Phenology, Distribution, and Host Specificity of Solenopsis invicta Virus-1

Authors: Valles, Steven; Strong, Charles; Oi, David; Porter, Sanford; Pereira, Roberto; Vander Meer, Robert - Bob; Hashimoto, Yoshifumi; HOOPER-BUI, LINDA - LOUISIANA STATE UNIV.; SANCHEZ-ARROYO, HUSSEIN - MEXICO; DAVIS, TIM - SANDHILLS RES. CENTER; KARPAKAKUNJARAM, VEDHAM - OKLAHOMA STATE UNIV.; VAIL, KAREN - UNIV. OF TENNESSEE; FUDD, GRAHAM - AUBURN UNIVERSITY; BRIANO, JUAN - ARGENTINA LAB.; CALCATERRA, LUIS - ARGENTINA LAB.; GILBERT, LARRY - UNIV. OF TEXAS; WARD, RUFINA - ALABAMA A&M UNIV.; WARD, KENNETH - ALABAMA A&M UNIV.; OLIVER, JASON - TENNESSEE STATE UNIV.; TANIGUCHI, GLENN - UNIV. OF HAWAII; THOMPSON, DAVID - NEW MEXICO STATE UNIV.

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2007
Publication Date: 2/25/2007
Citation: Valles, S.M., Strong, C.A., Oi, D.H., Porter, S.D., Pereira, R.M., Vander Meer, R.K., Hashimoto, Y., Hooper-Bui, L.M., Sanchez-Arroyo, H., Davis, T., Karpakakunjaram, V., Vail, K.M., Fudd, G., Briano, J., Calcaterra, L., Gilbert, L.E., Ward, R., Ward, K., Oliver, J., Taniguchi, G., Thompson, D.C. 2007. Phenology, Distribution, and Host Specificity of Solenopsis invicta Virus-1. Journal of Invertebrate Pathology. 96(1):18-27.

Interpretive Summary: The red imported fire ant was introduced into the United States in the 1930s and currently infests about 300 million acres. It causes significant economic losses in livestock and agricultural production and poses a serious threat to human health. USDA-ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) and South American Biological Control Laboratory (Argentina) in cooperation with scientists at Louisiana State University, Clemson University, Oklahoma State University, University of Tennessee, Auburn University, University of Texas, Alabama A&M University, Tennessee State University, New Mexico State University, and Colegio de Postgraduados (Mexico) have determined the seasonal prevalence, host specificity and distribution of the first virus discovered in the red imported fire ant. These tests were crucial requirements for the potential development of the virus for use in fire ant control programs.

Technical Abstract: Studies were conducted to examine the phenology, geographic distribution, and host specificity of the Solenopsis invicta virus (SINV). Two genotypes examined, SINV-1 and -1A, exhibited similar seasonal prevalence patterns. Infection rates among colonies of S. invicta in Gainesville, Florida, were lowest from early winter (December) to early spring (April) increasing rapidly in late spring (May) and remaining high through August before declining again in the fall (September/October). Correlation analysis revealed a significant relationship between mean monthly temperature and SINV-1 (p < 0.0005, r = 0.82) and SINV-1A (p < 0.0001, r = 0.86) infection rates in S. invicta colonies. SINV was widely distributed among S. invicta populations. The virus was detected in S. invicta from Argentina and from all U.S. states examined, with the exception of New Mexico. SINV-1 and -1A were also detected in other Solenopsis species. SINV-1 was detected in S. richteri and the S. invicta/richteri hybrid collected from northern Alabama and S. geminata from Florida. SINV-1A was detected in S. geminata and S. carolinensis in Florida and the S. invicta/richteri hybrid in Alabama. Of the 1,989 arthropods collected from 6 pitfall trap experiments from Gainesville and Williston, Florida, none except for S. invicta tested positive for SINV-1 or SINV-1A. SINV did not appear to infect or replicate within Sf9 or Dm-2 cells in vitro. The number of SINV genome copies did not significantly increase over the course of the experiment, nor were any cytopathic effects observed. Phylogenetic analyses of SINV nucleotide sequences indicated significant divergence between viruses collected from Argentina and the U.S.