Non-consumptive effects of Cyrtorhinus lividipennis (Hemiptera: Miridae) on development, wing dimorphism, and reproduction in Sogatella furcifera (Hemiptera: Delphacidae)

The white-backed planthopper (WBPH) Sogatella furcifera (Horváth) (Homoptera: Delphacidae) is a significant migratory pest of rice, and Cyrtorhinus lividipennis (Reuter) (Hemiptera: Miridae) is an important predatory natural enemy that targets planthopper eggs in rice fields. Although late nymphs of S. furcifera with greater mobility can effectively evade capture, it remains unclear whether non-consumptive effects (NCEs) of C. lividipennis affects survivors and how these effects are present. In this study, we selected 3rd to 5th instar nymphs of S. furcifera exposed to predation risk as a research model to explore the potential effect known as non-consumptive effects. Exposure to predation risk caused S. furcifera nymphs to delay their development, increased the proportion of long-winged adult females, and significantly reduced the number of eggs laid. Further analysis of physiological indices showed that key genes involved in wing-morph switching and ecdysone (20E) synthesis were downregulated after exposure to predation risk, accompanied by a significant decrease in the 20E titre in the 4th instar, which may represent a potential regulatory mechanism of planthoppers in response to predator stress. These results demonstrate that predation risk from C. lividipennis induces significant NCEs in S. furcifera. Populations exposed to this predation risk exhibit a significant increase in the proportion of long-winged individuals while simultaneously impairing developmental rates and reproductive output, a trade-off likely reflecting adaptive responses to predation risk. These findings provide useful data for monitoring pest populations in fields coexisting with natural enemies and for integrated pest management (IPM) in rice.