Pelecocera (Pelecocera) tricincta and Pelecocera (Chamaesyrphus) caledonica (Diptera, Syrphidae) reared from Rhizopogon fungal host in Finland

MtDNA COI barcodes have frequently been used in identification to associate an unknown life stage in insects with a known species. This study reports the discovery of hoverfly larvae in the fungal fruit bodies of Rhizopogonluteolus Fr. & Nordholm, 1817 in Finland. The identity of the larvae was firstly resolved using mtDNA COI barcodes generated from the larvae and tree-based identification confirming the species Pelecocera (Pelecocera) tricincta Meigen, 1822 and Pelecocera (Chamaesyrphus) caledonica (Collin, 1940) (Diptera, Syrphidae). Obtained pupae were reared into adult flies and produced the same two species. The morphological features of these mycophagous larvae are compared with those of other fungus-feeding hoverfly species. This study confirms Rhizopogonluteolus as fungal host for these Pelecocera species in the Western Palaearctic Region.

A molecular-based identification resource for the arthropods of Finland

To associate specimens identified by molecular characters to other biological knowledge, we need reference sequences annotated by Linnaean taxonomy. In this study, we (1) report the creation of a comprehensive reference library of DNA barcodes for the arthropods of an entire country (Finland), (2) publish this library, and (3) deliver a new identification tool for insects and spiders, as based on this resource. The reference library contains mtDNA COI barcodes for 11,275 (43%) of 26,437 arthropod species known from Finland, including 10,811 (45%) of 23,956 insect species. To quantify the improvement in identification accuracy enabled by the current reference library, we ran 1000 Finnish insect and spider species through the Barcode of Life Data system (BOLD) identification engine. Of these, 91% were correctly assigned to a unique species when compared to the new reference library alone, 85% were correctly identified when compared to BOLD with the new material included, and 75% with the new material excluded. To capitalize on this resource, we used the new reference material to train a probabilistic taxonomic assignment tool, FinPROTAX, scoring high success. For the full-length barcode region, the accuracy of taxonomic assignments at the level of classes, orders, families, subfamilies, tribes, genera, and species reached 99.9%, 99.9%, 99.8%, 99.7%, 99.4%, 96.8%, and 88.5%, respectively. The FinBOL arthropod reference library and FinPROTAX are available through the Finnish Biodiversity Information Facility (www.laji.fi) at https://laji.fi/en/theme/protax. Overall, the FinBOL investment represents a massive capacity-transfer from the taxonomic community of Finland to all sectors of society.

Global population genetic structure and demographic trajectories of the black soldier fly, Hermetia illucens

Background

The black soldier fly (Hermetia illucens) is the most promising insect candidate for nutrient-recycling through bioconversion of organic waste into biomass, thereby improving sustainability of protein supplies for animal feed and facilitating transition to a circular economy. Contrary to conventional livestock, genetic resources of farmed insects remain poorly characterised. We present the first comprehensive population genetic characterisation of H. illucens. Based on 15 novel microsatellite markers, we genotyped and analysed 2862 individuals from 150 wild and captive populations originating from 57 countries on seven subcontinents.

Results

We identified 16 well-distinguished genetic clusters indicating substantial global population structure. The data revealed genetic hotspots in central South America and successive northwards range expansions within the indigenous ranges of the Americas. Colonisations and naturalisations of largely unique genetic profiles occurred on all non-native continents, either preceded by demographically independent founder events from various single sources or involving admixture scenarios. A decisive primarily admixed Polynesian bridgehead population serially colonised the entire Australasian region and its secondarily admixed descendants successively mediated invasions into Africa and Europe. Conversely, captive populations from several continents traced back to a single North American origin and exhibit considerably reduced genetic diversity, although some farmed strains carry distinct genetic signatures. We highlight genetic footprints characteristic of progressing domestication due to increasing socio-economic importance of H. illucens, and ongoing introgression between domesticated strains globally traded for large-scale farming and wild populations in some regions.

