Demography and Population Models of Ticks of the Genus Ixodes with Long-Term Life Cycles

摘要

The most important parameters necessary for creation of population models for three-host species with long-term life cycles are discussed by the example of the ticks Ixodes persulcatus and I. ricinus. In these species, specimens of the same biologicalage may belong to different age cohorts and their calendar age may differ by several months or even years. Accurate estimation of the calendar age of singular individuals is difficu it is based on the extrapolation by its possible biological age andby belonging to the certain age cohort of a natural population. In order to possess a prognostic value, the population models must predict a single-moment population density of activated hungry specimens of all the three developmental stages and the probability of host-finding in hungry ticks during the questing period. The daily mortality of ticks of different developmental stages and phases of each stage (questing, feeding, preparation for molting, and diapause) should also be known. The population density of questing hungry ticks in the ecosystem is determined by the balance between the recruitment of new individuals into the population, their removal from the population by hosts, the dying of ticks from starvation, and the consumption of ticks by predators. At present, unfortunately, only some of these parameters are sufficiently known.