Identification of a small molecular insecticidal toxin Philanthotoxin-7,4 in the predatory stink bug, Arma custos

Due to the increasing resistance to traditional insecticides and their negative impact on the ecological balance of pest control, there is a global trend to reduce pesticide use and develop efficient, low-toxicity and environmentally friendly biopesticides.Toxins with insecticidal or paralytic activity derived from the venom of predatory natural enemies have emerged as a novel strategy for the development of novel biopesticides.In this study, a small molecular toxin, philanthotoxin-7,4 (PhTx-74), was identified in the venom gland homogenates of the predatory stink bug Arma custos (Hemiptera: Asopinae).Injection of PhTx-74 into Spodoptera litura (Lepidoptera: Noctuidae) larvae induced paralysis.Similarly, injections into Ostrinia nubilalis (Lepidoptera: Pyralidae) larvae and Nilaparvata lugens (Hemiptera: Delphacidae) nymphs resulted in paralysis and subsequent mortality.The feeding of PhTx-74 to Myzus persicae (Hemiptera: Aphididae) larvae showed that PhTx-74 caused death.In addition, PhTx-74 exhibited no toxicity to the non-target organisms Danio rerio (Cyprinidae: Danionidae).This study identifies a small-molecule toxin with paralytic effects, demonstrating the potential of predatory insect venoms as sources of insecticidal agents.