Meeting Abstract

3.2  Sunday, Jan. 4  Mineral dynamics during reproduction in insectivorous bats: skeletal integrity is favored over increased reproductive output HOOD, Wendy R*; BOOHER, Christina M; Auburn University; Auburn University wrhood@auburn.edu

Mammalian mothers supply most to all of the minerals necessary to support the development and ossification of their offsprings skeleton(s) from conception until weaning. Mother support this demand by partitioning dietary minerals and minerals mobilized from their own skeleton to growing offspring; if mineral availability is low offspring number and growth may be reduced. It has been suggested that the low calcium content of an insectivorous bats diet limits reproductive output to one or two young per reproductive bout. However, skeletal mineral dynamics and response to available calcium have not been adequately considered. With this presentation, we will review data on changes in maternal whole body and bone mineral content, examine changes in the 3-dimensional architecture of maternal bone, and describe the effects of calcium supplementation on reproductive output. We suggest that mothers are accumulating necessary mineral prior to demand. Although mineral is mobilized during lactation, maternal mineral reserves do not appear to drop below non-reproductive levels, as is observed in other mammals. We also show that mothers consuming supplemental calcium produce litters comparable in size and mineral content to mothers consuming a low amount of calcium equivalent to the calcium intake of free-ranging bats. The cumulative results of these studies suggest that adult female insectivorous bats are adapted to protect the structural integrity of the skeleton and efficiently utilize minimal calcium intake during reproduction, but are unable to increase reproductive output when dietary calcium is plentiful.