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, Thailand, Taiwan, the Philippines, Hong Kong, and the southern Chinese provinces of Guangdong, Guangxi and Fujian. There are also reports of ant hills in Macau, the former Portuguese enclave that borders the province of Guangdong. RIFA are known to have a strong, painful, and persistent irritating sting that often leaves a pustule on the skin.