[The age-related structure of an Ixodes ricinus population studied by using a rapid anatomical method].

A rapid anatomic method for the assessment of the physiologic age of ticks and their virtual age was used in studies of the age structure of a natural population of I. ricinus in the Moscow region. The anatomic method was found quite fit for the purpose. The findings evidence that the age structure of I. ricinus (active imago) population is heterogeneous with variously directed seasonal fluctuations. In spring the structure is the youngest (up to 60% of imagoes are in the second age, 8 months) and in the fall the females are mainly old, just starting to get younger (up to 90% are in the third and fourth ages, that is, aged a year). The structure is liable to changes with seasons and years. Geographic differences in the age structures were revealed: in the fall the Moscow region population is generally older than that of the St. Petersburg region. The anatomic method widens the potentialities of studying the age structure of the populations of tick-borne encephalitis vectors.