William A. Mason - US grants

ethology; neuroendocrine system; sympathetic nervous system; parasympathetic nervous system; stress; species difference; social group process; nutrient intake activity; catecholamines; social psychology; Saimiri; Ceboidea;

social behavior; animal developmental psychology; early experience; ethology; psychological stressor; coping; cortisol; heart rate; mother child interaction; Macaca mulatta; dogs;

social organization; social psychology; ethology; Saimiri; Ceboidea; species difference; animal ecology; socioenvironment; coping; nutrient intake activity; gender difference; social behavior; territoriality;

In most vertebrates, either sons or daughters typically disperse farther from the birthplace than offspring of the other sex before breeding. Theory suggests that which sex disperses depends on the mating system and the degree to which males and females invest care in offspring. In polygynous mammals males usually provide little care, and males disperse farther than females. In contrast, in monogamous birds males often provide substantial care, and females disperse farther than males. There is little understanding of dispersal in the few monogamous mammals in which males care significantly for offspring. Through genetic analyses and behavioral observations, this study will investigate patterns of natal dispersal in the dusky titi monkey, a monogamous South American primate characterized by paternal care. The study will also investigate adult reproductive behavior. Despite pairing monogamously, female titi monkeys mate with males other than their mates. Using genetic techniques and behavioral observations, this study will establish whether these extra pair matings produce offspring and will investigate the factors that guide female reproductive decisions and whether they affect paternal behavior and social dynamics between paired adults. The results will broaden understanding of factors that affect the stability of the family group in monogamous primates.

Significance Monogamy and extensive paternal care are rare traits in nonhuman primates andare important for the light they shed on the organization of primate social systems. Objectives The long-range objective of this program is to determine the behavioral and physiological processes that contribute to differences in social organization between the monogamous titi monkey (Callicebus) and the polygamous squirrel monkey (Saimiri). Male titi monkeys are heavily involved in the care of their infants whereas male squirrel monkeys avoid infants. The specific aim of this project is to examine the effects of parenthood on the reactions of male and female titi monkeys to infants. Results Attraction to infants has been measured in retrieval tests. To date, one adult male and six adult females have been tested in a before-after design First, as reproductively mature siblings living in their family groups; later, as parents with their first surviving infant. The effects of becoming a parent were variable, ranging from dramatic increases in the tendency to retrieve in some animals, to no change in others. The male failed to retrieve entirely when tested with its infant sibling, but retrieved on every trial with its first-born infant. At the other extreme, three females failed to retrieve consistently in either phase. Future Directions Based on performance of veteran parents, the number of consistent retrievers is expected to increase with additional parental experience. Hormonal changes accompanying changes in parental behavior will be examined in future research. KEYWORDS monogamy, parenting

psychology; environmental health; behavioral /social science research tag; Mammalia;