Originally published in the Union College Magazine, Fall 2011
When a Sigma Delta Tau sister was bitten by a bat she found in the house radiator, the ensuing pandemonium was like something straight out of a comically-bad horror film.
“There was this mad bat fear,” Kate Langwig ’08 recalled with amusement. “Everybody in the house panicked and wanted rabies shots. They were convinced they were being bitten in their sleep.”
Bats, though, are really no laughing matter. The winged mammals are dying at rates shocking to self-described bat-huggers like Langwig – at rates that should startle even ardent bat-haters. The little brown myotis, just one of several species at risk, could vanish from eastern North America in just 16 years if nothing changes.
But the disease that’s killing these creatures is baffling scientists around the world. No one knows exactly how or why white-nose syndrome is felling bats from Canada to Virginia, but Langwig is determined to find answers. In March, she won a National Science Foundation graduate research fellowship to further her work on white-nose syndrome at Boston University, where she’s a doctoral student.
White-nose syndrome (WNS)
White-nose syndrome first appeared in February 2006 in a non-commercial section of the famous Howe Caverns, just 45 minutes west of Schenectady. Scientists believe it’s possible a tourist unknowingly brought the sickness into the area from Europe. They think this because a newly described fungus associated with the disease – a fungus that grows in white puffs on the noses and skin of ill bats – appears to be European in origin.
“This fungus has never been documented before, and we have several reports from European researchers about a fungus there that resembles the one here genetically and morphologically,” Langwig said. “So we have this fungus that we think is the same as that on European bats, but there’s been no mortality there.”
Reasons for this aren’t completely clear, but American bat behavior likely makes them more susceptible. Unlike the European animals, bats on this side of the pond tend to form large colonies and cluster together, especially during certain times of the year.
“Right now, mass mortality occurs during the winter, when bats are hibernating together,” said Langwig, who studied neuroscience at Union. “The fungus is cold-growing, so it only appears on them during this time.”
&It's unclear how or if the fungus causes death directly, but affected bats seem to be depleting fat stores prematurely,” she continued. “They’re also flying around cave entrances as early as January and February, emerging months before they can survive. And emerging during the day, which is abnormal. We don’t yet know why they’re going out, it may be they’re looking for food or they’re thirsty.”
Whatever the reason, it’s fatal.
Over 1 million bats have died so far, with all six species of hibernating bats in New York affected, in addition to another three that live further south. The little brown myotis, previously the most common bat in eastern North America, has been hardest hit.
A study Langwig co-authored, published in Science in August 2010, predicts that even if WNS abates, the regional population is expected to collapse from an estimated 6.5 million individuals (pre-WNS) to fewer than 65,000 in less than 20 years.
The little brown (and other similar species) would be unable to recover quickly, even if infection rates decline, in part because of breeding habits.
"Bats are social and they form maternity colonies each spring, relying on the warmth of each other to help raise young," Langwig explained. "Females give birth to one pup each year, depending on the species, and they're very long-lived – the little brown myotis can live over 30 years."
"With slow reproduction and the massive loss of bats needed to make a successful maternity colony, what happens during the winter could have serious consequences beyond that one season."
What's being done?
Langwig, like many scientists, is involved in research she hopes will lead to greater understanding of WNS, and consequently, help bats recover. She's focusing her work on disease-susceptibility across species and transmission across landscapes.
"Not all species are declining equally, which could be really good news. If we figure out what's unique about the behavior and immune systems of less-affected bats, we could help those that are declining more rapidly," Langwig said. "I'm also investigating transmission – studying sociality, roost humidity and temperature, and broader ecologic factors – to see what impact these have."
“I felt these were critical questions we have to answer before we can act,” she continued. "It's very hard to manage populations when you don’t understand the basics of the disease. I'm hoping my research will identify factors that will allow for targeted disease management to ameliorate the consequences of white-nose syndrome."
And ameliorating these consequences is important. Bats are incredible bug-eaters and their absence could make summer outings decidedly more itchy, and agriculture decidedly more pesticide-dependent.
An article in the April 2011 edition of Science, co-authored by Thomas Kunz (Langwig’s mentor at BU), estimated that a single colony of 150 big brown bats in Indiana eats 1.3 million insects each year. A single little brown myotis can consume 4 to 8 grams each night during the active season. When extrapolated to the 1 million bats killed by WNS, that’s 660-1320 metric tons of insects no longer being eaten each year.
Monetarily, the article estimated the economic value of bats to agricultural pest suppression at roughly $22.9 billion a year.
This is an important lesson in the fragility of our ecosystems," Langwig said. “The Indiana bat, listed as an endangered species in 1968, was rebounding and flourishing in the North East before WNS. Even when we think we’re doing well, we need to be careful."
Langwig first learned this at Union, on a caving trip with associate biology professor Kathleen LoGiudice.
"We went to this cave about a mile from where I grew up and the bats were just gone, their numbers down from 1,000 to 30," recalled Langwig, who is from Schoharie, N.Y. "It brought to bear a serious wildlife issue in my own backyard."
"Bats have fascinated me since that trip,” she continued. "I know lots of people don’t share my interest, and hate bats, but their dislike only makes me want to help bats more. It only makes me want to teach people how wonderful and important they are."