Ticks (Acari: Ixodidae) infesting medium-sized wild mammals in southwestern Tennessee

Seven species of ixodid ticks (n=2,661) were found on medium-sized wild mammals (n = 295) during a 13-mo study in Shelby County, Tennessee. The seven tick species collected were Dermacentor variabilis (Say), Amblyomma americanum (L.), Rhipicephalus sanguineus (Latreille), Ixodes texanus (Banks), I. cookei (Packard), I. scapularis (Say), and Haemaphysalis leporispalustris (Packard). The raccoon had the greatest tick species diversity- in all of the aforementioned ticks except H. leporispalustris and R. sanguineus. The raccoon and opossum accounted for 96.9% of the ticks collected and were the most commonly captured medium-sized mammals. The only tick collected in high enough numbers for statistical analysis was D. variabilis. Mammal species and habitat type were the most important factors affecting the mean number of adult D. variabilis per mammal. The mean number of D. variabilis adults carried by raccoons was significantly higher than opossums. Whether a habitat occurred within Memphis city limits or outside city limits also affected the number of adult D. variabilis on mammals. The interaction between habitat, mammal, and whether inside or outside the city limits was near statistical significance. It is suggested that there is biological significance; within city limits, medium-sized wild mammals are forced into wooded areas where there is a subsequent increase in tick populations in these habitat patches