Carpenter ants are common insects that can become household pests. Their presence often becomes noticeable when they exhibit a behavior called swarming, a natural part of their life cycle. Understanding this behavior helps homeowners address potential infestations.
What is Carpenter Ant Swarming
Carpenter ant swarming involves the emergence of winged reproductive ants, known as alates, from an established colony. These alates are male and female ants with wings for mating. Swarming expands the species by allowing these individuals to mate and establish new colonies. After mating, male ants typically die, and fertilized females shed their wings to search for suitable nesting sites.
Carpenter ant swarmers are larger than typical worker ants, with some reaching up to three-quarters of an inch. While worker ants are wingless and built for excavation, swarmers have a more streamlined appearance suited for flight. Their presence indicates a mature colony.
When Carpenter Ants Swarm
Carpenter ant swarming typically occurs from late spring to early summer, often between mid-May and early July in many regions. Timing varies geographically, observed from February to June in the western U.S. and May to August in the eastern U.S. Environmental conditions like warm temperatures, high humidity, and recent rainfall trigger these events. Swarming often happens late afternoon into dusk, especially after rain when humidity is elevated.
For a swarm, soil temperatures need to be above 60°F and relative humidity over 70%. These conditions are optimal for successful mating flights and the establishment of new colonies. While outdoor swarms are common, indoor swarms can occur any time of year if the colony is located within warm structural voids, such as wall cavities or attics.
Distinguishing Swarming Ants
Differentiating carpenter ant swarmers from termite swarmers is important. Carpenter ant swarmers possess elbowed or bent antennae, while termite swarmers have straight, bead-like antennae. Another distinguishing feature is the body waist: carpenter ants have a constricted waist, while termites have a broad, thick waist.
Carpenter ant swarmers have two pairs of wings where the front pair is notably longer than the hind pair. In contrast, termite swarmers have two pairs of wings that are of equal length. Carpenter ant swarmers are generally larger (one-half to one inch), while termites are typically smaller (no more than one-half inch long).
The Significance of a Swarm
Observing a carpenter ant swarm signals that a mature, established colony is likely present within or very near a structure. Carpenter ant colonies typically take three to six years to mature enough to produce swarmers.
While winged swarmers do not directly cause structural damage, their presence indicates a hidden colony excavating wood for nests. This excavation can compromise the integrity of wooden structures over time. The presence of carpenter ants often suggests underlying moisture problems, as these ants prefer to nest in soft, moisture-damaged wood.
Actions When a Swarm Appears
Simply spraying visible ants is not sufficient, as this does not address the hidden colony. The initial step is verifying the ant species. Collecting a few specimens for identification can be helpful.
Locating the source colony is paramount for effective control, and carpenter ants often leave scent trails that can be followed. Since carpenter ants reside in concealed nests, professional pest control services are often necessary to locate and eliminate the entire colony. Professionals have specialized treatments and expertise to find nests in inaccessible areas, including addressing moisture problems.