitudes (500-1,500 m a.s.l.). Bumblebee-plant visitation networks were larger, more diverse and more generalized in the between intermediate altitudes (1,500-1,800 m a.s.l.), while nestedness peaked at low and high altitudes. Main conclusions Our results disclose the differential significance of the altitudinal zones of Mt. Olympus for the conservation of the diversity of bumblebees and their host plants, as well as of the interactions among them. Furthermore, they highlight the importance of this mountain, because of its South-European location, regarding climate change impacts on the bumblebee fauna of Europe. All in all, they point towards more reinforced conservation measures to be taken including the expansion of the protection status to the entire mountain.

Natural history specimen data collected and/or identified by Jelle Devalez, https://orcid.org/0000-0003-1110-0640. Claims were made on Bionomia, https://bionomia.net using specimen data from the Global Biodiversity Information Facility, https://gbif.org.

Fire, a frequent disturbance in the Mediterranean, affects pollinator communities. We explored the response of major pollinator guilds to fire severity, across a fire-severity gradient at different spatial scales. We show that the abundance of all pollinator groups responded to fire severity, and that bees and beetles showed in addition a significant species-diversity response. Bees, sawflies, and wasps responded to fire severity at relatively small spatial scales (250-300 m), whereas flies and beetles responded at larger spatial scales. The response of bees, sawflies, and wasps was unimodal, as predicted by the intermediate disturbance hypothesis, whereas flies and beetles showed a negative response. A possible explanation is that the observed patterns (spatial scale and type of response) are driven by taxa-specific ecological and life-history traits, such as nesting preference and body size, as well as the availability of resources in the postfire landscape. Our observational study provides an insight into the effect of fire severity on pollinators. However, future research exploring the explicit link between the pre- and postfire landscape structure and pollinator traits and responses is required for further establishment and understanding of cause-effect relationships.