July 07, 2008

White Nose Syndrome: It's Looking Bad for the Bats and That's Bad News for Us

An article in today's Nashua Telegraph discusses some new information about the white nose syndrome that is decimating bat populations in America's northeast. The news isn't good. If I'm understanding the article correctly, the Fusarium species that gives the disease its name is apparently only a symptom, not the cause of the disease. Researchers have not found, according to the article, any ebidence of a bacterial or viral pathogen (so much for my bacteria-based hypothesis). The focus now seems to be on a new fungus found in the bats that was previously unknown to mycology.

From what bat ecologists are saying, this seems like very bad news, indeed. Population losses among some species that play a major role in reducing the numbers of disease-vectoring insects range between 80 and 90%. Sad to say that it's feasible that we could be witnessing an extinction event for some Chiroptera, and they may just be the tip of the iceberg. The article also points out that fungal diseases have newly appeared or increased in prevalence in other taxa as well.

Disease taking a toll on state's bat population
By ANDREW WOLFE, Staff Writer

..."I think we're on the front end of something that's just going to be getting worse in the next few years," Reynolds said, adding later, "If the numbers are down and reproduction is down, the big impact will be next year. . . . This may be the front edge of the storm..."

White nose syndrome has hit hardest among little brown bats, one of the most common species, known for its voracious consumption of mosquitoes. A little brown bat eats about half its weight, or about 4,000 mosquitoes, every night...

"If in fact we have 500,000 fewer bats in the landscape this year, that adds up to about 2 billion insects that are not eaten each night," Vermont Fish and Game bat biologist Scott Darling said.

The scope of white nose syndrome has been compared to Colony Collapse Disorder, which has been decimating North American honeybees, and its cause has remained similarly elusive.

Experts from around the United States and Canada gathered last month in Albany, N.Y., to share information on the disease and try to coordinate strategies for dealing with it...

"Some sites have 90 percent loss," Reynolds said. "Others have as little as 80 percent loss, but it's all of that order."

Researchers simply don't know how far the disease may spread or how bad the impact might be, and they've been wary of predictions, mainly for fear that their estimates would sound incredible, Reynolds said.

"The reductions are overwhelming," Reynolds said...

So far, researchers have been unable to find any hint of a bacterial or viral cause, Reynolds said, but they've found a previously unidentified species of cold-weather fungus. The question is whether it's new to bats or just new to researchers.

"We know we're finding fungus, but we don't know that it's a new fungus for them," Reynolds said of the bats.

Scientists "didn't know this fungus existed before," Reynolds said. "The mycologist was almost giddy talking about it."

The new fungus isn't the same one that causes the distinctive white snouts, however, Reynolds said...

The combination of new funguses striking bees and bats and the recent worldwide amphibian fungus epidemic have Darling concerned about the entire "ecological infrastructure," he said...
I wish this writer hadn't written "funguses." The word is "fungi." Niggling, I know, but these are some of the most fascinating organisms in the world and if they're capable of causing ecological collapse we should at least get their name right. For that matter, what's killing amphibians isn't exactly a fungus but a chytrid; the Chytridiomycota are the sister group to the fungi, but they have flagellated gametes. True fungi never have flagella at any stage. Things change quickly, but I don't think that they're currently considered fungi (some kindly chytrid researcher may well correct me on this point, though).

Linguistic and taxonomic quibbling aside, the idea of an extra 2,000,000,000 mosquitoes surviving to reproduce every night is a scary prospect. A Bangladeshi victim of dengue hemmorhagic fever (DHF)Beyond the sheer annoyance of increased numbers, the potential for the expansion of diseases from eastern equine encephalitis to dengue should frighten the heck out of anyone. The solution to such outbreaks would likely be to increase spraying programs, and that may have benefits in the short-term, but it also opens the door to the evolution of resistance in mosquito populations in the long term. There are almost always unseen ecological effects down the road from pumping chemicals into ecosystems as well. The complexity of any given ecosystem — particularly those with enough warmth and moisture to produce large numbers of mosquitoes in the first place — largely preclude our being able to take every potential ramification of pesticide use on those systems into account given current technology. In other words, solving one problem in this manner carries a high risk of causing one or more new ones.

I'm not at all involved in this research (though sometimes I wish I was), but if there are already 80-90% die off rates and reproduction has taken a major hit among the survivors, then this is a problem that we'd best hope gets solved very quickly, indeed. Hemorrhagic fever can ruin a summer, to say the least.

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