Carpenter Ants: All You Need to Know in a Quick Guide

Carpenter ants are a common type of ant found throughout the world, known for their ability to nest within wooden structures.

These ants play a crucial role in the ecosystem by helping in the decomposition of dead and decaying trees.

However, they can also become problematic when they invade homes in search of food and shelter.

These insects are most commonly found nesting in moisture-damaged wood, making them sometimes referred to as the “termites of the northwest.”

Unlike termites, carpenter ants do not eat wood but excavate it to create their nests.

This behavior can potentially cause structural damage to homes and buildings if left untreated.

Carpenter ants vary in size, with North American species having some of the largest worker ants, measuring up to 12mm (0.5 inches) long, and queens reaching up to 20mm (1 inch) in length.

In addition to their size, these ants are known for their ability to create satellite colonies, increasing their potential for causing damage.

In the following article, we will explore the lifecycle, habits, and control measures of carpenter ants to help you better understand and manage these fascinating insects.

What Are Carpenter Ants

Identifying Carpenter Ants

Carpenter ants are large ants typically found in wooded areas.

They are known for their habit of tunneling through wood to create nests, but they do not eat wood like termites.

Some signs of carpenter ant infestation include piles of wood shavings outside holes or openings.

Here are some features to help identify carpenter ants:

• Size: Worker ants up to 12 mm (0.5 in) long
• Color: Typically black or dark-colored

Carpenter Ant Species: Camponotus Spp.

The genus Camponotus consists of over 1,000 species, collectively referred to as carpenter ants.

These ants play an important role in the forest ecosystem by breaking down dead, decaying trees.

The largest carpenter ants in North America belong to this genus, with queens reaching up to 20 mm (~1 in) in length.

Comparison Table: Termites vs. Carpenter Ants

Remember to maintain a vigilant eye for the presence of these ants in your home and take appropriate action if necessary.

Carpenter Ants Life Cycle and Behavior

Nest and Colony Formation

Carpenter ants typically create their nests in moist, decayed wood.

They can be found in trees, logs, stumps, and sometimes homes if they’re in search of food or seeking shelter.

Worker ants create tunnels in the wood while the queen lays eggs in the colony. Some examples of carpenter ant nesting sites include:

• Tree hollows
• Decayed stumps
• Wood structures with moisture problems

Carpenter ants colonies are complex and may contain satellite nests in addition to the main nest.

Satellite nests help the colony expand and provide additional space for brood rearing.

Foraging and Feeding Habits

Carpenter ants have specific foraging habits. They’re primarily nocturnal and follow scent trails left by other ants to locate food.

They prefer sugary, protein-rich foods and are often seen scavenging for:

• Aphid honeydew
• Insects
• Sweet items (inside homes)

Carpenter ants differ from termites, as they don’t consume the wood they inhabit.

They create galleries and tunnels within the wood to move around and discard the wood dust, known as frass, outside the nest.

Winged Carpenter Ants: Reproductive Swarmers

Winged carpenter ants are responsible for reproducing and forming new colonies.

They take part in a nuptial flight typically during late spring or early summer, where males and females mate mid-air.

Carpenter Ant Alate

After mating, the males die and the females lose their wings to become future queens.

Features of winged carpenter ants include:

• Larger than worker ants
• Two sets of wings
• Dark-colored, often black or reddish-brown

Here’s a comparison table of winged and worker carpenter ants for reference:

However, they can cause significant damage if they infiltrate homes and buildings in search of food and nesting sites.

Signs of Infestation

Damaged Wood and Tunnels

Carpenter ants make their nests in damp or rotting wood, creating irregular tunnels or galleries where eggs are laid.

They prefer softer fibers due to the ease of tunneling. Examples of damaged wood include:

• Hollow or weak areas in wooden structures
• Softened or crumbling trim and molding

Frass: Carpenter Ant Sawdust

Frass is produced by carpenter ants as they tunnel through wood. Look for:

• Piles of sawdust-like material near damaged wood
• Small, wood-colored debris around baseboards

Noises in Walls and Structures

Carpenter ants can produce faint noises inside walls and structures as they move or chew through wood. Listen for:

• Quiet rustling sounds
• Occasional cracking noises

Indoor and Satellite Nests

Carpenter ants can have indoor and satellite nests, with worker ants foraging up to 100 feet from their nests. Signs of indoor nesting include:

• Large groups of ants indoors
• Ants traveling in common paths between indoors and outdoors

Prevention and Control

Keep Your Property Dry and Well-Maintained

A crucial step in preventing carpenter ant infestations is maintaining a dry and well-maintained property. For example:

• Regularly clean gutters and downspouts to avoid water accumulation.
• Fix leaky pipes and faucets to reduce moisture.

Carpenter ants thrive in damp environments, so by eliminating moisture, you make your property less inviting to these pests.

Additionally, maintain your landscaping and trim tree branches that touch your buildings to reduce potential entry points for ants.

