Regional and caste‐specific variation in insecticide susceptibility in odorous house ants, Tapinoma sessile (Hymenoptera, Formicidae)

Abstract

AbstractAnts consistently rank as the number one household pest, and many species are pests in agricultural and natural habitats. Despite economic and ecological impact of pest ants, effective management still faces many challenges and control failures with liquid spray insecticides are common. The odorous house ant (Tapinoma sessile Say) is an adaptive and widespread pest ant found in North America. This study examined regional variation in T. sessile insecticide susceptibility to three classes of insecticides commonly used in ant control. T. sessile showed significant regional variation in insecticide susceptibility on a relatively small geographic scale. A comparison of colonies collected in urban vs. natural areas showed no significant difference in susceptibility in tests with lambda‐cyhalothrin and fipronil. In tests with dinotefuran, urban colonies were significantly more tolerant relative to natural colonies. These results suggest that habitat type and previous insecticide exposure do not reliably predict susceptibility levels in individual populations. Queens were significantly more tolerant relative to their worker counterparts across all insecticides. Higher insecticide tolerance in queens may explain why T. sessile is such a persistent pest in urban environments. The results provide a foundation for the development of more effective and efficient control methods for T. sessile and warrant further investigation of spatial and potentially temporal variability in insecticide susceptibility in ants.