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IRA FLATOW, host:

You're listening to TALK OF THE NATION/SCIENCE FRIDAY. I am Ira Flatow.

And we're going to be talking this hour for the rest of the hour about some unlikely good news about New Orleans. Residents are returning to find their flooded homes taken over by molds and fungi. Many houses are unstable. They'll have to be torn down. So what's the good news? Well, those houses may have many fewer termites. And what do termites sound like? We have some audio of termites. Maybe we'll be able to listen to them right now and here's...

(Soundbite of termites)

FLATOW: That's the sound of Formosan termites. That's not cooking eggs there; those are termites enjoying find dining inside the trees and woodwork of historic buildings in New Orleans. The city has the greatest concentration of historic architecture in the US, and some of the most endangered. And, you know, if you live in the South, you know about termites, and like the rest of the South, New Orleans is infested with termites. And there are domestic ones, but an unstoppable alien termite species, the Formosan termite, which sailed across the Pacific to New Orleans and jumped ship sometime, oh, during about the Second World War. And Formosan termites eat just about anything that contains wood fiber: trees, paper, cardboard, houses. And unlike the North American termite, they can gnaw through plaster, plastic, asphalt--even the paving, even thin lead and copper sheeting to get to their favorite eats. So they're particularly fond of the French Quarter where they've chowed down 99 percent of the buildings in the French Quarter. So the good news is that the termites are subterranean; they live underground. So lots and lots of them drowned hopefully during the recent floodings in New Orleans.

But the Formosan termites nest in trees and buildings too. They definitely suffered during the floods. They are enormous adaptable though, and my guests are going to tell us how the flooding may present Formosan termites with unique opportunities to spread. Even though some of them may be drowned, there may be now in the reconstruction effort an opportunity for them to spread to other parts of Louisiana or possibly other states in the rubble. Gregg Henderson is an expert in urban entomology, who's an expert on termite populations. He's professor of entomology at Louisiana State University. He's studied how termites respond to floods. Dr. Henderson joins us today by phone from his office at LSU in Baton Rouge, Louisiana.

Welcome to SCIENCE FRIDAY, Dr. Henderson.

Dr. GREGG HENDERSON (Louisiana State University): Thank you very much.

FLATOW: You're welcome. My second guest is Duncan Murrell. He's an independent journalist based in Pittsboro, North Carolina. And he's an editor at large at the University of Georgia Press series on natural history. He's interested in how insects and people interact, and in the August issue of Harper's Magazine, he published The Swarm. It's an article on Formosan termites in New Orleans, and Mr. Murrell joins us from the studios of WUNC in Chapel Hill, North Carolina.

Welcome to SCIENCE FRIDAY.

Mr. DUNCAN MURRELL (Journalist): Hi, Ira. Thanks for having me.

FLATOW: Fine. How are you? Let me ask you first, you've studied termites during previous floods, Dr. Henderson. What did you find about how they acted or reacted to those floods?

Dr. HENDERSON: Yes. I have actually. I've been interested in drowning termites for a long time. Actually we had worked with ants or I knew about the work with ants in the early 1900s and flies in the 1700s, so--and because termites live in the ground, obviously water could have some major impact on them. So I hooked up with a colleague of mine, Brian Forschler from the University of Georgia, and we decided to drown termites and see how long they could survive. And my hypothesis was that the Formosan subterranean termite, which has been called water termite because it is found associated close to waterways, might live--be able to stay underwater even longer than native species. But in fact, that was wrong. In our tests, we found that about 19 hours for about 50 percent of the native termites it would take before they drowned, and about 13 hours for Formosan subterranean termites to drown. What we had to our fortune, I guess we could say, is a flood in Georgia in 1992 after Hurricane Andrew, and Brian had been taking data in a field area, and we found a 77 percent reduction in termite populations after the flood. So we know that termites can drown. It may take several weeks, but they do drown.

FLATOW: And what about the ones that live in trees and things like that?

Dr. HENDERSON: Well, Formosan subterranean termites--it does seem to be a strategy for them to build a little bit above ground in trees or they can go up 30 stories in buildings and have a nice carton nest they're called inside that structure. Obviously, they're going to survive above ground out of the water, and as the water recedes, there is going to be quite a bit of food in the form of wet wood and brown fungus-infected wood that is very attractive to them.

