Half a million bats have succumbed to a mysterious fungal disease known as white-nose syndrome in two years. Found in seven states in the northeastern US, this syndrome has left biologists baffled since first discovered in 2006. While researchers are still trying to uncover the relationship of the syndrome to the bats, a recent study published in Frontiers in Ecology and the Environment e-View suggests a way to mitigate the syndrome devastating affect. Employing a mathematical simulation the researchers found that using localized heat sources on hibernating bats may preserve populations while a long-term solution is found.
 One little brown bat (Myotis lucifugus) affected with WNS at Howe’s Cave, New York. Photo by: Al Hicks, New York Department of Conservation. |
White nose syndrome causes hibernating bats to develop a whitish fungus on their faces and wings. Although it is still unclear why the disease is fatal, bats that suffer from it die from starvation during the winter months. The disease is potent: populations suffer 75 to 100 percent mortality rates.
“We have no idea why it’s spreading so rapidly,” says Justin Boyles, lead author of the study and a graduate student at Indiana State University.
Using simulations Boyles looked at the theory that the fungus does not kill bats directly, but causes them to wake frequently during hibernation. Bats stir out of hibernation from time to time like all mammals, however if forced to do it too often or for too long they will quickly use up their fat reserves, leading to starvation.
Using little brown bats as its subject, Boyles’ simulation model took into account several factors, including patterns of wakefulness from hibernation, body mass, and the percentage of body fat. Results showed that over 80 percent of bat fatalities in affected populations match the theory that the syndrome is affecting bats’ hibernation routine.
Employing the simulation model again, the researchers tested the idea that providing extra heat sources may be a way to save bats in infected populations.
“They already do this in the wild,” Boyles explains. “What we’re suggesting is accentuating that behavior.” When bats wake-up from hibernation they have been observed flying to the warmest areas of a cave, most likely to conserve energy while awake.
 Little brown bats (Myotis lucifugus) affected by WNS at a graphite mine. Photo by: Al Hicks, New York Department of Conservation. |
When man-made localized heat sources were added into the simulation models, mortality rates dropped significantly, from near 100 percent to around 8 percent.
With this data in hand, researchers are creating a system of wooden boxes and heating coils to create artificially warm spots in caves. Boyles warns that this is not a cure-all. In fact, it may allow the disease to spread further and faster: if infected bats are able to survive the winter then they will likely spread the syndrome to other populations. Despite this concern the artificially heating boxes will at least allow populations to stabilize while scientists search for a cure.
“I can’t even guess what the cure or the solution to this is going to be,” says Boyles. “This isn’t a cure. We’re going for a stopgap.”
With such high mortality rates, the researchers are betting that a stopgap is necessary to buy time while a cure is found.
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