Effects of calcium availability on reproductive output of big brown bats
Reproduction is a period of high calcium demand in vertebrates; therefore, calcium deficiency can limit reproductive output in mammals. Nutritional analyses show that insects are a poor calcium source, ...
suggesting that insectivorous species are more likely to be calcium deficient. During pregnancy, big brown bats Eptesicus fuscus consume between 8 and 18 times less calcium than they are estimated to require. To accommodate calcium demand during pregnancy, many mammals mobilize more calcium from the skeleton, and extensive bone loss has been observed in some bats during pregnancy. A conflict may arise between the female and developing embryo over allocation of limited calcium supplies, which could limit reproductive output with respect to offspring size, mass and number. The effects of calcium deficiency on these three factors were tested by providing pregnant captive big brown bats with either a calcium-deficient diet or a diet providing the daily calcium requirement, as estimated for pregnant big brown bats, from the time of capture until parturition. Neonates were compared between groups for size, mass and number per female, as were the effects of maternal mass and size on neonate mass and size. Maternal mass and litter mass were positively related for the calcium-deficient group, but not for the calcium-supplemented group. This suggests that there is some interaction between maternal mass and calcium availability, most likely due to the relationship between body mass and skeletal mass, and that calcium availability is limiting the overall biomass of young that a female can produce.
Title: Effects of calcium availability on reproductive output of big brown bats
Author: C. M. Booher