Patterns of genetic differentiation imply distinct phylogeographic history of the mosquito species Anopheles messeae and Anopheles daciae in Eurasia.

Detailed knowledge of phylogeography is important for control of mosquito species involved in the transmission of human infectious diseases. Anopheles messeae is a geographically widespread and genetically diverse dominant vector of malaria in Eurasia. A closely related species, An. daciae, was originally distinguished from An. messeae based on five nucleotide substitutions in its ribosomal DNA (rDNA). However, the patterns of phylogeographic history of these species in Eurasia remain poorly understood. Here, using internal transcribed spacer 2 (ITS2) of rDNA and karyotyping for the species identification we determined the composition of five Anopheles species in 28 locations in Eurasia. Based on the frequencies of 11 polymorphic chromosomal inversions used as genetic markers, a large-scale population genetics analysis was performed of 1932 mosquitoes identified as An. messeae, An. daciae and their hybrids. The largest genetic differences between the species were detected in the X sex chromosome suggesting a potential involvement of this chromosome in speciation. The frequencies of autosomal inversions in the same locations differed by 13%-45% between the species demonstrating a restricted gene flow between the species. Overall, An. messeae was identified as a diverse species with a more complex population structure than An. daciae. The clinal gradients in frequencies of chromosomal inversions were determined in both species implicating their possible involvement in climate adaptations. The frequencies of hybrids were low ~1% in northern Europe but high up to 50% in south-eastern populations. Thus, our study revealed critical differences in patterns of phylogeographic history between An. messeae and An. daciae in Eurasia. This knowledge will help to predict the potential of the malaria transmission in the northern territories of the continent.

First record of the invasive mosquito species Aedes koreicus (Diptera, Culicidae) in the Republic of Kazakhstan.

The natural distribution range of Aedes koreicus is Korea, China, Japan, and the Russian Far East. Since 2008, this species has been recorded as an invasive species in some European countries (Belgium, European Russia, Germany, Hungary, Italy, Slovenia, and Switzerland). The invasive mosquito species Ae. koreicus is reported from the Republic of Kazakhstan for the first time. Its morphological identification was confirmed by molecular-genetic analyses of ND4 sequences using specific primers. Aedes koreicus larvae were found in an artificial water reservoir together with the larvae of Culiseta longiareolata and Culex pipiens s.l. Aedes koreicus successfully overwintered in Almaty at low winter temperatures in 2018-2019. This suggests that the Ae. koreicus acclimation capacity is greater than it has been considered until now. We assume that Ae. koreicus will spread over the west and south of the Republic of Kazakhstan and territories of Kyrgyzstan and Uzbekistan Republics bordering the Almaty region.

TITLE: Premier signalement de l'espèce de moustique envahissante Aedes koreicus (Diptera, Culicidae) en République du Kazakhstan. ABSTRACT: L'aire de répartition naturelle d'Aedes koreicus est la Corée, la Chine, le Japon et l'Extrême-Orient russe. Depuis 2008, cette espèce a été signalée comme espèce envahissante dans certains pays européens (Belgique, Russie européenne, Allemagne, Hongrie, Italie, Slovénie et Suisse). L'espèce de moustique envahissante Ae. koreicus est signalée ici pour la première fois en République du Kazakhstan. Son identification morphologique a été confirmée par des analyses de génétique moléculaire de la séquence ND4 à l'aide d'amorces spécifiques. Des larves d'Aedes koreicus ont été trouvées dans un réservoir d'eau artificiel avec des larves de Culiseta longiareolata et Culex pipiens s.l. Aedes koreicus a hiverné avec succès à Almaty à de basses températures hivernales en 2018-2019. Cela suggère que la capacité d'acclimatation d'Ae. koreicus est supérieure à ce qui avait été envisagé jusqu'à présent. Nous supposons qu'Ae. koreicus s'étendra sur l'ouest et le sud de la République du Kazakhstan et les territoires du Kirghizistan et des républiques d'Ouzbékistan bordant la région d'Almaty.

Genomic differentiation and intercontinental population structure of mosquito vectors Culex pipiens pipiens and Culex pipiens molestus.

