The Extraordinary Diversity of Merodon avidus Complex (Diptera: Syrphidae)-Adding New Areas, New Species and a New Molecular Marker

In this paper, the Merodon avidus (Diptera, Syrphidae) species complex was revised, whereupon we discovered and described four new species for science: Merodon atroavidus Vujić, Radenković et Likov sp. nov., M. magnus Vujić, Kočiš Tubić et Ačanski sp. nov., M. nigroscutum Vujić, Radenković et Likov sp. nov. and M. pseudomoenium Vujić, Kočiš Tubić et Ačanski sp. nov. An integrative taxonomy approach was used to delimit species boundaries. Two molecular markers (the mitochondrial COI gene and nuclear 28S rRNA gene-newly analysed marker for the complex) and geometric morphometry of the wing shape, together with morphological data and distribution, successfully separated all species from the complex. The morphological variability of the analysed species is described and discussed and an illustrated diagnostic key for typical morpho-forms of species from the M. avidus complex is presented. A distribution map of all investigated species from the complex is provided. The level of endemicity of the M. avidus complex was discussed.

An updated checklist of the hoverflies (Diptera: Syrphidae) of Slovenia

This paper is an updated checklist of the hoverflies of Slovenia. Since the last checklist of 274 species published by de Groot & Govedič in 2008, a large number of additional specimens have been collected and studied. In the present study, 42 species are reported for the first time for the Slovenian hoverfly fauna. Sphegina sublatifrons Vujić, 1990 is deleted from the Slovenian list. In total, 362 species from 77 genera are reported. According to the IUCN European Red List of Hoverflies, 29 species are classified as Endangered, 9 as Vulnerable, 19 as Near Threatened, 302 as Least Concern and 3 as Data Deficient. The distribution of species per region in Slovenia is presented. With 243 species, Upper Carniola hosts the largest number of registered species, followed by Central Slovenia (233 spp.), Gorizia (230 spp.), Savinja and Littoral Inner-Carniola (both with 173 spp.), Coastal-Karst (133 spp.), Southeast Slovenia (71 spp.), Drava (60 spp.), Carinthia (56 spp.), Lower Sava (52 spp.), Mura (47 spp.) and Central Sava (8 spp.). A significant increase in the number of new records has been noted in recent decades, and the possible reasons for this trend are also discussed here.

Recent fire in a Mediterranean ecosystem strengthens hoverfly populations and their interaction networks with plants

Fire affects many critical ecological processes, including pollination, and effects of climate change on fire regimes may have profound consequences that are difficult to predict. Considerable work has examined effects of fire on pollinator diversity, but relatively few studies have examined these effects on interaction networks including those of pollinators other than bees. We examined the effects of a severe wildfire on hoverfly pollinators in a Mediterranean island system. Using data collected over 3 consecutive years at burnt and unburnt sites, we documented differences in species diversity, abundance, and functional traits, as well as hoverfly interactions with flowering plants. Hoverfly abundance and species richness peaked during the first post-fire flowering season (year 1), which coincided with the presence of many opportunistic species. Also in year 1, hoverfly pollination networks were larger, less specialized, more nested, and less modular at burnt (vs. unburnt) sites; furthermore, these networks exhibited higher phylogenetic host-plant diversity. These effects declined over the next 2 years, with burnt and unburnt sites converging in similarity to hoverfly communities and interaction networks. While data obtained over 3 years provide a clear timeline of initial post-fire recovery, we emphasize the importance of longer-term monitoring for understanding the responses of natural communities to wildfires, which are projected to become more frequent and more destructive in the future.

Integrative taxonomy of the Merodon aberrans (Diptera, Syrphidae) species group: distribution patterns and description of three new species

In this paper, we revise the Merodon aberrans species group of the genus Merodon Meigen, 1803 (Diptera: Syrphidae), providing morphological diagnoses and descriptions, molecular data for three species, as well as an illustrated key and a discussion of the different taxonomic characters used. We also discuss distribution patterns for this species group. The results revealed that the M. aberrans group is composed of five described species (M. aberrans Egger, 1860, M. brevis Paramonov, 1926, M. flavitibius Paramonov, 1926, M. hamifer Sack, 1913, and M. warnckei Hurkmans, 1993) and three new ones, namely M. hermonensis Vujić, Radenković et Likov sp. nov., M. petiolatus Vujić, Radenković et Rojo sp. nov., and M. retectus Vujić, Radenković et Likov sp. nov. Following a detailed study of the type material in different entomological collections, the status of several species is revised, one new synonym is proposed (subspecies M. aberrans isperensis Hurkmans, 1993 as junior synonym of M. flavitibius), lectotypes are designated for M. kneri Mik, 1867 and M. flavitibius, and paralectotypes are designated for M. hamifer and M. flavitibius. Seven out of eight species from the M. aberrans group are distributed in the Asian continent, namely all Caucasian countries, Turkey and Iran, confirming the notion about high diversity of Merodon species in these regions, but also highlighting the need for a systematic faunistic research.

