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United States Department of Agriculture

Agricultural Research Service

Title: Territorial Behavior of the Imported Fire Ant

Author
item Showler, Allan

Submitted to: Encyclopedia of Entomology
Publication Type: Book / Chapter
Publication Acceptance Date: April 9, 2003
Publication Date: April 30, 2004
Citation: Showler, A.T. 2004. Territorial behavior of the imported fire ant. In: Capinera, J.L., editor. Encyclopedia of Entomology Volume 3. 1st edition. Hingham, MA: Kluwer Academic Publishers. p. 14-16.

Interpretive Summary: The imported fire ant (IFA) is an exotic species introduced to the United States from parts of South America, and it has spread throughout much of the southeastern United States despite the presence of indigenous ant species. Studies using ingested dyes, radiotracers, and rare earth elements have demonstrated that the IFA is territorial, but the territories tend to shift over time to compensate for changing food availability, challenges to foraging areas by other IFA colonies, and environmental factors. Traits that have contributed to the IFA's rapid adaptation to the southeastern United States include aspects of the IFA's territorial behavior.

Technical Abstract: The imported fire ant (IFA), Solenopsis invicta Buren, is an exotic species introduced to the United States from parts of South America. It has spread throughout much of the southeastern United States despite the presence of indigenous ant species. The IFA uses tunnels that afford access to foraging areas. Studies using ingested dyes, radiotracers, and rare earth elements have demonstrated that the IFA is territorial, but territories tend to shift over time to compensate for changing food availabilities, challenges to foraging areas by other IFA colonies, and environmental factors. Increased food availability results in higher densities of IFA colonies because foraging territory areas are smaller than in areas where food is more scarce. Traits that have contributed to the IFA's rapid adaptation to the southeastern United States include a large colony population size, an omnivorous diet, mass foraging recruitment, massive aerial dissemination of reproductive females, and a stinging mechanism. Three traits are related to the IFA's territorial behavior: 1) tunneling that offers protection from trail disruption; 2) the ability to utilize foraging areas in water-saturated soil; and 3) temporally dynamic territory boundaries that permit efficient use of foraging areas. The combination of these traits has resulted in the IFA becoming the dominant formicid species in much of its range in the southeastern United States, even after eradication efforts were conducted using insecticides.

Last Modified: 8/30/2014
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