[Gender differences in the transmission of plague pathogen by fleas (Siphonaptera)].

The data of a long-term study of the relationships of the plague pathogen with male and female fleas, the vectors of this infection in Siberian natural foci, were analyzed. Gender differences were established in the rate of block formation and vector activity of fleas. In female and male fleas, these indices depend on both the species-specific features of ectoparasites and the pro-feeders used in the experiments, the season of their performance, and keeping conditions. The blocks of the proventriculus more frequently form in males of the majority of flea species, they more actively transmit a plague microbe to animals. The differences in both the rate of proventricular block formation and the pathogen transmission in different seasons were variously shown in males and females. They were clearly marked in one season and insignificant in another. Apparently, flea gender differences may affect the development of an epizootic situation since the sex ratio in these insects may vary in the natural foci of this infection depending on a season.