Characterization of preimaginal developmental stages of two cryptic South African species of the Merodon planifacies complex (Diptera: Syrphidae: Eristalinae: Merodontini), with differentiation through morphometry analysis

Merodon capi Vujić et Radenković, 2020 and Merodon roni Radenković et Vujić, 2020 are two cryptic species belonging to the Merodon planifacies Bezzi, 1915 species complex that have recently been described, with the differences between them being revealed by molecular and geometric morphometry studies of adult specimens. In the present study, the preimaginal morphology of both species is described and displayed, with the material used corresponding to samples taken from bulbs of Merwilla plumbea (Lindl.) Speta plants at two locations in KwaZulu-Natal province (South Africa). The preimaginal stages were compared, looking for morphological evidence supporting species divergence. Linear and geometric morphometric analyses of the larval posterior respiratory process were conducted for the first time and the results of these analyses support the separation of the two taxa. Information about the life cycle and the relation with the host plant is also provided. In addition, we carried out a preliminary study of the adult feeding requirements of the species, based on the description of the mouthparts and an analysis of the pollen present in the gut and on the integument of adults. The results of the study supports a close relationship between the preimaginal stages and plant species of the Hyacinthaceae family.

Contribution to the knowledge of the bee fauna (Hymenoptera, Apoidea, Anthophila) in Serbia

The current work represents summarised data on the bee fauna in Serbia from previous publications, collections, and field data in the period from 1890 to 2020. A total of 706 species from all six of the globally widespread bee families is recorded; of the total number of recorded species, 314 have been confirmed by determination, while 392 species are from published data. Fourteen species, collected in the last three years, are the first published records of these taxa from Serbia: Andrenabarbareae (Panzer, 1805), A.clarkella (Kirby, 1802), A.fulvicornis (Schenck, 1853), A.intermedia (Thomson, 1870), A.lapponica (Zetterstedt, 1838), A.pandellei (Pérez, 1895), A.paucisquama (Noskiewicz, 1924), A.simillima (Smith, 1851), Panurginusherzi (Morawitz, 1892), Epeoloidescoecutiens (Fabricius, 1775), Nomadaleucophthalma (Kirby, 1802), Chelostomanasutum (Pérez, 1895), Hoplitisclaviventris (Thomson, 1872), and Dasypodapyrotrichia (Förster, 1855). Almost all the species recorded so far in Serbia belong to the West-Palaearctic biogeographical region, except Megachilesculpturalis (Smith, 1853), which is an alien invasive species native to East Asia. According to the European Red List of bees, 221 species listed in this paper were assessed as Data Deficient; threatened species mostly belong to the families Apidae with 13 species, Colletidae with eight species, and Halictidae with five species. This study contributes to the knowledge of the distribution of bee species in Europe. The present work provides a baseline for future research of wild bee diversity in Serbia and neighbouring regions at the local and regional levels, and a basis for their conservation.

Taxonomic complexity in the genus Merodon Meigen, 1803 (Diptera, Syrphidae)

The genus Merodon Meigen, 1803 is distributed across the Palaearctic and Afrotropical Regions. The present work summarizes the knowledge from recent taxonomic and systematic revisions and includes an identification key for the five monophyletic lineages (namely albifrons, aureus, avidus-nigritarsis, desuturinus and natans), 24 species groups, two species subgroups and 10 unplaced species, along with diagnosis and illustrations. A list of 234 taxa, including 194 described and 40 undescribed species, is appended. Most of the species are distributed in the Palaearctic (209 taxa, 181 described), while 27 species (14 described) are known from the Afrotropical Region. Three lineages (aureus, desuturinus and natans) are present in the Afrotropical Region, as well as in the Palaearctic. The Afrotropical melanocerus species group of the desuturinus lineage and the bombiformis species group of the aureus lineage are endemic to the Afrotropical Region, and all other species groups belong to the Palaearctic fauna. The albifrons lineage contains six species groups (albifrons, constans, equestris, geniculatus, ruficornis and rufus) and two unplaced taxa. The aureus lineage includes five species groups (aureus, bombiformis, funestus, nanus and spinitarsis). The avidus-nigritarsis lineage is divided into 10 species groups (aberrans, aurifer, avidus, clavipes, fulcratus, italicus, nigritarsis, pruni, serrulatus and tarsatus) and eight unplaced taxa. The desuturinus lineage contains two species groups: the Afrotropical melanocerus group, with the melanocerus and planifacies subgroups plus the species M. cuthbertsoni Curran, 1939, and the Palaearctic murorum species group. The natans lineage consists of the natans species group plus the species M. segetum Fabricius, 1794.

