Adaptive Features of the Biology of Closely Related Species of Ixodid Ticks That Determine Their Distribution (Illustrated on the Example of the Taiga Tick Ixodes persulcatus Sch. 1930 and the Castor Bean Tick Ixodes ricinus L. 1758)

AbstractThe presented analytical literature review makes it possible to compare the adaptive capabilities of two closely related species of ixodid ticks, Ixodes persulcatus and I. ricinus, the main hosts and vectors of the most common and epidemically significant obligate, transmissible, natural focal infections in Eurasia—ixodic tick-borne borreliosis and tick-borne encephalitis. Studies on the influence of climatic factors on the number and distribution of these ticks and the formation of their fundamental ecological niches, which determine the establishment of the boundaries of their modern ranges, have been considered. The specific adaptive features of I. persulcatus and I. ricinus, their implementation in different geographic conditions (realized ecological niches), and the prerequisites for the formation and change of the sympatric area have been characterized. It is concluded that the variety of ecosystems that ticks of the compared species can inhabit limits the possibility of obtaining, at certain times, a thermal constant of development, i.e., the sum of effective temperatures necessary for egg development and the metamorphoses of larvae and nymphs.