Understanding the population structure and mechanisms of taxa diversification is important for organisms responsible for the transmission of human diseases. Two vectors of West Nile virus, Culex pipiens pipiens and Cx. p. molestus, exhibit epidemiologically important behavioral and physiological differences, but the whole-genome divergence between them was unexplored. The goal of this study is to better understand the level of genomic differentiation and population structures of Cx. p. pipiens and Cx. p. molestus from different continents. We sequenced and compared the whole genomes of 40 individual mosquitoes from two locations in Eurasia and two in North America. Principal Component, ADMIXTURE, and neighbor joining analyses of the nuclear genomes identified two major intercontinental, monophyletic clusters of Cx. p. pipiens and Cx. p. molestus. The level of genomic differentiation between the subspecies was uniform along chromosomes. The ADMIXTURE analysis determined signatures of admixture in Cx. p. pipens populations but not in Cx. p. molestus populations. Comparison of mitochondrial genomes among the specimens showed a paraphyletic origin of the major haplogroups between the subspecies but a monophyletic structure between the continents. Thus, our study identified that Cx. p. molestus and Cx. p. pipiens represent different evolutionary units with monophyletic origin that have undergone incipient ecological speciation.

Analysis of the Metaphase Chromosome Karyotypes in Imaginal Discs of Aedes communis, Ae. punctor, Ae. intrudens, and Ae. rossicus (Diptera: Culicidae) Mosquitoes.

In this study, cytogenetic analysis of the metaphase chromosomes from imaginal discs of Aedes (Diptera: Culicidae) mosquitoes-Aedes communis, Ae. punctor, Ae. intrudens, and Ae. rossicus-was performed. The patterns of C-banding and DAPI staining of the heteroсhromatin and the length of the chromosomes demonstrate species specificity. In particular, the Ae. punctor chromosomes are the shortest compared with Ae. communis, Ae. intrudens, and Ae. rossicus, and they also carry additional C and DAPI bands in intercalary regions. The Ae. intrudens chromosomes are the longest, they have pericentromeric C bands, and they almost lack any DAPI bands near the centromere of chromosome 3 versus Ae. communis, which has the largest pericentromeric DAPI blocks in all three chromosome pairs. Ae. rossicus also possesses DAPI bands in the centromeric regions of all chromosomes, but their staining is weaker compared with those of Ae. communis. Therefore, the analysis of karyotypes is a tool for species-level identification of these mosquitoes.

A comparative analysis of the metaphase karyotypes of Aedes excrucians, Ae. behningi, and Ae. euedes (Diptera: Culicidae) imaginal disсs.

Karyotypes of Aedes (Culicidae) mosquitoes (Ae. excrucians, Ae. behningi, and Ae. euedes) have been analyzed using the metaphase chromosomes of imaginal discs. Lacto-aceto-orcein, C-banding, and DAPI staining have detected species-specific features in the morphology and lengths of these chromosomes in the examined species. Species-specific features of chromosome 1 in the location of heterochromatin blocks have been shown. Thus, the metaphase chromosomes in the imaginal discs of Ae. excrucians, Ae. behningi, and Ae. euedes are a characteristic for species identification of mosquito species.

Mosquitoes of Anopheles hyrcanus (Diptera, Culicidae) Group: Species Diagnostic and Phylogenetic Relationships.

Herein, we report the results of study of Anopheles species in Primorsk and Khabarovsk regions of Russia. Three species of the Anopheles hyrcanus group: An. kleini, An. pullus, and An. lesteri were identified by molecular taxonomic diagnostics for the first time in Russia. Surprisingly, An. sinensis, which earlier was considered the only species of Anopheles in Russian Far East, was not observed. We analyzed nucleotide variation in the 610-bp fragment of the 5' end of the cytochrome c oxidase subunit I (COI) region. All species possessed a distinctive set of COI sequences. A maximum likelihood phylogenetic tree was constructed for members of the hyrcanus group. The examined Anopheles hyrcanus group members could be divided into two major subgroups: subgroup 1 (An. hyrcanus and An. pullus) and subgroup 2 (An. sinensis, An. kleini, and An. lesteri), which were found to be monophyletic.