Sex, stress and social status: Patterns in fecal testosterone and glucocorticoid metabolites in male Ethiopian wolves
ABSTRACT Ethiopian wolves, Canis simensis, live in large multi-male family packs, where males are philopatric and do not disperse. Within a pack, mating and breeding is largely monopolized by the dominant male and female, although extra-pack copulations are common, and subordinate males may sire pups in neighboring packs. Regardless of paternity, all males in a pack help rear the pups. We non-invasively studied patterns in fecal testosterone and glucocorticoid metabolite concentrations using radioimmunoassays of fecal samples collected from nine wild male Ethiopian wolves between August 2007 and February 2008. We tested the predictions of the Challenge Hypothesis, namely that fecal testosterone metabolite concentrations would be higher during the annual mating season, which is the portion of the reproductive cycle when mating and increased aggression typically occur, and lower when there were pups in the pack for which to care. Contrary to the predictions of the Challenge Hypothesis, we did not detect patterns in fecal testosterone metabolite concentrations associated with reproductive stage during our study period. Similarly, we found no patterns associated with reproductive stage in male fecal glucocorticoid metabolite concentrations. Dominant males had higher average fecal testosterone and glucocorticoid metabolite concentrations than did subordinates, which may be related to higher rates of aggression and mate guarding in dominant males of group-living canids, a pattern also reported in African wild dogs, Lycaon pictus.
- SourceAvailable from: Claudio Sillero
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- "Faecal samples were collected between 7 August 2008 and 20 February 2010 (see van Kesteren et al., 2012, 2013). The sampling time included two field seasons, one from August 2008 to February 2009 and one from July 2009 to February 2010, with two samples collected opportunistically in April and May 2008. "
ABSTRACT: Ethiopian wolves, Canis simensis, are an endangered carnivore endemic to the Ethiopian highlands. Although previous studies have focused on aspects of Ethiopian wolf biology, including diet, territoriality, reproduction and infectious diseases such as rabies, little is known of their helminth parasites. In the current study, faecal samples were collected from 94 wild Ethiopian wolves in the Bale Mountains of southern Ethiopia, between August 2008 and February 2010, and were screened for the presence of helminth eggs using a semi-quantitative volumetric dilution method with microscopy. We found that 66 of the 94 faecal samples (70.2%) contained eggs from at least one group of helminths, including Capillaria, Toxocara, Trichuris, ancylostomatids, Hymenolepis and taeniids. Eggs of Capillaria sp. were found most commonly, followed by Trichuris sp., ancylostomatid species and Toxocara species. Three samples contained Hymenolepis sp. eggs, which were likely artefacts from ingested prey species. Four samples contained taeniid eggs, one of which was copro-polymerase chain reaction (copro-PCR) and sequence positive for Echinococcus granulosus, suggesting a spillover from a domestic parasite cycle into this wildlife species. Associations between presence/absence of Capillaria, Toxocara and Trichuris eggs were found; and egg burdens of Toxocara and ancylostomatids were found to be associated with geographical location and sampling season.Journal of Helminthology 07/2014; 89(04):1-9. DOI:10.1017/S0022149X14000534 · 1.30 Impact Factor
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ABSTRACT: Spatial position within a group affects the value of group-living benefits such as reduced predation risk and improved foraging. The threat of predation, poor nutrition or increased competition from conspecifics can all cause stress. In many species, central positions are known to be more beneficial than peripheral positions in terms of reduced predation, vigilance and foraging. In this study, we examine whether spatial position within a group is associated with stress and anxiety in a troop of olive baboons (Papio anubis). We predicted that the benefits of occupying central positions would be reflected by a reduction in stress and anxiety for animals who spent the most time in the centre of the group. The study subjects appeared to compete actively for the centre of the group. Physiological stress measures (faecal glucocorticoid concentrations) were positively correlated with time spent in central positions. Time spent in central positions was positively correlated with proximity but negatively correlated with vigilance behaviours (alarm barks). Vigilance rates were positively correlated with measures of anxiety (self-scratch frequency). It is suggested that individuals experience chronic stress due to proximity to conspecifics in central positions, whilst perceived predation risk causes anxiety, with perceived predation risk experienced more by individuals on the periphery.Behavioural Processes 10/2014; 108. DOI:10.1016/j.beproc.2014.08.006 · 1.46 Impact Factor