Species distribution models reveal restricted areas for biological control of Bactrocera carambolae by its parasitoid Fopius arisanus in Brazil

Fopius arisanus (Sonan) is an exotic parasitoid used to control Bactrocera spp. In Brazil, it is suggested as a control agent for Bactrocera carambolae Drew & Hancock. The pest is currently restricted to the northern territory of Brazil; however, temperature changes may lead to an increase in its distribution. Species distribution models (SDMs) can predict a species’ potential geographic range in a particular climate change scenario. We aimed to predict the susceptible areas for expanding and establishing B. carambolae and its parasitoid, F. arisanus in Brazil, particularly, in the Amazon region. Climate layers were extracted from bioclimatic variables, and Random Forest was used to predict the SMDs for both Brazilian species under two climatic scenarios (intermediary and extreme). Our predictions showed a larger suitability area for B. carambolae establishment than for its parasitoids. Although B. carambolae is widespread, especially in the North and Midwest, F. arisanus has a limited area from west of Ceará State to North and East of Amapá State. Fopius arisanus had a low chance of increasing its geographical area under both climatic scenarios. The parasitoids and their hosts were similarly influenced by bioclimatic variables [precipitation seasonality (BIO15) and annual precipitation (BIO12)]. Our results revealed a limited compatibility area for both B. carambolae and F. arisanus in the Brazilian territory, with potential expansion of the pest compared with its parasitoid. In this context, the country’s northern regions face a “red alert flag” for implementing strategies to prevent the spread of pests by releasing parasitoids.