ARS | Publication request: The large decapitating fly Pseudacteon litoralis (Diptera: Phoridae): Successfully established on fire ant populations in Alabama

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 22, 2010
Publication Date: June 1, 2011
Citation: Porter, S.D., Graham, L., Johnson, S.J., Thead, L.G., Briano, J.A. 2011. The large decapitating fly Pseudacteon litoralis (Diptera: Phoridae): Successfully established on fire ant populations in Alabama. Florida Entomologist. 94:208-213.

Interpretive Summary: Red imported fire ants are much more common in the United States than they are in their South American homelands apparently because they have been able to escape natural enemies left behind in South America. In order to help correct this problem, researchers from three USDA-ARS research institutions (the Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL; the South American Biological Control Laboratory, Hurlingham, Argentina; the National Biological Control Laboratory, Stoneville, MS) and two Universities (Louisiana State ; Auburn, AL) cooperated to test-release a new species of decapitating fly as a highly host-specific, self-sustaining natural enemy against fire ants in the United States. The large fire ant decapitating fly, Pseudacteon litoralis from northeastern Argentina was successfully released in south central Alabama in 2005. Five years later, this fly is firmly established at this site and has expanded out at least 11 miles. Nevertheless, populations remain very low considering this fly is one of the most abundant fire ant decapitating flies in large areas of its range in South America. The reasons for low densities and why this fly was only established at one of nine release sites in four states (2003-2006) are unknown, but problems with host-matching, release procedures, weather conditions, and competition with previously released decapitating flies are discussed as possible factors.

Technical Abstract: The large fire ant decapitating fly, Pseudacteon litoralis Borgmeier from northeastern Argentina was successfully released as a self-sustaining biocontrol agent of imported fire ants in south central Alabama in 2005. Five years later, this fly is firmly established at this site and has expanded out at least 18 km. Nevertheless, populations remain very low considering P. litoralis is one of the most abundant fire ant decapitating flies in large areas of its range in South America. The reasons for low densities and why we were only able to establish this fly at one of nine release sites in four states (2003-2006) are unknown, but problems with host-matching, release procedures, weather conditions, and competition with previously released decapitating flies are discussed as possible factors.