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. The advent of genomics has provided new insights into population divergence between incipient taxa, changing our vision about the mechanisms of adaptation and speciation 1. Experimental data demonstrate highly heterogenous patterns of population differentiation in various groups of organisms 2. In addition to the classical model of allopatric speciation, when incipient taxa are isolated geographically 3 , it becomes obvious that ecological speciation or the development of reproductive isolation between populations as a result of adaptation to different environments is feasible and common in nature 4-6. Understanding the population structure and the mechanisms of taxa diversification in the changing environment is extremely important if the studied organisms are related to the transmission of human diseases 7. Members of the Culex pipiens complex are globally distributed throughout Europe, Asia, America, Africa, and Australia and represent competent vectors of the lymphatic filariasis parasite and encephalitis viruses, including the widely spread West Nile virus 8-11. However, despite the fact that Cx. pipiens was the first mosquito species described by C. Linnaeus in his "Systema Naturae" 12 , mosquitoes from the Cx. pipiens complex still represent "one of the major outstanding problems in mosquito taxonomy" because the

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.

Wolbachia is a group of maternally inherited endosymbiotic bacteria that infect and induce cytoplasmic incompatibility in a wide range of arthropods. Wolbachia species are involved and play a significant role in some evolutionary processes, e.g. those of rapid speciation. We have investigated the distribution of Wolbachia strains based upon the polymorphism of transposable element Tr1 and pk1 gene, in natural populations of the Cx. pipiens complex mosquitoes from Russian Federation, Republic of Kazakhstan, Kyrgyz Republic and Republic of Belarus.

Abstract. Herein, we report the results of study of Anopheles species in Primorsk and Khabarovsk regions of Russia.

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