Can Little Brown Bats Become Immune to White-nose Syndrome?

Research Issue

Little Brown bat cluster in a cave.White-nose syndrome (WNS) has decimated bat populations throughout the Eastern United States. The fungus erodes the skin of hibernating bats, causing individuals to wake from torpor. Waking up frequently causes bats to use energy they need to carry them through hibernation; the loss of fat reserves and increased dehydration can lead to mortality. Some species have seen such drastic losses in population throughout their range that they are now either listed or being considered for federal listing.

Once common, the little brown bat now finds itself among the species being considered for federal protection. More than a decade into the explosion of WNS, however, little brown bats are much reduced in number but there are survivors.  For scientists, this is an observation that needed to be both celebrated and investigated to determine if the species immune system may be adapting to this disease.

Our Research

To test whether WNS produced selection on a particular immune gene, Northern Research Station scientists and their partners compared allele diversity (how many variants of a gene are present) of the immune gene between persisting populations of little brown bats in New York, Vermont, and Pennsylvania, and populations in Wisconsin and Michigan that have not yet been exposed to the fungus that causes the disease. Results showed that allele diversity of this immune gene did not differ significantly between bats exposed and not exposed to WNS, indicating no signal of WNS selection in the bat’s immune response for this specific immune gene. However, the exposed, surviving populations showed very low genetic diversity following rapid population declines (genetic bottleneck), suggesting other factors  are stronger than directional selection at this time for this fungal pathogen.

Expected Outcomes

This research will inform land managers as they develop and implement strategies to ensure connectivity of these small, suviving populations to help recover genetic diversity needed to reduce their vulnerability to other stressors so they can begin to repopulate the landscape.

Research Results

Yi, Xueling; Donner, Deahn M.; Marquardt, Paula E.; Palmer, Jonathan M.; Jusino, Michelle A.; Frair, Jacqueline; Lindner, Daniel L.; Latch, Emily K. 2020. Major histocompatibility complex variation is similar in little brown bats before and after white‐nose syndrome outbreak. Ecology and Evolution. 10(1): 13 p. https://doi.org/10.1002/ece3.6662

Research Participants

Principal Investigators

  • Deahn Donner, Landscape Ecologist, USDA Forest Service, Northern Research Station
  • Paula Marquardt, Research Plant Geneticist, USDA Forest Service, Northern Research Station
  • Daniel Lindner, Research Plant Pathologist, USDA Forest Service, Northern Research Station

Research Partners

  • Last modified: October 27, 2020