Gustatory receptors in the abdominal terminus contribute to oviposition decisions in Anoplophora glabripennis

BACKGROUND: Anoplophora glabripennis (Asian longhorned beetle, ALB) is a wood-boring forest pest causing tree decline and mortality. The abdominal terminus is essential for oviposition and bears numerous chemosensilla, but its role in gustatory perception and host selection remains unclear. RESULTS: Eight sensilla were identified on the female abdominal terminus using scanning electron microscopy, including three putative gustatory sensilla. RNA-sequencing of the abdominal terminus identified 30 gustatory receptors (AglaGR1-30). Reverse transcription quantitative polymerase chain reaction profiling revealed distinct tissue- and developmental stage expression patterns for 14 detectable AglaGRs. Five AglaGR genes (AglaGR16/24/25/28/30) were successfully cloned and encode typical insect gustatory receptor proteins. AglaGR24 and AglaGR25 were putatively sugar-responsive based on phylogenetic inference, although their ligand specificities remain to be directly validated. RNA interference (RNAi) of five AglaGRs produced gene- and period-specific effects on oviposition-related behaviors, with AglaGR30 showing the most consistent effects, including significantly reduced Period II grooving and egg numbers, total egg number, and effective grooving rate (number of egg-bearing grooves/total number of grooves). CONCLUSION: Although BLAST analysis detected no significant off-target matches, RNAi specificity was not further validated by examining expression of non-target AglaGRs. This study systematically classified the sensilla on the abdominal terminus of ALB and functionally characterized the roles of its gustatory receptors. These findings establish gustatory receptors as key molecular targets for disrupting host selection, providing a scientific basis for developing RNAi-based biopesticides and behavior-modifying compounds that specifically interfere with oviposition decisions. © 2026 Society of Chemical Industry.