Role for a SIFamide Receptor in Regulating Foraging and Feeding via Carbohydrate Metabolism in <i>Spodoptera frugiperda</i> Larvae

The fall armyworm, <i>Spodoptera frugiperda</i>, is a major agricultural pest known for its voracious feeding and adaptive foraging behaviors, with neuropeptide signaling critically regulating these behaviors in insects. In this study, we identified and functionally characterized the SIFamide receptor (SIFaR) in <i>S. frugiperda</i> larvae using RNA-seq analysis. Clustered regularly interspaced short palindromic repeats (CRISPR)-mediated knockout (KO) of <i>SIFaR</i> resulted in impaired foraging efficiency, reduced locomotor activity, and significantly diminished feeding capacity. Transcriptomic profiling of SIFaR-KO mutant larvae revealed downregulation of five genes linked to carbohydrate metabolism. These findings uncover a role of SIFaR in modulating foraging and feeding behaviors via metabolic gene regulation, offering new molecular insights into lepidopteran behavioral ecology with foraging and feeding, and suggesting that SIFaR may serve as a potential target for pest control strategies.