Isolation of Queen Pheromone Components in Solenopsis invicta

Mentor: Robert K. Vander Meer

Project:   In the red imported fire ant, Solenopsis invicta, the queen releases a pheromone that functions in attracting worker ants.  This pheromone could be a potentially valuable tool to control the red imported fire ant, such as using it to enhance baits.  Previous studies have determined that this pheromone is stored in the queen’s poison sac (QPS).  To identify the active components within the poison that are responsible for this attraction, we used bioassay-driven fractionation.   We first modified a surrogate queen bioassay, where we added solvent extracts of QPSs to queen-size pieces of filter paper, allowed the solvent to evaporate and placed it into a petri dish arena with worker ants.  We monitored the number of ants visiting the treated filter paper as well as those visiting the control (solvent only) filter paper.  If there was attraction, the solvent extract of QPSs was fractionated via liquid chromatography.  The extract was applied to a silica gel column, which was then rinsed with solvents of different polarities in order to separate the components within the QPSs.  These fractions were tested using the modified surrogate queen bioassay to determine which fraction contained the active components.  This project will continue to use the surrogate queen bioassay, fractionation and evaluation by GC-MS to identify the queen pheromone.

Jennifer carrying out fire ant attraction bioassay.

Jennifer dissecting fire ant queen poison glands.