Rediscovering the mosquito fauna (Diptera: Culicidae) of Estonia: an annotated checklist with distribution maps and DNA evidence.

Female mosquitoes (Diptera: Culicidae) affect their hosts in numerous negative ways and are crucial to the spread of vector-borne pathogens. It is, therefore, important to have a detailed overview of regional mosquitoes, to be able to detect changes in species diversity and identify possible health threats. The aim of this study was to update the checklist of the mosquito fauna of Estonia for the first time since 1957. For this purpose, 24,344 adult mosquitoes (94% females) were collected in Estonia from 2008 to 2020 using various trapping methods. Specimens were primarily identified by morphological characteristics, but DNA barcoding based on the partial cytochrome c oxidase subunit 1 gene (COI) was also used. Species were included in the checklist based on historical records as well as new collections, while also considering reports from neighboring countries. Species records are supplemented with voucher specimens, distribution maps and DNA evidence. The updated checklist includes 34 species, 27 of which were confirmed with recently collected material. All in all, Aedes communis (de Geer, 1776) proved to be the most common mosquito in Estonia, accounting for 30.1% of the specimens collected. This is noteworthy, as this species has been implicated in the transmission of multiple disease agents present in the area. New evidence revealed the presence of Ae. hexodontus Dyar, 1916, Ae. sticticus (Meigen, 1838), Anopheles messeae Falleroni, 1926 and Culiseta bergrothi (Edwards, 1921) in Estonia.

Every Single Specimen Counts: A New Docosia Winnertz (Diptera: Mycetophilidae) Species Described from a Singleton.

A new species-Docosia caucasica sp. n.-has been described from material collected from the Lesser Caucasus Mountains in Georgia (Sakartvelo). The new species belongs to a group of Palaearctic species characterized by distinct posterolateral processes of gonocoxites and apically modified setae at the posteroventral margin of the gonocoxites medially. Within the group, D. caucasica sp. n. is most similar to D. landrocki Lastovka and Sevcík, 2006 in having a similar outline of the medial process of posteroventral margin of the gonocoxites and the gonostylus. There is also a marked difference within the partial cytochrome c oxidase subunit 1 gene (COI) sequence of D. caucasica sp. n. and other Docosia spp. available in public databases. As the new species is described from a single male specimen only, the adequacy and code compliance of that are discussed.

Friends in All the Green Spaces: Weather Dependent Changes in Urban Mosquito (Diptera: Culicidae) Abundance and Diversity.

Mosquitoes (Diptera: Culicidae) are universally recognized as troublesome pests and vectors of various pathogens and parasites. Understandably, the species makeup and diversity of individual populations depends on local and broad scale environmental trends, especially on temperature and hydrological variations. Anthropogenic landscapes make for unique habitats, but their effect on insects likely varies across climatic regions. The aim of this study was to investigate the diversity and seasonal patterns of urban mosquitoes in the boreal region. Specimens were collected with an insect net from May to September during three years and determined to species or species group level. Weather information was added to each data point and results analyzed using multivariate regression models. Fieldwork yielded 1890 mosquitoes from four genera. Both abundance and the effective number of species (ENS) significantly decreased during the study period. The number of collected mosquitoes had a negative correlation with wind speed and temperature, latter of which exhibited a negative association with humidity. Species succession followed predictable patterns, but with some variation between years. Still, Culex pipiens/Culex torrentium were the most abundant throughout the study. Importantly, all dominant species were known disease vectors. Our work showed that higher temperatures could result in fewer mosquitoes in boreal towns.

No evidence for African swine fever virus DNA in haematophagous arthropods collected at wild boar baiting sites in Estonia.

