Abundance and seasonal activity of adult Dermacentor reticulatus (Acari: Amblyommidae) in eastern Poland in relation to meteorological conditions and the photoperiod.

Investigations of the abundance and seasonal activity of adult D. reticulatus in relation to the eff ect of climatic conditions (temperature, humidity) and the photoperiod on host-seeking behaviour were conducted in eastern Poland (51°25'N) in 1999-2000. D. reticulatus host-seeking activity was observed between the end of March at 5°C temperature and 89% humidity, and the beginning of December at 6°C temperature and 92% humidity. The peak autumn activity found between September – November was more than 2-fold higher than the spring peak, which occurred between April – May. The activity of females, males, and the total number of adult ticks was correlated with the temperature (p<0.01) and photoperiod (p<0.01); additionally, no dependency was found between adult tick activity and humidity of the environment (p>0.05). Females predominated throughout almost the entire activity period, but the ratios between females and males varied in the particular seasons. Males predominated only after the activity of adult ticks ceased between June – second decade of August, which was related to the reproductive processes. The investigations demonstrated that the activity dynamics in D. reticulatus from eastern Poland is similar to that in the southern European population, but different from that in the north-eastern Polish, Russian and West European populations. This indicates a need to monitor the threats of diseases transmitted by D. reticulatus within different regions of its range of geographic distribution.