Sublethal Effects of Pyridaben on the Predatory Function of .

Pyridaben is a widely utilized, broad-spectrum contact acaricide, which has notable sublethal effects that impair the predatory capabilities of predatory mites, but the specific mechanisms that affect the predatory functions remain underexplored. When predatory mites hunt for prey, they may rely on Niemann-Pick-type C2 (NPC2) proteins to collect herbivore-induced plant volatiles (HIPVs) and other odor molecules to locate and pursue their prey. This study elucidated that pyridaben significantly diminished the predatory efficiency and searching behavior of the predatory mite . Key metrics, including predatory capacity () and predation rate () on various developmental stages of , were markedly reduced in treated mites compared to controls. The searching efficiency () also declined proportionally with the increased sublethal dose of pyridaben. A gene linked to olfactive functions, , was cloned from . Post-treatment with pyridaben at LC and LC concentrations resulted in a substantial downregulation of expression by 60.15% and 58.63%, respectively. Silencing in females led to significant reductions in the attack rate (), handling time (), predation efficiency (), and maximum predation rate (1/). The searching efficiency () was also lower than that of the control group, displaying a slight decline with the increasing prey density. The findings revealed that pyridaben exerted inhibitory effects on both the predatory function and searching efficiency of populations. The decrease in predatory performance at LC and LC concentrations was attributable to the suppression of gene expression. RNA interference (RNAi) studies corroborated that the gene plays a critical role in the predation process of . Thus, the underlying molecular mechanism through which pyridaben compromises the predatory function of likely involves the downregulation of expression.