Cheng-Wang Sheng

Insects rely on their visual systems to perform critical behaviors such as host location and phototaxis, and phototransduction, the conversion of photons into electrical signals, constitutes the core mechanism underlying visual function. Most research focuses on model insects like fruit flies, while common agricultural pests remain underexplored. This review integrates current knowledge of insect visual phototransduction to identify molecular and neural targets for precision pest management. This review systematically outlines the complete phototransduction pathway in insect vision: compound eyes and visual lobes exhibit structural specialization adapted to different ecological niches; rhodopsin synthesis and opsin diversity form the molecular foundation; the ‘opsin‐phospholipase‐transient receptor potential channels’ pathway and histamine‐acetylcholine dual‐transmitter branching achieve signal cascading and functional differentiation. Current research has led to the development of three environmentally friendly pest control technologies, first, vision‐based traps that capture pests by optimizing spectral, polarization, and color properties of materials; second, molecular tools such as CRISPR/Cas9, RNA interference, and anti‐sense DNA to target visual genes; and third, multimodal devices that combine sensory synergy with smart optical technologies for physical interception. Existing vision‐based pest control methods still face significant limitations in field applications and tend to be highly species‐specific. Future efforts should integrate basic vision research with practical applications to drive the transition from chemical dependency to ecologically friendly and precision pest management. © 2026 Society of Chemical Industry.

The fall armyworm (Spodoptera frugiperda), a lepidopteran pest of highly destructive, has developed resistance to organophosphate and carbamate insecticides through target-site mutations, including A201S and F290V in the ace-1 gene encoding acetylcholinesterase (AChE). Developing rapid and reliable methods to detect these mutations is crucial for monitoring resistance and guiding effective management strategies. Although S. frugiperda populations remain sensitive to the tested insecticides, the A201S and F290V mutations were identified in collected field samples. To facilitate detection, a sensitive and field-deployable loop-mediated isothermal amplification (LAMP) assay was developed, targeting these mutations within the ace-1 gene of S. frugiperda. The specificity and sensitivity of the LAMP assay was optimized for rapid detection, with reactions performed at 68 °C for 80 min. Results were visualized through color change and confirmed by gel electrophoresis. Validation using DNA from laboratory and field samples demonstrated complete agreement between the LAMP assay and DNA sequencing, affirming the accuracy and reliability of the method. The developed LAMP assay provides a simple, rapid, and effective tool for detecting the A201S and F290V mutations in the ace-1 gene of S. frugiperda. The assay’s simplicity, isothermal operation, and clear visual results make it a valuable tool for resistance monitoring and integrated pest management in agricultural settings.

RNA interference (RNAi) is being used to develop methods to control pests, yet its widespread application is limited by the high comprehensive application cost of dsRNAs. Here, we utilized the high identity matching between double-stranded RNA (dsRNA) and nontarget genes to achieve expanding the dsRNA insecticidal spectrum. First, we found that dsRNA was more likely to induce off-target effects in genes with higher transcript levels and higher sequence identity; the existence of either a completely contiguous matching sequence exceeding 15 nt or a partially contiguous matching sequence of 24 nt between genes can lead to off-target effects in Tribolium castaneum. Accordingly, we successfully interfered with T. castaneum and Laodelphax striatellus using dsRNA targeted against Nilaparvata lugens. Additionally, the use of dsRNA targeting L. striatellus effectively interfered with N. lugens, both instances resulting in lethal effects. Moreover, the dsRNA spray method proved to be more efficient than the rice seedling soaking method to deliver dsRNA. Our research offers new insights into expanding the insecticidal spectrum of dsRNA mediated by a high degree of sequence identity between genes.

The key mutations, such as the Gly-4891-Glu substitution and the Ile-4734 multiple substitutions within the ryanodine receptors (RyR), are linked to diamide resistance in fall armyworm (FAW), Spodoptera frugiperda. In this study, we found that FAW remained sensitive to cyantraniliprole and chlorantraniliprole, while its sensitivity to flubendiamide was reduced. Moreover, a low level of heterozygous mutation at I4743 was observed. To facilitate the detection procedure of these mutations, a simple and efficient loop-mediated isothermal amplification (LAMP) protocol was developed for operation. The reaction for detecting the G4891E and I4743 single or multiple mutations was carried out at 68 °C for 85 min and 68 °C for 85 min or 68 °C for 65 min, respectively. These LAMP reactions can be easily observed via visualization of the color change from pink to yellow. This assay provides a simple, convenient, and effective means of detecting mutations in the RyR of FAW for pest management purposes.

