Precise Regulation of Juvenile Hormone III R-Stereoisomer Synthesis by Apis mellifera through Specifically Binding Methyl-(2E,6E)-farnesoate and Strictly Controlling Its Titer

Juvenile hormone III (JH III) is a crucial hormone synthesized exclusively as R -stereoisomer in most insects. Herein, we established a mature Tris-HCl culture system for essential biochemical reactions and applied stable instrumental detection methods to analyze JH III, methyl farnesoate (MF) and juvenile hormone acid (JHA) using UPLC-MS/MS. Our results revealed that the R -JH III terminal synthesis pathway in Apis mellifera follows the “esterify then epoxidize” sequence, with precise methyl-(2 E,6 E )-farnesoate titer regulation and its spatial cis–trans isomerism, achieving selective R -JH III synthesis. Furthermore, we observed that the preferred generation of S / R -JH III chiral enantiomers varied depending on the spatial cis–trans isomerism of different MFs. Our results suggest that S -JH III could theoretically exist in insects, offering a novel perspective for understanding the synthesis mechanism of diverse complex juvenile hormones in different insect species.