Hide-and-seek with hoverflies: Merodon aureus – a species, a complex or a subgroup?

In order to disentangle the currently confused interpretations and nomenclature of Merodon aureus and M. aeneus, we have reviewed all existing type material and species names known to us as assigned synonyms of these taxa. We resolve M. aeneus as being a junior synonym of M. aureus. We designate a lectotype for M. aureus and a neotype for M. aeneus. Additionally, we provide evidence that M. aureus, together with two newly discovered taxa (M. calidus sp. nov. and M. ortus sp. nov.), represent a complex of cryptic species named the M. aureus species complex. This complex, together with the M. unicolor species complex and the species M. pumilus, is part of the M. aureus subgroup. The M. unicolor species complex comprises two cryptic species: M. unicolor and M. albidus sp. nov. The new species are described by applying an integrative taxonomic approach using several data types (COI and 28S rRNA genes, geometric morphometry of the wings, ecological and distributional data). Based on the COI gene sequence analysis and distributional data, the pupa previously described as an immature stage of the species M. aureus is redefined as an immature stage of the new species M. calidus. Speciation within the M. aureus subgroup is discussed in the context of the phylogeographic history in the studied region.

Revision of the Merodon serrulatus group (Diptera, Syrphidae)

The phytophagous hoverfly genus Merodon Meigen, 1803 (Diptera, Syrphidae), which comprises more than 160 species distributed in Palaearctic and Afrotropical regions, can be differentiated into multiple groups of species that harbor high levels of hidden diversity. In this work, the serrulatus species group of Merodon is revised, providing an illustrated key to species, a detailed discussion on the taxonomic characters and a morphological diagnosis, including also the first data about the preimaginal morphology of this species group. The study includes characteristics of the 13 species of the M. serrulatus group, along with the available distributional data. Moreover, descriptions are provided for seven new species, namely M. defectus Vujić, Likov & Radenković sp. nov., M. disjunctus Vujić, Likov & Radenković sp. nov., M. medium Vujić, Likov & Radenković sp. nov., M. nigrocapillatus Vujić, Likov & Radenković sp. nov., M. nigropunctum Vujić, Likov & Radenković sp. nov., M. opacus Vujić, Likov & Radenković sp. nov., and M. trianguloculus Vujić, Likov & Radenković sp. nov. In addition, the taxa M. serrulatus (Wiedemann in Meigen, 1822), M. bequaerti Hurkmans, 1993, M. hirsutus Sack, 1913, M. kawamurae Matsumura, 1916, M. sacki (Paramonov, 1936) and M. sophron Hurkmans, 1993 are redefined and redescribed. Following a detailed study of the type material sourced from different entomological collections, the status of all available taxa related to M. serrulatus is revised and a new synonymy is proposed: M. tener Sack, 1913 syn. nov. (junior synonym of M. serrulatus). The identity of M. trizonus (Szilády, 1940) could not be assessed as the type specimens are lost. Thus, the name M. trizonus is considered as nomen dubium. The monophyly and composition of this species group are assessed through Maximum Parsimony and Maximum Likelihood analyses of the mitochondrial COI and nuclear 28S rRNA gene sequences.

Conflict and congruence between morphological and molecular data: revision of the Merodon constans group (Diptera : Syrphidae)

We revise the Merodon constans species group of the genus Merodon Meigen, 1803 (Diptera: Syrphidae), provide morphological diagnosesand descriptions, as well as an illustrated key and a discussion on the different taxonomic characters used. In total, 15 species were studied, their geographic distributions are presented on maps, and nine new species are described. Two species are redefined and neotypes are designated, lectotypes are designated for five species, and onespeciesis reinstated as valid. Following a detailed study of type material in different entomological collections, the status of several species is revised and three new synonymies are proposed. The M. constans species group was resolved as being monophyletic within the M. albifrons lineage based on molecular analyses using COI and 28S rRNA gene sequences. Three species morphologically similar to M. constans (Rossi, 1794) but occurring outside its distributional rangewere supported as being valid and distinct species on the basis of molecular data, but they were not distinguishable based on morphological characters. By contrast, continental populations of M. analis Meigen, 1822 could not be separated from Mediterranean M. constans based on differences in COI or 28S rRNA genes. The same molecular markers could not discriminate between two other species pairs. We conclude that these molecular markers only partially resolve species within the M. constans group. Geometric morphometry of wing shape successfully separated M. analis and M. constans, as well as M. spineus Vujić, Šašić Zorić & Likov, sp. nov. in both species and population analyses.

