Pest control methods that can target pest species with limited environmental impacts are a conservation and economic priority. Species-specific pest control using RNA interference is a challenging but promising avenue in developing the next generation of pest management. We investigate the feasibility of manipulating a biological invader’s immune system using double-stranded RNA (dsRNA) in order to increase susceptibility to naturally occurring pathogens. We used the invasive Argentine ant as a model, targeting the immunity-associated genes Spaetzle and Dicer-1 with dsRNA. We show that feeding of Spaetzle dsRNA can result in partial target gene silencing for up to 28 days in the laboratory and five days in the field. Dicer-1 dsRNA only resulted in partial gene knockdown after two days in the laboratory. Double-stranded RNA treatments were associated with significant gene expression disruptions across immune pathways in the laboratory and to a lower extent in the field. We observed occasional changes in viral loads in dsRNA-treated groups. However, immune pathways disruption did not result in consistent increase in microbial infections, nor did they alter ant abundance in the field. Our study explores the feasibility of lowering a pest’s immunity as a control tool. We demonstate that it is possible to alter immune gene expression of pest species and pathogen loads, though in our system the affected pathogens did not appear to influence pest abundance. We provide advice on future directions for dsRNA-mediated immune disruption in pest species, including potential avenues to improve dsRNA delivery as well as the importance of the biology of the pest system and its pathogens.

TaqMan qPCR assays of Argentine ant immune genes and pathogen loads.