Maternal stress, glucocorticoids, and the maternal/fetal match hypothesis.

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: Could maternal stress enhance offspring phenotype? Elevated blood glucocorticoids (GCs) are thought to redirect a parent towards self-maintenance, presumably enhancing survival over current reproductive success. But could elevated GCs increase survival rates for both mothers and offspring? We've known for a decade or more that elevated maternal GCs can alter offspring phenotype. This in itself is exciting (in a mechanistic sense), as it represents a non-genetic maternal factor programming offspring phenotype, with changes lasting over the offspring's lifetime (Seckl, 2004). Over the last decade, data from the biomedical literature overwhelmingly supports relationships between prenatal stress and long-term health disorders (for review see Viltart and Vanbesien-Mailliot, 2007). Across the other vertebrate classes, elevation of glucocorticoids in the mother during egg production reduces offspring growth, condition, and body size However, evidence is mounting for an adaptive function of maternal stress. In 2004, Gluckman and Hanson proposed that maternal stress is a developmental cue to offspring, programming their future phenotype to better survive in harsh environmental conditions (assessed from the biomedical literature; Gluckman and Hanson, 2004). Hayward and Wingfield (2004) suggested an alternative view: maternal stress during development matches offspring need to maternal ability, 'lessening the burden of parental care' (from the comparative literature; Hayward and Wingfield, 2004). Gluckman and Hanson wrote of 'matching' between prenatal and postnatal environments to benefit the offspring, while Hayward and Wingfield indicated 'matching' between mother and offspring to benefit the mother. For his PhD dissertation, Dr. Oliver Love examined both maternal and offspring aspects of the match hypothesis. Love focused on embryonic GC exposure as the mechanistic link between environmental factors and fetal growth/development. To test this hypothesis , Love and Williams elevated maternal GC levels during lay to create offspring that may expect to be raised in poor conditions (Figs. 1A,B; Love et al., 2005). Male offspring from 'poor condition' (GC elevated) mothers had lower hatch mass, slower growth rate, and lower mass at day 5 after hatch as compared to the males from 'good condition' mothers (Fig. 1C; Love et al., 2005); female offspring showed no differences between groups. The reduction in male offspring mass and growth rate should make feeding young less challenging; the …