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How to Manage Pests

Key to Identifying Common Household Ants

Red imported fire ant—Solenopsis invicta
Subfamily: Myrmicinae

Red imported fire ant worker
Red imported fire ant characteristics

Identifying characteristics


  • Feed on living insects, dead animals, and honeydew from honeydew-producing insects
  • In homes, forage on sweet foods, proteins, and fats
  • Extremely aggressive; if disturbed, will swarm out of nests and attack in large numbers; can inflict a very painful sting
  • Travel in distinct trails along foundations, sidewalks, patios, up sides of buildings, along baseboards, and under edges of carpets
  • Colonies may split and move to new locations

Nest type and size

  • Nest in mounds with multiple openings in soil or lawns, usually in open sunny areas near a water source
  • If undisturbed, mounds may reach up to 18 inches high and 24 inches wide; they become dome-shaped after 2-3 years
  • Nests sometimes found in buildings, wall voids, crawl spaces, or under carpets
  • Large colonies of up to 500,000 workers with multiple queens

See also, red imported fire ant quick management tips.

For more information, see the Red Imported Fire Ant Pest Note

Statewide IPM Program, Agriculture and Natural Resources, University of California
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