PUP CONTACT PROMOTES PATERNAL RESPONSIVENESS IN MALE MEADOW VOLES

Male meadow voles, Microtus pennsylvanicus, were tested with unrelated pups to determine the social factors that affect the initiation of pa ternal responsiveness and the inhibition of infanticide. Adult males w ere initially more responsive to pups if they had been reared as neona tes with their fathers rather than with unfamiliar males. Decreased ag gression and facilitation of paternal responsiveness occurred most rel iably after extensive exposure to pups, even if exposure had occurred more than 2 months before testing. Unlike house mice, neither copulati on nor exposure to females enhanced male responsiveness to pups. Given that male meadow voles only nest with females and young during the co lder parts of the breeding season, it may be adaptive for paternal res ponsiveness to be triggered by pup exposure, rather than by some aspec t of earlier contact with the female.