Effects of social environment and experience on parental care, behavioral development, and reproductive success of prairie voles (Microtus ochrogaster)

Parental behavior and pup development were examined in prairie voles (Microtus ochrogaster) in a semi-natural environment under the following social conditions: mother with pups, mother with pups and juvenile offspring, parents with pups, and parents with pups and juvenile offspring. Prairie vole mothers spent less time in the natal nest caring for young and more time eating or drinking when both the male and juveniles were present. Prairie vole fathers contributed extensively to the rearing of young. They spent less time in the natal nest and more time eating or drinking in the presence of their juveniles. Fathers might also play an important role in facilitating the rates of litter development. Juvenile behavior was studied in the second experiment. Juveniles remained in the natal nest and exhibited alloparental care to their younger siblings. Their behavior might be influenced by the presence of fathers inasmuch as the juveniles spent more time in the natal nest and exhibited more alloparental care in the father present condition than in the father absent condition. In the third study, prairie vole parents who had juvenile exposure to their younger siblings had a larger surviving litter size, faster litter growth, and more rapid pup development than the ones without such exposure. Data from the fourth study suggest that the rearing experience could be acquired with one\u27s own offspring. Multiparous parents produced larger litters, spent more time in the natal nest, and exhibited more maternal care to their offspring than that of primiparous parents. The reproductive success for multiparous parents was also increased as measured by having more surviving pups at weaning. The experience, therefore, might play an important role in determining the reproductive success of prairie voles. The data suggest that an extended family structure might be a strategy for prairie vole parents to optimally care for young. This strategy might also enable the juveniles to benefit from the increased surviving litter size and pup development in their earlier reproductive efforts. Thus, mutual benefits might account for the existence of extended family units in prairie voles, in which the overall fitness for the whole family group could be increased