White nose syndrome | Manitoba wildlife officials mindful of potential outbreak after disease appears in four provinces
- three species of bats, the little brown bat, northern long eared bat and big brown bat, hibernate inside caves in Manitoba
- white nose syndrome was first detected in Canada in winter of 2009-10 in caves in Ontario and Quebec
- the disease, a fungus that grows on bat’s skin, causes the mammals to wake up more frequently during hibernation. Consequently, the bats starve to death over the winter
Wildlife officials in Manitoba are worried that a disease killing bats in Eastern Canada will soon arrive in Manitoba.
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White nose syndrome could have serious consequences for crop production in the province, said Bill Watkins, provincial conservation zoologist.
The small mammals eat a host of insects that destroy crops, such as beetles, crickets, moths, grasshoppers and midges.
“Collectively, they eat a lot of insects,” Watkins said. “There are some statistics available that suggest a bat will eat its own weight, every night, in insects.”
A paper published last year in the journal Science attempted to estimate the bats’ economic contribution to crop production in North America. Assuming a single little brown bat consumes four to eight grams of insects per night, one million bats would consume 660 to 1,320 tonnes of insects during the growing season.
Overall, bats are worth $3.7 to $53 billion a year to U.S. agriculture, the paper noted. Using a median figure, the authors said bats likely save American farmers $23 billion in annual pesticide costs.
Those figures are rough estimates, but there is no doubt that bats provide a valuable ecological service in North America.
As a result, a white nose syndrome outbreak in Manitoba caves will affect farmers because those bats spread across the province in the summer to feed on insects.
White nose syndrome first appeared in the eastern United States in 2006, when dead bats were discovered in caves around Albany, New York. The disease killed more than 90 percent of bats in infected caves, essentially wiping out entire colonies.
“The vulnerable (bat) species seem to be the ones that collect and hibernate. It spreads from bat to bat because they are all clustered very closely,” Watkins said.
Biologists have since detected the disease inside bat caves in 16 U.S. states and four Canadian provinces.
“Since then, it has spread widely throughout the New England states, into the Midwest, the Maritimes, Quebec and Ontario,” Watkins said.
“The nearest known location (to Manitoba) right now is just on the other side of Lake Superior, the northeast shore.”
A cave in New Brunswick had 6,000 bats in 2010 before the disease arrived. By 2012, only five bats remained in the cave and all five were infected with white nose syndrome.
The disease was named after the white fungus that grows by the bat’s nose. The fungus develops on the bat’s skin and for reasons that biologists don’t entirely understand, it causes the mammals to wake up during hibernation.
“The details are still confusing,” Watkins said. “But it appears the bats are arousing frequently during the winter and using up what little fat stores they have.”
According to U.S. estimates, white nose syndrome has killed five to six million bats across the U.S., said Ted Leighton, executive director of the Canadian Co-operative Wildlife Health Centre in Saskatoon.
Canadian biologists don’t know how many bats have died from the disease because many caves aren’t monitored and others aren’t accessible. However, biologists are finding dead bats outside caves in Canada, which is a clear sign of the disease.
“Most of the time (in Canada), what we detect is bats flying during the day in late winter, when they should still be hibernating,” Leighton said. “That’s a marker of the disease because they’ve run out of fat stores and they’re starving.”
The wildlife centre, university biologists and provincial wildlife specialists in Canada have formed a group to tackle white nose syndrome. It has borrowed a U.S. management plan for white nose syndrome and adapted it for Canada.
“Canada’s wildlife directors have agreed it’s an appropriate plan, but it’s not funded,” Leighton said.
The U.S. government is funding cave monitoring and research to study white nose syndrome, and Leighton said federal funding is also needed in Canada.
“Right now, we really don’t have the funds to properly monitor this disease,” he said. “That’s why we don’t know as much about this in Canada as we’d like to.”
The Manitoba government is asking explorers to stay out of bat caves because humans may be spreading the disease from colony to colony.
Anyone who knows of a site in the province where bats fly in and out of an opening in the ground should alert a conservation officer or another government representative.
