Fitness and cold tolerance of Spodoptera frugiperda fed on corn and two winter crops

Abstract

AbstractFall armyworm (FAW) Spodoptera frugiperda is a major migratory and polyphagous pest. Overwintering, migrating and colonizing characters of FAW are closely related to vegetation and host adaptation. In this study, we investigated oviposition preference, feeding preference of FAW, as well as fitness, cold tolerance of FAW larvae fed on spring and summer crop (corn) and two winter crops (cabbage, Brassica campestris and rape, B. napus). The results showed that FAW could complete their life cycle by feeding on cabbage and rape, although fitness was not as good as corn. FAW fed on cabbage had higher survival, female pupal mass and host suitability index than rape while larvae preferred to feed on rape leaves and females preferred to lay eggs on rape plants. In addition, FAW larvae fed on cabbage had the shortest recovery time from chill coma compared to corn and rape, indicating that cold tolerance of FAW larvae was improved by feeding on cabbage. Consequently, cabbage could be an ideal host for FAW which needed to survive and reproduce in winter. These results improve our understanding of host selection and adaption of FAW, as well as lay a foundation for predicting winter breeding areas of FAW.