[Range and ecology of Dermacentor reticulatus (Fabricius, 1794) in Mazuria focus. I. Defining current range].

During the vegetation periods of five subsequent years, ie. 1997, 1998, 1999, 2000 and 2001, a field study aimed at defining, the current range of Dermacentor reticulatus in the so-called Mazuria focus was conducted on an area of about 24.000 km2 . The total of 68 sites covered by the study were located between the Great Mazurian Lakes District in the east and the lower Vistula valley in the west. The presence of adult forms of Dermacentor reticulatus was confirmed in 23 sites. The westernmost sites were discovered in the vicinity of Brodnica and Elblag. Both sites are located at longitude 19 degrees 20' East.