Chapter 21 - Oxytocin And Individual Variation in Parental Care in Prairie Voles

Abstract

Prairie voles ( Microtus ochrogaster ) are socially monogamous rodents that display high levels of affiliative behavior and biparental care. Both males and females contribute to the rearing of their offspring with minimal or no difference in their response to pups. Sexually naive prairie voles of both sexes also display spontaneous parental responses when exposed to pups in nonreproductive contexts. This spontaneous parental response includes licking, grooming, and hovering over the pups immediately after the first exposure, as well as subsequent nest building, and retrieval. However, there is significant variability in parental responsiveness both within and across populations. According to studies and others using different populations of prairie voles, most males (70–80%) display spontaneous parental care, and a small percentage (10–20%) generally ignore or neglect the pups. Infanticidal responses in males are not uncommon but occur in only 10% of the cases. Sexually naïve female prairie voles, by contrast, are much more variable in their response to pups than males. About 50–60% of female prairie voles show spontaneous maternal responses when first exposed to pups, while about 40–50% either ignore/neglect the pups or display infanticidal behavior when exposed to them. It is found that variation in the response to pups in naïve females is associated with variation in measures of emotionality and nonmaternal affiliative behavior. Adult females that display maternal behavior spend less time immobile, and make more crosses through the center of an open field arena than females that attack pups. This observation suggests that females that display less anxiety-like behavior and/or increased exploratory behavior are more likely to interact positively with novel pups.