[Geographic variability in the sexually mature phase of Ixodes persulcatus (Ixodidae). Experience in using databases...

The aim of the article is to estimate geographic variation of Ixodes persulcatus adults as a whole. Intraspecific variation of the females and males of Ixodes persulcatus Schulze, 1930 has been studied in eight geographical localities ("populations") of its distribution range (fig. 1.). The distance between western and eastern localities is more than 8700 km, between northern and southern ones it is approximately 2900 km. Twenty five to thirty specimens of each sex were studied in each geographical locality. The following eleven characters were used (fig. 2, 3): length of scutum (conscutum), width of scutum (conscutum), length of anal ring, width of anal ring, length of spiracular plate, width of spiracular plate, length of gnathosoma, width of gnathosoma, length of II-III articles of palps, length of hypostome, length of tarsus 1. The multidimensional scaling method by means of software package SYSTAT was used for estimation of relationships between populations on the basis of morphometrical data. The differences between the populations were revealed only from absolute sizes of organs, whereas their proportions (i. e. shape) were constant in all geographical localities. Fig. 4, 1 shows that females from localities G (Primorski Territory) and C (Tien Shan Mountains) occupy extreme positions. Fig. 4, 2 shows that males from localities G (Primorski Territory) and D (SW Altai Mountains) on the one hand and A, B (European) on the other one occupy extreme positions. Locality C (Tien Shan Mountains) is similar to F (Western Sayan Mountains) and to European (A, B) whereas females of locality C differ from A, B and F. Taking into account the partial discrepancy of relationships between populations in sexes we have united the data on corresponding characters of both sexes in the aggregate data base (fig. 4, 3). This was possible owing to the multidimensional scaling method. Fig. 4, 3 shows isolated position of the population G (Primorski Territory), specimens of which are the largest in sizes. The populations D (SW Altai Mountains) and H (Sakhalin Island) are morphometrically most similar to the population G. The population C (Tien-Shan Mountains) is represented of the smallest specimens. The European populations (A and B) are closer to C. The largest sizes are typical of the populations G and D associated with relict Tertiary landscapes of Primorski Territory and SW Altai with which areas of ecological optimum of I. persulcatus coincide. The smallest sizes are observed in the European populations (A, B) near the north-western boundary of the distribution range of the species, as well as in the Alpine population of Tien-Shan Mountains, near the upper vertical boundary of the distribution range (2000-3000 m above sea level). Climatic conditions of the habitat in these areas are similar to those of the northwestern part of the distribution range of I. persulcatus.