Bucknell researcher studies bat hibernation for clues to white-nose syndrome
September 18, 2008
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LEWISBURG, Pa. -- Tucked in a basement laboratory at Bucknell University, a colony of little brown bats is getting ready to hibernate, and researchers are taking note.
The bats will be housed in a simulated cave this winter as part of a multi-state research effort to learn more about white-nose syndrome, a mysterious condition that is killing bats throughout the northeastern United States.
DeeAnn Reeder, an ecophysiologist and assistant professor of biology at Bucknell, will study hibernation patterns in the usually resilient little brown bat, one of the most common bat species in the United States. State and federal officials and other academic researchers are studying different aspects of the syndrome, which gets its name from the white fungus found on many ailing bats.
White-nose syndrome Little is known about white-nose syndrome, which was discovered in 2006 among a dying population of bats in New York.
“Basically, we know they have fungus growing on them, and they’re starving to death,” Reeder said.
Reeder and a team of researchers have received a $50,000 grant from the Wildlife Management Institute to study whether alternations in bat hibernation patterns are contributing to white-nose syndrome. About 600 bats in Pennsylvania, New York, Michigan, Vermont, Kentucky and possibly New Hampshire and West Virginia will be tagged with transmitters that collect body temperature readings during hibernation. Reeder is collaborating with Greg Turner, a biologist at the state game commission.
At the same time, a group of little brown bats -- some healthy and some possibly affected by white-nose syndrome -- will be collected and observed in Reeder’s laboratory at Bucknell to see how hibernation temperature influences immune function.
Multi-state research The multi-state research effort was launched during a June conference on white-nose syndrome in Albany. Scientists don’t know what is causing bats to die or even if a disease agent is involved. They surmise the syndrome may have something to do with hibernation patterns or diet changes making it more difficult for bats to survive. The condition could be caused by the fungus, a virus, bacteria or parasite, and it could be worsened by environmental factors such as subtle climate change and an increase in the level of pesticides among the insects that bats eat. A large number of bats in New York have been found dead or starving, flying erratically during the day and in cold temperatures, weeks before they normally emerge from hibernation. Not all of the infected bats have visible white fungus. Other symptoms include extreme weight loss, depleted fat reserves or the inability to awaken from hibernation. Cases also were found in Massachusetts, Connecticut and Vermont. Some bats in Pennsylvania have shown signs of the syndrome, but it is not known if the condition has taken hold here.
Bats are integral to the ecosystem, because they eat insects -- sometimes in quantities equaling their own body weight in one day. One of the concerns is that a diminishing population of bats will cause insect populations to proliferate, putting crops at risk.
Research questions Researchers at a number of institutions including Bucknell, Cornell University, Boston University and Fordham University, along with the U.S. Fish & Wildlife Service, the U.S. Geological Survey and state agencies including the Pennsylvania Game Commission, are providing matching funds or donating time and equipment to study various aspects of white-nose syndrome. Among the questions the research will address are whether little brown bats are putting on enough fat to survive the winter, altering their metabolic rates or using up their fat reserves prematurely.
Reeder’s research is pivotal to the multi-state effort to learn more about white-nose syndrome, said Susi von Oettingen, an endangered species biologist with the U.S. Fish & Wildlife Service. Previous research on bats has focused more on the spread of rabies, so there is not much information on normal hibernation patterns for bats.
The studies in Pennsylvania could show whether bats are contracting white-nose syndrome before they go into hibernation or if they are developing the condition during restful periods, von Oettingen said.
Hibernation “If they are all fat and happy when they go into hibernation, then something is happening in the winter,” she said.“If they are in poor condition when they go into hibernation, then something is happening in the summer.”
White-nose syndrome has affected at least six kinds of bats, including the endangered Indiana bat. The studies are focusing on little brown bats, however, because they tend to congregate in large groups, and they are easier to capture and study, von Oettingen said.
Reeder and her research team will collect data from bats in Pennsylvania in two ways. They will capture and glue transmitters, called WeeTags, on the backs of a portion of the bats this winter in the hope of recapturing the bats in the spring and collecting the data. The WeeTags, manufactured by Alpha Mach Inc., are an effective way of collecting information, Reeder said, because they record body temperatures every 10 minutes and are capable of storing 32,000 readings.
“The risk is the bats fly away, and there go your data,” she said.
Wireless transmitters Another sample of bats will be equipped with wireless transmitters, which detect body temperature and send signals to receivers placed in the caves where they hibernate.
“The challenge with transmitters is that they won’t last all winter,” Reeder said. “We can only do about 15 in a particular cave, and batteries may only last about two months.”
Preliminary research indicates that bats “warm up” or “arouse” about every 15 days during hibernation, which uses up precious fat reserves, Reeder said. Studying how often bats warm up from hibernating temperatures will help determine whether white-nose syndrome is affecting hibernation patterns, potentially contributing to their demise.
Baseline information “Nobody has done this very extensive winter work in the field,” Reeder said. “When white-nose syndrome started emerging, we looked around and realized we don’t have any baseline information. We don’t know what’s normal.”
The Wildlife Management Institute funds research and associated conservation activities that support implementation of priority actions of the State Wildlife Action Plans from members of the Northeast Association of Wildlife Agencies.
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