Just like honey bees, termites, and many wasp species, ants are social insects that live in colonies. A colony’s population is divided into different groups, or “castes,” and each caste is responsible for carrying out various duties to further the colony’s success. To put it simply, ant colonies consist of workers, soldiers and the queen, and most ants within a colony are workers. Workers are responsible for brood care, nest construction, and for the gathering of food, or “foraging.” Workers that are tasked with foraging are known as “scouts,” and while the exact foraging method employed by scout ants is not well understood, it is believed that they travel at random until a food source is located.

Once a scout ant locates a food source, they perform a taste test before returning to the nest to share their discovery with their fellow nestmates. Interestingly, after a scout ant locates a food source, they do not retrace their steps back to the nest; instead, scout ants take the most direct route back to the nest. It is believed that scout ants observe environmental landmarks like sticks, rocks, and plants during outgoing foraging expeditions, and they rely on their memory of these landmarks to find the most efficient way back to the nest.

After successfully locating a food source, scout ants secrete odorous “trail,” or “recruitment pheromones” during their return trip, which allows other worker ants (recruits) to follow these odors directly to the food source. These recruits also secrete trail pheromones during each subsequent trip, which prevents the odor trail from dissipating. The degree to which ants rely on trail pheromones to locate food sources varies from species-to-species, but following foraging ants within and around homes is the most reliable method of locating every nest that must be destroyed to eliminate infestations. Carpenter ants, pavement ants, odorous house ants, and Pharaoh ants are the most common household ant pests in Massachusetts, and each of these species rely on trail pheromones to locate and collect food.

Have you ever followed ant pests in your home only to find them disappear within a wall?