Ectoparasite fauna of the eastern woodrat, Neotoma floridana: composition, origin, and comparison with ectoparasite faunas of western woodrat species.

We collected ectoparasites from eastern woodrats, Neotoma floridana, from 3 sites in the southeastern United States: coastal South Carolina, southeast Georgia, and south-central Georgia. Twelve ectoparasite species were recovered from 47 woodrats in South Carolina (5 ticks, 5 mites, 2 fleas), 13 from 35 woodrats in south-central Georgia (1 tick, 10 mites, 2 fleas), and 4 from a small host sample (7) in southeast Georgia (2 ticks, 1 mite, 1 flea). New state records are established for the listrophorid mite Listrophorus neotomae from both Georgia and South Carolina, the myocoptid mite Myocoptes neotomae from Georgia, and the ceratophyllid flea Orchopeas sexdentatus pennsylvanicus from South Carolina. Different ectoparasites predominated on woodrats at each site with the tick Ixodes minor being the most commonly collected species in South Carolina, the American dog tick Dermacentor variabilis in southeast Georgia, and the chigger Euschoengastia peromysci in south-central Georgia. Most of the 17 species recovered are known to parasitize several species of mammals, especially rodents, and none of them are host specific to N. floridana. However, the fleas Epitedia cavernicola and Epitedia neotomae are host-specific ectoparasites of eastern woodrats in other parts of their range. Also, 1 species of tick, 2 mites, and 3 fleas parasitize eastern woodrats in addition to western woodrats. A similar lack of host specificity is apparent for the few previously documented collections of ectoparasites from eastern woodrats, including 1 detailed survey in Indiana. Conversely, Neotoma spp. woodrats inhabiting western North America are parasitized by a plethora of host-specific ectoparasites including 2 tick species, 5 mites (other than chiggers), 20 chiggers, 2 sucking lice, and 42 fleas. Recognizing that western biotas are typically more speciose than corresponding eastern biotas in North America, we further propose that because eastern woodrats are the most recent and eastern descendants of the ancestral Neotoma stock, (1) some ectoparasite species failed to accompany the eastern woodrat lineage in its eastward dispersals, and (2) there has been insufficient time for a diverse assemblage of ectoparasites to co-evolve with eastern woodrats.