Termites: What happened to all that infested wood debris after hurricane season 2005?
By Faith M. Oi

The National Pest Management Association annual convention has become one of my favorite meetings. Not only do I get to catch up with old friends and associates, but I get to hear first-hand what is on the cutting edge of technology and information for the pest management industry in different parts of the country. This year, after making sure our friends along the Gulf coast survived hurricanes Katrina and Rita, there was great discussion surrounding predictions of termite survival in flooded areas, what to do about treatments which probably washed out, and hurricane preparedness plans.

I attended a session in which Fred Strickland (Terminix International, VP Service and Technical) talked about the five “Ps” in hurricane preparedness plans – Preparation, People, Property, Protection, Prayer.
Preparation before hurricanes included taking care of treatment records and moving them if need be. (As Fred talked about the logistics of moving the records, I kept seeing flashes of the cable news coverage on the police evidence room that was destroyed.) They also made sure that they accounted for all of their people where technicians were responsible for notifying their branch managers of their whereabouts. What was really fascinating in a horrifying way were plans to take care of pesticides stored in flood prone areas. I can’t imagine trying to move pesticides in bulk to an alternate storage place, but the alternative is not acceptable either – ending up with hazardous waste on top of a weather disaster.

DID ALL THE TERMITES DROWN AND DIE?
Not by a long-shot. I heard from the folks in New Orleans that the Formosan subterranean termites were back in in-ground bait stations about three weeks after Katrina. Also remember that the Formosan subterranean termite is more apt to infest aerially when compared with the native subterranean termite, so a good number of termites would have been spared drowning.

The impact of periodic inundation by water still begs the question: How long can a termite hold its breath? In the early 1990s, my good friends and colleagues Brian Forschler (University of Georgia) and Gregg Henderson (Louisiana State University) observed that field populations of native subterranean termites decreased by 77 percent after a prolonged period of inundation (Forschler and Henderson. 1995. J. Econ. Entomol. 24(6):1592-1597.). It was a wet winter, yielding about 13 inches of rain over a period of about three weeks. The soil was nearly saturated during this time.

They tried to drown termites in order to determine the lethal time it would take to kill 50 percent and 90 percent of a test population (LT50 and LT90). Their first attempt to drown termites was an utter failure. If you put termites in a plastic container with nothing to hold on to, the termites float. It actually was a project in and of itself to figure out how to force the termites underwater. You have to let the termites grab on to something, then add the water into the container.

TERMITES ARE NOT ROCKET SCIENTISTS.
After termites had grasped on to something, Forshcler and Henderson dripped water into the plastic container and made some interesting observations. If termites were in galleries that were horizontal, termites would antennate (probe, feel or explore) the slowly advancing water and instead of attempting to flee, they would stop moving and allow the water to overtake them, becoming submerged. If termites were in vertically aligned galleries, termites would antennate the water and head up, toward the surface. But once the surface was reached, they would turn back toward the water. They would often repeat this process several times before stopping in the gallery and becoming inundated.
If you have nothing to do on a Friday or Saturday night and feel the need for some entertainment, you can try this experiment at home.

SO, HOW LONG CAN A TERMITE HOLD ITS BREATH?
Forschler and Henderson very patiently found that termites could hold their breath for a surprisingly long time. It took over 19 hours to kill 50 percent of the Eastern subterranean termites (R. flavipes), but only 11 hours to kill 50 percent of the Formosan subterranean termites. Interestingly, if termites were allowed to forage in soil and then the soil was saturated with water, the LT50 of Eastern subterranean termite was 67 hours! They hypothesized that pockets of air in the soil sustained the termites.
The authors concluded that it wasn’t surprising that the Formosan subterranean termite had the lowest lethal time. They typically build above-ground nests and are often found in chimneys, trees, roofs with leaks or as aerial infestations in buildings. The authors hypothesized that the reduced dependency on below-ground nesting and feeding sites would reduce the necessity for adapting to episodic inundation. However, the Eastern subterranean termite is more soil dwelling and it would make sense that it was more adapted to surviving episodic inundation.
It all made sense to me. And when you really think about it, if you were a social insect and your choices were certain death if you floated away from the colony or a chance of survival if you stuck with the colony – even in a flood – which would you choose?

There will be a lot of reconstruction going on in the next few years. Preconstruction treatment and strong building codes will ensure protection from termites. But what are they doing with all that debris from the demolition of existing structures? Some states were forced to bury the debris or move debris to landfills outside the hurricane stricken areas. I wouldn’t be surprised if we see termite problems where they didn’t exist before, particularly with the Formosan subterranean termite.

Another invasive species to keep your eyes open for is the arboreal termite, Nasutitermes corniger. Although the Ft. Lauderdale home of this termite was hit hard during hurricane Wilma, I am uncertain as of this writing, if any debris containing this termite has been transported outside of the known areas of infestation.

Oi is an assistant extension scientist at the University of Florida Entomology and Nematology Department in Gainesville.