FLATOW: Mr. Murrell, you went to New Orleans last May and actually observed these termites. Tell us about the voraciousness of these Formosan termites.

Mr. MURRELL: Well, I've seen the devastation that they can wreak on houses throughout New Orleans in the midcity region, in the Lower Ninth Ward--throughout I mean--but the funny thing is that you don't often actually see them doing their thing until it's too late and the house has fallen in or they begin to swarm. So no, I've never actually seen the termite chomping at a house, but I know they're there.

FLATOW: I see that commercial. They show that commercial where they fall apart and you know the--behind the walls. Yeah, no one sees them. How did they get here?

Mr. MURRELL: Well, you know, the best guess is that after World War II when war material was being shipped back from the Pacific theater and a lot of these ships were coming from ports in the South Asia or Southeast Asian region where they're endemic--they're natives to South China--that this war material came back with wood and--on wood pallets in the holds of wet ships or wet holds of ships, and one of the places that received a lot of this war material was New Orleans, in addition to Charleston, Houston and in some--the Lake Charles region also received some. And you know, the best guess is...

FLATOW: Yeah.

Mr. MURRELL: ...but somebody--people tossed this wood off, buried it, did something with it and these termites had the opportunity in--to get going in a paradise for termites.

FLATOW: Dr. Henderson, we've seen the levees fail in New Orleans. Could that have something to do with termite infestations?

Dr. HENDERSON: Well, that's an interesting question. It was actually technically the flood walls that failed along some of the sections, and I did have a concern about termites in flood walls. About two years ago I was surveying the Ernest N. Morial Convention Center, and I was looking to see where the termites were trying to get into the structure from, and I saw them in the cracks of the sidewalk and, as any good entomologist would do, I followed them to see where they were coming from. And to my shock, they were eating the fabric that's in the flood wall, and so they were replacing this material, which is made of cellulose--it's actually residue from sugar cane waste called bagasse--and they had completely cleaned that out and all you saw were termites in that space. And so there was a conc--I had a concern at that time. The Corps of Engineers was then brought in and we were told that it was not a safety issue for the flood wall, so I accepted their statement.

FLATOW: Are you willing to take another look at that?

Dr. HENDERSON: Well, as an entomologist I study insects and unless I go back for an engineering degree I'm not going to question an engineer's statements.

FLATOW: But it'd be something to bring up in any investigation of the failures of the walls, you would think.

Dr. HENDERSON: Well, I would think this is actually the--I was surprised nothing had come up earlier because it did end up on TV where the Corps of Engineers was explaining the situation. But I didn't hear anything about it until just now, until this question came up, that there may be a concern associated with termites.

FLATOW: What about all the fungi that we're going to see-the funguses in the houses when people go back, the molds? Will that affect the termite population?

Dr. HENDERSON: Almost certainly it will have some effect on termites in both good and bad ways. Fungi are competors of the same food source as the termites--cellulose--so if they get to the food before the termites, that could--not the homeowner cares who eats their house down first. But that could have an effect on their population, but while the fungus is actually attacking the wood in its early stages it's often very attractive to the termites--some of the brown-rot fungi produce some chemicals that are exactly the same as what the termites produce that they will then trail along to find food sources. So the trail pheromone termites use is being produced by some of these fungi and it's very attractive to them. Meanwhile, some of the mold fungi, some of the yellow and green--those pretty mold colors that you see--are actually parasites of the brown-rot fungi and attack the brown-rot fungi. And recently we just discovered that Formosan termites carry these parasitic fungi on their bodies and those--and transport them to the brown-rot fungi which then attack them. So the termites have an arsenal on their body to go after the brown-rot fungi and--so that they don't compete with them for the same food source, so...

FLATOW: Yeah.

Dr. HENDERSON: ...pretty interesting interactions going on.

Mr. MURRELL: Ira, if I can interject...

FLATOW: Yes, Duncan, jump in.

Mr. MURRELL: ...something there. When you go--when you drive around or when you would have driven around New Orleans and looked at some of the older and less affluent areas and noticed houses that were falling down, I mean, trying to diagnose why it was falling down would have been like trying to decide, you know, why a patient is dying when he has pneumonia, the flu and cancer. It was, you know, a compounding of effect. The--and--the house falls down. So you know, there are a lot of things that are endemic to that area that make house building difficult.