Seal Cracks and Crevices in Buildings

Carpenter ants can enter properties through tiny openings, so seal any cracks and crevices in your foundation, walls, and around doors and windows. For instance:

• Use caulk to seal gaps around pipes and wires.
• Install door sweeps to block entryways under doors.

Sealing these openings not only keeps carpenter ants out but also helps prevent other pests from accessing your property.

Store Firewood Properly

Firewood storage plays a critical role in controlling carpenter ant infestations. Proper storage includes:

• Storing firewood at least 20 feet away from buildings.
• Elevating firewood at least 18 inches off the ground.

By following these guidelines, you minimize the risk of carpenter ants nesting in the wood and migrating to nearby structures.

Home Remedies and Non-Toxic Solutions

Diatomaceous Earth and Borax

Diatomaceous earth (DE) is a natural and non-toxic option to control carpenter ants:

• Made from crushed, fossilized algae
• Damages ants’ exoskeletons, causing dehydration and death

To use DE:

1. Lightly dust-affected areas with DE.
2. Reapply after rain, as DE loses effectiveness when wet.

Borax, also known as boric acid, is an effective ant killer:

• Disrupts ants’ digestive systems and kills them
• Safe for humans when used correctly

Try this borax bait recipe:

1. Mix 1 part borax with 3 parts sugar.
2. Add water to make a paste.
3. Place in bottle caps or other small containers near ant trails.

Pros of DE and borax:

• Non-toxic to humans and pets
• Effective ant control

Cons of DE and borax:

• Need to reapply after rain or cleaning
• May take some time to show the results

Essential Oils and Dish Soap

Essential oils can be used as natural repellents for carpenter ants:

• Peppermint, tea tree, and eucalyptus are popular choices

To create an ant-repellent spray:

1. Add 10-15 drops of chosen essential oil to a spray bottle with water.
2. Shake well and spray around entry points and trails.

Dish soap is another easy solution for ant control:

• Destroys ants’ exoskeletons and suffocates them

Mix equal parts dish soap and water in a spray bottle, and apply directly on ants and their trails.

Pros of essential oils and dish soap:

• Natural, non-toxic solutions
• Readily available household items

Cons of essential oils and dish soap:

• May require frequent reapplication
• Not as effective for large infestations

Cleaning and Removing Food Sources

A clean home is less appealing to carpenter ants:

• Regularly remove trash
• Store food in sealed containers
• Clean up spills and crumbs immediately
• Fix leaking pipes and water damage

These steps will help keep carpenter ants at bay and reduce the chance of infestation.

Pros of cleaning and removing food sources:

• Prevents ant infestations
• Creates a cleaner, healthier living environment

Cons of cleaning and removing food sources:

• Requires consistency and effort
• May not be enough for existing infestations

Professional Pest Control Options

Insecticide and Bait Treatments

Carpenter ants can be managed using insecticide treatments or ant baits. Insecticides can be applied as a liquid or dust:

• Liquid insecticides can be applied directly to active ant nests.
• Dust insecticides can be applied to areas where ants are found entering a structure.

Ant bait treatments are placed where ants are found foraging for food. Carpenter ants prefer high-protein foods, so using a protein-based bait can be effective:

• Pros: Minimal environmental impact, and safe for use around children and pets.
• Cons: Longer time to achieve full control of the infestation.

For more information on insecticide and bait treatments, visit the UC IPM site.

Perimeter Treatments and Aerosols

Perimeter treatments involve applying a liquid insecticide around the foundation of a structure to create a barrier.

This method is typically used to stop ants from entering a building:

• Pros: Provides long-lasting protection, and deters other pests from entering the structure.
• Cons: Does not address the ants already inside a building and may require reapplication.

Aerosol treatments can be used for direct contact, spot treatments, or in cracks and crevices where ants are entering a structure.

They typically contain pyrethroids, which are effective against carpenter ants:

• Pros: Fast-acting and can provide immediate relief.
• Cons: Not a long-term solution, and may require multiple applications.

For more information on perimeter and aerosol treatments, consult the Penn State Extension webpage.

Hiring an Exterminator

If you are facing a severe infestation, hiring a professional exterminator can be the best option.

They can assess the situation, recommend appropriate treatments, and help you maintain control of the infestation:

• Pros: Personalized solutions and access to professional-grade products.
• Cons: Can be expensive and may require ongoing visits for complete control.

Remember these key factors when comparing treatment options:

Using a combination of these methods can often be the most effective way to address a carpenter ant infestation.

Conclusion

In conclusion, carpenter ants, belonging to the genus Camponotus, play a vital ecological role but can pose challenges when they infiltrate human dwellings.

Distinguished by their large size and dark color, they nest in damp wood, potentially causing structural damage.

Preventive measures include addressing moisture issues and sealing entry points, while management strategies range from natural remedies to professional extermination.

