Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2011
Publication Date: 6/1/2011
Publication URL: http://handle.nal.usda.gov/10113/55471
Citation: Allen, C., Valles, S.M., Strong, C.A. 2011. Multiple virus infections occur in individual polygyne and monogyne Solenopsis invicta ants. Journal of Invertebrate Pathology. 107(2):107-111. Interpretive Summary: The red imported fire ant is an invasive insect pest that currently infests about 300 million acres and causes economic losses that exceed 6 billion dollars annually in the United States. Solenopsis invicta viruses 1, 2, and 3 (SINV-1, -2, -3) are the first viruses discovered from the red imported fire ant. These viruses have significant potential of being used as biopesticides to naturally control this ant. The relationship between each of the viruses and the fire ant host is not understood at the individual level. In an effort to determine whether multiple viral infections can occur in individuals, scientists at the USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) have examined polygyne and monogyne colonies for the presence all three viruses simultaneously from individual fire ants. Although all three viruses can co-occur in individual ants, polygyne colonies are consistently infected with multiple viruses more often than monogyne colonies. Therefore, social form appears to play a prominent role in pathogen exposure and acquisition in fire ants.
Technical Abstract: Concurrent infections of Solenopsis invicta colonies with Solenopsis invicta virus 1 to 3 (SINV-1, SINV-2 and SINV-3) has been reported. However, whether individual ants were capable of supporting multiple virus infections simultaneously was not known, nor whether the social form of the colony (polygyne or monogyne) had an influence on the occurrence of multiple infection rates in individual ants. S. invicta field populations were sampled sequentially to establish whether multiple virus infections co-occurred in individual worker ants. In addition, the intra-colony virus infection rates were compared in monogyne and polygyne field colonies to determine whether social form played a role in the viral infection prevalence. All combinations of virus infection (SINV-1, SINV-2, or SINV-3 alone, SINV-1 & SINV-2, SINV-1 & SINV-3, SINV-2 & SINV-3, and SINV-1, SINV-2 & SINV-3) were detected in individual worker ants as well as queens in the field. Thus, individual S. invicta ants can be infected simultaneously with all combinations of the Solenopsis invicta viruses. Colony social form did have an influence the intra-colony prevalence of multiple S. invicta virus infections. Polygyne colonies exhibited significantly greater intra- and intra-colony single and multiple virus infections compared with monogyne colonies.