Three new Scandinavian species of Culicoides (Culicoides): Culicoides boyi sp. nov., Culicoides selandicus sp. nov. and Culicoides kalix sp. nov. (Diptera: Ceratopogonidae)

Towards modernizing the taxonomy of Mediterranean Culicoides using classical morphology, mtDNA barcoding, and MALDI-TOF MS protein profiling

Culicoides biting midges (Diptera: Ceratopogonidae) are a highly successful group of small (1-3 mm) hematophagous flies, infamous for the role they play as biological vectors for numerous pathogens of veterinary significance. The principal aim of the national animal disease surveillance program of Israel is to be able to rapidly sort and identify live field-captured insects including Culicoides for arbovirus screening. In this exploratory study, three identification methods-classical morphology, DNA barcoding, and MALDI-TOF MS-were applied simultaneously to individuals of 10 Culicoides species that commonly attack livestock in Israel. The strengths and limitations of the three methods are compared and evaluated. In essence, the CO1 barcoding and MALDI-TOF MS results closely matched those of classical morphology. Furthermore, at a higher level and in strong accordance with recognized subgenera, the 10 species, in the reconstructed phylogenies, coalesced into multiple deeper-branched monophyletic clades. However, some discrepancies between the molecular and protein profiling results did occur and proved difficult to assess in terms of taxonomic significance. This difficulty underscores how tricky it is to establish clear species limits when methods involving borderline cutoff values and similarity indices are used as a taxonomic aid. An added shortcoming of the pluralistic triple-method approach is that a significant percentage of the species-level depositions in the GenBank and BOLD databases are misidentified, hindering structured comparison and interpretation of the morphological and molecular results obtained. Aspects of the unresolved taxonomy of various biting midge assemblages within the Mediterranean basin, including minor changes to the Israeli Culicoides checklist, are discussed in light of the methods applied. It is observed that the direct access that classical morphology provides to the external environment (or species niche) is indispensable to the full and correct interpretation (and application) of concomitant molecular and protein profiling results. The Culicoides taxonomy of the future ought to be fully integrative, during which the assimilation of modern methodological advances should strengthen-rather than undermine-the morphological foundations laid down during the 260-year Linnaean epoch.

Barcoding of the Genus Culicoides (Diptera: Ceratopogonidae) in Austria-An Update of the Species Inventory Including the First Records of Three Species in Austria

Ceratopogonidae are small nematoceran Diptera with a worldwide distribution, consisting of more than 5400 described species, divided into 125 genera. The genus Culicoides is known to comprise hematophagous vectors of medical and veterinary importance. Diseases transmitted by Culicoides spp. Such as African horse sickness virus, Bluetongue virus, equine encephalitis virus (Reoviridae) and Schmallenberg virus (Bunyaviridae) affect large parts of Europe and are strongly linked to the spread and abundance of its vectors. However, Culicoides surveillance measures are not implemented regularly nor in the whole of Austria. In this study, 142 morphologically identified individuals were chosen for molecular analyses (barcoding) of the mitochondrial cytochrome c oxidase subunit I gene (mt COI). Molecular analyses mostly supported previous morphologic identification. Mismatches between results of molecular and morphologic analysis revealed three new Culicoides species in Austria, Culicoidesgornostaevae Mirzaeva, 1984, which is a member of the Obsoletus group, C. griseidorsum Kieffer, 1918 and C. pallidicornis Kieffer, 1919 as well as possible cryptic species. We present here the first Austrian barcodes of the mt COI region of 26 Culicoides species and conclude that barcoding is a reliable tool with which to support morphologic analysis, especially with regard to the difficult to identify females of the medically and economically important genus Culicoides.

Description of Culicoides (Culicoides) bysta n. sp., a new member of the Pulicaris group (Diptera: Ceratopogonidae) from Slovakia

Background

Species of the genus Culicoides Latreille, 1809 (Diptera: Ceratopogonidae) are mainly known as vectors of arboviruses such as bluetongue (BTV) and Schmallenberg (SBV). Among the known vectors, few species within the subgenus Culicoides Latreille, 1809 have been implicated in the transmission of BTV and SBV. Nevertheless, phylogenetic studies had revealed the presence of cryptic and undescribed species in Europe, raising questions about their vectorial role. A previous integrative study, associating morphology and barcode data, raised the hypothesis of the presence of undescribed species in Slovakia. The present study, combining morphological and molecular approaches, is aimed to support the hypothesis and a description of Culicoides bysta n. sp. is provided.

Methods

Series of male and female specimens were dissected and several of them were sequenced for the barcode region of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Bayesian inference phylogenetic analyses based on 72 cox1 sequences of the species belonging to the Pulicaris group of the subgenus Culicoides, were carried out and the frequencies of intra/interspecific variations were analyzed. The morphology of abundant material of the new species (31 females and 12 males) was examined and compared with the paratypes of Culicoides boyi Nielsen, Kristensen & Pape, 2015 and with specimens of Culicoides pulicaris Linnaeus, 1758. For females, suture distances on the eyes were newly evaluated as a diagnostic character and for males we assessed a new measurement on the ninth tergite and on the apicolateral processes.

Results

Both phylogenetic analysis and barcode distances supported the distinct status of the new species, Culicoides bysta n. sp. described as a member of the Pulicaris group based on the morphology of males and females. The new species is closely related to C. boyi and C. pulicaris but can be distinguished on the basis of the wing pattern and the ratio between the two eye sutures. Both newly evaluated characters, i.e. eyes in females and male genitalia appeared to be diagnostic for distinguishing the new species described herein.

Conclusions

The vector potential of the recently described species C. boyi and C. bysta n. sp. to transmit arboviruses, such as BTV and SBV, is unknown. When considering these two species as being close to C. pulicaris, the previous data, such as the vector implication for C. pulicaris in BTV transmission, should be revaluated in future.

New and poorly known Palaearctic fungus gnats (Diptera, Sciaroidea)

Background

Fungus gnats (Sciaroidea) are a globally species rich group of lower Diptera. In Europe, Fennoscandian peninsula in particular holds a notable diversity, ca. 1000 species, of which 10 % are still unnamed. Fungus gnats are predominantly terrestrial insects, but some species dwell in wetland habitats.

New information

Eight new fungus gnat species, belonging to the families Keroplatidae (Orfeliaboreoalpina Salmela sp.n.) and Mycetophilidae (Sciophilaholopaineni Salmela sp.n., S.curvata Salmela sp.n., Boletinasasakawai Salmela & Kolcsár sp.n., B.norokorpii Salmela & Kolcsár sp.n., Phroniasompio Salmela sp.n., P.reducta Salmela sp.n., P.prolongata Salmela sp.n.), are described. Four of the species are known from Fennoscandia only whilst two are supposed to have boreo-alpine disjunct ranges, i.e. having populations in Fennoscandia and the Central European Alps. One of the species probably has a boreal range (Finnish Lapland and Central Siberia). Type material of Boletinacurta Sasakawa & Kimura from Japan was found to consist of two species, and a further species close to these taxa is described from Finland. Phroniaelegantula Hackman is redescribed and reported for the first time from Norway. DNA barcodes are provided for the first time for five species.