Volume 9, Issue 6 p. 661-673

Wolbachia infections in native and introduced populations of fire ants (Solenopsis spp.)

D. DeWayne Shoemaker

Corresponding Author

D. DeWayne Shoemaker

Department of Biological Sciences, 3149 Wood Hall, 1903 West Michigan Avenue, Western Michigan University, Kalamazoo, MI 49008-5410, USA,

D. DeWayne Shoemaker, Department of Biological Sciences, 3149 Wood Hall, 1903 West Michigan Avenue, Western Michigan University, Kalamazoo, MI 49008-5410, USA. Tel.: 616 387 2084; fax: 616 387 5609; e-mail:[email protected]Search for more papers by this author
Kenneth G. Ross

Kenneth G. Ross

Department of Entomology, University of Georgia, Athens, GA 30602-2603, USA,

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L. Keller

L. Keller

University of Lausanne, Institute of Ecology, Batiment de Biologie, 1015 Lausanne, Switzerland,

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E. L. Vargo

E. L. Vargo

Department of Entomology, Campus Box 7613, North Carolina State University, Raleigh, NC, 27695-7613, USA,

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John H. Werren

John H. Werren

Department of Biology, University of Rochester, Rochester, NY 14627-0211, USA

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First published: 07 July 2008
Citations: 91

Abstract

Wolbachia are cytoplasmically inherited bacteria that induce a variety of effects with fitness consequences on host arthropods, including cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. We report here the presence of Wolbachia in native South American populations of the fire ant Solenopsisinvicta, but the apparent absence of the bacteria in introduced populations of this pest species in the USA. The Wolbachia strains in native S. invicta are of two divergent types (A and B), and the frequency of infection varies dramatically between geographical regions and social forms of this host. Survey data reveal that Wolbachia also are found in other native fire ant species within the Solenopsis saevissima species complex from South America, including S. richteri. This latter species also has been introduced in the USA, where it lacks Wolbachia. Sequence data reveal complete phylogenetic concordance between mtDNA haplotype in S. invicta and Wolbachia infection type (A or B). In addition, the mtDNA and associated group A Wolbachia strain in S. invicta are more closely related to the mtDNA and Wolbachia strain found in S. richteri than they are to the mtDNA and associated group B Wolbachia in S. invicta. These data are consistent with historical introgression of S. richteri cytoplasmic elements into S. invicta populations, resulting in enhanced infection and mtDNA polymorphisms in S. invicta. Wolbachia may have significant fitness effects on these hosts (either directly or by cytoplasmic incompatibility) and therefore these microbes potentially could be used in biological control programmes to suppress introduced fire ant populations.