Conclusions

We document the dynamic population genetic history of a cosmopolitan dipteran of South American origin shaped by striking geographic patterns. These reflect both ancient dispersal routes, and stochastic and heterogeneous anthropogenic introductions during the last century leading to pronounced diversification of worldwide structure of H. illucens. Upon the recent advent of its agronomic commercialisation, however, current human-mediated translocations of the black soldier fly largely involve genetically highly uniform domesticated strains, which meanwhile threaten the genetic integrity of differentiated unique local resources through introgression. Our in-depth reconstruction of the contemporary and historical demographic trajectories of H. illucens emphasises benchmarking potential for applied future research on this emerging model of the prospering insect-livestock sector.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-021-01029-w.

A multigene phylogeny of the eristaline flower flies (Diptera: Syrphidae), with emphasis on the subtribe Criorhinina

We present the first multigene phylogeny focused on Eristalinae (Diptera: Syrphidae) utilizing a dataset containing 120 flower fly species from across all four subfamilies and representing 13 out of 16 tribes. Eight genes were used in the construction of the phylogeny: mitochondrial cytochrome c oxidase subunit I and the nuclear genes 28S ribosomal DNA, Alanylt RNA Synthetase, the carbamoyl phosphate synthase domain of CAD, Period, RNA-binding Protein 15 (RBP–15, 5’), Casein Kinase 1 and TULP for a total of ~6.7 kB of data. Eristalinae is recovered as paraphyletic with strong support for the elevation of Cerioidini, Merodontini and Volucellini to subfamilial status. Deineches, Flukea and Malometasternum render Criorhinina paraphyletic with respect to the type genus Criorhina. A clade with Criorhina, Matsumyia and Sphecomyia is strongly supported. The generic concept of Criorhina is paraphyletic, while Sphecomyia is monophyletic and Matsumyia is monophyletic but requires expansion. Evidence supports the resurrection of Romaleosyrphus and the creation of new genera. Criorhinina (stat. rev.) is restricted to contain Criorhina, Matsumyia, Romaleosyrphus and Sphecomyia. Thirteen changes to the higher classification of Syrphidae are proposed.

The Genomic Resources Collection Policy of the Finnish Museum of Natural History

The Genomic Resources Collection is a separate, independently managed part of the natural history collections of the Finnish Museum of Natural History Luomus specifically intended for consumptive research. The GRC policy deals with the materials that are archived for the very purpose of enabling the study of biological diversity at the genome level, DNA extractions of animal, fungal and plant specimens, and animal tissue samples stored deep-frozen for purposes of future DNA extraction. The GRC policy defines the purpose of the collections, the objectives and content of the procedures and activities related to them, the distribution of responsibilities for collection management and maintenance in Luomus, and the principles of collection accumulation, preservation and accessibility.

The aim of the GRC is to store and loan genomic samples for research purposes. In taxonomic coverage the collection overlaps with all the taxonomically delimited specimen collections managed by the Zoology and Botany Units, but is distinguished as being directed to preserve the genomic (DNA) information irrespective of the phenotypic variation that are the focus of specimen collections. The GRC includes both Finnish and foreign samples, all legally and ethically obtained, mostly linked to a specimen voucher in the taxonomic collections. The GRC samples are documented and trackable in Luomus collections management system. In accordance with the Universities Act, the GRC belongs to the national natural science collections of Luomus. For their part, the GRC collection implement the mission of Luomus, which is to be “responsible for the preservation, accumulation and exhibition of the national natural history collections and for research and education relating to them”.

The puzzling mitochondrial phylogeography of the black soldier fly (Hermetia illucens), the commercially most important insect protein species

BACKGROUND

The black soldier fly (Diptera: Stratiomyidae, Hermetia illucens) is renowned for its bioconversion ability of organic matter, and is the worldwide most widely used source of insect protein. Despite varying extensively in morphology, it is widely assumed that all black soldier flies belong to the same species, Hermetia illucens. We here screened about 600 field-collected and cultured flies from 39 countries and six biogeographic regions to test this assumption based on data for three genes (mitochondrial COI, nuclear ITS2 & 28S rDNA) and in order to gain insights into the phylogeography of the species.

