Epitedia wenmanni was found on the white-footed mouse (Peromyscus leucopus) and only rarely on the prairie vole. Corrodopsylla hamiltoni was taken only from the two kinds of shrews (Blarina brevicauda and Cryptotis parva). Fleas on shrews may have a well-developed host preference. At any rate, Elton, Baker, Ford, and Gardner (1931) found that Doratopsylla dasycnemus rarely strayed from its normal host (Sorex araneus) to other small mammals. Peromyscopsylla scotti was taken from the white-footed mouse (Peromyscus leucopus), and had a habitat preference also. It was found only on those white-footed mice which were trapped in the woodlands at various places in Douglas County; white-footed mice which were trapped in areas of brush were free of this parasite.
Group 2: Fleas Commonly Found on Two or More Kinds of Small Mammals
Orchopeas leucopus was an outstanding example of this group. It was the most common flea on the deer mouse, the white-footed mouse, and the cotton rat. In certain areas it was common on the two voles (Pitymys nemoralis and Microtus ochrogaster). Ctenophthalmus pseudagyrtes is the most abundant flea on the two kinds of voles and on the large shrew (Blarina brevicauda), and was found sparingly on the cotton rat.
Several kinds of fleas do not belong in either of the above groups. Some fleas were accidental strays from mammals not included in [table 6]; and one flea (Rectofrontia fraterna) may prove to be a common nest parasite. Orchopeas howardii is common on tree squirrels (Sciurus niger and S. carolinensis). Nosopsyllus fasciatus is a cosmopolitan flea on Rattus norvegicus. Rectofrontia fraterna was taken once from a prairie vole. Since the only specimens in the University of Kansas Entomological Collections are from "mouse nests," this flea may be found to be a nest inhabiting parasite.
Some fleas are possible bridges by which a blood parasite could be transmitted from one kind of a mammal to another. If Ctenophthalmus pseudagyrtes acted as the intermediate host of a disease-causing organism, an epizootic from Microtus ochrogaster might be transmitted to Pitymys nemoralis or to Sigmodon hispidus or Blarina brevicauda. There are several other such potential bridges for blood parasites. Although [table 6] does not prove that individual fleas wander from one host to another, the frequency with which the several kinds of fleas are removed from live mice suggests that the fleas occasionally do so.
Lice (Anoplura)
Lice collected from the prairie vole were all of one species, Hoplopleura acanthopus (Burmeister). Of 59 voles examined for the presence of lice, 33 were found to be parasitized; the 59 voles had an average of 3.4 lice each. Other mice which used the same runways as the prairie vole had their own species of Anoplura. The cotton rat was host to Hoplopleura hirsuta Ferris, and the two species of Peromyscus were parasitized by Hoplopleura hesperomydis (Osborn).
The writer collected Hoplopleura acanthopus from Microtus californicus at Calaveras Dam, Alameda County, California, and from M. pennsylvanicus at Ithaca, Tompkins County, New York. Elton, Ford, Baker, and Gardner (1931) recorded this same species from M. argestis in England.
Lice on the prairie vole are the same species as those found on other species of Microtus in other areas, but since Anoplura of the prairie vole do not parasitize the cotton rat, the white-footed mouse, and the deer mouse, this host specificity of lice makes it unlikely that lice would carry blood parasites from the prairie vole to any of the latter named rodents.