[Host influence on the frequency of block formation in males and females of Citellophilus tesquorum altaicus Ioff, 1936 (Siphonaptera: Ceratophyllidae) and transmission the plague pathogen by these fleas].

Data obtained during feeding of Citellophilus tesquorum aitaicus Ioff, 1936 infested females and males (Siphonaptera: Ceratophyllidae), the main vectors of plague in Tuva natural plague locus, on the natural host and laboratory animal was analyzed. It was found that sexual differences in fleas depended on the type of the host. Females fed more actively on the longtailed ground Citellus undulatus than on white mouse. Alimentary activity of males on these animals was similar. Higher mortality of fed females and males was noted during feeding on mice. Frequency of formation of the "block" and transmission of the pathogen in males was higher during bloodsucking on the ground squirrel; in females, during feeding on mice. Thus, differences in the transmission of the plague pathogen, revealed in laboratory on white mice, can be quite different in nature. So, extrapolation of experimental data on natural processes of interrelations between plague pathogen and ectoparasites must be performed taking into account revealed peculiarities.