Mites (Acarina except Ixodoidea)
Many of the small mammals examined in this study had mites, some of which were collected and identified. Mites were collected from other species of voles in several localities in the United States and in one locality in Canada; as voles in widely separated regions are sometimes hosts to the same species of mites, these records will be presented here.
The frequency of some kinds of mites in the identified material suggests that they are more abundant than other kinds. The occurrence of mites on small mammals from Lawrence, Kansas, is presented in [table 7].
The following comments can be made concerning the specificity and geographic ranges of several species of mites:
Liponyssus occidentalis Ewing was found only on Cryptotis parva.
Eulaelaps stabularis (Koch) was one of the more common kinds found on the prairie vole. This mite is rather large (about 1 mm. long) and is frequently (with the following species) seen running through the pelage of its host. In addition to the records for this species in [table 1], it was found to be a common parasite on Pitymys pinetorum at Point Abino, Welland County, Ontario. Elton, Ford, Baker and Gardner (1931) found this same mite on Apodemus sylvaticus and Clethrionomys glareolus in England.
Atricholaelaps glasgowi, like the preceding species, was one of the commoner mites on the prairie vole. It was found also on Pitymys pinetorum at Point Abino, Welland County, Ontario; on Microtus pennsylvanicus at Ithaca, Tompkins County, New York; and on M. californicus at Calaveras Dam, Alameda County, California.
Atricholaelaps sigmodoni occurred only on the cotton rat.
Laelaps kochi was less commonly found than Eulaelaps stabularis and Atricholaelaps glasgowi. In Kansas the prairie vole and the cotton rat were hosts to Laelaps kochi, and it occurred on Microtus pennsylvanicus at Ithaca, New York, and on M. californicus at Berkeley, California.
Trombiculidae are commonly known by their larvae which are called chiggers or harvest mites. The white-footed mouse, the cotton rat, and the prairie vole were parasitized at Lawrence. In the winter these mites live in the ears of these small mammals, but in the summer they were found both in the ears and on the rump. Those obtained in winter were Ascoschöngastia brevipes (Ewing); other species may be involved.
Listrophoridae was represented on the prairie vole by a species of Myocoptes and a species of Listrophorus. These mites cling to the hairs of their host, and do not occur on the skin of the voles.
No evidence was seen that mites had any ill effect on the health of their hosts. No voles had scabs on the skin; and the ears were not swollen and disfigured as they sometimes are by chiggers. Although the identity of a specimen of mite could not be determined until it was mounted, a person could tell whether or not it was one of the larger, very active Laelaptidae, one of the hair-clinging Listrophoridae, or one of the tiny, orange Trombiculidae.
On July 12, 1946, three prairie voles were examined to determine the number of mites they supported. The voles were freshly caught, no one of them having been dead for more than five minutes before they were examined. These three voles had an average of 25 Laelaptidae, 22 Listrophoridae, and 53 Trombiculidae.
Six species of mites (Ixodoidea excepted) were found on the prairie vole. Four of these were collected also from other small mammals living in the same habitat as this vole. Two species of mites were found to occur on voles in New York, Kansas, and California.