The influence of phenotypic and genetic effects on maternal provisioning and offspring weight gain in mice.

Close interactions between mother and offspring are said to result in a coevolution of parental and offspring genotypes such that offspring are adapted in their solicitation behaviour to obtain maternal provisioning that maximizes their fitness. Few empirical studies have been conducted in this field and it remains unclear whether maternal provisioning and offspring weight gain are influenced by the same set of maternal and offspring phenotypic and genotypic factors. Using a cross-foster, split-litter design in mice, we found that overall maternal provisioning and offspring weight gain are significantly correlated but are affected by a different set of parameters, except for the effect of maternal bodyweight. While the level of maternal provisioning was influenced by both offspring and foster mother genotype, offspring weight gain was only affected by the number of males in the mixed litter. We suggest that this disparity may hint at the inefficiency of offspring solicitation behaviour or effects of sibling competition.