Gestational experience alters sex allocation in the subsequent generation.

A M Edwards,E Z Cameron,S R Horton,K Thomasson,E Wapstra,M A Ferguson-Smith,J C Pereira

doi:10.1098/rsos.160210

A M Edwards, E Z Cameron + Show 5 more

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https://doi.org/10.1098/rsos.160210

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Abstract

Empirical tests of adaptive maternal sex allocation hypotheses have presented inconsistent results in mammals. The possibility that mothers are constrained in their ability to adjust sex ratios could explain some of the remaining variation. Maternal effects, the influence of the maternal phenotype or genotype on her developing offspring, may constrain sex allocation through physiological changes in response to the gestational environment. We tested if maternal effects constrain future parental sex allocation through a lowered gestational stress environment in laboratory mice. Females that experienced lowered stress as embryos in utero gave birth to female-biased litters as adults, with no change to litter size. Changes in offspring sex ratio was linked to peri-conceptual glucose, as those females that had increasing blood glucose peri-conceptionally gave birth to litters with a higher male to female sex ratio. There was, however, no effect of the lowered prenatal stress for developing male embryos and their sperm sex ratio when adult. We discuss the implications of maternal effects and maternal stress environment on the lifelong physiology of the offspring, particularly as a constraint on later maternal sex allocation.

Highlights

Adaptive sex allocation hypotheses predict variation in the sex ratio of offspring where sex-specific fitness returns vary with local conditions and/or parental ability to invest [1,2,3,4]
Increases in blood glucose were more strongly associated with an increase in male offspring than treatment per se, suggesting that environmental interactions with glucose metabolism may be more influential than maternal effects
Embryonic female guinea pigs exposed to dexamethasone in utero have increases in glucocorticoid receptor and mineralocorticoid receptor mRNA in all regions of their hippocampus and altered GC levels, which are lower in the luteal phase but higher during oestrous [22]

Summary

Introduction

Adaptive sex allocation hypotheses predict variation in the sex ratio of offspring where sex-specific fitness returns vary with local conditions and/or parental ability to invest [1,2,3,4]. Such hypotheses are logically appealing and have resulted in numerous empirical tests, including in mammals (reviewed in [5,6,7]). The unpredictability of effect sizes suggests that parents may be physiologically constrained in their ability to skew the sex of their offspring [9,10]

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