Breaking family bonds: pair disruption alters female adolescent spatial neophobia but not other personality traits and corticosterone stress response in zebra finches (Taeniopygia guttata).

Adolescence is a sensitive period because it is associated with the ontogeny of key neurological, physiological, and behavioural systems. These systems can be permanently altered by social disruption during adolescence and therefore impair individuals' ability to cope with their environment later in life. We tested on captive zebra finches (Taeniopygia guttata) if pair disruption during emancipation affects the family social structure with potential consequences on the nutritional status, personality and corticosterone stress response of juveniles. We experimentally manipulated the social environment of 22 families during emancipation by replacing fathers with unfamiliar males (experimental families) or not (control families) and monitored the prevalence of affiliative, agonistic and sexual interactions between family members. We assessed offspring growth, timing of nutritional independence, body condition as well as five personality traits and corticosterone stress response to isolation. While we observed more agonistic and sexual behaviours in experimental families, we also observed more affiliative behaviours between experimental siblings and more maternal provisioning of the experimental juveniles. Among all the traits we tested, we only found a sex-dependent effect of the experimental treatment on spatial neophobia, suggesting that pair disruption may have long-term consequences on females' ability to cope with new environments. However, our findings suggest overall that emancipation is a less sensitive phase to social environment in comparison to the prenatal and early postnatal periods and that nutritional and social buffers may mitigate the lasting impacts of pair disruption on adolescent behavioural and stress response profiles in altricial species such as the zebra finch.