White-nose syndrome is a fungal disease killing bats in eastern North America, but disease is not seen in European bats and is less severe in some North American species. We show that how bats use energy during hibernation and fungal growth rates under different environmental conditions can explain how some bats are able to survive winter with infection and others are not. Our study shows how simple but nonlinear interactions between fungal growth and bat energetics result in decreased survival times at more humid hibernation sites; however, differences between species such as body size and metabolic rates determine the impact of fungal infection on bat survival, allowing European bat species to survive, whereas North American species can experience dramatic decline.
From late winter to summer 2011, the U.S. Geological Survey Arid Lands Field Station conducted mist-netting efforts at El Malpais National Monument and on adjacent lands belonging to Bureau of Land Management and U.S. Forest Service to detect the occurrence of white-nose syndrome or causal fungal agent (Geomyces destructans). During this assessment, 421 bats belonging to 8 species were documented at El Malpais National Monument and adjacent lands. None of these captures showed evidence for the presence of white-nose syndrome or G. destructans, but it is possible that the subtle signs of some infections may not have been observed.
Throughout the field efforts, Laguna de Juan Garcia was the only water source located on El Malpais National Monument and was netted on June 20 and 27, July 25, and August 2, 2011. During these dates, a total of 155 bats were captured, belonging to eight species including: Corynorhinus townsendii (Townsend’s Big-Eared Bat), Eptesicus fuscus (Big Brown Bat), Lasionycterics noctivagans (Silver-Haired Bat), Myotis ciliolabrum (Small-Footed Myotis), M. evotis (Long-eared myotis), M. thysanodes (Fringed Myotis), M. volans (Long-Legged Myotis), and Tadarida brasiliensis (Brazilian Free-Tailed Bat). Overall, Laguna de Juan Garcia had the greatest number of captures (79 bats) during one night compared to the other sites netted on adjacent lands and had the greatest species diversity of 8 species netted, not including Euderma maculatum (Spotted Bat) that was detected by its audible calls as it flew overhead. Laguna de Juan Garcia is an important site to bats because of its accessibility by all known occurring species, including the less-maneuverable T. brasiliensis that is known to form large colonies in the park. Laguna de Juan Garcia is also important as a more permanent water source during drought conditions in the earlier part of the spring and summer, as observed in 2011.
Lights, camera, action: behaviors of hibernating bats before and after WNS revealed by surveillance video
Cryan, P., J. Boyles, G. McCracken, K. Castle, D. Dalton, J. Yanez, J. Beeler, A. Wilson, A. Hicks, C. Herzog, R. vonLinden, S. Johnson, C. Hudson, T. Shier, and J. Coleman
White-nose syndrome (WNS) is an emerging disease of hibernating bats associated with cutaneous infection by the fungus Geomyces destructans (Gd), and responsible for devastating declines of bat populations in eastern North America. Affected bats appear emaciated and one hypothesis is that they spend too much time out of torpor during hibernation, depleting vital fat reserves required to survive the winter. The fungus has also been found at low levels on bats throughout Europe but without mass mortality. This finding suggests that Gd is either native to both continents but has been rendered more pathogenic in North America by mutation or environmental change, or that it recently arrived in North America as an invader from Europe. Thus, a causal link between Gd and mortality has not been established and the reason for its high pathogenicity in North America is unknown...
White-nose syndrome (WNS) is an emerging and devastating disease of hibernating bats in North America. WNS is caused by a cold-growing fungus (Geomyces destructans) that infects the skin of hibernating bats during winter and causes life-threatening alterations in physiology and behavior. WNS has spread rapidly across the eastern United States and Canada since it was first documented in New York in the winter of 2006. This new disease is causing mass mortality and detrimentally affecting most of the 6 species of bats that hibernate in the northeastern United States. Particularly hard-hit are the little brown bat (Myotis lucifugus), northern long-eared bat (Myotis septentrionalis), eastern small-footed bat (Myotis leibii), and federally endangered Indiana bat (Myotis sodalis). Several more species are also now known to be exposed to the fungus in the Midwest and Southeast. The sudden and widespread mortality associated with white-nose syndrome is unprecedented in any of the world’s bats and is a cause for international concern as the fungus and the disease spread farther north, south, and west. Loss of these long-lived insect-eating bats could have substantial adverse effects on agriculture and forestry through loss of natural pest-control services.
Tracking a Deadly Disease
Because WNS is spreading so rapidly, field surveillance data and diagnostic samples must be managed efficiently so that critical information can be communicated quickly among State and Federal land managers, as well as the public. The U.S. Fish and Wildlife Service, which plays a primary role in coordinating the Federal response to WNS, worked with the USGS Fort Collins Science Center’s Web Applications Team to develop the White-nose Syndrome Disease Tracking System. Version 1.0 of this system, released for Beta testing in May 2011, addresses two critical objectives:
enable state-level resource managers to effectively manage WNS field and laboratory data, and
provide customizable map and data reports of surveillance findings. The WNS Disease Tracking System subsequently was demonstrated to resource managers involved in the WNS response, and system users are assisting with in-depth testing. Once resource-management users are all trained (autumn 2011), they will begin populating the system with surveillance data, much of which will be immediately available to the public.
WNS version 1.0 was released into production in November, 2011 and state points-of-contact are currently being trainined. New users are providing ciritical feedback for WNS version 2.0, which is currently being planned with Fish and Wildlife Region 5 and the National White-nose Syndrome Data Management Team.
Key System Components
Disease Tracking: Customizable disease tracking maps and data exports for all U.S. states and counties
Disease Reporting: Tissue sample database management for authorized resource managers as well as a publicly accessible database of disease reporting contacts for all U.S. States and Federal resource management agencies
Diagnostic Labs: Directory of laboratories involved in white-nose syndrome diagnostic analyses
Tattered wings: bats grounded by White-Nose Syndrome’s lethal effects on life-support functions of wings [Audio Podcast]