ARS | Publication request: Aerosol delivery of trail pheromone disrupts red imported fire ant, Solenopsis invicta, foraging

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 13, 2012
Publication Date: April 26, 2012
Citation: Suckling, D.M., Stringer, L.D., Corn, J.E., Bunn, B., El-Sayed, A.M., Vander Meer, R.K. 2012. Aerosol delivery of trail pheromone disrupts red imported fire ant, Solenopsis invicta, foraging . Pest Management Science. 68:1572-1578.

Interpretive Summary: Imported fire ants cause over 6 billion dollars in annual control and damage costs in the United States and they are becoming a world-wide invasive pest ant. They infest Australia, Taiwan, China, Mexico and many Caribbean Island countries. Fire ant control relies on toxic drenches or baits that are bad for the environment and also affect non-target ant species. There is a need for biologically-based control methods, such as use of fire ant pheromones. To date suggested uses of pheromones for pest ant control have focused on making baits better. However, scientists at the Center for Medical, Agricultural and Veterinary Entomology, USDA, ARS, Gainesville, Florida USA, and the New Zealand Institute for Plant & Food Research Limited, Christchurch, New Zealand, collaborated to evaluate the effects an aerosol spray of the fire ant recruitment orientation pheromone, Z,E-'-farnesene, on the ability of fire ants to maintain recruitment trails to food resources. We found that the Z,E-'-farnesene in aerosol form effectively stopped orientation to the food source. Disrupting fire ant recruitment to resources on a large scale is expected to have negative effects on resource collection, colony size, colony migration, and other effects yet to be determined. Recently Argentine ant trails were disrupted for up to two weeks in the field using a microencapsulated trail pheromone. Further research is needed to establish the long-term effects and control potential for trail disruption in S. invicta.

Technical Abstract: Toxic bait systems are widely used for control of the fire ant, Solenopsis invicta, one of the most aggressive and invasive species in the world. We prepared the trail pheromone Z,E-a-farnesene (91% purity) from isomerised apple extracts and tested disruption of worker trail orientation using an aerosol formulation presenting a single puff with this compound. Trail-following behaviour was recorded by overhead webcam and ants digitised before and after presentation of the aerosol treatment at four rates (1.6, 16, 160, 1600 ng/cm2). The preferred concentration for trail following of our preparation in behavioural assays was 110 ng/cm. Within seconds of presentation of 1600 ng/cm2, trail disruption was observed, but only at the highest of four doses tested. Disruption was evident as reduced arrival success and reduction in the trail integrity statistic (r2), as well as increased deviation from the trail (degrees). The distribution of walking track angles was flattened, as observed in Argentine ants. The feasibility of using aerosol for delivery of trail pheromone was demonstrated. The main constraint is the commercial availability of the recruitment pheromone, Z,E-a-farnesene, in quantities and in the purity would needed for practical use. However, the production of Z,E-a-farnesene of high purity by industrial biotechnology may be possible in future.