THE INFLUENCE OF THE POSTNATAL MATERNAL ENVIRONMENT IN ACCOUNTING FORDIFFERENCES IN AGGRESSION AND BEHAVIORAL STRATEGIES IN MUS-DOMESTICUS

House mice of selection lines for short attack latency (SAL) and long attack latency (LAL) differ fundamentally in the way they interact wit h their environment. A previous study showed marked differences in mat ernal behaviour between dams from both lines. The present study was de signed to determine, by reciprocal cross-fostering, to what extent the postnatal SAL and LAL maternal environment contributes to observed di fferences in aggression and behavioural strategy between SAL and LAL m ice. At a subadult age there were neither differences in attack latenc y between lines nor between control and cross-fostered groups. In adul thood there was a significant difference in attack latency between SAL and LAL mice, which was not influenced by maternal type. Also coping, as measured by the readiness to encounter a challenge, was not influe nced by maternal type. Both at a subadult age as in adulthood, SAL mic e encountered unknown situations much faster than LAL mice, but there were no differences between control and cross-fostered groups. As foun d in previous studies, SAL mice were more routine-like in their behavi our than LAL mice. However, SAL mice that were reared by LAL dams were more flexible in their behaviour than SAL mice reared by their own mo thers. This postnatal maternal effect on behavioural flexibility was n ot found in LAL mice. It can be concluded that the significant differe nce in early experience between SAL and LAL mice, due to different pat terns of maternal effort, hardly contributes to the consistent differe nces in aggression, coping and behavioural flexibility between SAL and LAL mice.