Influence of rearing conditions on survival of progeny, its reproductive characteristics and correlation of sexes in the water vole, Arvicola terrestris

摘要

The water vole (Arvicola terrestris L.) litter numbers, its postnatal mortality, and sexual composition are related to the male's ability to accumulate energy for lactation. The litter in females with small weight gain during pregnancy was smaller in number, and the correlation was shifted in favor of to males. The mortality before weaning in subsequent litters of hte same females correlated positively (r = 0.37; p < 0.01; n = 7). Heretability of maternal qualities responsible for success of rearing the offspring was 0.64. The progeny of mothers with low maternal qualities produced relatively smaller and male-biased litters. The sex ratio regulation may be adaptive. Success of rearing off spring is a heritable trait. Therefore, the sex ratio shift in favor of males in progeny of "bad" mothers allows to prevent from spreading harmful heritable factors impairing a maternal quality and decreasing the reproductive potential of species.