Submitted to: Journal of Insect Biochemistry and Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 25, 2000
Publication Date: N/A
Interpretive Summary: The honey bee is an important beneficial insect, both for honey production and crop pollination. Therefore, the development of hormonally-based compounds to control pest insects must take into account the possible side effects on beneficial insects like the honey bee. We have examined hormone precursors in the honey bee and a peptide that has potential as a conrtol agent for their effect on hormone production in honey bee development. Laboratory tests revealed that precursor hormones could stimulate hormone production in immature honey bees, while a hormone isolated from the tobacco hornworm was ineffectual. The information from this research will be used by industry, government and university scientists in developing environmentally safe compounds to control pest insects.
Juvenile hormone (JH) is considered the prime endogenous signal for the induction of queen development in honey bees (Apis mellifera L.). At the beginning of the last larval instar, worker corpora allata synthesize considerably less JH than queen corpora allata due to a limited production of JH precursors and a caste- and stage-specific block of the terminal step in JH biosynthesis. As previously shown, the Manduca sexta allatotropin stimulates JH biosynthesis in honey bee corpora allata in a dose-dependent and reversible manner, but can not overcome the stage- specific block in the terminal step of JH precursor farnesoic acid, we found characteristic stage-specific differences regarding their effects on JH biosynthesis. From the end of the spinning stage on, corpora allata could be stimulated by farnesoic acid to a much higher extent than in earlier development stages, suggesting a sudden increase in epoxidase activity. M. sexta allatotropin, however, stimulated corpora allata become suddenly insensitive. These data suggest that in worker larvae, important changes regarding the regulation of the terminal enzymatic steps in JH biosynthesis occur at the transition from the spinning stage to the prepupal stage.