I’ve been trying to tune into developments with white-nose syndrome because it’s one of the worst emerging pathogens to hit North American wildlife in recent history. Ever since the first breakout in a New York cave in February 2006, this white fungus has killed off well more than a million bats from six different species. Sure, I know, there was some quibbling over whether the fungus was causal or secondary, but the bulk of the evidence seems to be pointing to it being causal. And for my story, a conservation biologist I interviewed at Bat Conservation International said, “We think the fungus is clearly the smoking gun,” so that cinched it up for me.
But I didn’t know, when I filed that story, about a research paper published March 5, 2009 in Frontiers in Ecology and the Environment, in which two authors offered experimental evidence based on computer models that artificially warming caves or mines throughout a bats hibernation period may thwart the disease process enough to quell the winter carnage. The paper says that by offering bats “thermal refugia” of 28C (about 82F) degrees, survival rates could be increased by up to 75 percent. This is premised upon the idea that bats are forced to burn through their fat stores too fast when infected by the Geomyces destructans fungus that causes WNS, because the skin infection itches and rouses them from their hibernating slumber. Being roused multiple times during hibernation then causes their metabolism to speed up, and they grow hungry due to running through their stored energy, forcing them to leave their caves too early and then starve for want of insects in mid- to late-winter.
Because G. destructans is a cold-loving fungus, the thermal refugia might also halt its growth on individuals during winter months. It is thought to be temperature limited at about 20C (68F), according to the paper’s authors. Because several different species of bats tend to use the same hibernation sites, called hibernacula, thermal refugia may also to help limit transmission between species. (more…)