Carpenter Ants

Carpenter ants construct two types of colonies: the main colony (sometime called “parent colony”), which contain the queen, young larvae, and workers and satellite colonies, which nest inside the structure and contain pupae, mature larvae, winged male and female reproductives (swarmers) and workers.

Ants from satellite nests are what homeowners will most likely see inside their home.

Carpenter ants carefully deposit debris called “frass” outside their nest via a slit-like opening called a “kick-out hole”. Frass may contain coarse sawdust, wood fragments, soil, and insect parts. Small cone-shaped piles of frass can be seen by homeowners.

Examining the kick-out hole near any frass will lead to smooth and sandpapered galleries (nest).

Carpenter ants habitually build their satellite nests around rotted window sills or door frames and around sinks or other moist, poorly drained places near kitchens and bathrooms. However, satellite nests do not need as much moisture as the main nest (where eggs are found) and can be found throughout a home, even in dry areas such as hollow doors and insulation.

Parent nests are always built outdoors and located in decaying or rotten wood such as in a tree, stump, woodpile, or landscaping materials.

Carpenter ant workers make a distinctive clicking sound (like crinkling cellophane) inside the wall.

Carpenter ants are black or red and black in color with an evenly rounded thorax when viewed from the side.

The waist contains one node (petiole: a stalk or peduncle that connects the abdomen and thorax).

As there are several species of carpenter ants present in Minnesota, it can be difficult to identify carpenter ants by their size alone. Additionally, carpenter ant workers are polymorphic, which means that within the same species, worker ants are not all the same size. Usually, the worker carpenter ants are about 3/8″ – 5/8″ in length.

The queen is larger and can reach up to one inch in length.

Another distinguished characteristic of carpenter ant species is the presence of a border of tiny hair at the end of their abdomen.

Other carpenter ant species may be more reddish-brown in color.

Carpenter ants are not aggressive.

Although it is possible, carpenter ants very rarely pinch (“bite”) humans. You might have to lie down in a hollow log infested with ants in order to get bitten.

Carpenter ants will bite and spray formic acid into the wound in defense and on contact.

Usually, their bite feels like a pinch and does not need medical attention unless the skin is broken and the bitten person is hypersensitive or allergic to the formic acid spray.

Yes. As their common name may indicate, carpenter ants are capable of boring into wood doors, windows, trim, cabinets, decking, and other wood materials to build a nest.

Unlike termites, carpenter ants do not eat the wood in your home; they excavate wood materials to make their galleries.

Carpenter ants prefer moist or damp wood, but in heavy infestations they may tunnel into solid wood. Infestations often begin in pre-existing, rotted holes or voids, and then expand into both decaying and intact adjacent wood around the original holes.

Although carpenter ants do cause damage and should be of concern, their nests grow at a relatively slow rate.

Also, remember that the nests are usually bored into wood that is already damaged due to water or dry rot. Therefore, you should be concerned about damage due to water leaks and take corrective steps as necessary.

The presence of rotted wood does not necessarily mean you have carpenter ants; however, the presence of carpenter ants may indicate a rotted wood issue in the structure. The extent of carpenter ant damage depends on the number of satellite nests found inside your house, as well as how long the ants have been tunneling inside the wall. Therefore, it is advisable to act fast when you see carpenter ants before they become a more significant problem in your home.

Carpenter ant workers are attracted by the presence of “weakened wood,” usually resulting from past water damage.

Several satellite nests (up to ten) can be associated and connected with a single parent colony via pheromone trails. These nests can be located as far as 300 feet away from the main colony.

Carpenter ants may become active and be seen inside the house on warm, sunny winter days. In this situation, it is important to identify where these ants are coming from. If carpenter ants are seen coming out of firewood during the winter, they will probably not build a new nest inside the house. Otherwise, if they are seen inside the home during the winter, and not associated with firewood, it definitely means you have a satellite nest inside the home, since the colonies outside the home are dormant during the winter.

It is usually NOT necessary to drill holes in order to treat carpenter ants.

The ants themselves need to have a means of getting in and out of the void areas, so we inspect and treat all those possible entry/exit points.

We may remove electrical outlets and switch covers, which gives us access to the carpenter ants’ common travel routes.

DRILLING HOLES IN EXTERIOR WALLS IS NOT EFFECTIVE because the insulation in the walls will usually prevent the insecticidal dust from freely flowing throughout the complete void area.

Homeowners should be able to expect that Adam’s pest control technicians will stop the damage being created by carpenter ants, not create more problems with unsightly holes in their walls and windows.