Systematic position and composition of Merodon nigritarsis and M. avidus groups (Diptera, Syrphidae) with a description of four new hoverflies species

The putative monophyly and systematic position of Merodon nigritarsis group was assessed based on morphological and molecular data of the mitochondrial COI and nuclear 28S rRNA genes. The previously reported concept of the group has been redefined, and M. crassifemoris Paramonov, 1925 is now excluded. The related M. avidus group is redefined here, including the Merodon avidus complex and M. femoratus Sack, 1913. Species delimitation of morphologically defined species of M. nigritarsis group was well supported by COI gene analysis, with the exception of M. alagoezicus Paramonov, 1925 and M. lucasi Hurkmans, 1993. Descriptions are given for three new species of the M. nigritarsis species group: Merodon cohurnus Vujić, Likov et Radenković sp. n., Merodon longisetus Vujić, Radenković et Likov sp. n. and Merodon obstipus Vujić, Radenković et Likov sp. n., and one new species from the M. avidus group: Merodon rutitarsis Likov, Vujić et Radenković sp. n. A lectotype is designated for M. femoratus Sack, 1913, and two new synonymies of this species were proposed: M. biarcuatus Curran, 1939 and M. elegans Hurkmans, 1993. Here we review 18 species from the M. nigritarsis group and six species from the M. avidus group and provide morphological diagnoses of the species groups. Additionally, diagnosis of 12 branches (groups or individual taxa) of M. avidus-nigritarsis lineage, an illustrated diagnostic key for the males, and distribution map are provided for the new species.

Stability and changes in the distribution of Pipiza hoverflies (Diptera, Syrphidae) in Europe under projected future climate conditions

Climate change is now considered a significant threat to terrestrial biodiversity. Species distribution models (SDMs) are among the modern tools currently used to assess the potential impacts of climate change on species. Pipiza Fallén, 1810 is a well known aphidophagous hoverfly genus (Diptera, Syrphidae) at the European level, for which sampling has been conducted across the region, and long-term databases and geo-referenced datasets have been established. Therefore, in this work, we investigated the potential current distributions of the European species of this genus and their response to future climate change scenarios, as well as evaluated stability in their ranges and potential changes in species-richness patterns. We applied three climate models (BCC_CSM1.1, CCSM4, HadGEM2-ES) to four representative concentration pathways (RCP 2.6, RCP 4.5, RCP 6.0, RCP 8.5) for two time frames (2050 and 2070). Our results show that the distribution of most Pipiza species may slightly differ under different climate models. Most Pipiza species were predicted not to be greatly affected by climate change, maintaining their current extent. Percentages of stable areas will remain high (above 50%) for the majority of studied species. According to the predicted turnover of species, northern Europe, could become the richest in terms of species diversity, thus replacing Central Europe as the current hot spot.

Two new European long-legged hoverfly species of the Eumerusbinominatus species subgroup (Diptera, Syrphidae)

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.

Disentangling a cryptic species complex and defining new species within the Eumerus minotaurus group (Diptera: Syrphidae), based on integrative taxonomy and Aegean palaeogeography

This study provides an overview of the Eumerus minotaurus taxon group, diagnosing a new species, E. anatolicus Grković, Vujić and Radenković sp. n. (Muğla, Turkey), and unraveling three cryptic species within E. minotaurus: E. karyates Chroni, Grković and Vujić sp. n. (Peloponnese, Greece), E. minotaurus Claussen and Lucas, 1988 (Crete and Karpathos, Greece) and E. phaeacus Chroni, Grković and Vujić sp. n. (Corfu and Mt Olympus, Greece; Mt Rumija, Montenegro). We applied an integrative taxonomic approach based on molecular, morphological and wing geometric morphometric data to corroborate and delimit cryptic species within the complex. In addition, we discuss the latent biogeographic patterns and speciation processes leading to configuration of the E. minotaurus group based on palaeogeographic evolution of the Aegean. Mitochondrial phylogeographic analysis suggested that speciation within the E. minotaurus group is attributable to formation of the mid-Aegean Trench and Messinian Salinity Crisis, and was integrated at the Pleistocene. We show that more accurate estimates of divergence times may be based on geological events rather than the standard arthropod mtDNA substitution rate.

