title: Oxytocin is associated with infant-care behavior and motivation in cooperatively breeding marmoset monkeys.
abstract: The neurohormone oxytocin (OT) is positively involved in the regulation of parenting and social bonding in mammals, and may thus also be important for the mediation of alloparental care. In cooperatively breeding marmosets, infants are raised in teamwork by parents and adult and sub-adult non-reproductive helpers (usually older siblings). Despite high intrinsic motivation, which may be mediated by hormonal priming, not all individuals are always equally able to contribute to infant-care due to competition among care-takers. Among the various care-taking behaviors, proactive food sharing may reflect motivational levels best, since it can be performed ad libitum by several individuals even if competition among surplus care-takers constrains access to infants. Our aim was to study the link between urinary OT levels and care-taking behaviors in group-living marmosets, while taking affiliation with other adults and infant age into account. Over eight reproductive cycles, 26 individuals were monitored for urinary baseline OT, care-taking behaviors (baby-licking, -grooming, -carrying, and proactive food sharing), and adult-directed affiliation. Mean OT levels were generally highest in female breeders and OT increased significantly in all individuals after birth. During early infancy, high urinary OT levels were associated with increased infant-licking but low levels of adult-affiliation, and during late infancy, with increased proactive food sharing. Our results show that, in marmoset parents and alloparents, OT is positively involved in the regulation of care-taking, thereby reflecting the changing needs during infant development. This particularly included behaviors that are more likely to reflect intrinsic care motivation, suggesting a positive link between OT and motivational regulation of infant-care.
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland. Electronic address: christa.finkenwirth@uzh.ch.
authors.forename: Christa
authors.initials: C
authors.lastname: Finkenwirth
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Eloisa
authors.initials: E
authors.lastname: Martins
authors.affiliation: Max-Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Deschner
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Burkart
mesh_terms: D000328:Adult; D000818:Animals; D002144:Callithrix / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D006120:Grooming / Q000502:physiology*; D006801:Humans; D007223:Infant; D008297:Male; D008425:Maternal Behavior / Q000502:physiology*; D009042:Motivation / Q000502:physiology; D010121:Oxytocin / Q000097:blood*; D010332:Paternal Behavior / Q000502:physiology*; D012919:Social Behavior; D012931:Social Environment
chemical_list: D010121:Oxytocin
keywords: Alloparental care; Callithrix jacchus; Cooperative breeding; Hormonal priming; Motivation; Oxytocin; Proactive food sharing