Abstract # 19:

Scheduled for Thursday, June 17, 2010 11:15 AM-11:25 AM: Session 5 (Medallion Ballroom B) Oral Presentation


SEASONAL BIRTH TIMING PREDICTS BASAL CORTISOL, ANTIBODY LEVEL, AND MOTHER-INFANT INTERACTIONS IN RHESUS MONKEY (MACACA MULATTA) INFANTS

J. Vandeleest1,2 and J. Capitanio2
1University of California-Davis, Psychology Department, One Shields Avenue, Davis, CA 95616, USA, 2California National Primate Research Center
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Infants born outside the birth season have a higher risk for mortality and within-season birth timing variation has been shown to affect infant birth weight and growth rates. It is unclear, however, how variation in birth timing within a birth season may affect the mother-infant relationship and infant health. The current study examined the relationship between birth timing and the mother-infant relationship, and measures of endocrine (i.e., cortisol) and immune (i.e., primary antibody response) function. Behavioral data were collected using twice weekly, ten minute focal observations when infants [N=19] were 4.5-5.0 months of age. At 5.75 months of age infants were vaccinated against Cholera toxin and blood samples were taken at 5.75 and 8.75 months of age. Multiple regression [α=0.05 for all analyses] indicated infants born later in the birth season had higher basal cortisol levels at 5.75 months and a reduced anti-Cholera antibody response at 8.75 months of age. Higher basal cortisol at 5.75 months also predicted reduced antibody levels at 8.75 months, and in fact cortisol mediated the relationship between birth timing and antibody level. Behavioral data indicated that late-born infants also had less nurturing mothers, more conflict with their mother, a lower rate of suckling, and spent less time in contact with their mother. These data suggest that birth timing can impact the mother-infant relationship and may have fitness consequences.