Double-stranded RNA (dsRNA) pesticides, those based on RNA interference (RNAi) technology utilizing dsRNA, have shown potential for pest control. However, the off-target effects of dsRNA pose limitations to the widespread application of RNAi and raise concerns regarding potential side effects on other beneficial organisms. The precise impact and underlying factors of these off-target effects are still not well understood. Here, we found that the transcript level and sequence matching jointly regulate off-target effects of dsRNA. The much lower expressed target genes were knocked down to a lesser extent than genes with higher expression levels, and the critical sequence identity of off-target effects is approximately 80%. Moreover, off-target effects could be triggered by a contiguous matching sequence length exceeding 15 nt as well as nearly perfectly matching sequences with one or two base mismatches exceeding 19 nt. Increasing the dosage of dsRNA leads to more severe off-target effects. However, the length of mismatched dsRNA, the choice of different RNAi targets, and the location of target sites within the same gene do not affect the severity of off-target effects. These parameters can be used to guide the design of possibly selective sequences for RNAi, optimize the specificity and efficiency of dsRNA, and facilitate practical applications of RNAi for pest control.

The fall armyworm (FAW), Spodoptera frugiperda, is a highly polyphagous invasive pest that damages on various crops. Pesticide control is the most common and effective strategy to control of FAW. In this study, we evaluated the toxicity of metaflumizone and indoxacarb against third-instar FAW larvae using the insecticide-incorporated artificial diet method under laboratory conditions. Both metaflumizone and indoxacarb exhibited substantial toxicity against FAW, with LC₅₀ values of 2.43 and 14.66 mg/kg at 72 h, respectively. The sublethal effects of metaflumizone and indoxacarb were investigated by exposing FAW third-instar larvae to LC₁₀ and LC₃₀ concentrations of these insecticides. Sublethal exposure to these two insecticides significantly shortened larval and adult developmental times, extended pupal developmental times, and led to reduced pupal weight, pupation rates, and adult fecundity in the treated parental generation at LC₁₀ or LC₃₀ concentrations, in comparison to the control group. We also assessed he transgenerational sublethal effects, and the findings indicated that metaflumizone and indoxacarb had comparable effects on the F0 generation, except for an observed significant increase in larval developmental time in the F1 generation. Furthermore, Larvae exposed to LC₁₀ or LC₃₀ concentrations of indoxacarb exhibited elevated activity levels of Multifunctional oxidase (MFO) and glutathione S-transferase (GST), which coincides with the observed synergistic effect of PBO and DEM. In conclusion, the high toxicity and negative impact of metaflumizone and indoxacarb on FAW provided significant implications for the rational utilization of insecticides against this pest.

The pH-sensitive chloride channels (pHCls) are unique chloride channels in invertebrates and have important roles in regulation of fluid secretion, food selection and intake. pHCls are widely expressed in insects, but little is known about their pharmacological properties and their sensitivity to metal ions. Herein, we isolated two cDNAs (Sfphcl1 and Sfphcl2) that encode SfpHCl1 and SfpHCl2 subunits from the fall armyworm Spodoptera frugiperda. The Sfphcl1 and Sfphcl2 demonstrated similar expression patterns with most abundant expression in the Malpighian tubules of the first instar larval stage. The cRNA of Sfphcl1 and Sfphcl2 were injected into Xenopus laevis oocytes singly or together in three different ratios of 1:4, 1:1 and 4:1 to characterize their function and investigate their zinc ion sensitivity. We found that SfpHCl1 and SfpHCl2 formed chloride channels in oocytes with a reversal potential that is consistent with chloride selectivity, but showed insensitivity to changes in external sodium concentrations. The extracellular pH shift and zinc-elicited inward currents in oocytes expressing SfpHCl1 and SfpHCl2 showed a similar EC50. These results provide the biophysical and pharmacological properties of pH-sensitive, zinc-gated chloride channels. Since the pHCls are present only in invertebrates, they may provide an ideal target for highly specific insecticides.