RESULTS

Our study reveals a surprisingly high level of intraspecific genetic diversity for the mitochondrial barcoding gene COI (divergences up to 4.9%). This level of variability is often associated with the presence of multiple species, but tested nuclear markers (ITS2 and 28S rDNA) were invariant and fly strain hybridization experiments under laboratory conditions revealed reproductive compatibility. COI haplotype diversity is not only very high in all biogeographic regions (56 distinct haplotypes in total), but also in breeding facilities and research centers from six continents (10 haplotypes: divergences up to 4.3%). The high genetic diversity in fly-breeding facilities is mostly likely due to many independent acquisitions of cultures via sharing and/or establishing new colonies from field-collected flies. However, explaining some of the observed diversity in several biogeographic regions is difficult given that the origin of the species is considered to be New World (32 distinct haplotypes) and one would expect severely reduced genetic diversity in the putatively non-native populations in the remaining biogeographic regions. However, distinct, private haplotypes are known from the Australasian (N = 1), Oriental (N = 4), and the Eastern Palearctic (N = 4) populations. We reviewed museum specimen records and conclude that the evidence for introductions is strong for the Western Palearctic and Afrotropical regions which lack distinct, private haplotypes.

CONCLUSIONS

Based on the results of this paper, we urge the black soldier fly community to apply molecular characterization (genotyping) of the fly strains used in artificial fly-breeding and share these data in research publications as well as when sharing cultures. In addition, fast-evolving nuclear markers should be used to reconstruct the recent invasion history of the species.

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.

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.

Taxonomic review of the Palaearctic species of the Cheilosia caerulescens-group (Diptera, Syrphidae)

The Palaearctic species of the Cheilosia caerulescens group (Diptera: Syrphidae) are revised in this work. The species group belongs to the genus Cheilosia subgenus Taeniocheilosia Oldenberg. One new species is described from north Caucasus, Cheilosia (Taeniocheilosia) circassica sp. n.Cheilosia primulae Hering is established as a junior synonym of Cheilosia laeviventris Loew. Four lectotype designations are made. The species of the Cheilosia caerulescens group are redescribed and illustrated, and a table of diagnostic characters and an identification key to species are provided. MtDNA COI barcodes were generated for several specimens of C. (T.) caerulescens Meigen and other Cheilosia (Taeniocheilosia) and Cheilosia s. str. taxa. Parsimony and maximum likelihood analyses did not place the morphologically similar C. hercyniae Loew in the C. caerulescens group but among other Cheilosia (Taeniocheilosia) taxa. The following eight taxa are included in the Cheilosia (T.) caerulescens group of species: Cheilosia armeniaca Stackelberg, 1960, C. caerulescens caerulescens (Meigen, 1822), C. caerulescens calculosa Skufjin, 1977, C. circassica sp. n., C. herculana Brădescu, 1982, C. kerteszi Szilády, 1938, C. laeviventris Loew, 1857, and C. venosa Loew, 1857.

Rediscovery and reclassification of the dipteran taxon Nothomicrodon Wheeler, an exclusive endoparasitoid of gyne ant larvae

The myrmecophile larva of the dipteran taxon Nothomicrodon Wheeler is rediscovered, almost a century after its original description and unique report. The systematic position of this dipteran has remained enigmatic due to the absence of reared imagos to confirm indentity. We also failed to rear imagos, but we scrutinized entire nests of the Brazilian arboreal dolichoderine ant Azteca chartifex which, combined with morphological and molecular studies, enabled us to establish beyond doubt that Nothomicrodon belongs to the Phoridae (Insecta: Diptera), not the Syrphidae where it was first placed, and that the species we studied is an endoparasitoid of the larvae of A. chartifex, exclusively attacking sexual female (gyne) larvae. Northomicrodon parasitism can exert high fitness costs to a host colony. Our discovery adds one more case to the growing number of phorid taxa known to parasitize ant larvae and suggests that many others remain to be discovered. Our findings and literature review confirm that the Phoridae is the only taxon known that parasitizes both adults and the immature stages of different castes of ants, thus threatening ants on all fronts.

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).

