New locations of Dermacentor reticulatus ticks in Western Poland: the first evidence of the merge in D. reticulatus occurrence areas?

The ornate dog tick, D. reticulatus, is the second most common tick species in Europe. It occurs across the temperate zone of Eurasia, from England and France to the basin of the Jenisej River in Siberia, and the occurrence area ranges from 56-57 degrees N latitude down to 52 degrees N latitude. The range is divided into two distinct parts, the West-European and the Eastern part. The western region covers France and northern Spain, South-western England and Wales, Germany, Austria, Czech, Western Slovakia and Hungary. The eastern region extends from the eastern part of Poland and Slovakia, through Belarus and Russia as far east as Siberia. The southern parts of this region cover Ukraine, Eastern Hungary and Romania. From the 1970s, D. reticulatus has expanded its area of occurrence. In Poland, the front of the area is historically situated along the Vistula River. From the 1980s new tick populations has appeared to the west of this border. In the past years, new populations of D. reticulatus appeared close to the western border of Poland near Szczecin and Wrocław. These are possibly the first observations of the merge between the two separated areas of D. reticulatus occurrence.