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United States Department of Agriculture

Agricultural Research Service

Title: Eradication of the Little Fire Ant, Wasmannia Auropunctata (Hymenoptera: Formicidae), from Marchena Island, Galapagos: on the Edge of Success?

Authors
item Causton, Charlotte - CHARLES DARWIN RES. STAT.
item Sevilla, Christian - CHARLES DARWIN RES. STAT.
item Porter, Sanford

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 4, 2005
Publication Date: June 1, 2005
Repository URL: http://www.bioone.org/perlserv/?request=get-document&issn=0015-4040&volume=088&issue=02&page=159
Citation: Causton, C.E., Sevilla, C.R., Porter, S.D. 2005. Eradication of the little fire ant, wasmannia auropunctata (hymenoptera: formicidae), from marchena island, galapagos: on the edge of success?. Florida Entomologist.88(2):159-168.

Interpretive Summary: The development of effective techniques to eradicate populations of invasive ant species is crucial to the conservation of native biodiversity. Researchers at the Charles Darwin Research Center in the Galapagos Islands, Ecuador and the USDA-ARS laboratory in Gainesville, Florida initiated an intensive program in 2001 to eradicate the invasive fire ant, Wasmannia auropunctata (Roger) from about 52 acres on Marchena Island in the Galapagos Archipelago. Dozens of linear transects were cut through the vegetation of the infested area to allow treatment and monitoring access. Poison bait was applied manually up to three times in the treatment area between March and October 2001. To date, five follow-up monitoring surveys have placed tens of thousands of monitoring sticks painted with peanut butter in a grid over the area of the former infestation. Two small colony fragments of about 0.1% of the area originally occupied by the little fire ant were detected in April 2002 and again in October 2002. Both sites were subsequently treated with poison bait. No Wasmania fire ants were found in May 2003 and April 2004. Monitoring surveys must continue for an additional two years to ensure eradication of any remaining colony fragments and verify the success of this program. This paper discusses the procedures used to kill the fire ant and monitor the efficacy of the eradication methods, the program's costs and its applicability to other island ecosystems.

Technical Abstract: The development of effective techniques to eradicate populations of invasive ant species is crucial to the conservation of native biodiversity. An intensive program was initiated in 2001 to eradicate the invasive fire ant, Wasmannia auropunctata (Roger) from ~21 ha on Marchena Island in the Galápagos Archipelago. Linear transects, approximately 10 m apart, were cut through the vegetation of the infested area and a buffer zone of 6 ha. Amdro® (Hydramethylnon) was applied manually up to three times in the treatment area at three-month intervals between March and October 2001. To date, five follow-up monitoring surveys have placed sticks painted with peanut butter in a grid 3-4 m apart. Two small colony fragments (0.1% of the area originally occupied by W. auropunctata) were detected in April and October 2002 and were subsequently treated with Amdro®. No W. auropunctata ants were found in May 2003 and April 2004. Five nocturnal surveys carried out in the immediate area of fire ant introduction did not detect any fire ants either. Monitoring surveys must continue for an additional two years to ensure eradication of any remaining colony fragments and verify the success of this program. This paper discusses the procedures used to kill the fire ant and monitor the efficacy of the eradication methods, the program's costs and its applicability to other island ecosystems.

Last Modified: 10/25/2014
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