Photos and VideosMore Photos and Videos
Alan C. Hicks
A cluster of three little brown myotis (Myotis lucifugus) infected with WNS at Graphite Mine in New York. Characteristic white fungal growth is visible on forearm, ears and nose areas. This image relates to an article that appeared in the Aug. 6, 2010, issue of Science, published by AAAS. The study, by Dr. Winifred Frick of Boston University in Boston, and colleagues is titled, "An Emerging Disease Causes Regional Population Collapse of a Common North American Bat Species."
New York's hibernating bats have been struck with a mysterious disease: a fungus that sets in during the winter and kills bats by spring. And the affected species might be all but extinct within 20 years, according to a new report by Boston University researchers.
The fungus, ominously named geomyces destructans, causes "White Nose Syndrome," so named because it visibly grows in bats' noses, wing joints, and other exposed skin, and eats their skin tissue while they hibernate during the winter. Because of the pain and irritation, the bats wake up too early and too often throughout the winter, and starve to death before spring.
Anyone who's gotten a fright from the nocturnal nuisances might have a hard time mustering up sympathy, but the researchers insist that shrinking bat populations will affect humans, too, and in more ways than one.
"Bats are important insect predators," postdoctoral researcher Winifred Frick, the report's author, told NBCNewYork. "An individual little brown bat will eat its body weight in insects each night." The researchers estimate that the 1 little brown bats that have died to date would have eaten 694 tons of insects, which includes mosquitos and others that 'bug' humans.
They also eat insects that prey on crops and forests, which will strain organic farms trying to find natural ways to keep their crops healthy, Dr. Thomas Kunz of Boston University, senior author of the report, told NBCNewyork, "and the people who normally do use pesticides are going to probably have to put more on the crops in order to maintain the standards that people expect in the grocery store."
According to a previous experiment by Kunz and his "bat lab" at Boston University, cotton farmers in Texas would have had to spray 2 additional pesticides--amounting to $750,000 in one season--if bats weren't around to curb insect populations.
Similar data doesn't yet exist for Northeastern agriculture, but, as the researchers point out, this sort of population plunge is unheard of to begin with.
"We've certainly seen disease wipe out other wildlife species, but the rapidity and severity of this crash is really unprecedented in North America," said Frick.
The fungus was first discovered by a spelunker in Howe Cavern near Albany in 2006. Since then, it has spread as far as Quebec, Oklahoma, and Tennessee. There are six species of hibernating bat in New York, all of which have shown signs of being infected with the fungus. Four of these have been seriously affected; the other two don't seem to show severe symptoms, said Kunz. This study focused on the 'little brown bat,' the most populous species in New York and the most affected by the fungus.
Strangely enough, however, this same fungus has been found on European hibernating bats, but New York bats' continental brethren don't show any of the symptoms of White Nose Syndrome: the European bats don't awaken and try to fly around in the winter, they don't lose their hibernation body fat and starve before spring, and they don't have scarred and "chewed" wings.
Considering those facts, researchers believe that European bats have built up an immunity to the fungus. "The working hypothesis is that this has been in Europe for a long time...and somehow got introduced to the U.S.," said Frick. Since Howe Cavern is a popular tourist attraction, "it likely came over on somebody's boots."
The fungus' long-term effects on bats and the surrounding ecosystem cannot yet be determined, researchers say. "Ecosystems are complex enough that it'll absorb some of the destruction from the loss of the species, but we don't know," she said. "It's important for us to study what exactly are going to be the impacts to humans from the loss of these bats."
Researchers have considered developing a vaccine or treatment, but this might not be a financially viable option. "Ideally there'd be more federal funds available," Frick said; "Colleagues of mine have testified before Congress to get congressional moneys allocated [to helping the bats] and they got just a fraction of what they asked for."
Frick emphasized protecting bats' summer habitats to ensure that any naturally resistant individuals don't die of other causes. Perhaps, then, enough will survive to eventually rebuild the population.
Kunz identified another concern: the bats who survive the winter emerge emaciated, lacking sufficient fat to produce the hormone leptin, which stimulates reproductive activity in female mammals. "So in that case, the bats are not only dying from fat loss, but those few that do survive may not have enough fat to reproduce the following spring," Kunz told NBCNewYork. "So you have a sort of double-jeopardy."