To repel the red imported fire ant: a review of progress, limitations, and prospects

The red imported fire ant, Solenopsis invicta, is one of the world's most damaging invasive species, causing billions of dollars in economic losses annually. Although chemical insecticides remain the primary control method, their application is increasingly constrained by resistance, as well as environmental and health concerns. Repellents offer a complementary approach when immediate and precise protection is needed. This review examines the current state of research on repellents against S. invicta. In total, 124 substances have demonstrated repellent activity against foraging, nesting, or defending behaviors of S. invicta. However, several limitations in S. invicta repellent studies challenge their real-world applicability. Although certain compounds have shown strong and persistent effects under laboratory conditions, field validation remains limited. Furthermore, most repellents have been evaluated in only a single behavioral context, and differences in experimental methods and evaluation criteria complicate comparisons across studies. There is also a significant gap in mechanistic understanding, with only a limited number of studies focusing on molecular targets, neural responses, or docking-based hypotheses related to repellency in S. invicta. Future research should prioritize standardized, multi-context evaluations, field validation, and mechanistic investigations to advance the practical application of S. invicta repellents.