Vole infant development is influenced perinatally by maternal photoperiodic history.

Vole pups were maintained from the time of conception in the same short-day (SD) photoperiod (10 h light/day, LD 10:14); groups differed only with respect to SD photoperiodic histories of dams before gestation, which simulated those experienced by dams breeding in autumn (SD-2, 2 wk of short days), midwinter (SD-21), or late winter (SD-26). Compared with SD-2 pups, offspring born to SD-26 dams matured more rapidly with respect to body size and reproductive status. Several other somatic and behavioral measures indicated that winter preparedness was greatest in pups whose dams had experienced 2 wk and least in those that had experienced 26 wk of SD treatment before conception. A cross-fostering design, in which pups gestated in long (LD 14:10) or short photoperiods were reared postnatally in the same or opposite day length, indicated that several photoresponsive traits are influenced predominantly by prenatal photoperiod, others by postnatal day length, and others by both photoregimens. Information is communicated to fetuses about the length of time dams have been exposed to short day lengths before mating as well as about the day length prevailing during gestation. The changes induced by the mother in her pups pre- and postnatally likely facilitate adaptation of newly weaned voles to seasonally varying environmental conditions.