PRENATAL SOCIAL STRESS MASCULINIZES THE FEMALES BEHAVIOR IN GUINEA-PIGS

This study investigated the influence of the social environment during pregnancy and lactation on the female offsprings' behaviour and body weight. The subjects studied were daughters whose mothers had lived: a ) in a stable social environment (SSE) during pregnancy and lactation; b) in an unstable social environment (USE) during pregnancy and lacta tion; c) in a SSE during pregnancy but in an USE during lactation; d) in an USE during pregnancy but in a SSE during lactation. The SSE was made by keeping the group composition (one male, five females) constan t; in the USE situation every third day two females from different gro ups were exchanged. After weaning (n = 4 x 3 = 12), groups of daughter s, consisting of four females each, were established, originating from the different categories of mothers. From their 41st through their 80 th day of age the spontaneous behaviour of the daughters was recorded in their home cages. When the mothers had lived in an USE during pregn ancy, the daughters displayed significantly higher amounts of male-typ ical courtship, play, and social orientation behaviour compared to dau ghters whose mothers had lived in a SSE during pregnancy. The stabilit y and instability, respectively, of the social environment during lact ation, however, had no significant influence on the daughters' prospec tive behaviour. The four categories of daughters did not differ in the ir body weights either at birth or at 80 days of age. Thus, the instab ility of the social environment during pregnancy obviously represented a mild stressor that nevertheless caused a distinct masculinization o f the daughters' behaviour.