Anchored enrichment dataset for true flies (order Diptera) reveals insights into the phylogeny of flower flies (family Syrphidae)

BACKGROUND

Anchored hybrid enrichment is a form of next-generation sequencing that uses oligonucleotide probes to target conserved regions of the genome flanked by less conserved regions in order to acquire data useful for phylogenetic inference from a broad range of taxa. Once a probe kit is developed, anchored hybrid enrichment is superior to traditional PCR-based Sanger sequencing in terms of both the amount of genomic data that can be recovered and effective cost. Due to their incredibly diverse nature, importance as pollinators, and historical instability with regard to subfamilial and tribal classification, Syrphidae (flower flies or hoverflies) are an ideal candidate for anchored hybrid enrichment-based phylogenetics, especially since recent molecular phylogenies of the syrphids using only a few markers have resulted in highly unresolved topologies. Over 6200 syrphids are currently known and uncovering their phylogeny will help us to understand how these species have diversified, providing insight into an array of ecological processes, from the development of adult mimicry, the origin of adult migration, to pollination patterns and the evolution of larval resource utilization.

RESULTS

We present the first use of anchored hybrid enrichment in insect phylogenetics on a dataset containing 30 flower fly species from across all four subfamilies and 11 tribes out of 15. To produce a phylogenetic hypothesis, 559 loci were sampled to produce a final dataset containing 217,702 sites. We recovered a well resolved topology with bootstrap support values that were almost universally >95 %. The subfamily Eristalinae is recovered as paraphyletic, with the strongest support for this hypothesis to date. The ant predators in the Microdontinae are sister to all other syrphids. Syrphinae and Pipizinae are monophyletic and sister to each other. Larval predation on soft-bodied hemipterans evolved only once in this family.

CONCLUSIONS

Anchored hybrid enrichment was successful in producing a robustly supported phylogenetic hypothesis for the syrphids. Subfamilial reconstruction is concordant with recent phylogenetic hypotheses, but with much higher support values. With the newly designed probe kit this analysis could be rapidly expanded with further sampling, opening the door to more comprehensive analyses targeting problem areas in syrphid phylogenetics and ecology.

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.

Descriptions of three new species of the genus Cheilosia Meigen from China (Diptera, Syrphidae)

Three species of genus Cheilosia (Diptera, Syrphidae: Eristalinae) from China are described as new to science, Cheilosia bullabucca Barkalov & Ståhls sp. n., C. lamproptera Barkalov & Ståhls sp. n. and C. yunnanensis Barkalov & Ståhls sp. n. We provide species descriptions and keys for their identification. The phylogenetic placements of the taxa was estimated based on their morphological characteristics and by analysing the taxa under parsimony using a mtDNA COI sequence dataset including a comprehensive set of Palaearctic previously generated Cheilosia spp. sequences representing all major subgenera. Based on both their morphological affinities and the molecular data. The Chinese taxa were placed in the subgenera Eucartosyrphus (C. bullabucca), Cheilosia s. str. (C. oblonga), Floccocheila (C. versicolor) while C. yunnanensis was not resolved as member of Cheilosia s. str. based on DNA despite sharing morphological characteristics with the subgenus. As the name Cheilosia (Nephocheila) prima Barkalov & Cheng from China is a junior homonym of Cheilosia (Cartosyrphus) prima Hunter, 1896 from the Nearctic region, for the Chinese species the new name Cheilosia (Nephocheila) primaria Barkalov & Ståhls nomen nov. is proposed.

Checklist of the families Opetiidae and Platypezidae (Diptera) of Finland

A checklist of the Opetiidae and Platypezidae (Diptera) recorded from Finland.

When mtDNA COI is misleading: congruent signal of ITS2 molecular marker and morphology for North European Melanostoma Schiner, 1860 (Diptera, Syrphidae)

