Their greatest threat, until now, has been fear led by fallacy. Now, a new threat could see their total annihilation. These night fliers’ affliction and demise is resulting from a deadly species of fungus (Pseudogymnoascus destructans), which propagates on a bat’s skin. This affliction has been reported to have killed millions of bats as of 2018 in the north-eastern United States and Canada. The culprit? White-nose syndrome (WNS).
What is White-nose syndrome?
White-nose syndrome first appeared in the winter of 2006-2007 in New York and New England. It is a rare fungus that has been ravaging bat populations while they hibernate from early October until early May in caves and abandoned mines.
The fungus is so called because of the distinctive white powdery appearance on dead and dying bats’ muzzles, ears and wings. To date, tens of thousands of bats have fallen victim. In fact, on average, 90 percent of hibernating bat populations have died. The numbers are rising.
What has biologists and researchers pondering is the very nature of the fungus. It is capable of reproducing and thriving in five degrees Celsius temperature which is the usual consistent temperatures within those caves and mines year round. These fungi ideally grow best at 15-30 degrees Celsius.
So… What is Causing Bats to die?
It is not known whether bats are dying because of the fungus or another reason. However, it appears that the ultimate cause of death is from dehydration and emaciation (weakness). It is almost certainly related to the fungus from all indications. Bats hibernate in substantial numbers in groups. For this reason, any detrimental factor to the bat populations would certainly have devastating effects.
It seems that bats are waking up more often from their hibernation and staying awake for longer periods of time, which is not the norm for bats. Their waking up process requires energy and they store these energy reserves in the form of fat for hibernation.
In a hibernated bat state, bats’ immune systems shut down and, generally, the bats are safe from bacteria and viruses since these organisms do not normally survive cold temperatures.
Awakening more often depletes their normal reserves and instead of having enough energy to last until April or May when they normally arise out of hibernation. Their energy is exhausted by January or February. They come out of their dwellings in search of food and find nothing, a possible explanation for the emaciation.
How Essential are Bats to the Environment?
Bats are essential to our ecosystem, perhaps more so than birds. Their primary feeds are moths, followed by mosquitoes and other insects. Nova Scotia is home to three species of bats – the northern long-eared, pipistrelle, and the little brown bat. The brown bat is the most common and highly susceptible to White-nose syndrome.
The average little brown bat weighs eight grams and is capable of consuming up to 1000 insects an hour, thus adding in controlling crop infestation, among other things, as well as human-biting insects. “It is estimated that bats save farmers in the U.S. 3 billion dollars annually in pest control services. In addition, numerous bat species provide crucial pollination and seed dispersal services.” Needless to say, a loss of these bat populations would have dire implications for both farmers and the general public.
It is believed that WNS does not afflict humans and their health. This affliction “has killed over 6 million bats in North America, and some bat species may go extinct, making this the most critical threat to wildlife today.” There is much to be learned and examined to provide a resolution to this syndrome with research being pursued in both the New England states and here in Canada. Our hope is that studies provide clues and subsequently some solutions before it is too late.
No bats in your backyard? Be careful what you wish for.