Red imported fire ant

The red imported fire ant (Solenopsis invicta), or simply RIFA, is one of over 280 species in the widespread genus Solenopsis. Although the red imported fire ant is native to South America, it has become a pest in the southern United States,Australia, the Caribbean,Taiwan,Hong Kong, the southern Chinese provinces of Guangdong,Guangxi and Fujian, and Macau. RIFAs are known to give a painful, persistently irritating sting that often leaves a pustule on the skin.

Overview

The red imported fire ant, a eusocial species, are far more aggressive than most ant species. Animals, including humans, often encounter them by inadvertently stepping on one of their mounds, which causes the ants to swarm up the legs, attacking en masse. The ants respond to pheromones released by the first ant that attacks, thereafter stinging in concert.

RIFAs successfully compete against other ants, and have been expanding their range. Recently, colonies of Rasberry crazy ant (also known as Old World crazy ants) have been introduced in the same ranges as RIFAs. These ants are ecologically dominant over fire ants, which has been limiting their range slightly.