It is not required that you leave. However, if you feel more comfortable, you can leave for about 2 – 4 hours until the application has completely dried.

If you stay in the house, homeowners, children, and pets should not be in the area while it is being treated.

Customers should advise the technician of any health-related issues present in the household so that the technician can take any appropriate precautions.

During Adam’s carpenter ant treatment, all pets must be moved to areas of the home which will not be treated and kept there until the treatment has dried.

Once the treatment is dry, pets may resume their normal activities.

The only pets that seem to be sensitive to minor changes in their environment are birds and fish. If you have birds, you may want to move them to another location.

Carpenter ants prefer sweet food, especially honeydew, but they can feed on a variety of food materials, such as dead insects, meat, grease, and fat.

Interestingly, carpenter ants change their feeding preference throughout the season. For example, they prefer protein-based food during the spring to accommodate larval development. During the summer, when adult workers are active, a switch is made to carbohydrates (e.g., honeydew) as an energy source for workers.

Foraging workers carry food back to the nest and feed it to the queen, larvae, and other members in the nest.

Carpenter ants are social insects and live in colonies. Each colony is made up of different cast members: one egg-laying queen, drones (male reproductives) and workers (major and minor).

Carpenter ants follow a complete metamorphosis, in which they go through four separate developmental stages (egg, larva, pupa, and adult) during their life cycle. Homeowners sometimes mistakenly refer to the pupa stage as “eggs” because they see the ants carry them from the parent nest to the satellite nests.

Each colony has only one wingless egg-laying queen. This queen normally lives for over 20 years in the parent/main nest outside the structure and lays over 70,000 eggs during her lifespan.

A queen of a mature colony will produce male and female “reproductives.” These will be transported into satellite nests during the pupa stage (usually in late summer).

The winged male and female reproductives emerge from satellite nests and swarm during the spring.

After mating, males soon die and the newly fertilized females lose their wings, and each queen then begins to establish a new colony in a small cavity in wood, under bark, in a rotted stump, etc.

Each new queen lays about 15-20 eggs over the next 15-20 days.

Carpenter ant eggs are always kept in the main colony outside where the moisture level is typically higher than inside a structure. Eggs usually hatch in 24 days, and newly emerged larvae go through four developmental instars within approximately 21 days. The queen rears the first brood from food reserves that are stored in her body. Therefore, workers from the first brood are smaller compared to workers of the next generation. However, further broods will be fed and cared for by worker ants.

Fully mature larvae pupate in cocoons for 21 days. Initially, the queen helps the first-generation workers emerge from their cocoons. Workers will take up this responsibility for the next generations.

The life cycle of carpenter ants last about 66 days from egg to adult in temperatures ranging from 70 °F to 90 °F.

• A main colony takes two or more years to reach maturity with over 3,000 workers.
• Carpenter ant workers live up to seven years, and are responsible for collecting food and excavating nests. They also feed, clean, care for, defend and expand the colony.
• Carpenter ant workers maintain trails between the parent and satellite colonies. It is common to see workers of carpenter ants entering buildings looking for food, especially buildings located within 300 feet of their parent nest. These infestations are more often experienced as the weather warms in the spring and cools in the fall.
• Worker ants are most active after sunset, and remain working throughout the night until sunrise. However, it is not unusual to see them foraging on their trails during the day.
• Depending on the temperature, carpenter ants are generally active from April to mid-October.
• The presence of an occasional ant infestation does not necessarily mean the presence of a nest in your home. When food is not abundant, forager ants may enter the house searching for food within 100 yards away from the nest. However, the continuous presence of ants inside the house, especially in large numbers, is a better indication of nesting inside the premises.
• Carpenter ants excavate into the wood to nest using the softest parts as channels and leaving the hard parts intact as a wall to support the gallery.
• Chambers made by carpenter ants are smooth and clean, giving them an almost sandpapered appearance. This smooth, clean form of the nest structure often appears as if it were done by carpenters, hence the name.
• The queen uses the sperm deposited at the mating flight time for all the eggs she will fertilize in her lifetime.
• The queen ant secretes pheromones (chemical signals) that regulate the behavior and some biological aspects of the other members of the colony.
• When the queen dies, the colony eventually dies.
• Carpenter ants can communicate by touch (tapping the antennas), smell (leaving pheromone trails, emitting formic acid when in danger, etc.), or sound (drumming their heads on the floor of their chambers).
• Workers must help the new adults emerge from the pupa case; otherwise they can’t emerge.
• At any given time, only 1-3% of the worker ants are outside the nest foraging for food and water.• In harsh conditions when food is not available, worker ants can live up to six months without food.