Pest Management Solutions -- University of Texas

Pheromone Control of Reproduction in Fire Ant Colonies

Principal Investigator:
Edward L. Vargo
Brackenridge Field Laboratory and Department of Zoology
University of Texas
Austin, TX 78712
Phone: 512/471-2825; Fax 512/475-6286

Funding Amount/2 Years: $148,228

Relevance/Implication of Project:
Research on naturally occurring chemicals that regulate physiology and behavior of imported fire ant colonies is one of the target areas listed under Pest Management Solutions in the state initiative. Pheromones play a central role in regulating reproductive development in S. invicta colonies. Knowledge of what the chemical constituents are and how they function could be used to develop species-specific forms of birth control which would disrupt reproduction in the imported fire ant but leave native ants unaffected.

Summary of Work to be Done:
The proposed research will continue and expand our work on queen pheromones and their role in regulating reproduction in colonies of the imported fire ant. Five effects of queen pheromones are currently under study in our lab: 1) inhibition of new virgin queens from undergoing reproductive maturation; 2) mutual suppression of egg laying among co-habiting queens in multiple-queen colonies; 3) inhibition over the production of new queens and males; 4) execution of young queens as they begin to lay eggs; 5) ability of queens to attract workers. The planned work will focus on the isolation and identification of the active compounds responsible for these different pheromonal effects, especially the first and last effects because of the existence of sensitive bioassays to study them. Previous work by our group and others has identified the poison gland as the source of both the pheromone inhibiting reproductive maturation in virgin queens and the pheromone mediating attraction of workers to queens. Evidence to date indicates that both of these pheromonal effects is mediated by a blend of compounds. We have made substantial progress in isolating and identifying some of the compounds inhibiting virgin queen reproductive maturation. We will continue this work to fully characterize the chemical composition of this reproduction suppressing pheromone. We will also work toward the isolation and identification of the compounds used by queens to attract workers. Identification of these pheromones may lay the groundwork for development of novel biopesticides to suppress imported fire ant populations.