The carpenter ant (Camponotus genus) is a structural pest known for excavating wood to build nests, which can cause significant property damage. Homeowners often become concerned when they see these large ants, especially if they are flying or near light sources. Understanding whether carpenter ants are attracted to light is key to managing their presence and controlling potential infestations.
Are Carpenter Ants Attracted to Light?
Adult worker carpenter ants, the non-winged ants typically seen foraging, are negatively phototactic, meaning they move away from light. These workers are primarily nocturnal, searching for food sources between sunset and midnight. This negative response keeps the majority of the colony hidden within the dark recesses of their nest galleries.
The question of light attraction changes when considering the reproductive members of the colony. The only time carpenter ants are seen with wings and in large numbers near light is during the swarming phase, or seasonal nuptial flight. These winged reproductive males and females, known as alates, emerge to mate and establish new nests, usually during warmer months.
During this emergence, the alates exhibit a positive phototaxis, or attraction to light, which can draw them toward indoor windows or outdoor lighting fixtures. If a homeowner discovers wings or winged ants on an interior windowsill, it strongly suggests a mature nest is established within the structure. This temporary attraction is a biological necessity for dispersal and mating, not a characteristic of the foraging worker ants that make up the bulk of the colony.
Distinguishing Swarmers from Other Flying Pests
The appearance of flying insects near light often causes confusion, as winged carpenter ants are frequently mistaken for flying termites, which also swarm. Correct identification is important because the presence of either insect signals a need for structural inspection. Examining a few physical characteristics helps determine whether the insect is an ant or a termite.
Carpenter ant swarmers have a distinctly segmented body with a narrow, pinched waist connecting the thorax and abdomen, giving them an hourglass shape. In contrast, termite swarmers have a broad, thick waist, making their body appear more uniform and cylindrical. This difference in body shape is one of the most reliable visual clues for distinguishing the two pests.
The antennae also provide a clear means of identification. Carpenter ants possess elbowed or bent antennae, while termites have straight, bead-like antennae. Furthermore, a close look at the wings reveals another difference: carpenter ants have two pairs of wings that are unequal in length, with the front pair being noticeably longer than the hind pair. Termites have four wings that are nearly identical in shape and size.
True Attractants and Prevention Strategies
While winged alates may be drawn to light during their brief swarming period, light is not the primary factor attracting a carpenter ant colony to a home. The true driving forces are moisture, suitable nesting sites, and readily available food sources. Carpenter ants do not consume wood like termites; instead, they excavate wood to create smooth galleries for their nests, preferring wood softened by water damage or decay.
Moisture is a significant attractant because damp wood is easier for them to tunnel through and provides necessary humidity for colony development. Sources of water, such as leaky pipes, clogged gutters, or poor drainage near the foundation, create ideal conditions for nest establishment. Addressing these moisture problems is a crucial first step in prevention.
Carpenter ants also forage for food, favoring sweets, proteins, and grease. Outdoors, they feed on dead insects and honeydew excreted by aphids. Indoor prevention strategies should focus on eliminating these food sources by storing pet food in sealed containers, promptly cleaning up spills, and ensuring all food waste is properly contained. Trimming tree branches that touch the structure and sealing exterior cracks and gaps are also effective steps to eliminate access points and discourage new colonies from forming.