The northern European taxa of genus Melanostoma Schiner, 1860 (Syrphidae, Diptera) are revised. A longstanding question concerning the number of Melanostoma taxa occurring in northern Europe prompted us to contrast and compare their morphological and molecular variability. Particular uncertainty concerned the putative existence of a sibling species of Melanostoma mellinum, and the identity of the taxon Melanostoma dubium in northern Europe due to existence of morphologically similar dark forms of M. mellinum in the northern parts of its distributional range. Partial sequences of two DNA markers, the mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI-3') and the nuclear second internal transcribed spacer (ITS2) were analysed separately under parsimony. The obtained COI-3'gene fragment showed taxon-specific haplotypes and haplotypes that were shared among the taxa. The ITS2 sequences presented genotypes unique to each species, and congruence with our independently established taxonomic entities. Based on congruent signal of the ITS2 sequences and study of morphological characters we establish the presence of four taxa in northern Europe: Melanostoma mellium (= M. dubium nec auctt., syn. n.), M. certum sp. n. (= M. dubium auctt.), M. mellarium stat. n. (= M. mellinum auctt. partim) and M. scalare. Lectotype designations were made for Musca mellina, Syrphus mellarius and Melanostoma mellinum var. melanatus.

THE FOLLOWING SYNONYMIES WERE ESTABLISHED

Melanostoma mellarium = Melanostoma melanatum syn. n.; Melanostoma mellinum = Scaeva dubia syn. n., Melanostoma tschernovi syn. n., and Melanostoma clausseni syn. n. Morphological circumscriptions of the taxa and an identification key are presented.

Shift in phenotypic variation coupled with rapid loss of genetic diversity in captive populations of Eristalis tenax (Diptera: Syrphidae): consequences for rearing and potential commercial use

Because of its importance as a pollinator and its potential economic usefulness for the biodegradation of organic animal waste, the genetic and phenotypic diversity of the drone fly, Eristalis tenax L. (Diptera: Syrphidae), was studied in both wild and captive populations from southeastern Europe. Wild specimens from a natural protected habitat (with low human impact), field crop habitat (semisynanthropic condition), and intensive pig farming habitat (synanthropic condition) were compared with a laboratory colony reared on artificial media An integrative approach was applied based on allozyme loci, cytochrome c oxidase I mitochondrial DNA, wing traits (size and shape), and abdominal color patterns. Our results indicate that the fourth and eighth generations of the laboratory colony show a severe lack of genetic diversity compared with natural populations. Reduced genetic diversity in subsequent generations (F4 and F8) of the laboratory colony was found to be linked with phenotypic divergence. Loss of genetic variability associated with phenotypic differentiation in laboratory samples suggests a founder effect, followed by stochastic genetic processes and inbreeding. Hence, our results have implications for captive bred Eristalis flies, which have been used in crop pollination and biodegradation of organic waste under synanthropic conditions.

DNA barcodes identify Central Asian Colias butterflies (Lepidoptera, Pieridae)

A majority of the known Colias species (Lepidoptera: Pieridae, Coliadinae) occur in the mountainous regions of Central-Asia, vast areas that are hard to access, rendering the knowledge of many species limited due to the lack of extensive sampling. Two gene regions, the mitochondrial COI ‘barcode’ region and the nuclear ribosomal protein RpS2 gene region were used for exploring the utility of these DNA markers for species identification. A comprehensive sampling of COI barcodes for Central Asian Colias butterflies showed that the barcodes facilitated identification of most of the included species. Phylogenetic reconstruction based on parsimony and Neighbour-Joining recovered most species as monophyletic entities. For the RpS2 gene region species-specific sequences were registered for some of the included Colias spp. Nevertheless, this gene region was not deemed useful as additional molecular ‘barcode’. A parsimony analysis of the combined COI and RpS2 data did not support the current subgeneric classification based on morphological characteristics.

Generic revision and species classification of the Microdontinae (Diptera, Syrphidae)

