Early life adversity ("ELA") can have lasting effects on development, influencing both survival and physical growth in wild animal populations. Maternal care plays a crucial role in these trajectories, being able to mitigate the impact of various adversities. Although recent studies suggest that ELA may also have intergenerational effects - where a mother's early experiences influence the fitness of her own offspring - the mechanisms underlying these effects remain poorly understood.

In this thesis, using over 10 years of demographic and behavioral data on wild mandrills, I analyzed how ELA influences early survival and physical development, as well as how it shapes mother-child relationships. I was particularly interested in the impact of maternal loss during early female development on their own maternal behavior in adulthood.

Les résultats ont montré que, premièrement, bien que les effets cumulés de l’ELA ne soient pas apparents sur l’ensemble de la période de la petite enfance (<4 ans), ils deviennent évidents lorsqu’on se concentre spécifiquement sur la première année de vie (Chapitre 2). De manière remarquable, ces résultats ont mis en évidence un lien potentiel entre l’ELA et la survie à l’âge adulte, l’ELA ayant un impact plus marqué sur le développement physique que sur la survie précoce.

Secondly, the study of variations in mother-infant relationships revealed that these relationships evolve during the first year of life, and that certain maternal traits, notably social rank and age, strongly influence caregiving behaviors (Chapter 3). Furthermore, the results showed that mothers who had lost their own mothers during development adopted different care behaviours towards their offspring (Chapter 4), suggesting a potential mechanism for intergenerational effects of ELA.

Finally, this thesis has repeatedly highlighted significant gender differences, underscoring distinct life trajectories that begin to take shape in the first year of life. This work contributes to a better understanding of how adverse conditions early in life influence individual development. Furthermore, it highlights the importance of integrating detailed behavioral data on mother-infant dyads to further explore these complex relationships and better understand how social behaviors can modulate these dynamics.
Friday March 14 at 10:00 am " Link to follow the defense" [Meeting ID: 924 1704 7387 / Passcode: 470630]