Chemical Ecology and Management of Imported Fire Ants

Imported fire ants (Solenopsis invicta and S. richteri) are invasive pests that were introduced into the United States via Mobile, Alabama, in the early twentieth century. As these species spread, interbreeding led to the emergence of hybrid populations. Their rapid expansion and ecological dominance prompted extensive control efforts, including chemical eradication campaigns and biologically informed strategies. Today, fire ants infest over 140 million hectares across the southern United States, affecting public health, agriculture, and ecosystems. Despite decades of research, many fire ant semiochemicals remain unidentified because of the ants' complex social behavior and because multicomponent chemical signals occur in trace amounts and are difficult to isolate, especially those involved in aerial mating. Additionally, components often lack activity unless presented in specific combinations. These challenges limit traditional bioassay-guided structure elucidation. This review summarizes advances in fire ant chemical ecology, highlights persistent knowledge gaps, and proposes innovative strategies to accelerate pheromone discovery and improve management.