Sustainable Solutions
University of Texas

Basic Biology of Pseudacteon phorid Flies and Development of Efficient Laboratory Production of Phorid Flies for Research on Fire Ant Biocontrol

Principal investigator:
Lawrence E. Gilbert
Section of Integrative Biology
University of Texas
Austin, TX 78712-1064

Funding Amount/2 Years: $357,430

Relevance/Implication of Project: 
Biological control of imported fire ants will constitute the ultimate in sustainable and economic solutions to this problem species. Given their demonstrated effects on host fire ants, phorid flies of the genus Pseudacteon are likely to be at least one key element of any future overall biocontrol success. Basic research on these insects is fundamental to the successful rearing and establishment of South American species in North America.

Summary of Work to be Done:
Phorid flies of the genus Pseudacteon constitute a large group (> 25) of parasitoid species primarily associated with the fire ant genus Solenopsis. Laboratory and field experiments have demonstrated that some Pseudacteon species are highly specific to the red imported fire ant, S. invicta. The demonstration that attacks of egg-laying phorids disrupt important activities of ant hosts such as foraging for food, has led to the hypothesis that these flies play an important role in the natural regulation of fire ant populations. Furthermore, field observations in South American localities indicate that suites of 3. 5 phorid species that attack the same ant colony in complementary ways could represent the ultimate in phorid pressure on fire ants. However, only two species of ant-attacking phorid flies have been successfully cultured to date. Thus, many key life-history details, such as where mating occurs, how flies locate hosts, level of host specificity, how flies survive harsh seasons when ants are inactive, and how pupal survival varies depending on microsite, are virtually unknown. Therefore, the parts of this project are conceived to work in concert and in an integrated fashion to broaden our comparative knowledge of critical aspects of phorid biology in order to bring additional species into culture; to improve the mass rearing methods of those in culture, such as Pseudacteon tricuspis; and to improve methods of introducing the flies in Texas. The ultimate long term goal is to develop methods for mass-rearing and field introductions of any Pseudacteon species which ecological and behavioral studies indicate may possess potential for the biocontrol of fire ants.