Submitted to: International Union for the Study of Social Insects Congress
Publication Type: Proceedings
Publication Acceptance Date: 6/13/2006
Publication Date: 8/30/2006
Citation: Porter, S.D. 2006. Fire Ant, Biology, Ecology, and Biocontrol. XV Congress IUSSI Proceedings. 114. Washington, D.C. July 30-August 4, 2006. Interpretive Summary:
Technical Abstract: The red fire ant Solenopsis invicta was accidentally introduced into the United States from South America sometime in the 1930s. These ants do best in open, disturbed habitats associated with human activities. Fire ants construct large earthen mounds which function as solar collecting devises. Fire ants function as primary consumers, predators, and scavengers. Adult workers rely on sugar solutions from plants for metabolic fuel while larvae require arthropod prey for growth. Fire ants use a network of branching foraging tunnels to collect their food. Mature fire ant colonies average between 100,000 and 200,000 workers. Colonies live about seven years. Fire ants use pheromones and other chemicals to recruit workers, signal alarm, recognize nestmates, control development of sexuals, and regulate queen oviposition. Fire ant populations in North America are 5-10 times higher than native populations in South America, apparently because they have escaped many of their natural enemies. The introduction of self-sustaining natural enemies offers the only real hope for permanent wide-area control of imported fire ants. To date, three decapitating flies in the genus Pseudacteon have been released as classical biocontrol agents of imported fire ants. A fourth species is awaiting release permits and a fifth species is awaiting host specificity tests in quarantine. Host specificity tests are being conducted with two microsporidian pathogens from Argentina in an effort to clear them for field release in the United States. Several viruses, a parasitic ant, a parasitic wasp, and several nematodes are also being investigated as potential biocontrol agents. Ultimately, it is hoped that the introduction of these and other biocontrol agents will tip the ecological balance back in favor of our native ants. If this happens, imported fire ant populations in North America may drop to levels similar to those in South America.