# Odorous house ant (Tapinoma sessile) > Small, common North American house ant that smells like rotten coconut or pine when crushed and often infests homes and structures. Source: https://insectscanner.com/species/odorous-house-ant/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Odorous house ants do not have a sting. Workers can bite but bites are minor and not venomous. The main concern is contamination of food. If crushed, they produce a strong, unpleasant odour. No specific first aid is usually required beyond cleaning if an ant contacts food or skin. **Pets:** Generally harmless to pets. Large numbers may contaminate pet food; remove and discard contaminated food and clean bowls. Baits placed for control can be toxic to pets if accessed, so keep baits out of reach. ## Quick facts - Scientific name: Tapinoma sessile - Also called: Sugar ant, Coconut ant - Order: Hymenoptera (Bees, wasps and ants) - Family: Formicidae (Ants) - Size: Workers 2.4-3.3 mm long; queens larger (about 4-5 mm) - Colours: Light brown, Dark brown, Black - Habitat: Urban and suburban areas, inside buildings (kitchens, wall voids), under stones, wood, mulch and in soil; tolerant of varied habitats - Range: Native to North America and widespread across the United States and southern Canada; found in diverse habitats from forests to cities - Active: Active year-round in heated buildings; outdoors mostly spring to fall and during warm parts of the day - Lifespan: Workers: months; queens: multiple years (can live several years in established colonies) - Effect on plants: Harmless - Pest: yes ## Overview Tapinoma sessile is a widespread North American ant commonly found in and around buildings. Workers are small and vary in colour from light brown to black. Colonies are flexible in size and structure; in natural settings they may be small, but in urban areas they can form large, multi-queen nests and extensive networks of satellite nests. They forage for sweets and greasy foods and are frequently noticed indoors on countertops, in kitchens and along baseboards. ## How to identify it Workers are small (about 2.4-3.3 mm), with a single petiole that is hidden by the gaster so the profile appears smooth. Body color ranges from light brown to dark brown or black. Antennae are 12-segmented and do not have a distinct club. When disturbed or crushed, workers emit a distinctive coconut-like or rotten pine odour. - Very small workers (2.4-3.3 mm) with a smooth profile because the petiole is hidden by the gaster - Colour variable from light brown to dark brown or black - When crushed, workers give off a distinctive odour often described as rotten coconut, pine, or moldy cheese - Do not have a distinct antenna club and have 12-segmented antennae ## Lookalikes - **Pavement ant** (Tetramorium caespitum): Pavement ants have a visibly sculptured head and thorax and a two-segmented petiole that is apparent in profile; they do not emit the coconut odour. - **Argentine ant** (Linepithema humile): Argentine ants are uniformly brown and form supercolonies; odour is not as strong and petiole is visible. Geographic overlap can occur but Argentine ants typically have different trail and nesting behaviour. ## Life cycle - **Egg:** Small eggs laid by queens; develop into larvae within about 1-2 weeks depending on temperature and colony conditions. - **Larva:** Larvae are cared for by workers and fed regurgitated food; they grow through several instars before pupating. - **Pupa:** Pupae are naked (not enclosed in cocoons, as in other Tapinoma) and metamorphose into adults over days to weeks. - **Adult:** Workers, males and queens: workers forage and maintain the nest; queens reproduce and sustain colony growth. ## Diet and predators - Young eat: Fed by workers on regurgitated liquids and protein-rich foods provided by foragers - Adults eat: Workers forage for sweets (nectar, honeydew, sugary human foods) and greasy or protein foods; attracted to pet food, spilled drinks and fruit - Predators of the young: Spiders, predatory insects, birds and other ant species - Predators of adults: Birds, spiders, predatory ants and small mammals ## Effect on plants and gardens Do not feed on or damage living plants in gardens; they may tend aphids for honeydew in some situations but are not a major plant pest. ### How to get rid of it Sanitation: remove food sources, store food in sealed containers, clean spills quickly. Seal entry points (cracks, gaps around pipes). Use sweet or protein-based baits (gel or station baits) placed along trails and near nest areas; baits are more effective than spraying visible workers because they allow poisoned workers to carry toxicant back to nest. In heavy infestations, a licensed pest control professional can treat nests and satellite nests. Avoid broad-spray surface insecticides as they often only disperse the colony and make control harder. ## Where and when to find it Indoors: kitchens, pantries, along baseboards, in wall voids and near food sources. Outdoors: under stones, logs, mulch and in soil. Look for trails leading to food or nest entrances. - Best time: Year-round indoors; outdoors best observed spring through fall during warm daylight hours and early evening when foraging peaks. - Tips: Follow ant trails to locate nests or bait placement points. To confirm species, crush a specimen on white paper and check for the characteristic coconut-like odour (use caution). Photograph the worker from above and side showing size and profile for ID. ## Fun facts - When crushed, odorous house ants emit a strong smell likened to rotten coconut or pine—this is one of the fastest field ID clues. - Urban colonies can become large and polydomous (many nests) with multiple queens, helping them persist year-round in buildings. - They are highly flexible foragers and will switch from sweet to protein foods depending on colony needs. ## Frequently asked questions ### Are odorous house ants dangerous? No — they are not venomous and pose little direct health risk. Their main problem is contaminating food. ### Do odorous house ants bite or sting? They do not sting. Workers can bite but bites are minor and not medically significant. ### Why are odorous house ants in my house? They enter buildings searching for food and moisture, attracted to sweets, grease and pet food. Indoor warmth also supports year-round activity. ### How do I get rid of odorous house ants? Remove food sources and seal entry points. Place sweet or protein bait stations along trails so foragers carry poison back to the nest. For large infestations, consult a pest control professional. ### Will sprays get rid of the colony? Surface sprays kill visible workers but often do not eliminate the nest and can cause the colony to split and disperse. Baits that are taken to the nest are usually more effective long-term. ### Why do they smell like coconut? They produce chemicals that many people perceive as a coconut- or pine-like odour when crushed; the exact chemical composition includes volatile compounds typical for this species. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/47340), [Wikipedia](https://en.wikipedia.org/wiki/Tapinoma_sessile). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.