Tuesday, October 21, 2008

Texas carpenter ants are lazy

My entomology career got its inauspicious start twenty-eight years ago when I interviewed for a pest control technician's job in Seattle, Washington. I knew I was interested in entomology at the time, had just graduated from college, and needed a job to help my wife go back to school. Little did I know how much of the next one and a half years of my life would be attending to carpenter ants.

Washington state, I learned, grows two things really well: slugs and carpenter ants. The slugs that fed on my garden tomatoes grew up to six inches long. The carpenter ants were everywhere. As I recall, about 75% of the accounts I carried as a residential pest control technician had something to do with carpenter ants. Carpenter ant damage is to Washington homes, about what termite damage is to Texas homes. I've since learned that the carpenter ant species plaguing Washingtonians is Campanotus modoc, the western black carpenter ant.

Since migrating south I've yet to see good evidence that Texas carpenter ants pose any significant threat to wooden structures. The worst damage I ever encountered was in my own home, where some carpenter ants had hollowed out some galleries in the foam insulation in a bathroom wall. On an athletic scale for carpenter ants, where C. modoc are the Superbowl champs, our wimpy Texas ants couldn't make it past the sofa with television remote and beer in hand.

The Texas carpenter ant community consists of different species than the one that pay the bills for Washington PMPs. Most Texas species have little interest in boring into solid wood, although they will nest in walls of buildings, and can be a nuisance. One difference is that colony sizes of carpenter ants in Texas are much smaller than C. modoc colonies, which may contain over 100,000 ants.

So a few weeks ago I was interested to receive this image from Jay Jorns, with JNJ Pest Control in Katy, Texas. It shows the contents of a Sentricon termite below-ground monitoring station (with sensor strip) that had apparently become home to a small colony of carpenter ants.

black carpenter ants in Sentricon termite monitorThe picture interested me because it shows the clean galleries typical of the structure-damaging carpenter ants of Washington and the eastern U.S., and because the station was checked regularly, it was unlikely that the ants had merely moved into termite-damaged wood. It was real wood damage, even if not from a home.

Jay sent me a follow-up sample of these ants, and they turned out to be the black carpenter ant, Campanotus pennsylvanicus. Although range maps show C. pennsylvanicus is found throughout all but the far western panhandle and far southern parts of Texas, it is not a common pest ant in the state, to my knowledge.

On the other hand, this carpenter ant is the principal structure-infesting ant in the east and upper midwestern parts of the U.S., where it is known to do structural damage. So why not so much a problem in Texas? I'm not sure. I'm hesitant to say that the black carpenter ant will never infest indoor homes in Texas, given their record in other parts of the country. But of all the carpenter ants in Texas, this species probably has the greatest potential for structural damage.

For anyone reading this blog, I am interested in seeing pictures of carpenter ant damage from anywhere in the U.S. Send me your images and I will post them online along with information about where the damage occurred (city, state) and your name (O fame!). Anyone from Texas who can show me bona fide carpenter ant damage to sound wood in a structure (not carpenter ants living in old termite galleries), I will send a copy of the very useful booklet, Ant Genera of Texas and praise you for your contribution to science on these pages. I look forward to hearing and learning from you.

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