Heat shock protein 70 (HSP70) regulates the stress tolerance and reproductive ability of insects. In this study, the SfHSP70-7 gene was cloned and identified from the rice pest Sogatella furcifera. SfHSP70-7 encodes a typical cytoplasmic HSP70 protein that has a conserved functional domain and is highly similar to the HSP70 homologous protein of Laodelphax striatellus. SfHSP70-7 was found to be widely expressed across all developmental stages, with the highest levels in nymphs and female adults. In terms of tissue distribution, it was particularly abundant in the gut and ovaries. Its expression was strongly induced by high/low temperatures and three insecticides (triflumezopyrim, sulfoxaflor, and imidacloprid), with the maximum induction under heat and triflumezopyrim stress. RNA interference (RNAi) efficiently silenced SfHSP70-7 and significantly increased the susceptibility of S. furcifera to triflumezopyrim and sulfoxaflor, but it had no effect on susceptibility to imidacloprid. RNAi knockdown of SfHSP70-7 markedly reduced survival by 45.5% (30 °C) and 38.9% (35 °C) under heat stress. In addition, gene knockdown can damage the reproductive performance of females by reducing oviposition and egg hatchability. These results indicate that SfHSP70-7 is involved in regulating the heat tolerance, insecticide adaptability, and reproductive regulation mechanism of S. furcifera, providing a potential target for pest control.

Heat shock protein 70 (HSP70) serves as a critical molecular chaperone governing environmental stress responses in insects. This study aimed to characterize the expression pattern of SfHSP70-8 and determine its functional role in thermotolerance and insecticide susceptibility in the white-backed planthopper, Sogatella furcifera. Here, we cloned and characterized SfHSP70-8, a cytosolic member of the HSP70 family from S. furcifera. The encoded protein contains characteristic conserved domains and shares close sequence identity with the HSP70 homolog of Laodelphax striatellus. Spatiotemporal expression profiling revealed ubiquitous transcription across all developmental stages, peaking in third-instar nymphs, and pronounced enrichment in the gut and fat body. Transcript levels were robustly elevated following exposure to both thermal extremes (10–40 °C) and LC₅₀ concentrations of triflumezopyrim, sulfoxaflor, and imidacloprid. RNAi-mediated silencing of SfHSP70-8 significantly compromised tolerance to triflumezopyrim and sulfoxaflor while leaving imidacloprid susceptibility unchanged, and markedly decreased survival rates under chronic heat stress at 30 °C and 35 °C. Collectively, these findings demonstrate that SfHSP70-8 functions as an essential regulator of thermotolerance and insecticide adaptation in S. furcifera, offering a potential molecular target for future development in sustainable pest management.