Adult male house mice born to undernourished mothers are unattractive to oestrous females

Abstract

In some mammal species, females in poor condition (e.g. poor nutritional state) give birth to a lower proportion of sons than do females in good condition. These skewed offspring sex ratios may be adaptive, because poor maternal condition can have a strong negative impact on the success of sons at intra-sexual competition. However, there is little information about the impact of maternal condition on the success of sons at being chosen as mates. Female house mice, Mus musculus, that are undernourished during gestation give birth to a lower proportion of sons, and those sons are smaller as adults than of well-nourished females. The preferences of oestrous females for the odours of adult sons of females that were well nourished and of those that were undernourished during gestation were tested, as well as the preferences of females for the odours of heavy and light males. Oestrous females preferred the odours of sons of well-nourished females and of heavier males. Hence, the sons of undernourished females may not be chosen as mates as often and may have lower reproductive potential than the sons of well-nourished females. These results and other evidence suggest that the skewed secondary sex ratios of undernourished female mice are adaptive.