Do females influence paternal responsiveness in male prairie voles Microtus ochrogaster by increasing the salience of infant odors?

Male prairie voles become more responsive to infants following cohabitation with a female. Exposure to female sensory cues prior to offspring birth may influence male paternal tendencies by modifying his response to infant odors in particular or to odors in general. To test these hypotheses, males were housed with an unfamiliar female or a same-sex sibling for 13 days then examined for their response towards either live infants or infant-like inanimate objects covered with one of three odors: water, infant, sub-adult. We recorded the number of males that retrieved and manipulated the infants or odor-covered objects and measured the frequency and duration of time males spent attending to them or engaged in other non-social activities. Female-Cohabited males approached the container holding infant-odor covered objects faster than Male-Cohabited males, but showed no differences in time spent manipulating those objects. Males in both groups spent more time manipulating live infants than odor-covered objects. However, Female-Cohabited subjects were more likely to manipulate odor-covered objects as well as live infants than Male-Cohabited subjects. Additionally, the frequency of self-grooming in Female-Cohabited males was higher for water-covered objects compared to Male-Cohabited males. In presence of water and live infants, Female-Cohabited males groomed themselves with greater frequency than in presence of infant odor or sub-adult odor. The data suggest that female cues increase the male’s sensitivity to infant odors and enhance the salience of non-social odors.