Odorous House Ants   (Tapinoma sessile)

Quick Look Pest Stats

Color: Brown to Black

Legs: 6

Shape: Segmented; oval

Size: 1/16″ – 1/8″

Antennae: Yes

Region: Throughout the U.S.




These ants nest outdoors under items on the ground, within landscape mulch, beneath loose bark on trees, under ground cover, in potted plants, and within piles of items, such as lumber, firewood, or bricks. Nests may readily be established inside homes, in walls, beneath carpeting, and other suitable voids or spaces. Odorous house ants may develop huge colonies containing thousands of workers and numerous queens.


Odorous house ants like to eat sweets and are especially fond of honeydew.


Colonies have many queens, and several thousand workers. The numbers change depending upon the time of year. They are known to move their nests every three months or so in response to rain. Mating takes place in the nest, so winged reproductive females are not often seen. Queens lose their wings after mating. In the course of a season, one queen averages about 350 eggs  Total developmental time depends on the time of year that the eggs are laid. For eggs laid in April to June, total development from egg to adult takes 5 to 9 weeks. For eggs laid from June to September, development takes 6 to 7 weeks. Eggs that are laid later in the season overwinter as larvae, which can take 6 to 7 months to complete development to adulthood. In indoor nests, when temperatures remain warm year-round, egg laying likely also occurs year-round.  If crushed, the workers give off a rotten coconut odor, hence their name. 


Odorous house ants do not pose a public health risk, but they can contaminate food and should be avoided. If you notice odorous ants in your property, contact an ant pest control specialist.


This ant can be difficult to control because it establishes multiple subcolonies and may nest in such a wide variety of sites. The keys to control are to find the colonies and subcolonies and treat them directly. Where the colonies cannot be found, baits may be attempted; however, several baits may be required before positive results are seen. Regular inspections and service are necessary to find and treat new colonies as they move in from neighboring properties. The services of a professional are very helpful when encountering these ants. To prevent, keep tree branches and other plants cut back from the house. Sometimes ants use these branches to get into your home. Make sure that there are no cracks or little openings around the bottom of your house. 


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