In the United States, pest control professionals manage carpenter ant pests within homes more often than any other ant pest. Carpenter ants are well known for establishing nesting sites within moist woodwork, which sometimes results in costly damage. Carpenter ants can be found throughout the country, but carpenter ant species that infest homes vary by region. The most economically significant carpenter ant pest species in the US is C. pennsylvanicus, or the black carpenter ant. This species infests homes in the eastern US, and colonies are most abundant near wooded areas, but virtually all homes in the region are vulnerable to carpenter ant infestations.

Carpenter ant mating swarms occur during the spring in Massachusetts, but winged carpenter ants that overwinter within heated homes swarm slightly earlier than outdoor carpenter ants. Winged carpenter ants generally emerge as one big swarm once per year, but large swarms may be followed by a few smaller swarms during some years. After swarming, workers leave the “parent nest” to forage and establish additional nests known as “satellite nests.” Parent nests are always located outdoors, and workers frequently invade homes in search of food sources. However, workers also frequently establish satellite nests within inaccessible indoor areas, such as wall voids. The parent nest is always located within moist and rotten wood sources in the natural environment, as the queen and her eggs require high moisture in order to develop properly. Since satellite nests only contain workers, these nests are often found in relatively dry wood sources.

Eliminating carpenter ant infestations can be difficult when workers establish multiple indoor satellite nests in areas where they cannot be readily detected visually. In order to fully eradicate infestations, all indoor satellite nests and the outdoor parent nest must be located and treated. Only the two primary carpenter ant pest species in the US, C. modoc and C. pennsylvanicus, have been thoroughly studied by scientists. Based on these studies, it seems that most black carpenter ant colonies are composed of one parent nest and as many as 10 to 12 satellite nests, but most black carpenter ant infestations within homes see fewer than ten, but more than three indoor satellite nests.

Have you ever found ants emerging from a wall opening?