White-nose syndrome (WNS) has decimated bat populations throughout the northeastern United States since its discovery in the winter of 2006-2007 outside of Albany, New York. The illness is so-named because a white fungus grows on the muzzle and wings of many affected bats; researchers have identified the fungus as Geomyces destructans, a cold-loving species previously unknown to science.
Many bats afflicted with WNS die during winter hibernation. Bats are frequently spotted flying outside caves in winter months, even in daylight. It is hypothesized that the fungus causes bats to itch and arouse too frequently during hibernation, expending precious energy reserves, and therefore leaving hibernacula to seek food that isn’t present. They starve to death, and in large numbers. In many hibernacula throughout the northeast, colonies have declined by 90-100%. Most bat species give birth to only one pup per year, so it is unlikely that affected populations will recover quickly from the devastating affects of WNS.
To date, it is believed that over 1 million bats have died as a result of white-nose syndrome. Six species of bats are currently known to be affected by WNS, including the endangered Indiana bat (Myotis sodalis). The little brown bat (Myotis lucifugus) appears to be the most severely affected by WNS. White-nose syndrome has spread rapidly – bats affected by WNS have been found in nine U.S. states, as far south as Virginia, and also in Canada. Researchers fear that WNS may continue to spread into the midwest, where the largest bat hibernacula exist.
Bats provide important ecosystem services: some bat species eat two-thirds their body weight in insects each night, including crop and human pests. Pesticide usage may increase as a result of the tons of insects no longer being consumed by bats, and trophic interactions on all levels are likely to be altered.
Many Questions Remain
Researchers believe that white-nose syndrome is spread primarily by bat-to-bat exposure, however, it is likely that humans may help facilitate its spread (see http://www.caves.org/WNS/Cave_Closures.htm for cave closures). The fungus may have been introduced to caves recently, or it may have existed previously and is only now beginning to affect bats. The fungus may or may not be the direct cause of bat mortality. Bats may be depleting fat reserves too quickly in the winter because they enter hibernation with too little fat in the first place. Some bats may be able to resist or survive WNS. In order to answer these questions, determine the cause (or causes) of WNS, and develop response strategies, we need your help to address these questions.