Modify bat hibernacula environments to increase bat survival
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
In laboratory conditions, the optimal temperature for the growth and performance of the white-nose syndrome fungus Pseudogymnoascus destructans has been found to be 12.5–15.8°C (Verant et al. 2012). Wild bats infected with white-nose syndrome were found to have higher fungal loads and greater population declines in hibernacula with warmer temperatures (Langwig et al. 2012, 2016). Warming or cooling hibernacula above or below these temperatures, e.g. by modifying airflow, may slow fungus growth and improve survival rates of infected bats.
Langwig K.E., Frick W.F., Bried J.T., Hicks A.C., Kunz T.H. & Marm Kilpatrick A. (2012) Sociality, density-dependence and microclimates determine the persistence of populations suffering from a novel fungal disease, white-nose syndrome. Ecology Letters, 15, 1050–1057.
Langwig K.E., Frick W.F., Hoyt J.R., Parise K.L., Drees K.P., Kunz T.H., Foster J.T. & Kilpatrick A.M. (2016) Drivers of variation in species impacts for a multi-host fungal disease of bats. Philosophical Transactions of the Royal Society B: Biological Sciences, 371.
Verant M.L., Boyles J.G., Waldrep Jr. W., Wibbelt G. & Blehert D.S. (2012) Temperature-dependent growth of Geomyces destructans, the fungus that causes bat white-nose syndrome. PLoS ONE, 7, e46280.
Supporting evidence from individual studies
A randomized, replicated, controlled study in 2013–2014 in a laboratory in Pennsylvania, USA (Johnson et al. 2014) found that bats infected with the white-nose syndrome fungus Pseudogymnoascus destructans were more likely to survive and stayed in hibernation for longer when placed in hibernation chambers at 4°C than at 10°C. A greater proportion of bats infected with the white-nose syndrome survived during hibernation at 4°C (43–67% of 14–15 bats) than at 10°C (7–53% of 14–15 bats). Infected bats also stayed in torpor for longer at 4°C (average 9–12 days) than at 10°C (6–7 days). For uninfected control bats, no significant differences were found between the two temperatures for survival (4°C: 80% of 14–15 bats survived; 10°C: 57% of 14–15 bats survived) or hibernation duration (4°C: average 13 days; 10°C: 11 days). In November 2013, 147 hibernating little brown bats Myotis lucifugus were collected from two mines. Bats were randomly placed into five groups for each of the two temperature treatments (4°C and 10°C; total 14–15 bats/group). Four groups were inoculated with different amounts of the white-nose syndrome fungus (500, 5,000, 50,000, or 500,000 spores). One control group was inoculated with a harmless saline solution. All bats were fitted with temperature dataloggers and placed within flight cages with internal chambers set to 4°C or 10°C (and ≤90% relative humidity) for 148 days.Study and other actions tested
Referenced paperJohnson J.S., Reeder D.M., McMichael J.W. III, Meierhofer M.B., Stern D.W.F., Lumadue S.S., Sigler L.E., Winters H.D., Vodzak M.E., Kurta A., Kath J.A. & Field K.A. (2014) Host, pathogen, and environmental characteristics predict white-nose syndrome mortality in captive little brown myotis (Myotis lucifugus). PLoS ONE, 9, e112502