Establishment and dispersal of the fire ant decapitating fly Pseudacteon tricuspis in North Florida


The decapitating fly Pseudacteon tricuspis Borgmeier was released at eight sites in North Florida between the summer of 1997 and the fall of 1999 as a self-sustaining biocontrol agent of the red imported fire ant, Solenopsis invicta Buren. Several releases used parasitized fire ant workers while most involved adult flies released over disturbed ant mounds. Establishment and dispersal of fly populations were monitored by disturbing about 10 fire ant mounds at each site and then inspecting them closely for hovering flies over a period of about 30 min. Overwintering populations of flies were successfully established at 6 of 8 release sites. Over several years, fly populations at these sites increased to levels as high or higher than those normally seen in their South American homeland. By the fall of 1999, flies had expanded out 1-6 km from five release sites and occupied about 125 km . By the fall of 2000 the five initial release sites plus one new site had fused into one large area about 70 km in diameter. The flies had expanded out an additional 16-29 km and occupied about 3300 km . By the fall of 2001 the flies had expanded out an additional 10-30 km and occupied approximately 8100 km . Fly dispersal was not related to wind patterns in the Gainesville area. Based on the above rates of dispersal and an establishment rate of 66%, we estimate that a state the size of Florida would require 5-10 releases spaced over a 3-year period to cover the state in 6-9 years. © 2003 Elsevier Inc. All rights reserved. 2 2 2

Document Type





Classical biological control, Establishment, Expansion, Florida, Formicidae, Host preference, Parasitoid, Phoridae, Pseudacteon tricuspis, Solenopsis invicta, United States, Wind drift

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Journal Title

Biological Control