Changes in physiological stress and behaviour in semi-free-ranging red-capped mangabeys ( Cercocebus torquatus ) following antiparasitic treatment

Abstract

Parasites are ubiquitous in wildlife populations, but physiological and behavioural responses of hosts to infection are difficult to measure. We experimentally treated semi-free-ranging red-capped mangabeys (Cercocebus torquatus) in Nigeria with antiparasitic drugs and examined subsequent changes in glucocorticoid production and individual behaviour. Because both parasites and stress impact energy balance and health, we measured (i) behavioural time re-allocation via activity budgets, (ii) social relationships (e.g. social connectivity and dominance hierarchy stability) and (iii) body condition. We collected triplicate faecal samples (n ¼ 441) from 49 individuals prior to and following treatment. Cortisol levels fluctuated in parallel with parasite abundance. Elevations in cortisol, but not parasitism, were related to reduced body condition. Behaviour also shifted according to infection status, with uninfected individuals spending more time foraging and less time resting and vigilant compared with when they were infected. Time spent feeding, travelling or socializing did not differ between pre-and posttreatment time periods. Group cohesion, but not dominance stability, changed following treatment, suggesting parasite-induced social avoidance. Together, these findings show a coordinated response to infection that promotes host tolerance through stress and energy conservation, reduces transmission risk and increases protection when infected hosts are vulnerable.

Predictors of helminth parasite infection in female chacma baboons (Papio ursinus)

“…First, in support of the idea that glucocorticoids are associated with immunosuppression ( Nava-Castro et al, 2011 ), we found that females with high fecal glucocorticoid concentrations harbored high quantities of Trichuris eggs. This result is consistent with other studies of nonhuman primates that have also found positive correlations between glucocorticoid concentrations and helminth parasite loads (e.g., red colobus monkey, Procolobus rufomitratus : Chapman et al, 2006 ; red-capped mangabey, Cercocebus torquatus : Friant et al, 2016 ; yellow baboon, P. cynocephalus : Akinyi et al, 2019 ; Barbary macaque, Macaca sylvanus : Müller-Klein et al, 2019 ). However, contrary to this result, we also found that females with high fecal glucocorticoid concentrations were at low risk of Oesophagostomum infection.…”

“…Indeed, we found that baboon hosts are especially sensitive to parasitism during the costliest phases of the reproductive cycle: pregnancy and lactation. Moreover, while most studies of wild animals have focused on the relationship between glucocorticoid concentrations and parasitism (e.g., Friant et al, 2016 ; Akinyi et al, 2019 ; Müller-Klein et al, 2019 ), our study supplements this body of literature by additionally testing the association between sex hormones (progesterone and estrogen) and parasitism. Interestingly, our findings reveal that the interaction between sex hormones, reproductive state, and parasite infection is quite complex, and that baboon hosts are differentially vulnerable to different genera of parasites, which suggests that individual characteristics of parasites and different hormonal and reproductive environments of the host mediate the course of infection.…”

Costs and drivers of helminth parasite infection in wild female baboons

“…The physiological costs associated with helminth infection may be reflected in hormones that indicate host energetic expenditure, such as glucocorticoids (GCs). Several studies, both experimental and observational in the wild, have found significant positive correlations between host GC levels and patterns of helminth infection (Friant, Ziegler, & Goldberg, 2016;Muehlenbein & Watts, 2010;Müller-Klein et al, 2018;Sures, Knopf, & Kloas, 2001).…”

Sick and Tired: Polyparasitism, Food Stress and Sickness Behaviour in a Gregarious Mammal

“…It is The copyright holder for this preprint this version posted April 22, 2021. ; https://doi.org/10.1101/2021.04. 22.440985 doi: bioRxiv preprint It has long been established that pathogens with high fatality rates, such as epidemic viruses, can drive population declines, and may contribute to local extinctions [1]. The effects of sub-clinical or non-lethal infections are often overlooked, however, despite costs to host health and fitness, and the consequent impact of such diseases on population viability [2].…”