Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2009
Publication Date: 6/1/2009
Citation: Valles, S.M., Oi, D.H., Porter, S.D. 2009. Kneallhazia (=Thelohania) Solenopsae infection rate of Pseudacteon Curvatus flies determined by multiplex PCR. Florida Entomologist. 92(2):344-349. Interpretive Summary: The red imported fire ant was introduced into the United States in the 1930s and currently infests about 300 million acres. Annually, it causes billions of dollars of losses in livestock and agricultural production and poses a serious threat to human health. Promising biological control agents of the red imported fire ant are the intra-cellular parasite, Kneallhazia solenopsae, and Pseudacteon curvatus, a phorid fly parasitoid. Recently, Kneallhazia solenopsae was reported to infect the Pseudacteon parasitoids. The relationship between these biological control agents is not currently known. Scientists at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, FL, have developed a molecular technique (PCR) capable of detecting Kneallhazia solenopsae in Pseudacteon flies. This method will permit studies to examine the role of Pseudacteon flies in the spread of Kneallhazia solenopsae in the fire ant population.
Technical Abstract: A multiplex PCR method was developed and utilized to determine the Kneallhazia solenopsae infection rate of individual Pseudacteon curvatus flies in north-central Florida. Among P. curvatus flies infected with K. solenopsae, two amplicons were produced, one of 800 nucleotides from the P. curvatus 18S rDNA gene, and one of 318 nucleotides from the K. solenopsae 16S rDNA gene. Multiplex PCR of DNA extracted from P. curvatus flies was capable of detecting 117.5 ±82.7 K. solenopsae spore equivalents. The mean K. solenopsae infection rate of P. curvatus from 4 sites in Gainesville and Williston, Florida, was 12.3 ±5.0 %. The K. solenopsae infection rate for P. curvatus was independent of the K. solenopsae infection rate observed among S. invicta in the vicinity of the fly collections. Not all P. curvatus flies that developed in K. solenopsae-infected fire ants were positive for K. solenopsae upon eclosion. Among 50 P. curvatus flies known to develop in K. solenopsae-infected S. invicta workers, 12 (24%) were positive for K. solenopsae at eclosion.