Social experience has been shown to mask or eliminate heritable effects on aggressive behavior in male mice. This work assesses the impact of social experience in females from lines of mice selectively bred for differential male aggressiveness. These results confirm the earlier report of cross-sex similarity in aggressive behavior after selection directed only at male behaviors ( Hood & Cairns, 1 988 ). Repeated test experience increased aggressive behavior of S 6 females. In addition, a genetic-developmental interaction was found, with enhanced aggressiveness in mature vs. young high-aggressive line females. Repeated test experience in 4 daily trials with mature S 15 females obscured the clear line differences in attack frequency obtained on the first trial. In particular, a few highly aggressive individuals emerged among the group-reared low-aggressive line females. Isolation housing did not alter female aggressiveness. These findings are discussed in regard to conceptions of genetic-experiential-developmental interactions, and the role of female social behavior in microevolutionary processes.