Close relatives of Mediterranean endemo-relict hoverflies (Diptera, Syrphidae) in South Africa: Morphological and molecular evidence in the Merodon melanocerus subgroup

An ongoing study of the genus Merodon Meigen, 1803 in the Republic of South Africa (RSA) has revealed the existence of new species related to M. melanocerus Bezzi, 1915. The M. melanocerus subgroup belongs to the Afrotropical lineage of the M. desuturinus group. Revision of all available material from museums and detailed analyses of newly -collected specimens from our own expeditions to RSA resulted in delimitation of five species: M. capensis Hurkmans sp. n., M. commutabilis Radenković et Vujić sp. n., M. drakonis Vujić et Radenković sp. n., M. flavocerus Hurkmans sp. n. and M. melanocerus. In addition to classical morphological characters, sequences of the mitochondrial COI gene are provided for four related taxa. Results of molecular phylogenetic analyses supports monophyly of the M. desuturinus group and confirmed delimitation between species. Links between Palaearctic and Afrotropical faunas of this group, as well as possible evolutionary paths, are discussed. Based on phylogenetic analyses, four lineages (putative subgenera) have been recognized within the genus Merodon; besides the three previously established ones, albifrons+desuturinus, aureus (sensu lato) and avidus-nigritarsis, one new lineage named natans is distinguished.

Revision of the Palaearctic species of the Merodon desuturinus group (Diptera, Syrphidae)

This revision of material belonging to the Merodondesuturinus group from the Palaearctic Region resulted in the delimitation of four species: Merodoncabanerensis Marcos-García, Vujić & Mengual, 2007; Merodondesuturinus Vujić, Šimić & Radenković, 1995; Merodonneolydicus Vujić, nom. n.; and Merodonmurorum Fabricius, 1794. Merodonmurorum is redescribed. A neotype for Merodonauripilus Meigen, 1830 is designated, which is a new junior synonym of Merodonmurorum. The related Afrotropical species Merodoncuthbertsoni Curran, 1939 is re-evaluated and compared to its sibling Palaearctic taxon Merodondesuturinus. An identification key for the Merodondesuturinus group is provided.

Three new Eastern-Mediterranean endemic species of the <i>Merodon</i> <i>aureus</i> group (Diptera: Syrphidae)

The Merodon aureus group (Diptera: Syrphidae: Eristalinae) comprises a number of different subgroups and species complexes, including the M. bessarabicus subgroup, which is revised here. In this study, we present an identification key to species complexes and species within the M. bessarabicus subgroup and focus on clarifying the taxonomic status of previously described species within this subgroup, based on a study of the type material. Merodon flavicornis Macquart, a species with an unknown type locality, is re-evaluated and recognized as a valid Western Mediterranean species from France. We describe a new species, M. adriaticus sp. n., from M. bessarabicus subgroup, as well as another two species with a clearly separate position within the M. aureus group due to their distinct morphological features: M. nisi sp. n. and M. robustus sp. n.. Results of the present study indicate the high diversity and endemism levels of the genus Merodon in Europe.

Molecular species delimitation in the genus Eumerus (Diptera: Syrphidae)

Eumerus is one of the most diverse genera of hoverfly worldwide. Species delimitation within genus is considered to be difficult due to: (a) lack of an efficient key; (b) non-defined taxonomical status of a large number of species; and (c) blurred nomenclature. Here, we present the first molecular study to delimit species of the genus by using a fragment of the mitochondrial cytochrome-c oxidase subunit I gene (COI) gene. We assessed 75 specimens assigned to 28 taxa originating from two biogeographic zones: 22 from the western Palaearctic and six from the Afrotropical region. Two datasets were generated based on different sequence lengths to explore the significance of availability of more polymorphic sites for species delimitation; dataset A with a total length of 647 bp and dataset B with 746 bp. Various tree inference approaches and Poisson tree processes models were applied to evaluate the putative 'taxonomical' vs. 'molecular' taxa clusters. All analyses resulted in high taxonomic resolution and clear species delimitation for both the dataset lengths. Furthermore, we revealed a high number of mitochondrial haplotypes and high intraspecific variability. We report two major monophyletic clades, and seven 'molecular' groups of taxa formed, which are congruent with morphology-based taxonomy. Our results support the use of the mitochondrial COI gene in species diagnosis of Eumerus.

