UC Davis

AbstractFor social animals, social relationships are massively important to an individual’s ability to survive and thrive. Some relationships, like pair bonds, involve a high degree of attachment and interact with physiological processes like stress, sleep, and reproduction. The projects in this dissertation represent a cross-section of influential life events and processes throughout a pair-bonding primate’s life and examine the impact of those events on the pair relationship and individual psychophysiology of captive coppery titi monkeys (Plecturocebus cupreus). In the first study, we observed nighttime activity as a behavioral proxy for sleep in newly formed pairs of titis to assess how they habituated to a new social and physical environment across their first week with a new mate. We also compared the frequency of nighttime and daytime affiliative behaviors between pair mates to assess the comparative frequency and role of such behaviors at different times of day in a diurnal species. In the second study, we examined the impact of hormonal contraceptive use on reproductive cycling and affiliation within pairs. The effects of physiological interventions are particularly important to understand in a laboratory setting where breeding is selectively managed, and relationships are studied in neuropsychological research. Finally, in the third study, we assessed the role of pregnancy and infant rearing on the relationship between co-parents and pair mates. Together, this work represents the first studies that quantify nighttime behavior, assess the impact of contraception, and consider the changing relationship between parenting partners in this diurnal, pair-bonding species.