Studies on wild house mice. VII. Prenatal maternal environment and aggression.

The effect of the maternal environment on intermale aggression was studied by means of embryo transfer of genetically selected aggressive (SAL) and nonaggressive wild house mice (LAL), and their reciprocal F1's, to standard (NMR1) females. No effect was found on the attack latency scores (ALS), i.e., aggression: all genotypes born and raised under natural conditions showed an ALS similar that of genotypes born and raised by NMR1 females. Since previous studies on wild house mice failed to demonstrate postnatal effects on aggression, and the present results indicate the absence of prenatal maternal environmental effects on aggression, the primacy of genetic over maternal variance in the development of adult intermale aggression in wild house mice is indicated.