Red Imported Fire Ant

Red Imported Fire Ant
(Solenopsis invicta; syn: Solenopsis wagneri)


  • Medium-sized red ant, 3 – 6mm in length (1/8-1/4 inch) and reddish to brown in color
  • Extremely aggressive ants that swarm and sting when disturbed
  • Native to South America, accidentally introduced to Alabama in the 1930s as a stowaway in cargo, has since spread across the southern United States, Australia, Hong Kong and Taiwan.


  • Large “super colonies” of 300,000 ants form cone-shaped nests in yards, parks, golf courses and pastures. Heavily infested areas may contain 120 colonies per hectare (300 colonies per acre).
  • RIFA aggressively defend their nests by swarming and stinging whatever disturbs the nest. RIFA have attacked and blinded or killed cattle and other domesticated animals, wild animals including ground nesting birds, beneficial insects and mammals.
  • Fire ant stings may result in injury or death. There have been more than 80 human deaths — including five in nursing homes — attributed to anaphylactic shock from fire ant stings. 42 percent of visits to venom clinics have been because of fire ant stings. Typical reactions to stings include burning and itching, followed by white pustules that may last a week or more.
  • RIFA eat spouting seeds and chew on flower buds, seedlings, saplings and fruit, causing serious damage to crops.
  • Parks, yards and other infested areas require quarterly treatment with pesticides
  • RIFA also tend to infest electrical equipment, causing damage to items such as traffic signal boxes, air conditioners and sprinkler systems.
  • Costs to agriculture in the U.S. is estimated at $750 million per year. Non-agricultural costs are estimated at $5 billion per year.

In Hawaii:

  • Not known to be present in Hawaii at this time. However, they could easily arrive hidden in cargo, carried by planes or ships, or even in infested mail parcels, as was seen in 1991, when an infested package from Florida was intercepted at a Honolulu post office.
  • The Hawaii Department of Agriculture, the U.S. Department of Agriculture and other agencies are on the lookout for RIFA. However, so much of our incoming cargo goes uninspected due to the tremendous volume of incoming goods. In addition, containers of cargo get delivered to grocery stores, hardware stores, nurseries and garden shops and even to our neighborhoods, and RIFA can arrive concealed in almost anything.
  • New Zealand is trying to keep these ants out and actively monitors for RIFA around ports of entry. They have been successful at eradicating the ants twice: In 2001, a single red imported fire ant nest was found at Auckland International Airport. The nest was destroyed and ongoing surveillance has found no further nests in the area. In 2004, a nest was found and eradicated at the Port of Napier.

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