Odorous House Ant

Tapinoma sessile

Odorous house ant

Adult odorous house ant; hidden node (Fort Ord UCSC Reserve, Antweb.org)

odorous house ants

Adult odorous house ants (Susan Ellis, Bugwood.org)

house ant

Adult odorous house ant and larva (Dale Ward, Discoverlife.org)


  • dark brown to black
  • 1/8 inch long
  • ants of one size
  • one node (bump between middle and rear body sections); node difficult to see
  • emit an odor similar to coconuts when disturbed or smashed
  • raise abdomens in air and run around when disturbed

Nesting Habits

  • outdoors: nests shallow, in mulch next to buildings and in soil under protection
  • indoors: nest in wall voids and under carpet, usually near water pipes or heaters


  • insects and sweets, especially honeydew excreted by aphids and other insects
  • forage indoors for sweets, cooked vegetables, fruit and pastries


  • contaminate foods such as sweets, meats, dairy products and vegetables

IPM Recommendations

  • Locate and destroy all nests to avoid reinfestation. (Follow ants back from their food source.)
  • Clean ant trails with soap and water.
  • Trim shrubbery and trees away from buildings.
  • Store food in airtight containers and dispose of trash regularly.
  • Seal potential ant entryways.
  • Use a bait specific to the odorous house ant.