A pervasive fungal infection could potentially wipe out a regional population of bats in eastern North America within 16 years. White-Nose Syndrome (WNS) is a disease responsible for mass mortality among several bat species and is predicted to lead to regional extinction of what had once been one of the region’s most common bat species, according to a paper released recently in Science Magazine.
Biologists at the Kunz Bat Lab at Boston University report that WNS has managed to destroy significant numbers of bats throughout the area since it was first discovered outside of Albany, N.Y., in 2006. The illness gets its name from a cold-loving white fungus that grows on the muzzle and wings of infected bats. Researchers say the fungus, Geomyces destructans, was previously unknown to science.
Winter is usually a time for bat hibernation, but researchers have observed that WNS bats exhibit strange behavior. In recent winters, these naturally nocturnal creatures have been seen flying around even during the day in a desperate search for food.
Bats are voracious insect eaters. Approximately 50,000 big brown bats are estimated to consume as much as 15 tons of mosquitoes and other insects each summer, according to a study from Boston University.
One theory suggests that WNS-infected bats rapidly deplete their winter fat reserves, prompting them to leave their hibernation cave in search of food at a time of year when there aren’t any insects to eat. Sick and starving, the infected bats soon perish. Meanwhile, the winter cold encourages WNS to spread.
A U.S. Fish and Wildlife Service study in the winter of 2009 revealed an alarming rate of bat mortality, with as much as 95 to 100 percent of entire colonies being decimated due to the virulent WNS. Biologists are greatly concerned about high bat mortality as these creatures have such a low reproductive rate—most bats raise only one pup per year—and a population suffering a large die-off from WNS would take decades to regain its numbers.
While 7 species are found to have been affected by WNS, 1 species is predicted to suffer regional extinction within as little as 16 years, according to the recently published study. Previously one of the most common bat species in North America, the little brown myotis (Myotis lucifugus) has been hardest hit by WNS, and biologists warn that their disappearance will have a substantial impact on ecosystem integrity.
For over a year, the Massachusetts Division of Fisheries and Wildlife has urged residents throughout the state to report on bat colony activity in homes and other buildings, in an effort to help scientists gain a better understanding of WNS. Residents with buildings featuring both big and little brown bats are encouraged to report summer colonies to agency biologists for further study.