In the Lyme light: individual trait determinants of Borrelia burgdorferi infection in Peromyscus mice

Disease ecologists commonly use abiotic factors (e.g. temperature and moisture) or measures of biodiversity (e.g. species richness) to predict Lyme disease transmission patterns, but variance in infection probability among individuals within a population is poorly understood. Most studies assume intraspecific consistency, but recent evidence suggests that individual traits, such as animal personality, may drive differences in encounter rates with infected vectors and pathogen transmission probabilities through differential space use and microhabitat selection, leading to intraspecific variation in infection probability. In addition, because vectors and hosts are nonrandomly distributed across a landscape, land-use changes that modify key habitat features-such as forest management practices-may substantially alter associations between individual traits and infection probability. To address these gaps in our knowledge, we used a large-scale capture-mark-recapture study targeting Peromyscus mice in Maine, United States, to test whether personality drives probability of Borrelia burgdorferi infection in hosts within managed forest compartments with different silvicultural treatments. Specifically, we tested effects of individual phenotypic traits (physical and behavioral) and environmental traits (microhabitat and forest type) on infection probability within 2 species: P. leucopus and P. maniculatus. We found evidence that boldness negatively influences infection probability in P. maniculatus, and that body mass positively influences infection probability in both species. We found no effect of mouse density, microhabitat, or forest type in our analyses. These results suggest that personalities vary in their functional contributions to the natural cycle of B. burgdorferi, and that broader integration of behavioral diversity in disease ecology studies may aid in identifying key transmission zones for this rapidly expanding vector-borne zoonosis. In this study, we investigate the effect of personality in 2 Peromyscus species on Borrelia burgdorferi infection probability. Our results reveal preliminary evidence of nonrandom infection probability in hosts by boldness, which indicate that between-individual behavioral differences are potentially important drivers for infection status. We discuss possible mechanisms, including the risk-of-parasitism hypothesis, and endorse broader integration of behavioral diversity in disease ecology.