title: Does hierarchy stability influence testosterone and cortisol levels of bearded capuchin monkeys (Sapajus libidinosus) adult males? A comparison between two wild groups.
abstract: Testosterone and cortisol are hormones expected to play a major role in competitive behaviours (i.e. aggression), and are related to rank and hierarchical stability. Through a non-invasive technique, we analyzed faecal testosterone (FTM(1)) and cortisol (FCM(2)) metabolites of dominant and subordinate males from two wild groups of bearded capuchin monkeys. One group had a stable dominance hierarchy while the other had an unstable hierarchy, with a marked conflict period related to a male take-over. In the unstable hierarchy group (1) the dominant male had higher FTM peaks than subordinates, and (2) basal FTM levels were higher than in the stable group. These findings are in accordance with the Challenge Hypothesis and rank-based predictions, and confirm that in Sapajus libidinosus hierarchy stability, social status, aggression rates and testosterone are closely related. Dominants of both groups had higher basal and peak FCM levels, suggesting that in S. libidinosus the dominant male has a higher allostatic load than subordinates, related to his role in protection against predators, intragroup appeasement, and control of food sources. Finally, we suggest that males of S. libidinosus are resistant to testosterone suppression by cortisol, because in the unstable group in spite of an increase in FCM there was also an increase in FTM during the conflict period. This article is part of a Special Issue entitled: Neotropical Behaviour.
authors.affiliation: Institute of Psychology, University of São Paulo, Av. Prof. Mello Moraes, 1721, CEP 05508-030 São Paulo, Brazil. Electronic address: olimendonca@gmail.com.
authors.forename: Olívia
authors.initials: O
authors.lastname: Mendonça-Furtado
authors.affiliation: Institute of Psychology, University of São Paulo, Av. Prof. Mello Moraes, 1721, CEP 05508-030 São Paulo, Brazil. Electronic address: edaes.mariana@gmail.com.
authors.forename: Mariana
authors.initials: M
authors.lastname: Edaes
authors.affiliation: Institute of Medical Biochemistry, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria. Electronic address: Rupert.Palme@vetmeduni.ac.at.
authors.forename: Rupert
authors.initials: R
authors.lastname: Palme
authors.affiliation: Institute of Mathematics and Statistics, University of São Paulo, Rua do Matão, 1010, CEP 05508-090 São Paulo, Brazil. Electronic address: agatha.srodrigues@gmail.com.
authors.forename: Agatha
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Institute of Psychology, University of São Paulo, Av. Prof. Mello Moraes, 1721, CEP 05508-030 São Paulo, Brazil. Electronic address: siqueira@usp.br.
authors.forename: José
authors.initials: J
authors.lastname: Siqueira
authors.affiliation: Institute of Psychology, University of São Paulo, Av. Prof. Mello Moraes, 1721, CEP 05508-030 São Paulo, Brazil. Electronic address: patrizar@usp.br.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Izar
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000378:metabolism; D002428:Cebus / Q000378:metabolism*; D003220:Conflict, Psychological; D005243:Feces / Q000737:chemistry; D006854:Hydrocortisone / Q000032:analysis*; D008297:Male; D012930:Social Dominance; D013739:Testosterone / Q000032:analysis*
chemical_list: D013739:Testosterone; D006854:Hydrocortisone
keywords: Aggression; Allostatic load; Challenge hypothesis; Dominance; Hormones