Jie Luo

Juvenile hormone III (JH III) plays a central role in insect development and reproduction and has long been assumed to occur exclusively as the R-enantiomer. Here, we demonstrate that Sclerodermus guani exclusively synthesizes the S-enantiomer of JH III (S-JH III), as confirmed by electron circular dichroism (ECD) analysis and TD-DFT simulations. S-JH III is consistently present across developmental stages, peaking during the egg stage, and is also predominant in related species, suggesting taxon-specific stereoselectivity. In vitro and in vivo assays identified methyl farnesoate (MF) as the preferred precursor, with a strong bias toward S-JH III production. Enzymatic kinetics of purified SgCYP15A1 revealed significantly higher affinity and catalytic efficiency for S-JH III. Transcriptome analysis showed that S-JH III, but not R-JH III, upregulated genes involved in ovarian development and reproductive regulation. These findings uncover a highly stereoselective JH III biosynthetic pathway in S. guani and highlight its potential relevance to hymenopteran evolution and reproductive control. This finding not only expands current understanding of JH biosynthesis but also presents opportunities for developing stereoselective hormone analogs to enhance the behavioral efficacy of parasitoids in biological pest management.

Juvenile hormone (JH) plays an important role in regulating various insect physiological processes. Herein, a novel method (chiral and achiral) for the simultaneous detection of five JHs was established by processing a whole insect without complicated hemolymph extraction. The proposed method was used to determine the distribution of JHs in 58 insect species and the absolute configuration of JHs in 32 species. The results showed that JHSB₃ was uniquely synthesized in Hemiptera, JHB₃ was unique to Diptera, and JH I and JH II were unique to Lepidoptera. JH III was present in most insect species surveyed, with social insects having generally higher JH III titers. Interestingly, JHSB₃ and JHB₃, both double epoxidation JHs, were found in insects with sucking mouthparts. The absolute conformation of JH III and the 10C of the detected JHs were all R stereoisomers.

The juvenile hormone (JH) plays a key role in the development of honeybee larvae and the alteration of adult behavior. Verification methods of types and stereoisomers of JHs in honeybees were established in this study. The regulatory modes of different stereoisomers of JH III on the social behaviors of honeybees were revealed by the disparity of interaction and RNA-seq. This result represented the first assessment of the effects of R-JH III and S-JH III in honeybee interactions; the former (367 times in total) was significantly higher than the latter (235 times in total); honeybees with high JH titers are always welcome in the colony because the effect of JH III on bees involves the sensing and signaling of hormones, and R-JH III is much more active than S-JH III in this regulation. Efficient R-JH III may be the insurance for bees to establish their social system advantages.

Juvenile hormones (JHs) play a crucial role in the development of honey bee (Apis mellifera) worker larvae. Juvenile hormone analogs (JHAs), insecticides widely used in pest control, have been reported to affect the health and survival of honey bee worker larvae. However, the molecular mechanisms of JHAs in the honey bee remain unclear. In this study, we treated honey bee worker larvae with pyriproxyfen, fenoxycarb, and methoprene, three different JHAs. We monitored the changes in the transcription of genes encoding major JH response enzymes (CYP15A1, CYP6AS5, JHAMT, and CHT1) using RT-qPCR and analyzed the transcriptome changes in worker larvae under JHA stress using RNA-seq. We found that the enrichment pathways differed among the treatment groups, but the classification of each pathway was generally the same, and fenoxycarb affected more genes and more pathways than did the other two JHAs. Notably, treatment with different JHAs in the honey bee changed the JH titers in the insect to various extents. These results represent the first assessment of the effects of three different JHAs on honey bee larvae and provide a new perspective and molecular basis for the research of JH regulation and JHA toxicity in the honey bee.