German, A., Unit of Vertebrate Pest Control, Institute of Plant Protection, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel

Parental investment affects the weaning weight of the Levant vole, and this in turn affects the voles' adult weight, the absolute (but not relative) weight of the testes and the seminal vesicles in adult males, and the size of the females' first litters, even in conditions of an unlimited food supply. The compensatory growth of small individuals only slightly reduces the effect. Weaning weight affects the rate of maturation only in females. The decisive role of parental investment is also confmned by a much closer similarity in body weight (at all ages) among siblings than among nonrelated individuals. © 1993 Taylor and Francis Group, LLC.