Development of meadow voles is influenced postnatally by maternal photoperiodic history.

The importance of maternal photoperiodic history during lactation on the postnatal development of meadow vole pups was tested by cross-fostering pups on the day of birth between photorefractory females (housed for 26 wk in a 10:14-h light-dark cycle before mating) and photosensitive females (housed for 2 wk in a 10:14-h light-dark cycle before mating). Control pups were cross-fostered to females with the same photoperiodic history as the gestational dam. Somatic growth and food intake of cross-fostered pups were influenced by the photoperiod of the postnatal lactating dam. Pre- and postnatal maternal photoperiodic history interacted with the sex of the offspring to influence reproductive development. Pelage development was determined exclusively by the prenatal maternal photoperiodic history. The impact of a postnatal maternal influence on pup development of photoperiod-sensitive traits is discussed.