title: Do newborn vocalizations affect the behavioral and hormonal responses of nonreproductive male common marmosets (Callithrix jacchus)?
abstract: Parental care in mammals is influenced by sensory stimuli from infants, such as sight and sound, and by changes in the hormone levels of caretakers. To determine the responsiveness of common marmoset (Callithrix jacchus) adult males with and without previous experience in caretaking to newborn sensory cues, we exposed twelve males to infant vocalization recordings and assessed their hormonal and behavioral responses. Males were placed in the testing cage for 10 min under two conditions: (a) control condition (exposure to adult conspecific vocalization recordings), and (b) experimental condition (exposure to infant vocalization recordings). We recorded the frequency of approach towards the sound source, the time spent near it and locomotion frequency of males in the cage under both conditions. Blood samples were collected after each test for cortisol, measured by the enzyme immunoassay method. Infant vocalization affects the behavioral and hormonal responses of non-reproductive male common marmosets. All males approached and spent more time near the sound source and showed an increase in locomotion during infant vocalization exposure compared to the control condition. Successive exposure to infant vocalization increased the responsiveness in inexperienced males. Cortisol levels were significantly higher following infant vocalization exposure compared to the control condition. These findings support the assumption that sound stimuli from the newborn are critical in initiating and maintaining caretaker responsiveness and that cortisol seems to be important for alertness to sensory stimuli, modulating their motivation to interact with infants.
authors.affiliation: Departamento de Fisiologia, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Campus Universitário, Caixa Postal 1511, Natal, RN, 59078-970, Brazil. maricelebarbosa@yahoo.com.br.
authors.forename: Maricele Nascimento
authors.initials: MN
authors.lastname: Barbosa
authors.affiliation: Departamento de Fisiologia, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Campus Universitário, Caixa Postal 1511, Natal, RN, 59078-970, Brazil.
authors.forename: Maria Teresa da Silva
authors.initials: MT
authors.lastname: Mota
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D002144:Callithrix / Q000502:physiology*; D003463:Cues; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D010332:Paternal Behavior; D012737:Sex Factors; D014828:Vocalization, Animal
chemical_list: D006854:Hydrocortisone
keywords: Alloparental care; Callithrix jacchus; Cortisol; Infant vocalizations; Marmosets; Previous experience