The pelage of prairie voles, pine mice, deer mice, and shrews forms a habitat for many kinds of parasitic arthropods. The fleas, lice, and mites from the prairie vole were collected, counted, and identified. The ectoparasites from the other small mammals living in the same habitat as the prairie vole were also considered. Some ectoparasites begin to leave the host when it dies, and any counts of ectoparasites made from snap-trapped voles may fall short of the number which was on the animal when it was alive. The average number of fleas recorded from live voles exceeds that found on snap-trapped voles (see [table 4]). The numbers of lice and mites were estimated, but selected voles were examined to obtain absolute numbers of these kinds of ectoparasites.
The fleas, lice, and mites were mounted on one inch by three inch glass slides; the ticks were preserved in 70 per cent alcohol. Dr. E. W. Baker identified the mites; Dr. R. A. Cooley and Dr. Glen M. Kohls, the ticks; Dr. G. W. Wharton, the chiggers; and Dr. Gordon F. Ferris, the lice. To each of these gentlemen I am grateful. The fleas were identified by myself.
Fleas (Siphonaptera)
The information on the average numbers of fleas on voles was obtained from live-trapped and some snap-trapped voles. Fleas were counted only on voles which were removed from the traps within twenty-four hours after the traps had been last examined. The average numbers of fleas found on prairie voles in this study are given in table 4.
Table 4. Average Numbers of Fleas on Prairie Voles[C]
| Subadults | Adults | |
|---|---|---|
| Live-trapped voles | 1.9 (73) | 3.4 (29) |
| Snap-trapped voles | 1.1 (26) | 1.3 (27) |
[C] The fleas on the live-trapped voles are all Ctenophthalmus pseudagyrtes Baker, and those on snap-trapped voles represent several species (see [table 2]). The numbers in parentheses are the numbers of voles examined.
[Table 5] shows the average degree of infestation for ten months of an eleven month period. The monthly averages for the most part show no variations. The latter half of February provides an exception in that a series of 22 snap-trapped voles and 11 live-trapped voles taken at that time had on the average, 9.7 and 5.3 fleas respectively. Pine mice (Pitymys nemoralis) occurred in small numbers in the area where Microtus ochrogaster was live-trapped, and Ctenophthalmus pseudagyrtes was the flea found to be common on both of these voles.