Development of Fearfulness in Birds: Genetic Factors Modulate Non-Genetic Maternal Influences

Abstract

The development of fearfulness and the capacity of animals to cope with stressful events are particularly sensitive to early experience with mothers in a wide range of species. However, intrinsic characteristics of young animals can modulate maternal influence. This study evaluated the effect of intrinsic fearfulness on non-genetic maternal influence. Quail chicks, divergently selected for either higher (LTI) or lower fearfulness (STI) and from a control line (C), were cross-fostered by LTI or STI mothers. Behavioural tests estimated the chicks' emotional profiles after separation from the mother. Whatever their genotype, the fearfulness of chicks adopted by LTI mothers was higher than that of chicks adopted by STI mothers. However, genetic background affected the strength of maternal effects: the least emotional chicks (STI) were the least affected by early experience with mothers. We demonstrated that young animal's intrinsic fearfulness affects strongly their sensitivity to non-genetic maternal influences. A young animal's behavioural characteristics play a fundamental role in its own behavioural development processes.

Motherless quail mothers display impaired maternal behavior and produce more fearful and less socially motivated offspring

“…Indeed, the females used as adoptive mothers for the brooded chicks had been selected for a particular level of emotionality . As maternal emotional reactivity is transmitted to fostered chicks (Houdelier et al, 2011;Richard-Yris, Michel, & Bertin, 2005), using mothers from different lines can affect chicks in such a way that they appear either more or less fearful than non-brooded chicks.…”

Effects of Dark Brooder Rearing and Age on Hypothalamic Vasotocin and Feather Corticosterone Levels in Laying Hens

“…Maternal care in chicks also promotes exploratory behavior (21). Both fearfulness (22) and knowledge about potential threats is communicated from (surrogate) mother hens to chicks (23,24), suggesting that (aspects of) maternal care may have long-term effects on (among other things) the HPA-axis, including CORT release.…”

Maternal care affects chicks’ development differently according to sex in quail

“…For example, quail chicks brooded by foster females explore and disperse more in a novel environment than non‐brooded chicks (de Margerie et al, ). Young mammals and birds can inherit the level of fear reaction of their adult caregiver (Bertin & Richard‐Yris, ; Calatayud & Belzung, ; Gerull & Rapee, ), and they are more or less sensitive to this parental effect according to their genetic predispositions (Houdelier et al, ). The fact that only females appear to be affected by foster female's activity may reflect intrinsic sex differences that may be (1) physiological and/or (2) functional.…”

“…She can modify the behavior of her offspring to better adapt them to their predicted future environment (Champagne, Francis, Mar, & Meaney, ). For instance, mothers can alter feeding preferences (Avery, ), social motivation (Formanek, Houdelier, Lumineau, Bertin, & Richard‐Yris, ), fearfulness (Houdelier et al, ; Shimmura et al, ), sexual preferences (Kendrick, Haupt, Hinton, Broad, & Skinner, ), and maternal behavior (Pittet, Bot, Houdelier, Richard‐Yris, & Lumineau, ). Furthermore, each female expresses individual differences in maternal care.…”