The effect of alloparental experience and care on anxiety-like, social and parental behaviour in adult mandarin voles

Social experiences, especially during early development, have profound effects on the brain and behaviour in later life. We examined whether the provision of alloparental care by older siblings affects anxiety, sociability and parental behaviour at adulthood in both them and the younger siblings for which they care. Using mandarin voles, Microtus mandarinus, we kept the older litter in the parentsʹ cage at weaning where they provided alloparental care to younger siblings of the next litter. We found that mandarin voles that had cared for younger siblings displayed significantly more locomotor activity in a novel environment and engaged in more social investigation of unfamiliar same-sex individuals. Females of this group also provided more parental care compared to control voles. Individuals cared for by older siblings demonstrated lower levels of anxiety and aggression, and higher levels of parental investment at adulthood, compared to control animals. These results suggest that providing alloparental care increases locomotor activity, social investigation and maternal care in adulthood, and that receiving alloparental care reduces levels of anxiety and aggression and increases biparental care in adulthood. Giving and receiving alloparental care has clear benefits in this species and suggests that alloparental care may increase the inclusive fitness of both givers and receivers.