Land-use change drives present and future distributions of Fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

The fall armyworm (Spodoptera frugiperda J.E. Smith) is one of the most notorious pests of several crops in the world. However, to date, few studies have simulated the future distribution patterns of fall armyworm under rapid global changes. Though the relative influences of climate and land-use on species distribution might depend on the spatial scales of the studies, it is not known whether this rule is applicable to pests which mostly feed on crops. Here, we developed MaxEnt models to explore the distribution patterns of fall armyworm, as well as the relative influences of land-use change, topography and climate change on them. Under the present conditions and scenarios of RCP 2.6 and 8.5 (the most optimistic and pessimistic emissions scenarios, respectively), high potential habitats of fall armyworm were mostly recorded along the east coast areas of the USA, the State of Florida, Mexico, Central America, southern part of Brazil, central Africa, and southern Asia. Among all of the continents, Africa will face the greatest increase of the threats from fall armyworm in future. Under RCP 2.6 scenario, both the potential habitats and areas with increased habitat suitability were larger than those under RCP 8.5. Therefore, much more effort is required to control fall armyworm under RCP 2.6 scenario. Compared to climate change, land-use changes are more important in shaping the distribution patterns of fall armyworm. Therefore, the concentration of resources might modify the relative influence of climate and land-use in species distributions at large scales. Thus, regulating land-use might prove effective for mitigating the proliferation of fall armyworm. In general, C4 annual crops and managed pastures provide more suitable habitats for fall armyworm than C3 annual crops. Our findings demonstrate that delineating resource concentrations could provide a new approach towards controlling fall armyworm under current and future global change.