Abstract # 5828 Poster # 65:

Scheduled for Saturday, September 13, 2014 07:00 PM-09:00 PM: Session 11 (Decatur B) Poster Presentation


EXPLORING THE VARIABLE WEANING STRATEGIES OF CAPTIVE FEMALE RHESUS MACAQUES (MACACA MULATTA) USING STABLE ISOTOPE ANALYSIS

K. A. Partrick and L. J. Reitsema
The University of Georgia , Athens, Georgia, USA
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     Weaning is a critical life history stage, since nursing is energetically costly and suppresses ovulation. A female must wean her offspring to resume sexual receptivity without compromising infant survival. Behavioral observations can be bias due to comfort nursing, which falsely identifies an infant as nursing. We employ stable isotope analysis to track the transition from a breast fed to self-fed diet in rhesus macaques. We test the hypothesis: 1) Infants wean upon reaching 2/3 adult body size (threshold weight hypothesis) and investigate factors (dominance rank, parity, and infant sex) known to influence weaning. Plasma samples were collected from 8 mother infant dyads housed at Yerkes Primate Research Center. Mother samples at infant age: 2 and 5 months and infant samples at: 2, 5-8, and 10 months were assayed for carbon and nitrogen stable isotopes. Infant’s ?15N and ?13C values were indistinguishable (7.01‰+/- .39‰) from their mothers between 5-8 months of age, sooner than predicted by the threshold weight hypothesis. Male infants weaned sooner (age 6 months versus age 8 months). A strong relationship was found regarding rank, with low-ranking mothers weaning sooner (r2=.628, p=.019). No relationship was found for parity (r2=.249, p=.208). Results contrast those of behavioral study suggesting these components need to be objectively proven. Inadequate nutrition compromises infant vitality; therefore, understanding optimal weaning strategies sheds light on developmental health and maternal fitness.