Effects of ovariectomy, social instability and social status on female Macaca fascicularis social behavior

Abstract

The effects of ovariectomy, social instability and social status on affiliative and agonistic behavior were studied in 44 females housed in 10 unimale groups. Five of the groups contained ovariectomized females and five groups contained intact females. The membership among three groups of intact females (n=13) and three groups of ovariectomized females (n=13) was reorganized every three months (unstable), and the other groups were left undisturbed (stable) for the 22 month study. The behavior of each female was recorded during 160 (stable) or 190 (unstable) 15 min focal observations of each subject. The social status of each female was determined by outcomes of agonistic interactions. It was hypothesized that the effects of social instability and status would be more pervasive than the effects of ovariectomy. It was found that ovariectomy reduced interfemale affiliation and increased male-female agonism. Social instability increased submissions to males and females and time spent alone, and decreased interfemale affiliation. Dominant animals were more aggressive and less submissive than subordinates. Thus, ovariectomy influenced both isosexual and heterosexual social interaction, implying mediation of these behaviors, at least in part, by ovarian hormones.