Bat disease expected this winter at most Western Pennsylvania sites
Carl Pierce has explored caves since 1974, but was unprepared for what he saw last year in a West Virginia cave.
"There were dead bats on the wall. There were others clinging to the wall. There were bats on the floor, stomping around. Many had maggots crawling over them. It looked like a horror movie. It was just awful," said Pierce, 46, a Mt. Lebanon electrical engineer and longtime member of the Pittsburgh Grotto, a chapter of the National Speleological Society.
Most people never see that sort of biological wreckage up close. Yet the white-nose syndrome that killed the bats Pierce encountered is so lethal and prolific that researchers are concerned about the potential extinction of five hibernating bat species in North America.
"We have never seen anything like this. It is catastrophic. Many hibernating bat species could be facing extinction. At best, it could take decades or centuries for the bat population in the Northeast and Midwest to rebound," said Maylea Bayless of Austin-based Bat Conservation International.
The loss of bats from the disease, which kills nearly 90 percent of them, could threaten the region's agriculture. Bats eat pests that attack crops and such invaders as the emerald ash borer, which devastated ash trees in the Midwest and Northeast.
In Western Pennsylvania caves and mines, white-nose fungus, or Geomyces Destructans, is expected to peak during this winter's bat hibernation.
"The western part of the state will be the last place (in the state) to get the disease. The majority of the sites will probably have it this winter," said Greg Turner of State College, a biologist with the Pennsylvania Game Commission. The agency monitors the disease, first found in 2006 in upstate New York.
According to a U.S. Fish and Wildlife Service report released last month, the fungus has killed as many as 6.7 million bats in 16 states and four Canadian provinces. In six years, the disease has moved as far west as Oklahoma.
The fungus grows only in temperatures between 39 and 59 degrees and will not tolerate temperatures above 68. The infection causes bats to wake too frequently from temporary hibernation and starve to death through excess activity. Symptoms include loss of body fat, unusual winter behavior and damage and scarring of wing membranes.
This month, officials confirmed the disease in two caves near Cleveland that they closed. They suspect it at several Western Pennsylvania sites, including an abandoned U.S. Steel mine. They have identified it at various mines and caves in the region since 2009.
Creepy but critical
Not everyone knows or cares about the extent of the problem, Bayless said. After all, bats have a mixed -- if not creepy -- reputation.
Long associated with witchcraft, black magic and darkness, bats were included in the witches' brew in Shakespeare's "Macbeth." Dozens of vampire movies have cemented the creatures' sinister image. Many consider the idea of a bat inside a home worse than finding a mouse or cockroaches.
Bats are perhaps nature's best pest control system. The furry, nocturnal flying mammals eat mosquitoes, moths and beetles that can destroy crops, particularly fruits and vegetables.
The economic value of bats to farmers averages $74 per acre, according to a study by professors at the University of Tennessee and Boston University. Bats save farmers in Pennsylvania nearly $300 million each year, that study found.
A bat's appetite is staggering, said Ann Froschauer, a spokeswoman for the U.S. Fish and Wildlife Service, which tracks the spread of the fungus.
"One bat can eat its body weight in insects each night, about 1,000 mosquitoes in an hour. I like to tell the schoolchildren I talk to (that) that would be like me eating 50 pizzas or 500 Quarter Pounders every night," she said.
In one summer, 150 bats can eat 38,000 cucumber beetles, 16,000 June bugs, 19,000 stink bugs and 50,000 leafhoppers, said John Whitaker, a life sciences professor at Indiana State University.
Cucumber beetles attack corn, spinach and various vine plants. The larvae of corn rootworms have the greatest impact; they can reduce corn productivity by 10 to 13 percent. Insecticide to control them costs $15 to $25 per acre, Whitaker said.
'It can be pretty dramatic'
Hibernating bats spend winters in caves and, in this area, abandoned mines. Since the first reported Pennsylvania case of white-nose syndrome in 2009 in Mifflin County, officials have confirmed the disease in 41 caves or abandoned mines in the state.
The disease creates a graphic and disturbing aftermath.
"Bats have piled up near the entrance of the cave or on people's homes. It can be pretty dramatic," Turner said.
One effect of the disease is the disruption of hibernation. Bats typically wake every month. During outbreaks, they can wake up every four to seven days.
Aura Stauffer, a biologist with the Department of Natural Resources, said she saw hundreds of dead bats clinging to a pump house near Shamokin in Northumberland County in subfreezing weather.
"It was January, 20 degrees or so outside. They should not have even been out of hibernation at that point. That's how disorienting this disease is for them," she said.
Stauffer has conducted research at several caves in Westmoreland and Fayette counties that have infected bats, including Barton Cave in Forbes State Forest near Uniontown.
Many of the caves were never open to the public during winter, and some have been closed since 2009 to prevent people from helping spread the disease. Federal officials have taken similar action elsewhere, including closing all the caves in Monongahela National Forest in West Virginia, 180 miles south of Pittsburgh, year-round.
The origin of the disease is a mystery.
As with the gypsy moth, Dutch elm disease and the Asian carp, white-nose fungus is imported. It is present in bats in Europe but does not sicken them. Bats sometimes get inside shipping containers on large ships and arrive alive elsewhere.
The more likely scenario of how the disease arrived here is that fungal spores were carried on someone's clothes or shoes, said Turner of the Game Commission.
"People probably caused this. But we have no proof."Additional Information:
The fast-spreading, white-nose fungus, or Geomyces Destructans, could wipe out these five species of bats in the United States:
• Eastern small-footed bat
• Little brown bat
• Northern long-eared bat
• Indiana bat
• Tri-colored bat