Climate and human-modified landscapes influence spread of invasive agricultural pest Popillia japonica Newman in American Midwest and Great Plains

Japanese beetle (Popillia japonica) is an invasive agricultural pest throughout the eastern United States and its distribution is expanding westward. Understanding how climate and land use intensification interact to affect Japanese beetle population dynamics and spread is essential to predict which areas are vulnerable to increased pest pressure. In this study, we combine data from the Global Biodiversity Information Facility (GBIF) with data from local state agricultural agencies and University extension offices to model how land cover and climate affect Japanese beetle occurrences at the leading edge of an invasion front in the central United States over 5 years. We found that beetle occurrences were positively correlated with proportion of developed areas, proportion of corn and soybean, minimum temperature, and precipitation within counties, and negatively correlated with the proportion of grassland and pasture, and maximum temperature. We modeled Japanese beetle occurrences in the near future and for future climate scenarios and found high probability of occurrence for Japanese beetles across the entire region. Our study highlights the importance of supplementing community science data in rural areas and including a time variable when assessing habitat associations for invasive species in novel areas.