No abstract

The relationship between oviposition preference and offspring performance is critical to an understanding of the interaction between herbivores and host plants. Although the topic has been addressed widely in plant species‐herbivore systems, it has rarely been investigated in plant stage‐herbivore systems. In this study, we evaluated oviposition preference and offspring performance of the rice leaf folder (RLF), Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae), on rice plants at the seedling (SS), tillering (TS), and booting (BS) stages. In preference assays, females deposited more eggs on TS and BS than on SS plants in cage tests, and preferred TS and BS odors over SS odors in Y‐tube olfactometer tests. Offspring performance was affected by plant stage. The RLF offspring performed well when the larvae fed on BS leaves, as indicated by the highest larval survival and pupation rate and the greatest adult longevity. RLF offspring performed also well when the larvae fed on TS leaves, where fecundity was the highest. The high RLF offspring performance on TS and BS plants coincided with high larval consumption of TS and BS leaf mass relative to SS leaf mass. Our findings confirm the prediction of the preference–performance hypothesis. The results explain the pest damage patterns in mixed croppings of one‐ and two‐season rice and are of significance for management of the pest through synchronization of rice planting.

Spodoptera frugiperda (J. E. Smith), which attacked China in 2019, remains a significant threat to wheat production. Wheat–faba bean intercropping systems prevent damage caused by wheat aphids; however, the potential role in S. frugiperda control remains unclear. Here, the adaptability and preferences of S. frugiperda to wheat and its common intercropped plant, faba bean, were evaluated to implement an eco-friendly approach for S. frugiperda management. Their adaptability showed that both hosts could support S. frugiperda to complete their life cycle; however, the larvae performed worse on faba bean compared with on wheat. The biochemical analysis revealed that faba bean plants had lower contents of soluble sugars and total proteins but higher levels of phenolics and tannins than in wheat leaves. The gravid S. frugiperda preferred (during the preference assays) to oviposit on wheat rather than on faba bean plants in cage tests. The wheat odor was preferred over the faba bean odor in the Y-tube olfactometer bioassays. The morphological scanning electron microscopy (SEM) showed increased trichome density on wheat leaves. Therefore, the faba bean plants displayed antibiosis on larvae and were repellent to female moths, thus, suggesting that faba bean plants could serve as a push crop to be intercropped with wheat for S. frugiperda control for wheat fields.