title: Social status and helminth infections in female forest guenons (Cercopithecus mitis).
abstract: OBJECTIVE
  When resource competition within primate social groups is effective, high-ranking individuals generally gain fitness benefits. Contrary to expectations, female Cercopithecus mitis form linear dominance hierarchies without evidence for rank-related variation in fitness-relevant measures, raising questions about the evolution of guenon social structure. Here, we test whether social status predicts gastrointestinal helminth infections, known to influence health and morbidity in other mammalian hosts. In addition, we assess whether infections contribute to stress responses as indicated by fecal glucocorticoid (fGC) levels.
  
  
  METHODS
  We quantified infections and hormone levels in 382 fecal samples from 11 adult female Sykes' monkeys (C. m. albogularis) over four months in one wild study group at Gede Ruins, Kenya. Using a generalized estimating equations technique, we modeled the odds of infection, relative infection intensity, and fGC variation.
  
  
  RESULTS
  High-ranking females were less likely infected with Trichuris and Trichostrongylus, had lower fecal egg counts for both taxa, and overall lower helminth richness than low-ranking females. An inverse relationship between rank and Trichuris egg counts existed also in a study population of blue monkeys (C. m. stuhlmanni), where we collected comparable data over a shorter period. Regardless of rank, lactating females were more likely than non-lactating females to be infected with Trichuris, and had higher fecal egg counts for both Trichuris and Oesophagostomum. Lastly, we report evidence that Trichuris infections exacerbated energetic stress and that food supplementation by tourists increased infection levels.
  
  
  CONCLUSIONS
  Our findings suggest that high-rank may provide long-term health and energetic benefits for female C. mitis, with potential fitness implications.
authors.affiliation: Department of Evolutionary Anthropology, Duke University, Durham, NC.|National Museums of Kenya, Institute of Primate Research, Nairobi, Kenya.
authors.forename: Steffen
authors.initials: S
authors.lastname: Foerster
authors.affiliation: National Museums of Kenya, Institute of Primate Research, Nairobi, Kenya.
authors.forename: Kiio
authors.initials: K
authors.lastname: Kithome
authors.affiliation: Department of Ecology, Evolution and Environmental Biology, Columbia University, NY.
authors.forename: Marina
authors.initials: M
authors.lastname: Cords
authors.affiliation: Smithsonian Conservation Biology Institute, Front Royal, VA.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Monfort
mesh_terms: D000818:Animals; D000885:Anthropology, Physical; D002521:Cercopithecus / Q000469:parasitology* / Q000502:physiology*; D005243:Feces / Q000469:parasitology; D005260:Female; D006374:Helminthiasis, Animal / Q000503:physiopathology*; D006790:Host-Parasite Interactions; D007630:Kenya; D012930:Social Dominance; D013312:Stress, Physiological
keywords: dominance rank; energetic stress; parasite-host dynamics; primate socioecology