Fire Ant - Invasive Species

Invasive Species

For more details on invasive subspecies, see Red imported fire ant.

Although most fire ant species do not bother people and are not invasive, Solenopsis invicta, known in the United States as the red imported fire ant (or RIFA) is an invasive pest in many areas of the world, notably the United States, Australia, the Philippines, China and Taiwan. The RIFA was accidentally introduced into the United States aboard a South American cargo ship that docked at the port of Mobile, Alabama, in the 1930s, and came to infest the majority of the Southern and Southwestern United States.

In the US the FDA estimates that more than US$5 billion is spent annually on medical treatment, damage, and control in RIFA-infested areas. Furthermore, the ants cause approximately $750 million in damage annually to agricultural assets, including veterinarian bills and livestock loss, as well as crop loss. Over 40 million people live in RIFA-infested areas in the southeastern United States. Between 30 and 60% of people living in fire ant-infested areas are stung each year. Since September 2004 Taiwan has been seriously affected by the red fire ant. The US, Taiwan and Australia all have ongoing national programs to control or eradicate the species, but, except for Australia, none have been especially effective. In Australia, an intensive program costing A$175 million had by February 2007 eradicated 99% of fire ants from the sole infestation occurring in south-east Queensland.

In just seventy years, according to a study published in 2009, lizards in parts of the United States have evolved to have longer legs and new behaviors that aid them in escaping fire ants.