[Principles of predicting the density of rodent flea populations]

The paper gives the indices of abundance of fleas of different species of rodents in their fur and in their burrows and lays emphasis on the general mechanisms by which the density of these blood-sucking insects is a species-specific (populational) sign and does not greatly differ from the mean many-year values. By using Citellophylus tesquorum and other specias as an example, the authors present the results of a study of natural mortality in fleas, which suggest that the mean longevity of imagoes and death in the preimaginal phases of development are a hereditary sign. An example of calculation of the death ratio "K" in the imaginal phases is given and evidence is provided for compiling the signs of the density of fleas in taking individual samples of a field material and calculating the abundance indices of specific species.