[Exoskeleton anomalies among taiga tick males from populations of the Asiatic part of Russia].

The taiga tick (Icodes persulcatus, Schulze, 1930) is the main and most epidemiologically dangerous vector of tick-born encephalitis virus (TBEV) and Borrelia in most parts of Russia's territory (Alekseev et al., 2008). The purpose of this article is to describe the incidence rate of I. persulcatus males with exoskeleton anomalies in populations of the Asiatic part of Russia. A total of 2630 taiga tick males were morphologically analyzed. They were collected in Far Eastern, Siberian and Ural Federal Districts (respectively, FEFD, SFD, UFD) in 15 geographically remote locations. It is shown that in all populations there are adult ticks with impaired exoskeleton, among which two types dominate: twin dents at the back of conscutum (P11), and uneven surface of conscutum - a "shagreen skin" (P9). The frequency of abnormalities in males from the areas with temperate monsoon and temperate continental climate (FEFD) was definitely lower (6.5 ± 1.05 %), than in individuals from the territories of SFD (29.7 ± 1.03 %) and UFD (25.8 ± 3.93 %) with continental and sharply continental climate. FEFD territory is also characterized by a less number of males having two simultaneous exoskeleton anomalies. Similar district-preconditioned differences in the frequency of recorded body distortions are also typical of females, with a higher percentage of deviant individuals in comparison with males. Thus, the identified polymorphism of exoskeleton structure of the taiga tick may reflect the natural phenogeographical variability of this trait and might not be the result of human impact.

[EXOSKELETON ABNORMALITIES IN TAIGA TICK FEMALES FROM POPULATIONS OF THE ASIATIC PART OF RUSSIA].

Studies of the phenotypic structure of Ixodes persulcatus (Schulze, 1930) populations in relation to their exoskeleton abnormalities are important in both theoretical and practical respects. The data on the species' population structure in Asiatic part of Russia are fragmentary. The goal of the study was to describe taiga tick population structure based on the pattern of females' exoskeleton abnormalities revealed in Asiatic part of Russia. A total of 3872 I. persulcatus females from 16 geographically remote sites of Far Eastern, Siberian, and Ural Federal Districts (FEFD, SFD, and UFD accordingly) were studied. It was demonstrated that all the populations possessed specimens with exoskeleton abnormalities. The «shagreen skin¼ abnormality was dominant in all these areas. At the same time, the percentage of abnormalities among the specimens collected to the north of 55°N is considerably higher (63.4 ± 3.39 %) than that of samples from the SFD southward territories (33.1 ± 3.43 %). The frequency of abnormalities in its turn is lower (24.4 ± 1.93 %) in the females from the territories with moderate monsoon and moderate continental climate (FEFD) than that in specimens from SFD and UFD areas with sharp continental climate. Thus, such polymorphism of the females' exoskeleton structure may reflect the natural phenogeographical variability of the character rather than the result of the anthropogenic impact. 403

[POLYMORPHISM IN THE PHENOTYPIC STRUCTURE OF A POPULATION OF TAIGA TICK AND ITS EPIDEMIOLOGICAL SIGNIFICANCE].

The paper presents the results of 10-year (2005-2014) observations of an Ixodespersulcatus Schulze population. The purpose of this investigation was to trace long-term changes in the structure of the taiga tick population from the proportion of specimens with external skeletal anomalies and to assess a relationship between the pattern of imago phenotypic variation and the virus percentage of a carrier. There were a total of reports of the external skeletal structure of 1123 females gathered from plants to a flag in an area at 43 km from the Baikal Road connecting Irkutsk and the settlement of Listvyanka (Irkutsk Region). The proportion of specimens with anomalies averaged 37.8 +/- 1.88%. Four-to-seven varying anomalies were annually recorded. There was a preponderance of scutum impairment (an average of 17.0 +/- 3.08% of all females) that was a conglomerate of prominences and indentations along the entire clypeus surface and that was denoted P9. The nature of a change in the proportion of ticks with two anomalies (average monthly registration rate, 2.5 +/- 0.66%) is exhibited by three-year high-frequency oscillations whereas the specimens with P9 anomalies fail to show so clear cycling. The percentage of virus-containing taiga ticks was individually determined estimating the level of tick-borne encephalitis virus antigen by an enzyme immunoassay. A total of 4022 ticks were examined. The male and female data were pooled. There was a positive correlation between the change in the proportion of females with P9 anomaly and the infection of ticks in the examined population (Spearman's correlation coefficient, 0.88; P < 0.01). This supports the earlier observation of the greater epidemiological significance of the imago of a taiga tick with external skeletal anomalies particularly with considerably marked ones.