According to entomologists at the University of California, there are over 12,000 species of ants worldwide. Most of these ants are harmless, but one species that can cause a problem in your home is the carpenter ant. Carpenter ants damage wood, fiberglass insulation and drywall.

Carpenter ants can't eat solid food; their main diet consists of honeydew and tree sap.


Carpenter ants can be black with dark red legs, or have a black and red body. Worker ants are different sizes, ranging from 1/4 to 1/2 inch in length. A smaller species of carpenter ant is yellow and black and only grows to be between 1/8 and 5/16 inch long. Carpenter ants don't sting, but they do bite and spray formic acid into the wound, causing it to burn. Carpenter ants give off a strong odor when they're bothered. Swarms of flying carpenter ants, which include reproductive members, are usually seen in the spring.


Carpenter ants damage wood and drywall in your house by tunneling into it to build galleries for raising their young. Unlike termites, they don't eat the wood. Look for piles of coarse sawdust, insulation, drywall gypsum, or dead bug parts, which the carpenter ants have pushed out of the excavated tunnels. The tunnels will be located above these materials. Carpenter ants can cause structural damage to homes. How serious the damage is depends on how many nests have been built and how long the ants have been living in your home.


Carpenter ants make two types of nests. The main nest is often located in a tree outside, since they prefer moist wood. However, they also make "satellite" nests in other locations where they're working. Satellite nests only contain workers, no queen, eggs or larvae. Look for indoor nests around sinks, poorly sealed windows, in locations where there's a leaky roof, and in moist places behind a dishwasher. One technique for finding a nest is to use the blunt end of a screwdriver to tap on wooden surfaces while listening for the hollow sound that damaged wood makes. In addition, carpenter ants in a nearby nest will respond to your tapping by making a rustling sound.


Carpenter ants are hard to control but you do need to find and destroy their nests. This can be done by following them back to their nest after baiting them with a small amount of diluted honey placed on the nonsticky side of a piece of masking tape. This should be done at night when the ants are active. You can kill carpenter ants by drilling a number of small 1/8-inch holes into the wall in front of their nest and spraying boric acid into the nest. Insecticides like carbaryl can also be used on outdoor nests.


Swarming ants are sometimes mistaken for termites, but it's easy to tell the two insects apart. Winged carpenter ants are larger than termites and have bent antenna, a narrow waist and front wings that are larger than their hind wings. Termites have beaded antennae, a broad waist and wings that are the same size. The holes they make in wood and drywall look dissimilar as well. Termites create ragged holes, which they plug up with dirt. Carpenter ants make smooth galleries with no mud or wood particles attached.