Is bone loss a physiological cost of reproduction in the Great fruit-eating bat Artibeus lituratus?

PLoS One. 2019 Mar 28;14(3):e0213781. doi: 10.1371/journal.pone.0213781. eCollection 2019.

Abstract

During mammalian pregnancy and lactation, the maternal demand for calcium is increased to satisfy fetus and newborn skeletal growth. In addition to the dietary intake, females use the calcium contained in their bones to supply this increased demand, leading to a decrease in maternal bone mineral content. In reproductive insectivorous female bats, bone loss has been described as a physiological cost of reproduction, due to the reported increased risk of bone fracture. This physiological cost may be the mechanism underlying the conflict between increasing litter size and maintaining wing skeletal integrity, which would help to explain the small litter size of most bat species. If bone loss is a linking cost between reproduction and survival in bats, and most bat species have small litter sizes, one would expect to find a loss of bone and an increasing probability of bone fracture during pregnancy and lactation in other non-insectivorous bats. In this study, we tested for the existence of this cost in the Great-fruit eating bat, Artibeus lituratus. We analyzed trabecular structure, bone strength and bone mineral content for the humerus bone, hypothesizing that bone loss during reproduction in females would increase the risk of fracture. Our results showed a decrease of 22-31% in bone trabecular area in lactating females, rapidly compensated following weaning. Bone strength did not differ among reproductive and non-reproductive groups and seems to be more influenced by bone organic components rather than mineral contents. Since we observed bone loss during reproduction yet the humerus strength seems to be unaffected, we suggest that bone loss may not represent a physiological cost during reproduction for this frugivorous bat.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Body Weight
  • Bone Density
  • Cancellous Bone / chemistry
  • Cancellous Bone / metabolism*
  • Cancellous Bone / pathology
  • Chiroptera / growth & development
  • Chiroptera / physiology*
  • Compressive Strength
  • Female
  • Lactation
  • Pregnancy
  • Reproduction / physiology*

Grants and funding

The authors acknowledge the financial support of the Minas Gerais State Agency for Research and Development (FAPEMIG- PPM 00687-17), and the National Counsel of Technological and Scientific Development (CNPq- PQ 305093/2017-7 and MCTIC 408503/2018-1) and Coordination of Improvement of Higher Level Personnel (Capes). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.