Reproductive strategy of armadillos (Xenarthra: Cingulata): is the carapace a source of minerals during lactation?

ACTIS, E. A. ; MOSCONI, S. ; JAHN, G. A.; SUPERINA, M.

Oklahoma

Congreso; 94th Annual Meeting of the American Society of Mammalogists; 2014

American Society of Mammalogists

Armadillos (Xenarthra: Cingulata) are well identifiable by their ossified carapace. Their offspring have rapid growth rates and require high mineral levels. However, armadillos feed on a low-quality diet mainly consisting of insects, a poor source of calcium and phosphate, which raises the question how lactating females obtain the needed minerals to provide their offspring sufficient quantities for the development and hardening of their carapace. The main objective of this study was to evaluate whether armadillos demineralize their carapace or endoskeleton during lactation. We performed computed tomography of twenty-six female and thirteen male dead pichis (Zaedyus pichiy) of different age classes and reproductive status, and compared bone mineral density (BMD) of their marginal scutes, compact and spongy bone of the carapace, and femoral bone. Yearlings of both genders had significantly lower BMD values than adults. BMD of marginal scutes and femoral heads, but not of other carapace regions, was significantly higher in lactating females and males than in adult females without signs of gestation or lactation. Also, lactating females tended to demineralize scutes and femora over the course of lactation. We conclude that lactating females use parts of both their carapace and their endoskeleton as mineral sources to provide calcium and phosphate to their offspring. We hypothesize that females accumulate calcium during pregnancy and require a minimum level of mineralization to successfully breed.