Crisis in the Caves - Bat Protection Reaches Critical Point
A little brown bat shows sign of infection with white-nose syndrome.
Spring 2017
By Anna Wright, Research Assistant
There is one pathogen sweeping the nation that only specializes on torpid (hibernating) bats. Known as Geomyces destructans, the pathogen invades the exposed skin of torpid bats during hibernation and disrupts their regular patterns of arousal, leading to a disease known as white nose syndrome. These irregular arousal bouts increase fluid and electrolyte loss across damaged wing tissue, alter activity levels, and reduce clustering, major detrimental effects on the bat’s tight winter energy budgets.
Since 2006, researchers have confirmed white nose syndrome bats in more than two dozen states, including Michigan, in 2013. There have even been sightings of bats flying outside of their caves in the middle of winter. With no available insects to feed on, and stored fat diminished, these bats die. White -nose syndrome effects more than a half a dozen bat species in Michigan, including the most common species, little brown bats, as well as the U.P.’s big brown bats and northern long-eared bats.
Outside of the entrance of a dark, winding cave in Ontonagon County a team of scientific researchers lead by Dr. Maartin Vonhoff, a professor of biological sciences at Western Michigan University, are working together to test a substance called chitosan, a type of fiber taken from the shells of crustaceans and insects that acts against the fungus killing these bats. The substance has previously been proven to be successful in laboratory experiments with infected bats.
The treatment works by preventing the fungus from growing. Not only is the fungus halted in its growth, but the chitosan also has wound-healing capabilities. White-nose syndrome causes the fungus to grow across the skin and wings of bats, leading to holes in their wings. This treatment speeds up the healing of these wounds, thus increasing their survival rate.
To apply the chitosan treatment, bats are carefully removed from their roosting sites, tested for white-nose syndrome by swabbing their skin, and then treated appropriately. If the bats test negatively for the syndrome they are given a control solution containing everything but the chitosan. Application of these substances will allow the researchers to test if the treatment on the bats has an impact on their survival.
By Anna Wright, Research Assistant
There is one pathogen sweeping the nation that only specializes on torpid (hibernating) bats. Known as Geomyces destructans, the pathogen invades the exposed skin of torpid bats during hibernation and disrupts their regular patterns of arousal, leading to a disease known as white nose syndrome. These irregular arousal bouts increase fluid and electrolyte loss across damaged wing tissue, alter activity levels, and reduce clustering, major detrimental effects on the bat’s tight winter energy budgets.
Since 2006, researchers have confirmed white nose syndrome bats in more than two dozen states, including Michigan, in 2013. There have even been sightings of bats flying outside of their caves in the middle of winter. With no available insects to feed on, and stored fat diminished, these bats die. White -nose syndrome effects more than a half a dozen bat species in Michigan, including the most common species, little brown bats, as well as the U.P.’s big brown bats and northern long-eared bats.
Outside of the entrance of a dark, winding cave in Ontonagon County a team of scientific researchers lead by Dr. Maartin Vonhoff, a professor of biological sciences at Western Michigan University, are working together to test a substance called chitosan, a type of fiber taken from the shells of crustaceans and insects that acts against the fungus killing these bats. The substance has previously been proven to be successful in laboratory experiments with infected bats.
The treatment works by preventing the fungus from growing. Not only is the fungus halted in its growth, but the chitosan also has wound-healing capabilities. White-nose syndrome causes the fungus to grow across the skin and wings of bats, leading to holes in their wings. This treatment speeds up the healing of these wounds, thus increasing their survival rate.
To apply the chitosan treatment, bats are carefully removed from their roosting sites, tested for white-nose syndrome by swabbing their skin, and then treated appropriately. If the bats test negatively for the syndrome they are given a control solution containing everything but the chitosan. Application of these substances will allow the researchers to test if the treatment on the bats has an impact on their survival.
Caves like the one pictured above are common roosting sights for bats in Michigan.
A second treatment project applies a chemical agent to the inside of mines or caves, rather than the bats themselves, in hopes of killing the fungus before the bats return to hibernate. For this project, the Michigan DNR has partnered with the Wisconsin DNR and the University of California Santa Cruz to treat two abandoned mines in the western U.P.. During the summer, before the bats return for winter, chlorine dioxide is sprayed to kill all the fungal spores throughout the mine. The theory is that this will clean the site and reduce infection rates in the bats. The chlorine dioxide has been approved by the U.S. Environmental Protection Agency and is commonly used in the food industry to clean food processing plants.
The chlorine dioxide spray is made of ultra-fine droplets that disperse through the cracks and crevices within the mine. Within 45 minutes, it breaks down to inert chemicals (salt and water) with no residual traces. There were also several sites in Wisconsin treated the same way.
Another problem the bats face is human assisted spread of white-nose syndrome. To help combat this, the DNR has installed gates at the entrances of abandoned iron and copper mines and caves. These custom steel structures are designed to keep the public out and ensure public safety while allowing the bats to come and go.
White-nose syndrome is a devastating disease, however, with treatment and preventive measures, the bats of Michigan may just have a more hopeful future.
The chlorine dioxide spray is made of ultra-fine droplets that disperse through the cracks and crevices within the mine. Within 45 minutes, it breaks down to inert chemicals (salt and water) with no residual traces. There were also several sites in Wisconsin treated the same way.
Another problem the bats face is human assisted spread of white-nose syndrome. To help combat this, the DNR has installed gates at the entrances of abandoned iron and copper mines and caves. These custom steel structures are designed to keep the public out and ensure public safety while allowing the bats to come and go.
White-nose syndrome is a devastating disease, however, with treatment and preventive measures, the bats of Michigan may just have a more hopeful future.