Species-Specific Anti-Tick Strategies in Sympatric Rodents: Behavioral and Physiological Responses to Blacklegged Tick Parasitism

Host-parasite coevolution may result in diverse defensive strategies across related species. We investigated how three sympatric Pennsylvania rodent species respond to blacklegged tick (Ixodes scapularis) parasitism through controlled laboratory experiments using wild-caught white-footed mice (Peromyscus leucopus), southern red-backed voles (Clethrionomys gapperi), and meadow voles (Microtus pennsylvanicus). Behavioral observations following tick infestation revealed that meadow voles significantly increased grooming frequency and duration in response to tick presence. White-footed mice showed minimal behavioral changes, while southern red-backed voles exhibited intermediate responses. Capsule experiments preventing mechanical tick removal revealed distinct patterns across three sequential infestations. Southern red-backed voles demonstrated increased tick feeding duration from the first to the third infestation (3.9 to 5.4 days) while tick weights decreased substantially (3.2 to 2.1 mg). This pattern suggests compromised tick feeding efficiency, which is indicative of developing acquired tick resistance. White-footed mice maintained consistent feeding patterns across infestations, supporting their status as tolerant hosts. Meadow voles reduced tick feeding duration with effective behavioral defenses. Our findings demonstrate that sympatric host species have distinct strategies for managing tick parasitism. These species-specific responses could reflect different evolutionary histories with tick parasitism and may influence tick population dynamics and pathogen transmission patterns in natural communities.