Effects of different periods of post-weaning separation on father-son interaction and recognition in mandarin voles

Abstract

We measured the behavioural responses of adult and adolescent mandarin voles (Microtus mandarinus) to determine the influence of post-weaning separation on father-son interaction and recognition. We found that levels of adolescent social investigation directed towards the father or towards an unfamiliar and unrelated adult male peaked on postnatal day 28 (P28) and P35. Adolescents at P21 (weaning age), P28 and P35 spent less time investigating their fathers compared to encounters with unrelated males. Adult male social investigation behaviour peaked during encounters with P35 and P45 adolescents for both fathers and unrelated males. Amicable behaviour decreased and agonistic behaviour increased as the duration of separation increased. Adult males showed more amicable behaviour (from P21–P35) and less agonistic behaviour (from P28–P45) toward their sons than to unrelated adolescents of the same age. No significant difference in amicable or agonistic behaviour was found for P60 encounters. These results indicate that behavioural patterns of adult-adolescent interactions may be determined by adolescent development and prior familiarity. Fathers can recognise their sons up to 24 days post-weaning, suggesting mandarin voles are capable of forming durable father-offspring bonds.