The "fire ant" part of their name refers to the burning sensation you feel when you get stung, especially by several to many ants at once. With most people, the immediate burning sensation goes away in a few minutes. A day or so later, the imported fire ant's unique venom forms a white fluid-filled pustule, or blister, at the sting site that is very characteristic: only fire ant venom causes this symptom. Worker ants bite and sting aggressively and repeatedly. Black and red imported fire ants are native to central South America. They were not imported on purpose. They were stowaways on ships traveling to the U.S. from South America into the port of Mobile, Alabama. The black imported fire ant arrived around 1918, while the red arrived around 1930. Since their arrival they have spread throughout the Southeastern U.S. Presently, the black imported fire ant is found only in northeast Mississippi, northwest Alabama, and in Tennessee. The red imported fire ant or a hybrid between the red and the black species is found primarily in the southeastern quarter of the continental U.S. The red imported fire ant is also found in parts of California and New Mexico. For the latest distribution of imported fire ants, please look at the APHIS USDA - U.S. quarantine map.