|Calcaterra, L. - USDA-ARS-ARGENTINA|
|Briano, Juan - USDA-ARS-ARGENTINA|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 12, 2000
Publication Date: N/A
Interpretive Summary: The two imported fire ants, Solenopsis invicta and Solenopsis richteri are major pests in the southern U.S. infesting over 310 million acres. The higher densities of these pests in the U.S., 5 times more than in South America, are partially a result of biological release from their natural enemies present in their native land. The parasitic ant, Solenopsis daguerrei, in South America is being considered as a candidate for biological control of the imported fire ant in the U.S., however, before it can be introduced into the U.S., its specificity must be confirmed. Scientists from the ARS, Center for Medical, Agricultural & Veterinary Entomology and South American Biological Control Laboratory report on the field host specificity of Solenopsis daguerrei in Argentina. Over 4000 ant nests representing 8 different species of ants were examined for the presence of Solenopsis daguerrei. It was found only in nests of the two fire ant species. The authors conclude that Solenopsis daguerrei is a specific parasite of fire ants and would not attack other ant species. This species may be a good candidate for the biological control of imported fire ants in the U.S.
Technical Abstract: The field host specificity of the parasitic ant S. daguerrei (Santschi) was studied in the area of San Eladio (BA), Argentina. A total of 4,316 colonies were visually detected and examined for the presence of adults and/or queens of the parasite. Two additional samplings were made in Las Flores (BA) and Colon (ER), Argentina. In addition, we used bait traps to estimate the richness of omnivorous ants in the area. S. daguerrei was found exclusively parasitizing the fire ants, Solenopsis richteri Forel and S. invicta Buren. We found it in 3.9 percent of the colonies of S. richteri in San Eladio, in 9.3 percent of the ones in Las Flores, and in 12.5 percent of the S. invicta colonies in Colon. The ant nests examined (4,316) represented 8 different species in 4 subfamilies. However, 96 percent of them corresponded to S. richteri. The other species found were: Pheidole bergi Mayr, Acromyrmex spp. Mayr, Camponotus punctulatus Mayr, Neivamyrmex sp. Shuckard, Linepithema humile Mayr, and Brachymyrmex sp. Mayr. Ants of all species occupied 49 percent of the bait stations. S. richteri occupied almost 45 percent of the bait traps (91 percent of the occupied baits) and accounted for nearly 95 percent of all trapped ants. Most of the ant genera detected visually during the surveys were also sampled in similar proportions using bait traps. The only species trapped that had escaped visual detection was Crematogaster quadriformis Roger. The visual detection combined by the use of bait traps revealed an overall ant's richness of 10 species. Compound nests (23) were also recorded during the surveys. These results are encouraging to keep S. daguerrei as a good candidate for the biological control of imported fire ants in the United States.