AbstractThe Chinese white pine beetle (Dendroctonus armandiTsai and Li) is a significant pest of pine forests in the Qinling and Bashan Mountains of China. Adult males commonly produce frontalin using precursors synthesized through the mevalonate pathway, which is regulated by juvenile hormone III (JHIII). In this study, the expression levels of mevalonate pathway genes were quantified after phloem feeding and topical application of the JHIII solution. The frontalin was quantified by gas chromatography‐mass spectrometry. Both the phloem feeding and JHIII treatments produced an evident upregulation in the male gut, mainly in 3‐hydroxy‐3‐methylglutaryl‐CoA synthase (HMGS) and 3‐hydroxy‐3‐methylglutaryl‐CoA reductase (HMGR). Moreover,HMGS,HMGR, isopentenyl diphosphate isomerase, and geranyl diphosphate synthase/farnesyl diphosphate synthase were upregulated in fed and JHIII‐stimulated males ofD. armandiunder both conditions (solitary and paired). The expression levels were higher in paired compared to solitary males. Males had higher expression levels compared with females. Correspondingly, the phloem‐feeding males produced more frontalin than JHIII‐treated males, and the production of frontalin was higher in paired males than in solitary males. The knockdown of mevalonate pathway genes using RNAi in vivo effectively reduced the messenger RNA level of these genes and inhibited the production of frontalin. Among them, the silencing ofHMGRorHMGSgenes reduced the synthesis of frontalin most significantly.