Host selection and adaptation of the invasive pest Spodoptera frugiperda to indica and japonica rice cultivars

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is an invasive pest in China that can feed on many different crops. However, its host selection and adaptability to Chinese rice cultivars are largely unknown. It is assumed that S. frugiperda can achieve food adaptation within several generations. Life time parameters, such as survival rate, body weight, developmental time, and the number of eggs laid, were compared across different generations (F1 and F3) for insects fed on two different rice cultivars, i.e., japonica and indica, and on corn, i.e., the main host. The results revealed that the two cultivars differed in their suitability for S. frugiperda, and this insect was more adaptable to japonica rice than indica rice in the first generation of their host change. Compared to corn, the growth, development, and survival of insects on rice cultivars were much lower and longer in both of the tested generations. Although S. frugiperda can complete its growth and development on japonica or indica rice cultivars, this insect pest had a significant preference for corn plants for adult oviposition and larvae food selection. The long-term development of three generations on the non-preferred hosts could influence an insects' life parameters and possibly make them more adaptable to the new feeding environment. Further studies of the host selection and utilization of S. frugiperda on various rice cultivars is necessary to determine the threat this pest poses to rice, and to develop sustainable pest management practices.

Automated summary

The study found that Spodoptera frugiperda had a stronger adaptability to japonica rice compared to indica rice, but growth, development, and survival rates of the insect on both rice cultivars were lower and longer than on corn.