Host Specificity in Two Additional Pseudacteon spp. (Diptera: Phoridae), Parasitoids of Solenopsis Fire Ants (Hymenoptera: Formicidae)

We tested the host specificity of two South American Pseudacteon phorid flies, P. obtusus Borgmeier and P. borgmeieri Schmitz, on North American colonies of the red imported fire ant, Solenopsis invicta Buren, and the tropical fire ant, S. geminata (F.). Sequential host specificity tests conducted in the laboratory indicated that P. obtusus was highly specific to S. invicta. In individual trials, 20 females attacked S. invicta but none attacked S. geminata. Pseudacteon borgmeieri females, in contrast, attacked both Solenopsis species. Six of the eighteen known South American Pseudacteon species have now been tested for host specificity, and 4 of the 6 reveal a high degree of specificity to S. invicta, thus representing good biocontrol candidates.