Predicting suitable habitats for the Brazilian peppertree biological control agent Pseudophilothrips ichini (Thysanoptera: Phlaeothripidae) in Florida

Invasive plants are rapidly entering new ecosystems due to globalisation, increased trade, and frequent disturbances of natural habitats. <i>Schinus terebinthifolia</i> Raddi, known as the Brazilian peppertree, is a particularly aggressive invasive shrub in Florida, Hawaii, Texas, and California. Due to its aggressive growth and the damage it can cause to ecological systems, it is considered one of the worst upland invasive species in the state of Florida, prompting extensive biological control efforts. The classical biological control agent, <i>Pseudophilothrips ichini</i>, was approved for release in Florida in 2019, with over 6 million thrips released to date. However, the establishment and persistence of these thrips have been inconsistent, and little research has been conducted to understand these patterns. Here, we employ ecological niche modelling as a tool to predict suitable habitats for Brazilian peppertree and <i>P. ichini</i>. Ecological niche models were calibrated using location data of both organisms from their native ranges and bioclimatic data from WorldClim. These models accurately predicted the potential distribution of Brazilian peppertree (AUC_training= 0.914, AUC_validation = 0.913) and <i>P. ichini</i> (AUC_training= 0.934, AUC_validation = 0.918). The projections indicated that most of Florida is climatically suitable for the Brazilian peppertree, aligning with its known distribution. However, discrepancies were observed between the projected and actual distribution of <i>P. ichini</i>, suggesting that additional environmental or biotic factors may influence their establishment. Further research is necessary to refine these models and enhance the integration of <i>P. ichini</i> into pest management programmes to better conserve time, resources, and funds.