Developmental Continuity of Individual Differences in Rhesus and Capuchin Monkey Biobehavioral Development
Champoux, Pierre, Hommer, Roma, Rupp, Shannon-Lindell, Suomi
Research carried out during the past year (1) characterized a polymorphism in the MAO-A receptor gene for rhesus monkeys, with three distinctive alleles documented among members of the LCE rhesus monkey colony; (2) identified rearing condition differences in the development of circadian rhythms in activity for rhesus monkeys during the first five months of life as well as differences in acquisition and performance on a variety of cognitive and motivational tasks during the first 18 months of life; (3) characterized rearing condition differences in total brain volume and in specific neocortical and limbic brain regions in yearling rhesus monkeys by using MRI scans; (4) documented rearing condition differences in relative social dominance among juvenile rhesus monkeys that changed in qualitative fashion during their adolescent and adult years; (5) demonstrated a predictive relationship between measures of orientation and attention at two weeks of age and amount of alcohol consumed in early adulthood by rhesus monkeys independent of sex or type of early experience; (6) documented a strong positive relationship between brainstem serotonin transporter availability and alcohol consumption in young adult rhesus monkeys; (7) demonstrated a sensitization of CRH response over repeated social separations in juvenile rhesus monkeys; (8) identified a predictive relationship between CSF 5-HIAA concentrations of free-ranging rhesus monkey males at three years of age and levels of aggression, reproductive success, and mortality up to 10 years of age; and (9) documented predictive relationships between individual differences in measures of capuchin monkey infant behavioral activity and HPA reactivity at six and 12 months of age, respectively, which in turn were predictive of individual differences in a variety of specific measures of social behavior and environmental exploration over the next five years of life that paralleled previous findings in rhesus monkeys, despite major differences between the two species in overall rates of social activity and in social group structure and dynamics.

Adaptation of Laboratory-Reared Monkeys to Field Environments
Robbins, DeVinney, Carosi, Wagner, Taurio, Ulland, Yang, Suomi
A second major ongoing program of research in the CBGS has been the investigation of how rhesus monkeys and other nonhuman primate species born and raised under different laboratory conditions adapt to placement into environments that contain specific physical and social features of the monkey's natural habitat. In this research, adaptation is assessed by examining behavioral repertoires and by monitoring a variety of physiological systems in these subjects, yielding broad-based indices of relative physical and psychological well-being. The responses of subjects to experimental manipulation of selected features of their respective environments are also assessed in similar fashion. Whenever possible, field data are collected for appropriate comparisons. An additional focus is on investigating the cognitive, behavioral, and social processes involved in adaptation to new settings or circumstances. Many of the studies employ capuchin monkeys because they are unique among monkeys species in their propensity to manufacture and use tools to modify their physical environment. Research carried out during the past year (1) documented a predictive relationship between individual differences in maternal care received by rhesus monkey infants and their subsequent distress exhibited following the birth of a younger sibling in a wild-living rhesus monkey population on Cayo Santiago Island (PR); (2) characterized individual differences in the form and amount of infant-directed aggression and other aspects of maternal behavior among rhesus monkey mothers living in the LCE's five-acre field enclosure at the NIH Animal Center; (3) identified differences between abusive behavior of mothers directed toward their offspring and aggressive behavior directed toward other members of their social group; (4) documented instances of kidnapping of rhesus monkey infants by nonkin juvenile and adult females and related such behavior to differences in social rank between the infants' mothers and their kidnappers; (5) characterized individual differences in alloparenting behaviors toward infants by adult male rhesus monkeys (living in the five-acre field enclosure) as a function of the infants' gender and their mothers' age, social rank, and previous maternal experience; (6) characterized the development of social grooming patterns and conflict resolution over the second and third year of life in monkeys reared in the absence of adults; and (7) characterized changes in steroid hormone secretion associated the introduction of contraceptives in adult female capuchin monkeys.