INFLUENCE OF METEOROLOGICAL FACTORS ON THE ACTIVITY OF THE ADULT TAIGA TICK (IXODES PERSULCATUS SCH., IXODINAE) IN ST. PETERSBURG AND ITS ENVIRONS
The article deals with influence of meteorological factors on the activity of the taiga tick Ixodes persulcatus Sch. in St. Petersburg and its environs. The results of correlation analysis of meteorological data (21 index) and data on ticks collected in 1980-2012 allowed determining linear dependence between 11 meteorological indices and average amount of ticks. Factor analysis reduced dimentionality down to 3 indices: sum of temperatures higher than +5.0 °C, sum of precipitation higher than 5 mm per year, and Selyaninov hydrothermal coefficient. It was demonstrated that, at the background of the general tendency for the decrease of the average number of active ticks in the studied territories, correlation between the amount of ticks and meteorological indices can significantly vary as in the correlation density, so in the character and in dependence of microclimatic features of the collecting site. When variability of the mean abundance of ticks during years of investigation is low, the method of collecting can significantly affect the results of the statistical analysis. This fact must be taken in consideration during prognosis of both dates of the beginning of epidemiological season and its intensity.