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

Animal space use and spatial overlap can have important consequences for population-level processes such as social interactions and pathogen transmission. Identifying how environmental variability and inter-individual variation affect spatial patterns and in turn influence interactions in animal populations is a priority for the study of animal behaviour and disease ecology. Environmental food availability and macroparasite infection are common drivers of variation, but there are few experimental studies investigating how they affect spatial patterns of wildlife. Bank voles (Clethrionomys glareolus) are a tractable study system to investigate spatial patterns of wildlife and are amenable to experimental manipulations. We conducted a replicated, factorial field experiment in which we provided supplementary food and removed helminths in vole populations in natural forest habitat and monitored vole space use and spatial overlap using capture-mark-recapture methods. Using network analysis, we quantified vole space use and spatial overlap. We compared the effects of food supplementation and helminth removal and investigated the impacts of season, sex and reproductive status on space use and spatial overlap. We found that food supplementation decreased vole space use while helminth removal increased space use. Space use also varied by sex, reproductive status and season. Spatial overlap was similar between treatments despite up to threefold differences in population size. By quantifying the spatial effects of food availability and macroparasite infection on wildlife populations, we demonstrate the potential for space use and population density to trade-off and maintain consistent spatial overlap in wildlife populations. This has important implications for spatial processes in wildlife including pathogen transmission.

Zoos as Sentinels? A Meta-Analysis of Seroprevalence of Terrestrial Mammalian Viruses in Zoos.

The One Health framework links animal, human, and environmental health, and focuses on emerging zoonotic pathogens. Understanding the interface between wildlife and human activity is critical due to the unpredictable nature of spillover of zoonotic pathogens from animals to humans. Zoos are important partners in One Health because of their contributions to education, conservation, and animal health monitoring. In addition, the housing of wildlife in captive and semi-natural settings makes zoos, especially relevant for detecting animal-related pathogens. A first step to determine the utility of zoos in contributing to pathogen surveillance is to survey the peer-reviewed literature. We, therefore, retrieved data from the previous 20 years and performed a meta-analysis to determine global patterns of viral seroprevalence in mammals housed in zoo collections from peer-reviewed literature. We analysed 50 articles, representing a total of 11,300 terrestrial mammals. Increased prevalence was found in viruses strictly targeting specific host taxonomy, especially in viruses transmitted through direct contact. Potentially complex patterns with geography were also identified, despite uneven sampling. This research highlights the role zoos could play in public health and encourages future standardized epidemiological surveillance of zoological collections.

Corticosterone response by Peromyscus mice to parasites, reproductive season, and age.

A common response to parasite infestations is increased production of glucocorticoid hormones that regulate immune function. We examined relationships between ectoparasite infestations and fecal corticosterone metabolites (FCM) in deer mice (Peromyscus maniculatus). Furthermore, we experimentally removed fleas to determine if reductions in ectoparasites affected FCM production. Individuals were assigned to control (no flea removal) or treatment (anti-flea application, physical combing) groups and individuals were recaptured to assess changes in FCM concentrations. There was a significant and negative effect of number of anti-flea treatment applications on FCM concentrations of deer mice. However, models including host biology traits and environmental predictors had a better model fit compared to models containing ectoparasite predictors. In particular, there was a significant relationship of deer mouse FCM with date and host age, where glucocorticoid production decreased towards the end of the breeding season and increased with age. Overall, adverse events associated with reproduction and age class, rather than ectoparasites, may be more important to variation in glucocorticoids of deer mice.

Corrigendum to "Parasite species co-occurrence patterns on Peromyscus: Joint species distribution modelling" [IJP: Parasites Wildlife 12 (2020) 199-206].

[This corrects the article DOI: 10.1016/j.ijppaw.2020.04.011.].

Parasite species co-occurrence patterns on Peromyscus: Joint species distribution modelling.

Hosts are often infested by multiple parasite species, but it is often unclear whether patterns of parasite co-occurrence are driven by parasite habitat requirements or parasite species interactions. Using data on infestation patterns of ectoparasitic arthropods (fleas, trombiculid mites, cuterebrid botflies) from deer mice (Peromyscus maniculatus), we analyzed species associations using joint species distribution modelling. We also experimentally removed a flea (Orchopeas leucopus) from a subset of deer mice to examine the effect on other common ectoparasite species. We found that the mite (Neotrombicula microti) and botfly (Cuterebra sp.) had a negative relationship that is likely a true biotic species interaction. The flea had a negative association with the mite and a positive association with the botfly species, both of which appeared to be influenced by host traits or parasite life-history traits. Furthermore, experimental removal of the flea did not have a significant effect on ectoparasite prevalence of another species. Overall, these findings suggest that complex parasite species associations can be present among multiple parasite taxa, and that aggregation is not always the rule for ectoparasite communities of small mammals.