Socially induced infertility: familial effects on reproductive development of female Mongolian gerbils

We examined social influences on age at first reproduction in female members of 240 litters of Mongolian gerbils, Meriones unguiculatus. The results indicated that: (1) sisters inhibit one another's reproductive development, although this mutual inhibition is more strongly expressed in the presence than in the absence of an older, reproductively active female, (2) either sexual incompatibility develops between male gerbils and females that they help to rear, or female gerbils need to be exposed to strange males in order for their reproductive development to proceed to sexual maturity, (3) exposure of adult males to young females increases the males' subsequent latency to impregnate females other than those to which the males were exposed. Taken together the results suggest that age at first impregnation of female Mongolian gerbils living in family groups can be influenced by interactions with their sisters, dam and father, as well as with unfamiliar males.