Have you seen Red Imported Fire Ant (Solenopsis invicta)?
Hawaii Early Detection Network Priority Pest for all islands of Hawaii


Red imported fire ant
RIFA is reddish-brown with a dark opaque abdomen
Red imported fire ant
(Top) An early stage nest mound only a few weeks and (Bottom) a characteristic cone shaped mound
Rubber vine
Pus filled blister caused by RIFA stings last for days

Identification: The red imported fire ant is not currently known to occur on any Hawaiian island. This small reddish-brown ant can vary in size, from 3-6 mm (1/8-1/4 in). Head size is always the same proportion to body size, with no "big-headed" workers. This ant has an opaque shiny black abdomen. The ants build dome shaped mounds of fine soil, usually in sunny areas, but can appear anywhere. These mounds are variable in size, from a few inches wide to 0.6 m (2 ft) and have no visible opening. When these mounds are disturbed, the red imported fire ant will aggressively swarm out of the nest and sting anything with proximity. These stings cause blisters filled with white pus that last for several days.
Impacts: 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. RIFA stings cause blisters fi lled with white pus which lasts for several days. In infested areas, they may cause injury or death to livestock, pets, and wildlife; damage crops, ornamental plants, electrical equipment, and irrigation systems; and cause serious declines in biodiversity.
Dispersal Mechanism: RIFA are primarily dispersed via human activities such as cargo and nursery plant shipments. This ant is not known to be anywhere in Hawaii. If you think you have found the red imported fire ant in Hawaii- let someone know!

More information about this pest external link


Red Imported Fire Ant look-alikes:


Tropical fire ant (Solenopsis geminata):
The tropical fire ant is common throughout Hawaii. A microscope is required to tell the difference between the tropical and red imported fire ants. This small red ant is 3-6 mm (1/8-1/4 in) long. Some of the workers will have proportionately large, square heads. This ant is restricted to dry coastal areas and nests in the soil, it does not construct mounds. Tropical fire ant stings will cause irritation, but should not cause white pus filled blisters that persist for days.

Tropical fire ant

Tropical fire ant worker with a proportionately large head

Other Ants:
There are over 40 types of ants in Hawaii. Most of these ants are black to pale brown and slightly transparent. Most other ants build mounds that will have a visible opening or be surrounded by an area that is stripped of vegetation. No other ant in Hawaii will aggressivly swarm like the red imported fire ant. (See also the Little Fire Ant- Maui County priority pest page.)

Last Updated: . If you have any questions about the Hawaii Early Detection Network contact reportapest-maui@lists.hawaii.edu.