The presence of a mother counteracts prenatal stress in a precocial bird

Abstract

In many species, prenatal maternal stress leads to long-lasting changes in physiological and behavioural individual characteristics. However, these prenatal effects can be modulated by the postnatal environment and especially by maternal care. The impact of maternal care on the modulation of prenatal maternal stress effects has been investigated mainly in mammalian models but, surprisingly, remains little explored in avian species. In this study, we determined the extent to which the subsequent effects of prenatal maternal stress on offspring growth and emotional responses are modulated by the presence of an adoptive mother during postnatal development using a precocial bird, the Japanese quail, Coturnix coturnix japonica , as our study species. All experimental quail chicks were the offspring of females that experienced an environmental stressor induced by a socially unstable environment during laying and egg production. Previous reports showed that social instability of laying quail increased their offspring's emotional reactivity and that this was related to an increase in yolk testosterone levels in their eggs. In this study, offspring hatched from socially unstable females were raised either with or without adoptive mothers. We found that mothered chicks were lighter during their first 3 weeks of age and that their emotional reactivity was lower (i.e. as shown by increased exploratory behaviours in a novel environment, decreased neophobic responses in the home cage and decreased responses to social separation) relative to nonmothered chicks. Thus, our results highlight that maternal care could counteract the phenotypic consequences of prenatally stress-exposed birds. Our results clearly highlight that even in precocial species the presence of the mother has a fundamental importance in modulating the effects of prenatal conditions on the ontogeny of offspring behaviour and that this might be a key mechanism driving phenotypic plasticity in wild populations. • Maternal care in Japanese quail counteracts prenatal stress effects. • Mothered chicks have a lower level of emotional reactivity than nonmothered ones. • Maternal care's influences are similar in mammals and birds.