Tapinoma sessile is a small, adaptable ant species commonly known as the odorous house ant. This native ant is widespread throughout the United States, found in natural and urban environments, including residential homes. They are a common household pest, often found in homes due to their attraction to food and water.
Identifying Odorous House Ants
Odorous house ants are small, ranging from 1/16 to 1/8 inches (1.5-3.2 mm). Their color varies from brown to blackish-brown. A distinguishing physical characteristic is their single, flattened petiolar node, often concealed by the gaster.
A primary identifier for Tapinoma sessile is the distinct odor they release when crushed. This smell is often described as resembling rotten coconut, blue cheese, or even turpentine. This unique scent is a reliable way to differentiate them from other small, dark ant species.
Habitat and Behavior
Odorous house ants exhibit ecological tolerance, establishing nests in diverse habitats across North America. They commonly reside under rocks, logs, soil, forests, meadows, and even sandy coastal areas. They are known for their ability to frequently relocate their nests, sometimes in response to environmental changes.
These ants are adaptable, often forming polydomous (multiple nests) and polygynous (multiple reproducing queens) colonies. Such colonies can be large, potentially housing thousands of workers. Their diet is varied, including honeydew produced by aphids, floral nectar, other sugary foods, and greasy substances. They often forage in trails, moving quickly in search of resources.
Odorous house ants often enter homes seeking food, water, or shelter. Their presence indoors can increase, especially during periods of adverse weather, such as heavy rains or extreme heat, which may drive them inside. They are often found in kitchen and pantry areas, attracted to available food sources.
Managing Odorous House Ant Infestations
Preventing odorous house ants from entering homes involves several strategies. Sealing cracks and crevices in foundations, around windows, and utility entry points can block their access. Properly storing food in airtight containers and promptly cleaning up spills and crumbs reduces their food supply. Managing moisture inside and outside the home, such as fixing leaky pipes and ensuring proper drainage, also helps, as they are attracted to humidity.
Addressing existing infestations often requires a multi-pronged approach. Baiting is a common and effective control method, as ants carry the bait back to the colony, targeting the source of the problem. Targeting the entire colony, including the queens, rather than just individual foraging ants is important, as colonies can split and spread if only surface ants are eliminated. Cleaning ant trails with soapy water or household cleaners can disrupt their pheromone communication, making it harder for others to follow. For persistent or large infestations, professional pest control services may be necessary.