Carpenter Ants

Food

Outdoors: plant juices, insects, honeydew from insects, spiders. Indoors: sweets, grease, meat, eggs. Carpenter ants follow a regular trail when foraging.

Biology

A mature colony of western carpenter ants may have 10,000-20,000 workers or up to 100,000. Swarmers aren’t produced until the colony matures. In the West, swarmers may appear between February and June. There is usually just one functional, wingless queen per colony. Development from egg to adult takes at least 60 days.

Damage

The hollowing of wood for nests can weaken a structure. Also, bites can be painful.

Prevention

Carpenter ants require a water source. To prevent these ants in the house, eliminate sources of moisture or standing water. Keep tree branches and other plants cut back from the house. Sometimes pests use these branches to get into your home. Make sure that there are no cracks or little openings around the bottom of your house. Make sure that firewood and building materials are not stored next to your home. Carpenter ants like to build nests in stacks of wood.

Detection

Look for piles of sawdust-like shavings, sometimes with bits of insulation and insect parts. Listen for rustling sounds from within the walls. (A listening device is useful.) Watch for foraging trails outside, especially between 10 am and 2 pm. Be alert to the emergence of swarmers. With a tool gently tap exposed wood and rafters, listening for a hollow sound which might indicate a nest cavity. A knife blade will easily sink into the wood if a nest is present. Check attics, basements, and crawl spaces. Check wires and pipes. Locate high moisture areas. (A moisture meter can be useful.)