African swine fever (ASF) is a highly pathogenic viral disease affecting all Suidae, with Ornithodoros moubata complex soft ticks acting as the biological arthropod vectors of the causative agent, African swine fever virus (ASFV). While ASFV is also transmissible via direct contact, pig products and fomites, other arthropods may be involved in virus transmission and persistence. Therefore, we checked various groups of blood-feeding arthropods collected during summer 2017 in wild boar habitats on the Estonian Island of Saaremaa for the presence of ASFV. Saaremaa had the highest ASF infection prevalences in Estonia in 2017, with an incidence of 9% among hunted wild boar. In addition to ASFV, we tested for other selected pathogens. In total, 784 ticks, 6,274 culicoid biting midges, 77 tabanids and 757 mosquitoes were tested as individuals or pools. No ASFV-DNA was found in any of them although about 20% of the tick samples tested positive for swine DNA. By contrast, tick-borne encephalitis virus-RNA was detected in one out of 37 tick pools (2.7%) and Borrelia burgdorferi s.l.-DNA in 20 individual ticks and 17 tick pools (25.2% of all samples). No Schmallenberg virus was detected in the Culicoides specimens. In conclusion, we found no evidence for Ixodes ricinus ticks, Culicoides punctatus and Obsoletus complex biting midges, Aedes spp., Anopheles spp. and Culiseta annulata mosquitoes, and Haematopota pluvialis tabanids playing a role in ASFV transmission in the wild boar population in Estonia.

Novel Mitochondrial DNA Lineage Found among Ochlerotatus communis (De Geer, 1776) of the Nordic-Baltic Region.

The Ochlerotatus (Oc.) communis complex consist of three Northern American species as well as a common Holarctic mosquito (Diptera: Culicidae) Oc. communis (De Geer, 1776). These sister species exhibit important ecological differences and are capable of transmitting various pathogens, but cannot always be differentiated by morphological traits. To investigate the Oc. communis complex in Europe, we compared three molecular markers (COI, ND5 and ITS2) from 54 Estonian mosquitoes as well as two COI marker sequences from Sweden. These sequences were subjected to phylogenetic analysis and screened for Wolbachia Hertig and Wolbach symbionts. Within and between groups, distances were calculated for each marker to better understand the relationships among individuals. Results demonstrate that a group of samples, extracted from adult female mosquitoes matching the morphology of Oc. communis, show a marked difference from the main species when comparing the mitochondrial markers COI and ND5. However, there is no variance between the same specimens when considering the nuclear ITS2. We conclude that Oc. communis encompasses two distinct mitochondrial DNA lineages in the Nordic-Baltic region. Further research is needed to investigate the origin and extent of these genetic differences.

Diversity of Diptera Species in Estonian Pig Farms.

In light of the African swine fever outbreaks in Estonian pig farms during the past few years, the question of the vector potential of Diptera in the pig farm environment has risen. However, the arthropod fauna of the pig farm environment is currently not well established. Hence, the aim of this study was to clarify the species diversity in pig farms. In total, 22 Diptera species or species groups were found in Estonian pig farms. There were altogether 186,701 individual arthropods collected, from which 96.6% (180,444) belonged to the order of true flies (Insecta: Diptera). The remaining 3.4% were from other insect orders, arachnids, or just damaged and unidentifiable specimens. The activity density and diversity of dipterans differed significantly between 12 sampled farms but not throughout the sampling period. The present study is amongst the few to provide a large-scale overview of pig-farm-associated Diptera in the temperate climate zone.

The northernmost record of a blood-sucking ectoparasite, Lipoptena fortisetosa Maa (Diptera: Hippoboscidae), in Estonia.

BACKGROUND: Deer keds are obligatory haematophagous parasites of large homeothermic animals, particularly cervids. Two of the five known species occurring in Europe-Lipoptena cervi (Linnaeus) and L. fortisetosa Maa-are known to have a relatively wide distribution. Lipoptena fortisetosa is considered to have been introduced into Europe with sika deer from the Eastern Palaearctic and is continuously expanding its range. Little is known about the medical importance of deer keds, but they can cause hair loss in cervids and are suspected to be vectors of several diseases. NEW INFORMATION: Details of the distribution of Lipoptena fortisetosa in Europe, including its northernmost record, are provided. This species has been shown to have a viable population in Southern Estonia. Furthermore, the differences from allied L. cervi are discussed, based on morphological and molecular characters.