Tapinoma sessile, or “odorous house ants,” as they are more commonly known, are very common insect pests within homes and buildings throughout the US. These ants get their common name from the odorous defensive fluid they emit when threatened or crushed under foot. Odorous house ants are one of the most common indoor ant pest species in the US, and they can be relatively difficult to control. A 2016 nationwide survey revealed that odorous house ants were the third most commonly encountered indoor ant pests by pest control professionals. The odorous house ant is also becoming the dominant ant pest species in many urban and suburban areas of the midwest and northeast. These ants are the most ecologically tolerant of all ant pest species in the US, as they are able to establish colonies in a variety of different landscapes and climatic conditions. For example, odorous house ants are found throughout the US at elevations ranging from sea-level to 10,000 feet, and colonies in Massachusetts are often found on sandy beaches, grassy fields, rural marshes and wooded areas.

Odorous house ants invade Massachusetts homes during most months of the year, but infestations are particularly common during the fall when their honeydew-excreting insect food sources become scarce in the natural environment. In response to this decrease in food sources, odorous house ants invade homes in search of sweet-tasting food sources. Odorous house ants are commonly found invading homes in search of food after bouts of rainfall as well, as rainfall prompts their insect food sources to seek shelter in harborages that are well hidden from predators.

Odorous house ant workers prefer sweets, but they will consume virtually any human food source, including grains, vegetables, fruit and meat. Workers invade interior living areas from well hidden outdoor and indoor nests, and given their need for high moisture environments, their nests are commonly found around plumbing in wall voids. Outdoor nests may be located beneath tree bark, in plant structures, in other animal nests, and within the shallow top-soil beneath stones, logs, and plant matter. Odorous house ants generally mate within nests, as opposed to swarming, and one single female reproductive and a few male workers can leave an existing nest in order to establish an entirely new nest. Because of this, it is not uncommon for multiple odorous house ant nests to be found within wall voids, behind baseboards, beneath floorboards and other obscured indoor areas.

Have you ever sensed a pungent odor after crushing ant ant?