title: Social competition and plasma testosterone profile in domesticated canaries: an experimental test of the challenge hypothesis.
abstract: The challenge hypothesis predicts that plasma testosterone (T) concentration is high when male-male competitions are high and decreases when males are engaged in paternal care. In monogamous species, T concentration increases at the beginning of the breeding period and decreases after egg laying. According to the challenge hypothesis, increasing competition should also lead to T increase. The aim of our study was to test this hypothesis. In a first experiment, we measured the T profile of domesticated canaries housed with their mate in separated cages without competition. In a second one, we created a competition by housing male and female domestic canaries together (in an aviary) and emphasized this competition by limiting food access. We also studied social status effect. Our results showed no effect of social status in both sexes and no differences in female's T concentration. Concerning males, we obtained a clear monogamous T profile from the ones housed in a low competition situation and a polygamous profile from the others housed in high competition situation. Thus, our results support the hypothesis of the plasticity of the mechanisms controlling T concentration according to environmental conditions.
authors.affiliation: Laboratoire d'Ethologie et Cognition Comparées, Université Paris 10 Nanterre, Bâtiment H, 200 Avenue de la République, 92 001 Nanterre Cedex, France. maelle.parisot@u-paris10.fr
authors.forename: Maëlle
authors.initials: M
authors.lastname: Parisot
authors.forename: Aurélie
authors.initials: A
authors.lastname: Tanvez
authors.forename: André
authors.initials: A
authors.lastname: Lacroix
authors.forename: Eric
authors.initials: E
authors.lastname: Vallet
authors.forename: Nathalie
authors.initials: N
authors.lastname: Béguin
authors.forename: Gérard
authors.initials: G
authors.lastname: Leboucher
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D002171:Canaries / Q000502:physiology*; D003163:Competitive Behavior / Q000502:physiology*; D005260:Female; D008297:Male; D012919:Social Behavior; D012930:Social Dominance; D012931:Social Environment; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone