Mammoth Cave scientists studying white nose syndrome

FILE: “The Historic Entrance to Mammoth Cave is a natural opening that has been used by people for 5,000 years.” (Photo By NPS/Wikimedia commons, Public Domain)

MAMMOTH CAVE NATIONAL PARK, Ky. — Scientists at Mammoth Cave National Park are taking part in two studies regarding white-nose syndrome, or WNS.

WNS is caused by a fungus growing on bats’ muzzles, wings and tails and while it is not harmful to humans, it is known to have killed millions of bats across the country.

It apparently came to the United States from Eurasia sometime around 2005. It was first found in caves in upstate New York and has been found in several states, including South Dakota, Wyoming, Texas, Kentucky and Washington.

It was detected at Mammoth Cave in 2013.

“There are lots of people all over the country looking at ways to prevent or treat or suppress the growth of white-nose syndrome, or keep bats from having a high mortality from it,” said Dr. Rick Toomey, Cave Resource Management Specialist and Research Coordinator at MCNP.

One possible preventive measure scientists are looking at is the use of bacteria to stop the growth of WNS but won’t cause harm to the bats. The study involves testing bacteria found on bats in caves in New Mexico and Arizona to see if the bacteria has antagonistic effects against WNS. Currently, WNS has not been detected in New Mexico or Arizona.

MCNP scientists have been afraid the bacteria that could be used to suppress the growth of WNS could harm cave crickets, cave beetles and other creatures found inside Mammoth Cave, so they have been working with researchers in New Mexico and New York to conduct preliminary tests in petri dishes to see what effect the bacteria might have on cave organisms.

“So far the experiments have gone well,” Toomey said. “It didn’t hurt the crickets in any way. They walked right over the petri dishes with it. They didn’t have any issues so far it looks like.”

The other study MCNP is involved with is using ultra-violet light to see how it might affect cave organisms.

MCNP scientists are working with scientists at Lava Beds National Monument in northeastern California and Oregon Caves National Monument and Preserve in southwestern Oregon on the study.

Research so far has shown the fungus that causes WNS does not have the ability to fix damage caused by ultra-violet light.

“Virtually everything on earth has genetic pathways to help them fix chromosome damage caused by ultra-violet light, because anybody who is in the sun gets ultra-violet light and ultra-violet light damages genetic material,” Toomey said.

Without the ability to fix damage caused by ultra-violet light, the fungus dies.

“We want to wipe out white-nose syndrome in the cave, but we don’t want to wipe out all the bacteria and fungus in the cave,” he said, adding that the microbial life in the cave is often the basis for the food chain in the cave. “We need that bacteria and fungus. The critters need it for the cave to function correctly.”

The testing at all three national parks began this fall before the bats went into hibernation. The scientists tested the bacteria and fungus growing in caves at all three national parks and then shined ultra-violet light on cave walls. They will conducts tests again later to see if the ultra-violet had any effect on the bacteria and fungus inside the caves.

“We want to see how much damage we do to that microbium and does it recover,” Toomey said.

MCNP scientists are also looking at how effective ultra-violet light is in getting rid of WNS in the area that is being tested for the effects of ultra-violet light on bacteria and fungus.

There are 13 species of bats found at Mammoth Cave. Eight of the 13 are commonly found in caves at the national park, and seven of the eight are susceptible to WNS.

The reason why scientists are so interested in bats is because they are the most important controller of night-flying insects, such as mosquitoes, moths and beetles.

“Mosquitoes are a relatively small part of their diet. What they are really controlling are moths and beetles. A lot of these moths have caterpillars that are agriculture pests,” Toomey said. “They are keeping us from having to use more pesticides on crops by going out there being the first line of defence against a lot of these insects.”

WNS has proven to effect various bat populations at the national park.

One species affected is the Northern Long-Eared Bat.

At one time the Northern Long-Eared Bat was one of the most common bat species found at Mammoth Cave.

In 2005, the national park conducted a study that involved capturing bats. Approximately 45 per cent of the bats captured during that study were Northern Long-Eared Bats.

In 2017, a survey of the national park’s bat population was conducted as part of the Southeastern Bat Diversity Network Bat Blitz. MCNP was chosen as a location for the Bat Blitz because of the presence of white-nose syndrome at the national park.

During the Bat Blitz, which lasted for one week, 850 bats were captured. Two of the 850 were Northern Long-Eared Bats.

There have also been declines in the Little Brown Bat, Tri-Color Bat and the Indiana Bat populations at Mammoth Cave due to WNS.

“If we see very many more declines in the Little Brown Bat we are going to run out of them,” Toomey said. “Little Browns and Tri-colours are being evaluated (for the endangered species list).”

Some bats species at Mammoth Cave seem to be doing well, despite WNS. Those species are the Evening Bat, the Red Bat and the Gray Bat.

Both the Evening Bat and the Red Bat are tree-dwelling bats, while the Gray Bat is a cave-dwelling bat.

All three species are benefitting from the decline in the Northern Long-Eared, Little Brown and Tri-Color bat populations because there is less competition for food. While the Gray Bat develops WNS, it doesn’t seem to die from it, he said.

Another bat species, the Rafinesque Bat, also seems not to be affected by WNS.

MCNP scientists are currently surveying the Rafinesque Bat and other bats not susceptible to WNS to see how their populations are doing. In January and February, MCNP scientists will be surveying caves with susceptible bats to determine if there are further affects from WNS, he said.

To lessen the likelihood of spreading WNS, visitors who tour caves at MCNP are asked to walk across bio-hazard mats containing a solution that will clean the bottoms of their shoes.