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US Fish & Wildlife Service FieldNotes

Spying on Bats - Multiple surveillance methods shed light on hibernation behavior of WNS-infected bats

Region 3, January 30, 2013
Humidity can damage electronic equipment used in the cave, so the cameras are housed in airtight, watertight cases.
Humidity can damage electronic equipment used in the cave, so the cameras are housed in airtight, watertight cases. - Photo Credit: n/a
Dr. Paul Cryan of the U.S. Geological Survey assembles camera systems to be deployed in Wyandotte Cave.
Dr. Paul Cryan of the U.S. Geological Survey assembles camera systems to be deployed in Wyandotte Cave. - Photo Credit: n/a
This image, taken with a thermal camera in Wyandotte Cave, shows a cluster of Indiana bats.  Brighter images are bats that are awake and burning precious energy reserves needed to survive the winter.  Darker images are bats in hibernation with lower body termperatures and reduced metabolic rates that conserve energy.
This image, taken with a thermal camera in Wyandotte Cave, shows a cluster of Indiana bats. Brighter images are bats that are awake and burning precious energy reserves needed to survive the winter. Darker images are bats in hibernation with lower body termperatures and reduced metabolic rates that conserve energy. - Photo Credit: n/a
Entrance to Wyandotte Cave in Indiana’s O’Bannon Woods State Park.
Entrance to Wyandotte Cave in Indiana’s O’Bannon Woods State Park. - Photo Credit: n/a

Wyandotte Cave in Indiana’s O’Bannon Woods State Park is the site of a collaborative study led by the Indiana Department of Natural Resources to examine hibernation behavior of bats that roost in sites infected with white-nose Syndrome. The project, funded primarily by the U.S. Fish and Wildlife Service’s WNS Grants to States, uses multiple technologies to assess behavior of hibernating bats. Technologies deployed at the site include near-infrared and thermal cameras to obtain video imagery of hibernating bats, a beam-break gate that detects and records the dates and times that bats enter and leave the site, and acoustic bat detection systems. We are hopeful that data gathered through these multiple passive surveillance systems and analyzed comprehensively will allow for insights into WNS that no single system would provide.
WNS is caused by a newly-described fungus (Geomyces destructans) that invades the skin tissue of the nose, ears and wings of cave-dwelling bats during hibernation. While the prolific white fungal growth that forms on the nose may be the most striking sign of infection, scientists believe bat wings may be the most important target. During hibernation, the large surface area of a bat’s wings performs critical physiological services such as regulating the animal’s body temperature, water balance and gas exchange with its external environment. These life processes, vital to survival, are disrupted when healthy wing membranes are digested by the invading fungus. WNS-infected bats can exhibit a number of harmful behaviors (for example, increased activity during hibernation that may include leaving the hibernaculum, even during daylight hours) that appear to be triggered by their inability to regulate metabolic activities and maintain homeostasis (steady internal conditions). Recording these behaviors is the target of the surveillance systems deployed at Wyandotte.
Wyandotte Cave, which was found to be infected with WNS in January 2011, houses the country's largest known winter population of the federally-endangered Indiana bat (60,000 in 2011). The 2012-13 winter marks the second consecutive year of multiple surveillance methodologies at this historic cave. In February 2013, a team of biologists will also be entering the site to conduct a survey of hibernating bats. This visit will enable us to estimate the size of the population in the cave and to conduct active WNS surveillance (for example, determining if dead bats are present in the site). Results of this survey will also help us to assess how well our passive surveillance systems reflect the status and impact of WNS at this site.
Collectively the research and surveillance activities at Wyandotte Cave will help scientists define the processes through which dermal infection by Geomyces destructans results in the onset of disease and, ultimately, causes mortality. Understanding these mechanisms is critical to efforts to manage WNS-affected sites.

Contact Info: Lori Pruitt, (812) 334-4261 , lori_pruitt@fws.gov