Potential economic impact of invasion by the Red Imported Fire Ant Solenopsis invicta in Okinawa, Japan

We estimated the potential economic impact of the introduction and spread of the Red Imported Fire Ant (RIFA) Solenopsis invicta Buren, 1972 to Okinawa Prefecture, Japan, based on a previous study that performed a similar estimation for Hawaii. Impacts were assessed assuming that the government made a minimal effort to abate a RIFA invasion, and that RIFA spread to all potential habitats. As a result, the economic loss directly caused by RIFA was estimated to be approximately 19,248 million yen per year, including the costs borne by households, agriculture, infrastructure and recreation facilities, as well as the estimated minimal government intervention expenditure. The economic value of the outdoor activities foregone by residents and tourists was estimated to be approximately 24,610 million yen per year. Thus, this study estimates the total economic loss caused by RIFA in Okinawa to be approximately 43,858 million yen per year. Our findings highlight the importance of evaluating the economic impact of RIFA when considering the necessity of countermeasures and budgeting for a RIFA invasion. However, further studies are needed to more precisely estimate the cost in Japan, because the current estimate was unable to take into account differences in social systems and customs between Japan and the United States.