Great Basin Naturalist


Fleas obtained from deer mice and each of three sympatric rodents collected at the same times and places are quantified. When deer mice and canyon mice were caught together, 18.9 percent of the infested deer mice had canyon mouse fleas while 20.8 percent of infested canyon mice carried deer mouse fleas; long-tailed vole fleas were collected from only 3.9 percent of the deer mice but 67 percent of the voles associated with deer mice had fleas normally found on the latter; reciprocity was lowest between deer mice and desert wood rats, with three wood rat fleas found among 155 fleas collected from 33 deer mice, and 12 deer mouse fleas among 403 fleas found on 52 wood rats. Rodent nesting habits, particularly the willingness of deer mice to den in a wide variety of situations, is thought responsible for many stray associations. The long-term evolutionary effect of flea dependency on wood rat denning habits is briefly discussed.