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ABSTRACT Mice in the genusPeromyscusare abundant and geographically widespread in North America, serving as reservoirs for zoonotic pathogens, includingBorrelia burgdorferi(B. burgdorferi), the causative agent of Lyme disease, transmitted byIxodes scapularisticks. While the white‐footed mouse (Peromyscus leucopus(P. leucopus)) is the primary reservoir in the United States, the deer mouse (P. maniculatus), an ecologically similar congener, rarely transmits the pathogen to biting ticks. Understanding the factors that allow these similar species to serve as a poor and competent reservoir is critical for understanding tick‐borne disease ecology and epidemiology, especially as climate change expands the habitats where ticks can transmit pathogens. Our study investigated immunological differences between these rodent species. Specifically, we compared the expression of six immune genes (i.e., TLR‐2, IFN‐γ, IL‐6, IL‐10, GATA‐3, TGF‐β) broadly involved in bacterial recognition, elimination, and/or pathology mitigation in ear biopsies collected by the National Ecological Observatory Network (NEON) as part of their routine surveillance. A principal components analysis indicated that immune gene expression in both species varied in two dimensions: TLR2, IFN‐γ, IL‐6, and IL‐10 (comprising PC1) and TGF‐β and GATA3 (comprising PC2) expression tended to covary within individuals. However, when we analyzed expression differences of each gene singly between species,P. maniculatusexpressed more TLR2, IL‐6, and IL‐10 but less IFN‐γ and GATA3 thanP. leucopus. This immune profile could partly explain whyP. leucopusis a better reservoir for bacterial pathogens such asB. burgdorferi. 

Abstract Identifying the factors that affect host–parasite interactions is essential for understanding the ecology and dynamics of vector‐borne diseases and may be an important component of predicting human disease risk. Characteristics of hosts themselves (e.g., body condition, host behavior, immune defenses) may affect the likelihood of parasitism. However, despite highly variable rates of parasitism and infection in wild populations, identifying widespread links between individual characteristics and heterogeneity in parasite acquisition has proven challenging because many zoonoses exist over wide geographic extents and exhibit both spatial and temporal heterogeneity in prevalence and individual and population‐level effects. Using seven years of data collected by the National Ecological Observatory Network (NEON), we examined relationships among individual host condition, behavior, and parasitism byIxodidticks in a keystone host species, the white‐footed mouse,Peromyscus leucopus. We found that individual condition, specifically sex, body mass, and reproductive condition, had both direct and indirect effects on parasitism by ticks, but the nature of these effects differed for parasitism by larval versus nymphal ticks. We also found that condition differences influenced rodent behavior, and behavior directly affected the rates of parasitism, with individual mice that moved farther being more likely to carry ticks. This study illustrates how individual‐level data can be examined using large‐scale datasets to draw inference and uncover broad patterns in host–parasite encounters at unprecedented spatial scales. Our results suggest that intraspecific variation in the movement ecology of hosts may affect host–parasite encounter rates and, ultimately, alter zoonotic disease risk through anthropogenic modifications and natural environmental conditions that alter host space use. 

Promoting regeneration of native trees, likeQuercusspp., is a priority for land managers given the ecological and economic importance of oak woodlands. Although direct seeding may promote recruitment ofQuercusspp., the effectiveness of direct seeding may be greatly reduced in environments where the activity of granivorous rodents is high. Importantly, the activity of granivorous rodents may be highest in environments where oak restoration is most desired, such as habitats invaded by non‐native woody shrubs. Implementing chemical deterrents to granivory should promote direct seeding success; yet it is essential to understand if those deterrents are effective in challenging restoration situations (e.g. areas with dense invasive shrub cover). Moreover, it is important to determine whether chemicals that deter granivory have undesired effects on beneficial ecological interactions, such as animal‐mediated seed dispersal. We used multi‐field site experiments in shrub‐invaded and shrub‐cleared forest plots to compare the removal and dispersal ofQuercus rubraacorns with seed coats treated with a pepper‐based capsaicin extract versus acorns treated with control solutions (i.e. water and ethanol). Seed removal was quantified for 37 days, and seed survival and dispersal were quantified by relocating nail‐tagged acorns after 8 weeks. We found that capsaicin‐treated seeds had a significantly higher probability of survival compared to seeds treated with control solutions; the presence of the invasive shrubRhamnus catharticaincreased post‐dispersal seed consumption regardless of seed‐coat treatment; capsaicin did not affect acorn dispersal distance; and the concentration of capsaicin coatings on acorns declined over time in the field. 

The utility of seed addition to promote tree regeneration can be greatly limited by animals that consume seeds. Moreover, given that restoration often occurs in forests where invasive shrubs are abundant, and evidence that invasive shrubs can increase granivory, it is important to explore whether methods for reducing granivory work equally well in invaded and uninvaded habitats. We used a multi-site field experiment spanning 160 days to explore whether coating seeds of Prunus serotina with capsaicin extract leads to reduced granivory in habitats with or without invasive shrubs ( Rhamnus cathartica). Capsaicin-coated seeds were removed at a similar rate to uncoated seeds, but seeds in invaded plots had a 78.8% higher rate of removal compared to plots without invasive shrubs. Our findings suggest that managers seeking to encourage regeneration of native trees using direct seeding should consider invasive shrub removal as a top priority to limit the loss of seeds once sown. 

Long-term ecological datasets contain vast behavioral data, enabling the quantification of among individual behavioral variation at unprecedented spatiotemporal scales. We detail how behaviors can be extracted and describe how such data can be used to test new hypotheses, inform population and community ecology, and address pressing conservation needs.