Carpenter Ants

Carpenter ants (Camponotus spp.) are indoor and outdoor pests found across the entire U.S. When they enter the home, they can take advantage of soft, weak, water-damaged wood for their nest sites, and will also feast on sweets, meats, and crumbs. At Sunday, we follow an Integrated Pest Management approach to prevent and manage pest issues. Although Sunday products cannot be used to treat carpenter ants, we have some identification and prevention tips to help you make informed pest management decisions.

Get to Know Carpenter Ants

How to ID carpenter ants

There are many different species of carpenter ants, but most are black or reddish brown in color. Worker ants can vary in size and can be anywhere between ¼ and 1 inch long (the largest of the indoor pest ants!). Speaking of other ants – carpenter ants can commonly be confused with other ant species, and winged queen and male carpenter ants can look similar to termites. 

 

A few ways to tell these pests apart:

  • Look at the waist. Carpenter ants have a single plate-like node (a little bump between the second and third body sections), and that second body section is smooth and even along the arch. Harvester and fire ants both have double-noded waists, and termites don’t have nodes – their bodies are the same width from top to bottom. 
  • Check out the wings. Winged queens and male carpenter ants have shorter hindwings than front wings, while termite wings are evenly sized. 
  • Examine the antennae. Carpenter ants have elbowed antennae, but fire ant and harvester ant antennae are straight. Termite antennae have a “beaded” appearance. 

 

Where Do Carpenter Ants Live? 

Unfortunately, carpenter ants can be found indoors and outdoors. Parent colonies contain an egg-laying queen, brood, and thousands of worker ants. Satellite colonies are usually within 300 ft. of the home, and contain only worker ants, which travel between the parent and satellite colonies. 

 

Outdoor colonies will usually be found in: 

 

  • decaying trees, tree roots, stumps, or logs
  • wooden structures like fence posts or in window casings

 

Inside, carpenter ant colonies are an indicator species – they take advantage of already soft, weak wood, weakened by exposure to water leaks, condensation, or poor air circulation. Carpenter ants may also nest in wood that was previously infested with termites. Consistent indoor sightings of 20+ worker ants any time of the year, or winged ants in late winter through spring, might be an indication of a nearby colony. 

 

Additional signs of an infestation include finding coarse sawdust-like material that includes insect body parts, dead carpenter ants, insect parts and other debris coming from cracks in wood structures, or hearing rustling or gnawing sounds coming from nest sites. To scout out the home, check:

 

  • behind bathroom tiles 
  • around tubs, sinks, showers, and dishwashers 
  • in attic beams, wall voids, or foam insulation
  • under roofing
  • hollow doors, door frames, and window casings

 

When Are Carpenter Ants Active? 

Carpenter ants create perennial nests. They will be active outside when temperatures are above freezing and are most active between sunset and midnight (this is the best time to inspect for carpenter ants!) during the spring and summer. When temperatures drop, carpenter ants will hibernate over the winter, but if they make their way inside, they can be active year-round. 

 

Natural Pest Prevention and Reduction Practices

Prevent carpenter ants from entering the home or yard by doing the following:

 

  • identify and replace moisture-damaged wood that may serve as a home for colonies
  • reduce humidity in bathrooms, kitchens, and attics – particularly if bathroom and clothes dryer fans vent into the attic space
  • clean rain gutters and make sure downspouts direct water away from the home 
  • store firewood away from the home and off the ground
  • remove tree stumps and moisture-damaged trees from the yard
  • prune branches that touch the home (allows easy access to the house)
  • seal cracks and openings in the foundation and places where wires, pipes and other utilities (like phone and cable wires) enter the home
  • remove dead insects from window sills and other areas, as these can serve as a food source for carpenter ants

 

If you suspect you might have an infestation, finding the nests (all of them!) is important for control. For outdoor nests, look for sawdust at the base of trees or wooden structures, and check for ants moving up and down the trees/posts at night as they enter and exit the nest. 

 

Indoors, tap along baseboards, window and door frames, and other wood surfaces, listening for the hollow sound of damaged wood. You can also use a flashlight with a red film over the lens to follow ants back to their nests at night. You’ll know you’ve found carpenter ants if you see smooth, clean tunnels (galleries) that don’t contain soil or frass (feces). 

 

Sunday Pro Tip: You can also get some freshly killed crickets or mealworms from the pet store and place them in the ants’ foraging path – they’ll collect the tasty meal, and you can follow them back to their parent nest! This is a great activity to do with kids!

 

Additional Pro-tips & Sustainability Tips

Carpenter ants and their satellite nests can be vacuumed up, if you find them, but insecticides are the only truly effective way to get rid of colonies. Always follow pesticide label instructions, and remember: the label is the law!   

 

Cited sources

Hahn, J. Carpenter ants. University of Minnesota Extension. 

Jacobs, S. Carpenter ants. PennState Extension.

Potter, M. Carpenter ants. University of Kentucky Entomology. 

Waldvogel, M. and P. Alder. Biology and Control of Carpenter Ants. NC State Extension.