Understanding their behavior, lifecycle, and control methods is essential for maintaining a harmonious coexistence with these industrious insects.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about carpenter ants. Scroll down to have a look at some of them.

Letter 1 – Carpenter Ant

want tio know
just want to know what type of ant this is it is an inch long thank you
allan mckee
Lewiston,ID

Hi Allan,
This is a Carpenter Ant in the genus Camponotus.

Letter 2 – Carpenter Ant

Some neat bugs!
Hi Bugman!
Near Lake Erie, while birding, I spotted this ant. It seemed ‘different’ to me and I’m cluelss as to his unwilling meal. I found it and others like it climbing a tree of which half was rotten. (The rotten half had a delightful colony of baby garter snakes looking up into the bright sun above). Thanks for your help.
Cathy Wilson

Hi Cathy,
These big black ants are Carpenter Ants.

Letter 3 – Carpenter Ant

Subject: New ants spotted
Location: Southeast Washington TriCities
August 21, 2017 7:54 pm
Have been seeing these larger type ants on my back patio the last 4-5 days and have never seen these before with the reddish abdomens. Have recently been swarmed with Mediterranean Seed Bugs and wonder if there is some relationship. What is the name of these ants?
Signature: Gerry Presby

Dear Gerry,
This looks like a Carpenter Ant, and your indication that you are seeing “larger type ants” supports that identification as Carpenter Ants are quite large.  Your individual resembles this image posted to BugGuide that is identified as being in the genus Camponotus Subgenus Tanaemyrmex.

Letter 4 – Carpenter Ant Alate

Subject: what bus is this?
Location: Washington, D.C.
May 9, 2014 10:20 am
Please help identify this bug found in a home.
Signature: Vika

Hi Vika,
This looks like the winged reproductive form or alate of a Carpenter Ant.  See this image on BugGuide for comparison.

Letter 5 – Carpenter Ant Alate

Subject: Wasp, Ant, Other?
Location: Winnipeg, Manitoba, Canada
August 25, 2015 3:07 pm
I have been seeing this bugs around my place and I would like to know what they are? Where are they hiding in my house? Should I be concerned?
Signature: James

Dear James,
This looked to us like a Carpenter Ant alate, the winged caste of reproductive males and females that embark on a nuptial flight to mate and begin new colonies.  We suspect they may be coming from within your house and when they emerged, they found themselves indoors instead of outside. 

We once had a colony living in gorgeous, old cedar floor to ceiling paneling in a Highland Park, Los Angeles bungalow, and each year they would emerge.  The head on your individual seemed small compared to most images we have seen, but we found a matching image labeled “Male carpenter ant, Camponotus sp., Massachusetts” on the BugEric blog.  BugGuide lists the genus throughout North America.

Letter 6 – Carpenter Ant Alate

Subject: What’s this bug
Location: North Carolina
May 28, 2017 10:46 am
They seem to have showed up out of no where and there are a lot of them sitting somewhat peacefully all around and all over the outside of our home.
Signature: Thanks Joe.

Dear Joe,
This looks to us like a male Carpenter Ant alate, the winged reproductive form that swarms when conditions are right, often a warm sunny day after a good rain. 

It might be a Camponotus castaneus based on this BugGuide image, a species BugGuide calls the Reddish Carpenter Ant and states:  “Nests in rotting logs, soil under rocks, etc., or even in exposed soil.”

Letter 7 – Carpenter Ant Alate

Subject: WTB ?
Location: N.E. Alabama
May 28, 2017 10:03 am
My daughter n law was bit by what she described as a flying ant outside. Later the next day I found this in the floor of my laundry room thinking it mite have been what bit her.
Signature: Dmeado

Dear Dmeado,
Earlier today we posted an image from North Carolina of what we believe to be a male Carpenter Ant alate, the winged reproductive form that swarms when weather conditions are right.  We believe your image is that of a female Carpenter Ant alate, possibly Camponotus castaneus, based on this BugGuide image. 

We believe the best way to distinguish the males from the females is the shape of the head and the longer antennae on the males as he uses his antennae to help locate a female.  BugGuide notes:  “Alates noted May-June (Mississippi) and September (Mississippi, North Carolina)” so your swarm seems quite on schedule.

Letter 8 – Carpenter Ant Alate

Subject:  To identify flying insect
Geographic location of the bug:  Portland, Oregon
Date: 08/14/2018
Time: 06:17 PM EDT
Your letter to the bugman:  We found dozens of these inside the house today. I think they got in when we opened doors, but we’re not sure. They are just under 1/2″ long, brown, and appear to have a 3 section body with wings.
How you want your letter signed:  Is this carpenter ant, or something else?

This does appear to be a reproductive Carpenter Ant alate, and the wing veinage looks like that of this individual on BugGuide, so we believe you are correct.  If you found them in your house, we believe they probably swarmed from inside rather than entering from the outside.