Role of small mammals in population dynamics and dissemination of Amblyomma americanum and Dermacentor variabilis (Acari: Ixodidae) at Land Between The Lakes, Tennessee.

Abstract

We studied the relationship between small mammals, Amblyomma americanum (L.), and Dermacentor variabilis (Say) in an oak/hickory woods and an old-field habitat at Land Between The Lakes, Tennessee. The seven small-mammal species captured were Peromyscus leucopus, Microtus ochrogaster, Microtus pinetorum, Blarina brevicauda, Cryptotis parva, Reithrodontomys humulis, and Mus musculus. Only three subadult A. americanum were collected from small mammals, but high densities of free-living A. americanum were present. Therefore, we concluded that small mammals were not principal hosts of A. americanum. In the woods, 115 P. leucopus were examined for ticks, with a mean of 0.03 nymphal D. variabilis and 1.4 larvae per mouse. In the field, 49 P. leucopus were examined, with 0.3 larvae and 0 nymphs per mouse. We collected a total of 68 larval and 10 nymphal D. variabilis from M. ochrogaster and one larva from M. pinetorum. Although male P. leucopus traveled farther and had more ticks than females, we found no significant difference in numbers of ticks per mouse by sex and no significant correlation in numbers of ticks per mouse by weight, total length, or maximum distance traveled. This was most likely because a small percentage of the mice carried most of the ticks. We concluded that small mammals could reinfest a control area with D. variabilis but not with A. americanum.