Fire ant decapitating fly cooperative release programs (1994- 2008): Two Pseudacteon species, P. tricuspis and P. curvatus, rapidly expand across imported fire ant populations in the southeastern United States
1 USDA, APHIS, PPQ, Center for Plant Health Science and Technology, Gulfport Laboratory, 3505 25th Avenue,
Gulfport, MS 39501
2 Center for Medical, Agricultural and Veterinary Entomology, USDA-ARS, 1600 SW 23rd Drive, Gainesville, FL
32608
3 USDA, APHIS, PPQ, Eastern Region Office, 920 Main Campus Drive, Raleigh, NC 27606-5213
4 Department of Entomology and Plant Pathology, Auburn University, 301 Funchess Hall, Auburn, AL 36849-5413
5 Department of Entomology, 400 Life Sciences Building, Louisiana State University Agricultural Center, Baton
Rouge, LA 70803
6 Brackenridge Field Laboratory and Section of Integrative Biology, The University of Texas, Austin, TX 78712
Abstract
Natural enemies of the imported fire ants, Solenopsis invicta Buren, S. richteri Forel (Hymenoptera: Formicidae), and their hybrid, include a suite of more than 20 fire ant decapitating phorid flies from South America in the genus Pseudacteon. Over the past 12 years, many researchers and associates have cooperated in introducing several species as classical or self-sustaining biological control agents in the United States. As a result, two species of flies, Pseudacteon tricuspis Borgmeier and P. curvatus Borgmeier (Diptera: Phoridae), are well established across large areas of the southeastern United States. Whereas many researchers have published local and state information about the establishment and spread of these flies, here distribution data from both published and unpublished sources has been compiled for the entire United States with the goal of presenting confirmed and probable distributions as of the fall of 2008. Documented rates of expansion were also used to predict the distribution of these flies three years later in the fall of 2011. In the fall of 2008, eleven years after the first successful release, we estimate that P. tricuspis covered about 50% of the fire ant quarantined area and that it will occur in almost 65% of the quarantine area by 2011. Complete coverage of the fire ant quarantined area will be delayed or limited by this species' slow rate of spread and frequent failure to establish in more northerly portions of the fire ant range and also, perhaps, by its preference for red imported fire ants (S. invicta). Eight years after the first successful release of P. curvatus, two biotypes of this species (one biotype occurring predominantly in the black and hybrid imported fire ants and the other occurring in red imported fire ants) covered almost 60% of the fire ant quarantined area. We estimate these two biotypes will cover almost 90% of the quarantine area by 2011 and 100% by 2012 or 2013. Strategic selection of several distributional gaps for future releases will accelerate complete coverage of quarantine areas. However, some gaps may be best used for the release of additional species of decapitating flies because establishment rates may be higher in areas without competing species.
Keywords: biocontrol, biological control, distribution, expansion, Formicidae, Phoridae, Solenopsis invicta, Solenopsis richteri
Correspondence:
aanne-marie.a.callcott@aphis.usda.gov,
bsanford.porter@ars.usda.gov,
cron.d.weeks@aphis.usda.gov,
dgrahalc@auburn.edu,
esjohnson@agcenter.lsu.edu,
flgilbert@mail.utexas.edu
Editor: J. P. Michaud was editor of this paper.
Received: 6 November 2008 | Accepted: 15 April 2010 | Published: 18 February 2011
Copyright: This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.
ISSN: 1536-2442 | Volume 11, Number 19
Callcott A-M A, Porter SD, Weeks Jr. RD, Graham LC, Johnson SJ, Gilbert LE. 2011. Fire ant decapitating fly cooperative release programs (1994-2008): Two Pseudacteon species, P. tricuspis and P. curvatus, rapidly expand across imported fire ant populations in the southeastern United States. Journal of Insect Science 11:19 available online: insectscience.org/11.19
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