Ecological networks are more sensitive to plant than to animal extinction under climate change

Impacts of climate change on individual species are increasingly well documented, but we lack understanding of how these effects propagate through ecological communities. Here we combine species distribution models with ecological network analyses to test potential impacts of climate change on >700 plant and animal species in pollination and seed-dispersal networks from central Europe. We discover that animal species that interact with a low diversity of plant species have narrow climatic niches and are most vulnerable to climate change. In contrast, biotic specialization of plants is not related to climatic niche breadth and vulnerability. A simulation model incorporating different scenarios of species coextinction and capacities for partner switches shows that projected plant extinctions under climate change are more likely to trigger animal coextinctions than vice versa. This result demonstrates that impacts of climate change on biodiversity can be amplified via extinction cascades from plants to animals in ecological networks.

Revision of the West-Palaearctic species of the tribe Cerioidini (Diptera, Syrphidae)

The West-Palaearctic cerioidines (Syrphidae: Cerioidini) are revised, including species of the genera Ceriana Rafinesque, Primocerioides Shannon, and Sphiximorpha Rondani. Three new species are described, Ceriana glaebosa van Steenis & Ricarte sp. n. (Cyprus), Ceriana media van Steenis & Ricarte sp. n. (Afghanistan and Iran) and Ceriana skevingtoni van Steenis & Ricarte sp. n. (Armenia, Azerbaijan and Iran). The following names are proposed as junior synonyms: Cerioides caucasicus Paramonov, 1927 [= Ceriana conopsoides (Linnaeus, 1758)], Ceria binominata Verrall, 1901 [= Sphiximorpha garibaldii (Rondani, 1860)], Ceriana worelli, Brădescu, 1972b [= Sphiximorpha garibaldii (Rondani, 1860)] and Sphiximorpha hiemalis Ricarte, Nedeljković & Hancock, 2012 [= Primocerioides regale Violovitsh, 1985]. Identification keys, biological data and distribution maps for the studied taxa are provided. Conops vaginicornis Schrank, 1803 is discarded as a synonym of Ceriana conopsoides and should be considered as nomen dubium.

Bee (Hymenoptera: Apoidea) and hoverfly (Diptera: Syrphidae) pollinators in Pannonian habitats of Serbia, with a description of a new Eumerus Meigen species (Syrphidae)

The diversity of bee (Hymenoptera: Apoidea) and hoverfly (Diptera: Syrphidae) pollinators from ten localities in Vojvodina, Serbia was surveyed. Among different types of Pannonian habitat (grasslands, heathland and scrub, woodland and forest habitats) all localities were categorised as forest and steppe. They were in protected areas, mostly undisturbed by human activity. Censuses of pollinators took place from 30 March to 10 October, 2014. We recorded 218 pollinator species; 135 bee species (42 Halictidae; 32 Apidae; 29 Andrenidae; 24 Megachilidae; 7 Colletidae; 1 Melittidae) and 83 species of hoverflies. We describe a new species of hoverfly, Eumerus pannonicus sp. nov., and compare it to other similar species. Based on our study, the Special Nature Reserve of Pašnjaci Velike Droplje is critical for the conservation of this new Eumerus-being only found at this locality-and other species such as Chrysotoxum lineare (Zetterstedt), which is rare in Europe and protected under Serbian legislation. The highest numbers of bee species were recorded in the Deliblato and Subotica sand areas (40 and 32, respectively), while Fruška Gora Mountain and the Vršac Mountains harboured the highest number of hoverfly species.

Molecular and Morphological Inference of Three Cryptic Species within the Merodon aureus Species Group (Diptera: Syrphidae)

The Merodon aureus species group (Diptera: Syrphidae: Eristalinae) comprises a number of different sub-groups and species complexes. In this study we focus on resolving the taxonomic status of the entity previously identified as M. cinereus B, here identified as M. atratus species complex. We used an integrative approach based on morphological descriptions, combined with supporting characters that were obtained from molecular analyses of the mitochondrial cytochrome c oxidase I gene as well as from geometric morphometry of wing and surstylus shapes and environmental niche comparisons. All applied data and methods distinguished and supported three morphologically cryptic species: M. atratus stat. nov., M. virgatus sp. nov. and M. balkanicus sp. nov., which constitute the M. atratus species complex. We present an identification key for the sub-groups and species complexes of the M. aureus species group occurring in Europe, describe the taxa and discuss the utility of the applied methods for species delimitation. The estimated divergence times for the species splits of these taxa coincide with the Pleistocene Günz-Mindel interglaciation and the Great interglaciation (between the Ris and Mindel glacial periods).

