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We studied the seasonal dynamics of summer flight of horseflies (Diptera, Tabanidae) belonging to 30 species from 6 genera. The results of the study showed that the number of horseflies is regulated mainly by abiotic factors such as temperature and relative humidity. The flight of horseflies begins at an air temperature not lower than + 150C and relative humidity not lower than 57%. Species differences in the seasonal intensity of the summer flight of horseflies were revealed. The following groups were identified by the beginning of summer flight: spring (end of May), early summer (beginning of June) and summer (beginning of July). Differences in the timing of departure are associated with optimal conditions for the development of larvae and pupae of horseflies, depending on abiotic factors such as temperature and humidity. An algorithm is proposed for calculating the long-term seasonal dynamics of summer activity of horseflies using indicators of average weekly, average monthly temperatures and relative humidity and the sum of effective temperatures. A similar algorithm can be used to predict the activity of summer horseflies.

1756 adult individuals of ticks Dermacentor reticulatus (Fabricius, 1894), D. marginatus (Sulzer, 1776) and Ixodes ricinus (Linnaeus, 1758) collected from vegetation in April-May 2018 and 2019 in natural foci of tularemia in forest and floodplain-valley types of the forest-steppe zone of the European Russia (Voronezh region) were investigated. Ticks (2 individuals in a pool) were studied by RT-PCR for the presence 16S rRNA gene fragment (amplicon size 218-226) in the Francisella genome. All positive samples were checked using species-specific primers and probes complementary to a fragment of the lpnA gene and the ISFtu2-element. Francisella DNA content in I. ricinus ticks from the forest biotope was found almost 20 times less than in D. reticulatus. The amount of Francisella DNA in D. reticulatus ticks collected in all studied floodplain-valley foci was more than 5 times greater than in D. marginatus. All positive tick pools of D. marginatus ticks were identified as Francisella tularensis, in contrast to D. reticulatus, which contained not only the DNA of F. tularensis, but also the unidentified DNA of Francisella genus bacteria. 15 % of them were found in D. reticulatus ticks from a forest-type focus and 5 % - in three floodplain-valley biotopes (in total). This may indicate the presence of endosymbionts of the FLE group in ticks of D. reticulatus. Thus, D. marginatus may be an important joint of the tularemia parasitic system of foci of the floodplain-valley type, however, these ticks take a slightly lesser part in the epizootic process than D. reticulatus in the European part of the forest-steppe zone. Adult forest ticks I. ricinus are occasional hosts of bacteria F. tularensis.

On the basis of twenty years of research in the Northeastern Russia, the issues concerning the validity, ecology, and zoogeography of Neoechinorhynchus tumidus van Cleave et Bangham, 1949 are discussed. This paper presents data on the infection of arctic chars of the genus Salvelinus by acanthocephalans in several mountain lakes of this region. Findings of N. tumidus in whitefish (Coregonidae) from lakes of other mountain regions of southern and Western Siberia are described. Paleogeographic reconstructions of vast lake basins in Siberia are considered. These hypotheses give an idea of probable habitats of ancestral forms of salmonid fish which currently serve as obligatory definitive hosts of N. tumidus in their Asian range. On the basis of the available data on the ways of formation of isolated populations of arctic char and whitefish in continental mountain areas, it is suggested that the modern range of the acanthocephalan N. tumidus is related to the distribution of such fish populations in Northern Asia.

X-ray micro-computed tomography (micro-CT) is a non-destructive method widely used for visualization of three-dimensional structures. Application of micro-CT for comparative morphology is limited due to low x-ray contrast of soft animal tissues, but staining can increase image quality for such specimens. We suggest that micro-CT may be used for rough visualization of branched sporocysts of Digenea within intact hosts, and tested this approach on sporocyst of Leucochloridium paradoxum. Two infected mollusks were treated following two different protocols. One specimen was scanned in ethanol; the other was dried before scanning. Anatomical features of the host were better visible on microtomographic sections of the dried specimen. Regardless of the sample preparation, full-grown and underdeveloped broodsacs of the sporocyst were visible, but we could not trace its central part. We suggest how the micro-CT protocol can be modified for better results on branched digenean sporocysts.

Fauna and ecological preferences of mosquitoes (Diptera: Culicidae) were studied in 2005-2019 in the territory of the "Nurgush" Reserve located in Kirov Province. The article presents data on twin species from the Anopheles maculipennis group in Kirov Province identified by DNA barcoding. A complete list of the Culicidae from the "Nurgush" Reserve includes 25 species, 5 of which are identified for the first time in the reserve and in Kirov Province: Anopheles beklemishevi Stegniy et Kabanova, 1976, A. daciae Linton, Nicolescu and Harbach, 2004, Culiseta morsitans (Theobald, 1901), C. alaskaensis (Ludlow, 1906) and Culex torrentium Martini, 1925.

Ticks are vectors and reservoirs of pathogens of various infectious diseases in both humans and domestic animals. Among the infections associated with ticks in Russia, the most significant are tick-borne encephalitis, Crimean-Congo hemorrhagic fever, and tick-borne borreliosis. And the main vectors of these diseases were the most studied species in Russian fauna, while other tick species remain poorly studied. The currently available lists of ticks in Russia are not complete and do not represent modern taxonomic views on this group of arthropods. Based on analysis of the literature, this study examines the species diversity and distribution of all naturally occurring tick species in Russia. Based on the study of all available literature sources, it has been established that the fauna of ticks in Russia includes 68 species. The status of some rare and poorly researched species is also discussed.