Abstract
In prairie voles (Microtus ochrogaster), biparental care of offspring is typical, and paternal absence in the pre-weaning development of offspring alters biobehavioral development. We sought to determine whether this altered development is due to the absence of specific paternal qualities or a general reduction in pup-directed care. We compared the biobehavioral development of pups reared under conditions of biparental (BPC), maternal-plus-alloparental (MPA; i.e., mother and older sister), and maternal only (MON) care. Older sisters provided a quantity of care equal to or greater than that of fathers. Growth rate and developmental milestones were unaffected by family composition, with the exception of earlier fur growth in MON conditions. In adulthood, we tested behaviors on an elevated plus maze, spontaneous alloparental care, and partner preference formation. We found no significant differences on the elevated plus maze and only marginal differences in alloparental care. While both female and male MON individuals showed deficits in partner preference formation, MPA females showed typical partner preference formation. However, the alloparental substitution of fathers was not sufficient for the typical development of partner preference formation in males. We conclude that paternal care plays a differentially important role in the social development of female and male prairie vole offspring.