Guest post by DeeAnn M. Reeder
White-nose syndrome (or WNS), an emerging infectious disease of hibernating bats, was first noted in New York during the winter of 2006/2007. Named for the visible white fungus that grows in the skin of the bats’ muzzles, ears, and wings, WNS causes a suite of symptoms, including flying during the day, flying during the middle of winter, and arousing from hibernation much too frequently, leading to starvation. One hypothesis for the frequent warm-ups is that the sick bats are dehydrated, as infection in their wing tissue may disrupt their normal physiological processes (this video shows a dehydrated bat, possibly suffering from WNS, eating snow:
Scientists currently estimate the number of bats killed by WNS at between 5.7 and 6.7 million (to watch the progression of WNS across North America, see this storymap), and have identified the culprit as the newly-described cold-loving fungus Geomyces destructans (Gd). The fungus, which our bats largely have no immunological resistance to, is believed to have been brought by people from Europe to North America (think of when small pox was brought to the New World). Research in my lab and others has demonstrated that this fungal pathogen has found the Achilles’ heel of bats. During hibernation, when bats drop their body temperatures to just above freezing—precisely the right temperature for the growth of this unusual fungus—they shut off their immune systems. While this may allow bats to save energy during the winter, it also lets the fungus grow relatively unchecked.
The loss of these wonderful creatures is a wildlife tragedy. Even for people who don’t find bats charismatic, the “ecosystem services” that they provide are hard to ignore: the millions of NWS-infected bats that are estimated to have died thus far would have eaten approximately 8,000 tons of insects each summer, which translates to millions of dollars worth of insect control (pesticides not needed) no longer being provided by bats. A variety of scientists are working on examining different aspects of WNS, with studies that range from the molecular to the behavioral and from carefully controlled laboratory studies to field studies of naturally infected bats. Researchers are particularly interested in mitigation and control strategies, and are now focusing not only studying WNS where it is currently actively killing bats but also on helping those bats that have apparently survived WNS.
Additional WNS resources:
Dr. DeeAnn Reeder is an associate professor of biology at Bucknell University whose research interests include comparative behavior and physiology in mammals and global mammalian systematics and biodiversity. Her North American work focuses exclusively on solving the mystery of White-Nose Syndrome; her current projects emphasize understanding the bat’s physiological response to the fungus that causes WNS. At Bucknell, Dr. Reeder maintains what may be the only facility that can house hundreds of captive insectivorous bats both while hibernating and during the active period. She is coeditor of the third edition of Mammal Species of the World: A Taxonomic and Geographic Reference, published by Johns Hopkins University Press.