Precocial bird mothers shape sex differences in the behavior of their chicks

Abstract

Compared to mammals and altricial birds, evaluations of differences related to precocial birds' sex have often been limited to sexual behavior. Nevertheless, the extensive use of precocial bird models for investigating behavioral development issues requires in depth knowledge concerning the emergence of sex differences. Here, we evaluated behavioral differences between Japanese quail chicks in relation to their sex. We know that maternal influences are strong and early social environment shapes behavioral development in this species. Therefore, we investigated the emergence of sex differences in two very different early social situations to evaluate the impact of precocial bird mothers on sex differences. We assessed behavioral differences related to sex of (1) non-brooded chicks and of (2) brooded chicks, using various ethological tests to evaluate emotional reactivity and social motivation differences related to sex. Our results show that both non-brooded and brooded chicks present behavioral differences related to sex. They differed greatly according to chicks' early experience. Sex-related differences between maternally deprived (non-brooded) chicks concerned mainly fearfulness, whereas differences between male and female brooded chicks concerned mainly their reactions to social isolation. We hypothesize that mothers attenuate sex differences related to fearfulness by being a model for responses to fear-eliciting situations and by providing a similar secure basis to both males and females. We finally propose that mothers induce differences in chicks' sociality by providing asymmetrical care toward males and females.

Incubation temperature influences the behavioral traits of a young precocial bird

“…The Open Field trial is a common way to measure exploratory behavior by quantifying the behavior of an animal in an unfamiliar open environment, where more movement and vocalization indicates more proactive behavior (Bertin & Richard‐Yris, ; Daisley et al., ; Formanek et al., ; Pittet et al., ). On 6 and 13 dph, each duckling was individually placed in an empty outdoor aviary room (5.5 × 2.5 m) with a grid system on the floor forming 0.25 × 0.25 m squares.…”

“…The Emergence trial is a common trial used to quantify boldness, where proactive individuals are more likely to emerge quickly from a sheltered area into an unknown environment than reactive individuals (Formanek et al., ; Pittet, Coignard, Houdelier, Richard‐Yris, & Lumineau, ; Pittet el al., ). On 8 and 15 dph, each duckling was placed in a wooden box (0.5 × 0.5 × 0.5 m) and given 1 min to acclimate (Pittet et al., , ).…”

“…The behavior of social species while alone in a familiar environment is commonly used to quantify social behavior (Bertin & Richard-Yris, 2005;Formanek, Houdelier, Lumineau, Bertin, & Richard-Yris, 2008;Pittet, Houdelier, & Lumineau, 2014b). More movement and vocalization indicates a more active response to social isolation and thus, a more proactive style of seeking out others (Koolhaas et al, 1999).…”

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

“…A first study in quail chicks did not report evidence of sex differences in social and emotional behaviors (Mills & Faure, ). But recently, Pittet, Houdelier, and Lumineau () showed fearfulness differences in motherless individuals, with males being more fearful than females. This sex difference was less strong in brooded chicks.…”

Mother‐chick interactions are affected by chicks’ sex and brood composition in Japanese quail

“…Moreover, precedent study had shown that males are more sensitive (i.e. they called more) than females to the separation from their mothers at the end of the mothering period, an indication that the mother‐male chick relationship is stronger at that time (Aigueperse, Pittet, Nicolle, Houdelier, & Lumineau, ; Pittet, Houdelier, & Lumineau, ).…”