title: Oxytocin facilitates fidelity in well-established marmoset pairs by reducing sociosexual behavior toward opposite-sex strangers.
abstract: Behavioral strategies that facilitate the maintenance of social bonds are critical for the preservation of high-quality social relationships. Central oxytocin (OT) activity modulates the behavioral features of socially monogamous relationships in a number of mammalian species (including marmoset monkeys), and plays a vital role in the behavioral maintenance of long-term social relationships. Two distinct variants of OT have been identified in some New World primates (including marmosets; Lee et al., 2011). The marmoset variant of the oxytocin ligand (Pro(8)-OT) is structurally distinct from the consensus mammalian variant of the oxytocin ligand (Leu(8)-OT), due to a proline substitution at the 8th amino-acid position. The goal of the present study was to determine if treating marmosets with Pro(8)-OT, relative to treatments with Leu(8)-OT, control saline, or an OT antagonist, had modulatory effects on the behavioral maintenance of long-term social relationships in marmosets. Treatment with the Pro(8) variant, but not the Leu(8) variant, of OT facilitated fidelity with a long-term partner by reducing time spent in close proximity with an opposite-sex stranger. However, this facilitative effect of Pro(8)-OT on proximity behavior manifested itself differently in male and female marmosets, such that females preferred to interact socially with their partner rather than a stranger when treated with Pro(8)-OT, while males spent less time in close proximity with both their partner and a stranger when treated with Pro(8)-OT. Furthermore, treatment with Pro(8)-OT, but not Leu(8)-OT, significantly delayed the expression of sexual solicitation behavior toward an opposite-sex stranger in both male and female marmosets, but had no effect on sociosexual behavior directed toward a long-term partner. These results suggest that the OT system is highly involved in reducing fidelity-threatening behaviors in well-established marmoset pairs, and that the effects were only produced by species-specific OT ligands.
authors.affiliation: Callitrichid Research Center, Department of Psychology, University of Nebraska - Omaha, USA. Electronic address: jonryancavanaug@unomaha.edu.
authors.forename: Jon
authors.initials: J
authors.lastname: Cavanaugh
authors.affiliation: Callitrichid Research Center, Department of Psychology, University of Nebraska - Omaha, USA.
authors.forename: Aaryn C
authors.initials: AC
authors.lastname: Mustoe
authors.affiliation: Callitrichid Research Center, Department of Psychology, University of Nebraska - Omaha, USA.
authors.forename: Jack H
authors.initials: JH
authors.lastname: Taylor
authors.affiliation: Callitrichid Research Center, Department of Psychology, University of Nebraska - Omaha, USA; Department of Biology, University of Nebraska - Omaha, USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: French
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D002144:Callithrix; D001892:Camphanes / Q000494:pharmacology; D005260:Female; D008297:Male; D010121:Oxytocin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D010152:Pair Bond; D010879:Piperazines / Q000494:pharmacology; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D012919:Social Behavior
chemical_list: D001892:Camphanes; D010879:Piperazines; D010121:Oxytocin; C086206:L 368899
keywords: Fidelity; Oxytocin; Pair-bond relationships; Partner-preference; Pro(8)-OT; Social behavior