The Association between Male Offspring Aggression and Paternal and Maternal Behavior of Peromyscus Mice

Abstract

Parents influence offspring aggression through genetic and non-genetic mechanisms, although the latter are less well understood. To examine potential non-genetic effects of parents on offspring, we cross-fostered the highly aggressive and biparental California mouse (Peromyscus californicus) and the less aggressive, less parental white-footed mouse (Peromyscus leucopus). In-fostered animals within each species were used as controls. We examined associations between the foster parents' behavior and aggression of the fostered male offspring in resident-intruder (R-I) and neutral arena aggression tests. When both species and fostering groups were combined, R-I aggression of offspring was positively associated with paternal time spent retrieving pups. In contrast, aggression in a neutral arena was negatively associated with a composite score of maternal behavior. We discuss how our findings regarding paternal retrievals may explain previously reported effects of cross-fostering on male aggression.