FLATOW: Now in the clean-up effort, if there are termites in the wood still living there and the voracious Formosan termites that, you know, hitchhiked here 50 years ago, if they take this wood up and dispose it around the country or in different parts of the South, are we not then just spreading the termites to other places.

Mr. MURRELL: Oh, I--first of all, I don't think that the plan is to take this wood and spread it around the South. However, you know, there are a lot of plans to do a lot of things there right now, and the city and state and federal government are--have a lot on their plates. The city has never been very good at--successful at keeping wood from moving out of south Louisiana, and at the moment they just have an extraordinary amount of debris to get rid of, some of which may still contain active colonies of these termites. And I think it is a real concern that even with the best of intentions, and I believe that Thad Allen, the vice admiral who's heading things up down there, has said that they will not be moving, you know, wood material out of New Orleans.

You know, you're talking about an effort that requires--well, they've contracted with four main contractors, and as was reported in The Times-Picayne this morning, there will probably be 23,000 subcontractors. And you know, it only takes a couple of subcontractors to take the--you know, cut a corner, take the wood someplace else and you're spreading this termite. And it's man's actions that have spread this--brought this termite to North America and have spread it a little bit farther throughout the Southeast. So I'm not terribly sanguine about the city's ability to keep wood product from leaving Orleans Parish, especially given the, you know, host of other things that they're concerned about at the moment.

FLATOW: I'm Ira Flatow. This is TALK OF THE NATION/SCIENCE FRIDAY from NPR News.

Dr. Henderson, go ahead.

Dr. HENDERSON: One thing to add is certainly the homeowners can help out in this matter. And what LSU Ag Center is attempting to do, and should be on our Web site by the end of today, is put out information on what the homeowners should and should not be doing about the wood debris, and certainly not trying to move it out of the state or out of the areas of infestation and at least making them aware of what to look for and how to deal with the debris. Certainly if they bury wood in their back yards, they're going to be burying little termite farms for later on. And there's a lot of issues along those lines, but the debris does have to be taken up and put somewhere, and we certainly don't want it laying on the ground for very long because you also have a fire hazard...

FLATOW: Yeah.

Dr. HENDERSON: ...as can result from that.

FLATOW: And you don't want to burn it either.

Dr. HENDERSON: Some wood can be bur--well, the homeowner doesn't want to burn it...

FLATOW: No. Yeah.

Dr. HENDERSON: ...that's for sure. But some wood can be incinerated and some can't, just as what they're finding out along the Mississippi and the contractors do have knowledge about wood treated or wood painted--lead-painted wood and etc., so we think there--it's going to get done properly but the homeowner does have a major role to play in helping us in this.

FLATOW: I only have about a minute left, gentlemen. Dr. Henderson, so what do you think about the prognosis of the population? Do you think it'll be significantly reduced?

Dr. HENDERSON: I do. I think both in Lake Charles and New Orleans we're going to see an initial significant reduction. I do think--you know, termite populations--their hardest time is in the early stages. As the two-winged termites, the alates, mate and start a colony, their survivorship tends to be very low. But what we're dealing with here are pockets of large populations that survived, and they'll be able to come back fairly quickly. But I think within the next year we're going to see a reduction. But they'll come back; that's for sure.

FLATOW: Gentlemen, I want to thank you very much for taking time to talk with us. Dr. Gregg Henderson, professor of entomology at LSU. Duncan Murrell, journalist in North Carolina, author of The Swarm in the August issue of Harper's Magazine, a really interesting read on these termites. He's also editor at large at the University of Georgia Press natural history series. Thanks again for taking time to join us today.

Dr. HENDERSON: Thank you.

Mr. MURRELL: Thanks, Ira.

FLATOW: You're welcome. Also thanks also to Richard Mankin and Eric Daniels of the Agricultural Research Service on the University of Florida for the sounds of those Formosan termites eating before. That was really interesting.

(Credits)

FLATOW: If you'd like to surf over to our Web site at SCIENCE FRIDAY we've got some good goodies for you there. SCIENCE FRIDAY's Kids' Connection is there, free teaching materials. Just click on the `for teachers' button on the left side. Also, you can podcast SCIENCE FRIDAY and download our podcasts from there on sciencefriday.com as well as leave us e-mail and suggestions for future editions of SCIENCE FRIDAY.

Have a great weekend. If you're celebrating the New Year, a sweet New Year to you. I'm Ira Flatow in New York.

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