Insecticide Susceptibility and Mechanism of Spodoptera frugiperda on Different Host Plants

Spodoptera frugiperda (J.
E. Smith)
is a worldwide economically important crop pest. Although the individuals
of S. frugiperda that invaded China
have been characterized as the corn strain, they also have the ability
to damage other crops in China. The physiological and behavioral responses
of S. frugiperda to different host
plants are poorly understood. In the present study, we investigated
the host plant preference, fitness costs, and differences in detoxification
gene expression and microbiome composition between two S. frugiperda strains that fed on different crop
plant diets. The results showed that S. frugiperda larvae exhibited no obvious preference for corn or rice, but significant
suppression of development was observed in the rice-fed strain. In
addition, the corn-fed strain showed higher insecticide tolerance
and detoxification enzyme activities than the rice-fed strain. Moreover,
multiple detoxification genes were upregulated in the corn-fed strain,
and microbiome composition variation was observed between the two
strains. Together, the results suggest that population-specific plasticity
is related to host plant diets in S. frugiperda. These results provide a theoretical basis for the evolution of
resistance differences in S. frugiperda and are helpful for designing resistance management strategies for S. frugiperda aimed at different crops.