Mass-flowering crops dilute pollinator abundance in agricultural landscapes across Europe

Mass-flowering crops (MFCs) are increasingly cultivated and might influence pollinator communities in MFC fields and nearby semi-natural habitats (SNHs). Across six European regions and 2 years, we assessed how landscape-scale cover of MFCs affected pollinator densities in 408 MFC fields and adjacent SNHs. In MFC fields, densities of bumblebees, solitary bees, managed honeybees and hoverflies were negatively related to the cover of MFCs in the landscape. In SNHs, densities of bumblebees declined with increasing cover of MFCs but densities of honeybees increased. The densities of all pollinators were generally unrelated to the cover of SNHs in the landscape. Although MFC fields apparently attracted pollinators from SNHs, in landscapes with large areas of MFCs they became diluted. The resulting lower densities might negatively affect yields of pollinator-dependent crops and the reproductive success of wild plants. An expansion of MFCs needs to be accompanied by pollinator-supporting practices in agricultural landscapes.

Phylogeographic patterns of Merodon hoverflies in the Eastern Mediterranean region: revealing connections and barriers

We investigated the phylogeographic patterns of Merodon species (Diptera, Syrphidae) in the Eastern Mediterranean. Ten species were sampled on five different islands and mainland sites as a minimum. All samples were screened for their mtDNA COI barcode haplotype diversity, and for some samples, we additionally generated genomic fingerprints. The recently established zoogeographic distribution categories classify these species as having (1) Balkan distribution; (2) Anatolian distribution; (3) continental areas and large islands distribution; and (4) with wide distribution. The ancestral haplotypes and their geographical localities were estimated with statistical parsimony (TCS). TCS networks identified as the ancestral haplotype samples that originated from localities situated within the distributional category of the species in question. Strong geographical haplotype structuring was detected for many Merodon species. We were particularly interested to test the relative importance of current (Aegean Sea) and past Mid-Aegean Trench) barriers to dispersal for Merodon flies in the Aegean. We employed phylogenetic β-diversity (Pβ total) and its partition in replacement (Pβ repl) and richness difference (Pβ rich) to test the importance of each explanatory variable (interisland distance, MAT, and island area) in interisland differences using partial Mantel tests and hierarchical partitioning of variation. β-Analyses confirmed the importance of both current and past barriers to dispersal on the evolution of group. Current interisland distance was particularly important to explain the replacement of haplotypes, while the MAT was driving differences in richness of haplotypes, revealing the MAT as a strong past barrier whose effects are still visible today in the phylogenetic history of the clade in the Aegean. These results support the hypothesis of a highly restricted dispersal and gene flow among Merodon populations between islands since late Pleistocene. Additionally, patterns of phylogeographic structure deduced from haplotype connections and ISSR genome fingerprinting data revealed a few putative cases of human-mediated transfers of Merodon spp.

Brachyopa minima (Diptera: Syrphidae), a new species from Greece with notes on the biodiversity and conservation of the genus Brachyopa Meigen in the Northern Aegean Islands

An on-going study of the hoverfly fauna of the Northern Aegean Islands (Greece) has revealed the presence of four species of the genus Brachyopa Meigen. During the survey the following species were found: B. bicolor (Fallén), B. quadrimaculosa Thompson in Kaplan & Thompson, B. minima Vujić & Pérez-Bañón sp. nov. and an unidentified species very close to B. pilosa (Collin). Morphological characters and mitochondrial COI barcodes were used to link different life stages of B. minima, and to identify a larval specimen of B. bicolor. In this study adult and larval morphology and habitat preferences for B. minima are described. The description of larval morphology of B. bicolor and Brachyopa sp. aff. pilosa is amended too. An identification key to the adults of the B. quadrimaculosa group sensu Kassebeer (2002) in the Eastern Mediterranean (Greece, Israel and Turkey) is provided. The importance of specific microhabitats for the continued existence of these taxa is discussed.

