Changes in response to odors during the reproductive period in male and female prairie voles (Microtus ochrogaster)

In prairie voles, Microtus ochrogaster (Wagner, 1842), the onset of parental caring differs by sex and reproductive condition. Maternal caring is displayed abruptly at parturition, whereas paternal caring intensifies gradually during the reproductive period. To determine if changes in odor responsiveness contribute to sex differences in onset of parental behavior, voles were given a choice to investigate various odors at different times during the reproductive cycle. Subjects were either sexually naive or mated. Mated pairs cohabited until mid-gestation, late gestation, or 3 days postpartum. Voles crossed a tunnel to explore a row of three filter papers covered with infant odor, orange extract, or saline. Males and females exhibited different odor preferences. Males preferred infant odor to saline and orange extract, whereas females preferred infant odor and saline to orange extract. Mating changed the odor investigative behaviors in both males and females. Some voles vigorously manipulated odor-covered p...