Red Imported Fire Ants In South Florida

Solenopsis Invicta

Red Imported Fire Ants (RIFA, for short) are the most common species of fire ant in South Florida and many coastal areas of the southern USA. RIFA ants have a reddish color and are polymorphic, which means they have many sizes ranging from 1/15 to 1/4 inch in length. As the name suggest, RIFA ants were introduced in the United States around 1933 with infested soil from South America used for weight distribution in ships. RIFA are omnivorous; however, their primary diet is insects.

Red Imported Fire Ants are either single-queen (monogyme) or multi-queended (polygyne). Monogyme colonies have more mounds per acre than polygyne. Mature mounds are rounded, about 18” high and 24” wide, with tunnels underground extending several feet. RIFA ants nests outside but they also nest adjacent to the foundation walls.

RIFA will defend their nests aggressively with painful stings. When the mound is disturbed workers swarm out of the ground ready to sting.

Before they sting, each ant grabs the skin of the victim with their mandible for leverage. Fire ants have 4 teeth on the inner side of their mandible. As they grab the skin it curls the abdomen and insert the stinger repeatedly. The venom causes a burning sensation and a white postulate form on the skin. The protein in the venom is life-threatening, causing anaphylactic shock to a small number of people, less than 1% of the population.