An integrated approach to delimiting species borders in the genus Chrysotoxum Meigen, 1803 (Diptera: Syrphidae), with description of two new species

Integrative taxonomy tests the validity of taxa using methods additional to traditional morphology. The existence of two different morphotypes in specimens identified as Chrysotoxum vernale Loew (Diptera: Syrphidae) prompted their taxonomic study using an integrative approach that included morphology, wing and male-surstylus geometric morphometrics, genetic and ecological analyses. As a result, a new species is recognised, Chrysotoxum montanum Nedeljković & Vujić sp. nov., and C. vernale is re-defined. A lectotype and paralectotypes are designated for C. vernale to stabilize this concept. An additional species, Chrysotoxum orthostylum Vujić sp. nov., with distinctive male genitalia is also described. The three species share an antenna with the basoflagellomere shorter than the scape plus pedicel and terga with yellow fasciae not reaching the lateral margins. This study confirms the value of integrative approach for resolving species boundaries.

Revision of the species of the Merodon nanus group (Diptera: Syrphidae) including three new species

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.

Three new species of the Merodon nigritarsis group (Diptera: Syrphidae) from the Middle East

Descriptions are given of three new species of Merodon Meigen (Diptera: Syrphidae) in the nigritarsis species group from the Middle East: Merodon angustus Vujić et Radenković n. sp., Merodon hakkariensis Vujić et Radenković n. sp. and Merodon quadraticus Vujić et Radenković n. sp. In addition, diagnostic characters are given for the nigritarsis group and distribution maps are presented for the new species and closely related taxa.

Key for European species of the Cheilosia proxima group (Diptera, Syrphidae) with a description of a new species

A new hoverfly species, Cheilosia barbafacies Vujić & Radenković sp. n. (Diptera, Syrphidae), is described and distinguished from the closely related species Cheilosia pascuorum Becker, 1894, based on material collected from the mountains of the Balkan Peninsula. Diagnostic characteristics and an identification key for the members of the proxima group of Cheilosia s. str., including the new taxon, are provided.

Wing geometric morphometric inferences on species delimitation and intraspecific divergent units in the Merodon ruficornis group (Diptera, Syrphidae) from the Balkan Peninsula

A study of the Merodon taxa on the Balkan Peninsula, a region with a number of Pleistocene refugia, provides a useful framework for examining evolutionary processes and detecting hidden biodiversity. The phenotypic diversity of 22 samples of the Merodon ruficornis group on the Balkan Peninsula was examined using landmark-based geometric morphometrics. The boundaries of the species M. ruficornis, M. trebevicensis, M. auripes, M. armipes, and M. Ioewi were well defined based on wing shape and size. Canonical variate analysis showed that wing shape possessed sufficient differences to discriminate the species with a successful classification rate of 75-92% for males and 82-100% for females. The observed interspecific differentiation is generally in agreement with a previous study of the M. ruficornis group using a traditional morphological approach and molecular markers (allozyme loci, COI mtDNA). The spatial variability between conspecific populations and interpopulation variation were assessed based on both wing shape and size for male specimens. Phenotypically divergent units were delineated within previously defined species of the M. ruficornis group, indicating the possible presence of evolutionary independent units within the taxa analysed.

Identification of the species of the Cheilosia variabilis group (Diptera, Syrphidae) from the Balkan Peninsula using wing geometric morphometrics, with the revision of status of C. melanopa redi Vujić, 1996

The present study investigates phenotypic differentiation patterns among four species of the Cheilosia variabilis group (Diptera, Syrphidae) using a landmark-based geometric morphometric approach. Herein, wing geometric morphometrics established species boundaries that confirm C. melanopa and C. redi stat. nov. as evolutionarily independent entities or separate species within the previously described C. melanopa species. Seventeen samples of C. lasiopa, C. variabilis, C. melanopa and C. redi from 11 localities on the Balkan Peninsula were analysed. Based on wing shape and size, both species boundaries and intraspecific divergent units were delineated indicating the possible presence of evolutionarily independent units within the analysed taxa. Significant differences in wing size were obtained among the analysed species and canonical variate analysis showed that wing shape was sufficiently different to allow the correct classification of 99.7% and 100% individuals of males and females, respectively. Considerable wing size variation was detected among males and females of conspecific populations of C. melanopa and males of C. variabilis. Contrary to partial discrimination based on the male wing shape among conspecific populations of C. redi and C. variabilis, clear separation of conspecific populations of C. melanopa (for both sexes) and females of C. redi and C. variabilis was observed. The UPGMA cluster analysis based on squared Mahalanobis distances revealed a close similarity between C. melanopa and C. redi, whereas C. lasiopa was the most divergent species. Results presented in this study utilize wing shape and size as new taxonomic characters in delimitating the closely related species and populations of the Cheilosia variabilis group.