Effects of food supplementation and helminth removal on space use and spatial overlap in wild rodent populations

Abstract

Animal space use and spatial overlap can have important consequences for pathogen transmission. Identifying how environmental variability and inter-individual variation affect spatial patterns to drive transmission heterogeneity in wildlife is a priority for effective management of wildlife disease. However, there are few experimental studies investigating how food abundance and macroparasite infection affect transmission opportunities in wildlife. Wild bank voles (Myodes glareolus) are a useful study system to investigate spatial patterns of wildlife and are amenable to experimental manipulations. We conducted a replicated, factorial field experiment in which we added food and removed helminths in wild vole populations in natural forest habitat and monitored vole space use and spatial overlap using capture-mark-recapture methods. Using a combination of home range and network analyses, we quantified vole space use and spatial overlap. We then compared the effects of food addition and helminth removal and investigated the impact of season and sex on space use and spatial overlap. We found that space use was impacted by breeding season and sex but not by food addition or helminth removal. Sex-based, seasonal changes in shared space use were more notable with food addition. Food addition also increased the frequency of, and variability in, spatial overlap occurring between individual voles at trapping locations, while helminth removal had no effect. Our work provides empirical evidence quantifying the spatial effects of food abundance and macroparasite infection on wildlife populations. We demonstrate the potential for high food abundance to increase spatial overlap relevant for pathogen transmission. Our findings also suggest that individual contributions to transmission may be heterogeneous within populations and that season and sex are important covariates to consider when identifying when and with whom transmission is most likely to occur.

Effects of food supplementation and helminth removal on space use and spatial overlap in wild rodent populations

“…5061/ dryad. r4xgx d2mp (Mistrick et al, 2024). Full code for all analyses and figures is available on GitHub (https:// github.…”

“…Vole capture data used for this analysis are available through the Dryad Digital Repository https://doi.org/10.5061/dryad.r4xgxd2mp (Mistrick et al., 2024). Full code for all analyses and figures is available on GitHub (https://github.com/jmistrick/vole-spatial-manuscript) and is archived with Zenodo https://doi.org/10.5281/zenodo.10603001 (Mistrick, 2024).…”

Experimental manipulation of food availability and macroparasite prevalence reveal differential effects on space use in wild rodents

“…Here, Mistrick et al. (2024) demonstrate that food availability can have nuanced downstream effects on the structure of potential contact, and thus parasite transmission, networks. First, food supplementation consistently decreased space use.…”

“…The study by Mistrick et al. (2024), in the current issue, simultaneously manipulated both food availability and pathogen loads in a two‐by‐two factorial design, giving us realistic insights into how these factors play out together. Across 12 sites in southern Finland, Mistrick et al.…”

“…Across 12 sites in southern Finland, Mistrick et al. (2024) experimentally increased food availability, dewormed voles using anti‐helminthics, did both treatments, or did neither. These treatments revealed direct effects on patterns of space use whereby increasing food availability substantially decreased space use (by increasing site fidelity and population sizes, which possibly also reduced territory sizes), while deworming for helminths increased space use.…”