With 552 species group names available (excluding misspellings), the Microdontinae constitute the smallest of the three subfamilies of Syrphidae. Paradoxically, this subfamily is taxonomically the least organized of the three: 388 species names were previously classified in a single genus, Microdon Meigen, 1803. The present paper introduces a new generic classification of the Microdontinae, relying partly on the results of phylogenetic analyses of morphological and molecular data as published in other papers, and partly on examination of primary type specimens of 347 taxa, plus additional material, and original descriptions. A total number of 67 genus group names (excluding misspellings) are evaluated, redescribed, diagnosed and discussed, with several implications for their taxonomic status. Of these, 43 names are considered as valid genera, 7 as subgenera, 17 as synonyms. Two generic names (Ceratoconcha Simroth, 1907, Nothomicrodon Wheeler, 1924) are left unplaced, because they are known from immature stages only and cannot be reliably associated with taxa known from adults. The following 10 new genera are described by Reemer: Domodon, Heliodon, Laetodon, Menidon, Mermerizon, Metadon, Peradon, Piruwa, Sulcodon and Thompsodon. A key to all genera, subgenera and species groups is given. A total number of 26 new species are described in the following genera: Archimicrodon Hull, 1945, Ceratrichomyia Séguy, 1951, Domodon, Furcantenna Cheng, 2008, Heliodon, Indascia Keiser, 1958, Kryptopyga Hull, 1944, Masarygus Brèthes. 1908, Mermerizon, Metadon, Microdon, Paramixogaster Brunetti, 1923, Piruwa, Pseudomicrodon Hull, 1937, Rhopalosyrphus Giglio-Tos, 1891, and Thompsodon. New lectotypes are designated for Ceratrichomyia behara Séguy, 1951 and Microdon iheringi Bezzi, 1910. A total number of 267 new combinations of species and genera are proposed. New synonyms are proposed for 19 species group names. Three replacement names are introduced for primary and secondary junior homonyms: Microdon shirakiinom. n. (= Microdon tuberculatus Shiraki, 1968, primary homonym of Microdon tuberculatus de Meijere, 1913), Paramixogaster brunettiinom. n. (= Mixogaster vespiformis Brunetti, 1913, secondary homonym of Microdon vespiformis de Meijere, 1908), Paramixogaster sackinom. n. (= Myxogaster variegata Sack, 1922, secondary homonym of Ceratophya variegata Walker, 1852). An attempt is made to classify all available species names into (sub)genera and species groups. The resulting classification comprises 454 valid species and 98 synonyms (excluding misspellings), of which 17 valid names and three synonyms are left unplaced. The paper concludes with a discussion on diagnostic characters of Microdontinae.

Is the mega-diverse genus Ocyptamus (Diptera, Syrphidae) monophyletic? Evidence from molecular characters including the secondary structure of 28S rRNA

Phylogenetic relationships between two New World Syrphinae taxa (Diptera, Syrphidae), i.e. the highly diverse genus Ocyptamus and the large genus Toxomerus, were analysed based on molecular characters. The monophyly of both taxa was tested and the taxonomic status of included subgenera and species groups was examined. Toxomerus constitutes the monogeneric tribe Toxomerini with more than 140 described species, while Ocyptamus (tribe Syrphini) is a very diverse genus (over 300 spp.) with multiple recognised subgenera and species groups. Sequence data from three gene regions were used: the mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI) and the nuclear 28S and 18S ribosomal RNA genes. The secondary structure of two expansion segments (D2, D3) of the ribosomal 28S RNA gene is presented for the family Syrphidae and used for the first time in a multiple sequence alignment. Molecular data were analysed using parsimony, maximum likelihood and Bayesian inference. Toxomerus was always recovered as monophyletic within Ocyptamus, and relationships to other New World taxa such as Salpingogaster (Eosalpingogaster) were well-supported. Only the subgenera and species groups of Ocyptamus were consistently recovered as monophyletic lineages, thus the apparent non-monophyly of Ocyptamus demands reclassification of this clade.

Phylogenetic analysis of the genus Cheilosia (Diptera, Syrphidae) using mitochondrial COI sequence data

The genus Cheilosia is one of the most diverse and speciose genera of Syrphidae (Diptera). The phylogenetic relationships of the hoverfly genus Cheilosia was investigated for the first time using molecular data. The mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI) was chosen for sequencing; 1341 characters were obtained for 24 ingroup taxa and these were analyzed with parsimony. The monophyly of the genus Cheilosia was well supported. Current taxonomic division of Cheilosia into two subgenera (sg. Nigrocheilosia and sg. Neocheilosia) and most nonformalized species groups based on morphology were supported by the monophyletic groups identified in the molecular analysis. The phylogenetic informativeness of COI in resolving the subtribal relationships within the tribe Cheilosiini remains ambiguous.