Ask the Experts: DeeAnn Reeder on bat research
DeeAnn Reeder at work.
Posted: February 04, 2010
LEWISBURG, Pa. — Welcome again to "Ask the Experts," a regular web feature that highlights the expertise of various Bucknellians in a range of topics related to current news events and other timely subjects. || Ask the Experts archive
This week, we asked Assistant Professor of Biology DeeAnn Reeder, who is part of a multi-state effort to identify and combat white-nose syndrome in bats, to talk about the disease and how it may affect the ecosystem. Reeder's research focuses on the hibernation patterns of little brown bats, the most common type of bat found in the Northeast. Her work has been featured extensively in media across the country, including most recently in The Sacramento Bee and The Philadelphia Inquirer.
Q: What is white-nose syndrome and how was it discovered?
A: White-nose syndrome is an emerging infectious disease that was described in hibernating bats in the winter of 2006-2007. It was discovered by a state wildlife biologist and cavers in the state of New York and since then has spread throughout New England and into the Mid-Atlantic states. It was found by several wildlife biologists who noticed that it was affecting these hibernating bats and that they all appeared to have this fluffy stuff coming out of their noses. We now know the fungus takes over a lot of the skin tissue, but the nose is a very obvious place where it starts because it's a nice, moist environment.
The fungus that's associated with white-nose syndrome is the most likely candidate for the pathogen or disease-causing organism, but that has not yet been proven. Typically fungal infections don't kill animals. Typically, animals get fungal infections when they are immune-compromised. We know a fair amount about what white-nose syndrome is doing to the bats but we don't know exactly why they die. We know their hibernation patterns are altered in a way that would cause them to lose weight. We know that in many cases they appear to have starved to death. What we don't know is how you go from a fungal infection in your skin to starving to death.
Q: How many states are involved in the effort to find out about white-nose syndrome and what is being done to find the causes and a possible cure for the condition?
A: Pennsylvania, New York, Vermont, New Hampshire, Massachusetts, New Jersey, Connecticut, Virginia, West Virginia all have bats with white-nose syndrome, but there are more states involved because people are getting ready. In Kentucky and Tennessee, for example, those folks are trying to do surveillance and learning as much as they can about it.
Given that we think a million bats have died so far, there are relatively few people working on this, but there are labs throughout the country studying the causes and effects. We, the white-nose research community, are trying to understand what is happening with the bats behaviorally and physiologically and then trying to work out potential mitigation strategies. One aspect of that is trying drug treatments, which were started in my lab on Jan. 27. There are a number of agents that have anti-fungal properties, including some natural products and drugs with Terbinefine, the active compound in over-the-counter antifungal creams for athlete's foot, which has been demonstrated to kill the fungus.
Q: How do bats benefit people and the ecosystem in general and what are the expected long-term effects of the demise of various bat populations?
A: Bats do a lot of things in terms of the role they play in the ecosystem. The bats that are affected by white-nose are insectivorous bats that hibernate, so they perform an ecosystem service in that they eat a significant number of insects. We estimate that a million bats have died so far. Those million bats would have eaten 694 tons of insects last year.
Bats prefer to eat moths, and many of those could be agricultural pests. They also eat mosquitoes. There's not another nighttime insectivorous kind of organism that will come in and take their place. Birds are out during the day. These insects come out at night. So we may see populations of mosquitoes go up. Mosquitoes are associated with disease. We may spray for those. We may spray more for agricultural pests, so we may see an increase in pesticide use.
Q: What bat species are affected and is there a chance that we will lose some or all of these species?
A: Six species of bats have been affected so far. I think that one of those species, the big brown bat, will probably be OK. I think the other species -- the little brown bat, the tri-colored bat, small footed myotis, the Northern long-eared myotis and the Indiana bat, which is critically endangered already, are all equally highly susceptible. We are probably going to add the Virginia big-eared bat and the gray bat, which are endangered.
I think within several years there will be practically no bats left in Pennsylvania. New York is empty. Massachusetts is empty. There are just handfuls. One of our sites that we study heavily, the Shindle Iron Mine, normally has over 1,000 bats. Now it has six. Even if there are survivors, these bats may become functionally extinct, meaning that we might have some small populations but they will be below a viable population size. They are not going to have enough genetic diversity. There are not going to be enough individuals to find each other for mating. Even if low numbers of bats survive, I'm not sure they will be able to rebuild. These are long-lived, slow-reproducing animals; they have one pup a year and juvenile survival is only 50 percent. It could take decades to rebuild populations, and that's a best-case scenario.
Q: Why are some bats apparently not affected?
A: We have two species of tree bats and we have no indication that they're getting it. They hibernate in trees, not in caves, and they tend to be more solitary. We think it is transmitted between bats that are all cave hibernators. The big brown bat goes into hibernation last and leaves earliest and they hibernate alone. Those two factors could mean that the fungus doesn't have a long enough time to drag them down, but that's a real unknown. If we can understand why one species is more affected than another, maybe we can understand why some species may or may not get it.
New editions of "Ask the Experts" will appear on the Bucknell University website on most Thursdays during the fall and spring semesters and on occasion throughout the summer. If you have ideas for future questions or are a faculty or staff member who would like to participate, please contact Sam Alcorn.
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