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Red Imported Fire Ant (RIFA)
Solenopsis invicta

RIFA info HEAR links External links
This page contains information about the red imported fire ant (Solenopsis invicta) and its potential impacts in Hawaii, including links to some of the best Solenopsis invicta sites on the web. If you know of other sites to which there should be a link from this page, please e-mail the HEAR webmaster at webmaster@hear.org.

Information about Solenopsis invicta and its potential impacts in Hawaii

Native to Brazil, red imported fire ants (also known as RIFA) are small reddish-brown ants, with workers ranging in size from about 3-6 millimeters in length. RIFA are often identified by their nest mounds, where brood is reared. Mounds are often built in open sunny areas, and depending on soil type, can reach up to one meter wide at the base, and one meter high. RIFA colonies are extremely productive compared to other ant species, and grow rapidly. Worker ant densities can average up to 1500-3000 ants/m2. Workers are armed with a powerful sting, which they use both for defense and to subdue prey.

The red imported fire ant is an extremely destructive, highly invasive, and notoriously aggressive stinging ant that is impossible to eradicate once established. This species' Latin name (invicta) appropriately means "invincible". RIFA were introduced to the United States in the 1930s. Dispersed primarily via human activities, they have invaded over 300 million acres across the southern U.S. despite federal quarantine measures. Though this ant has not yet established in Hawaii, it established a foothold in California in 1998. With the enormous quantity of cargo, and people, arriving in Hawaii from California, the risk of this ant becoming the next major severe pest invasion in Hawaii is high.

RIFA pose a serious threat to human health. Large numbers of ants will rapidly swarm on, and relentlessly sting, anything unfortunate enough to disturb them. In the U.S., millions of people are stung each year and over 80 people have died from their injuries. Deaths are mainly attributed to hypersensitivity to RIFA venom, a condition that occurs in about 1% of the human population. Children and infants have the highest sting rate. Tourists/visitors from uninfested areas are another high-risk group.

RIFA, however, threaten more than human health. In infested areas, they threaten injury or death to livestock, pets, and wildlife; damage crops, ornamental plants, electrical equipment, and irrigation systems; and cause serious declines in biodiversity. Because they are impossible to eradicate once established, repeated pesticide treatments are needed to maintain reduced ant numbers and protect human health. These treatments can be costly, can make "organic" gardening difficult, and can lead to contaminated water supplies. For commercial plant producers, the regulations associated with shipping infested material to uninfested areas add significant costs.

Although Hawaii already has three species of "fire ants" (two true fire ants, Solenopsis geminata and Solenopsis papuana; and Wasmannia auropunctata, referred to as the "little fire ant"), the RIFA is by far a much more aggressive, dangerous and destructive invader.

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HEAR Solenopsis invicta info

The following information about red imported fire ants (Solenopsis invicta) is available at the Hawaiian Ecosystems at Risk project's (HEAR's) website:

red imported fire ant (RIFA) (Solenopsis invicta)

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Links to external Solenopsis invicta sites

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This page was created on 14 January 2000 by PT, and was last updated on 04 April 2002 by PT. The HEAR website is indexed on AltaVista.