Responsiveness of honey bee (Apis mellifera L.) corpora allata to allatoregulatory peptides from four insect species

Five neuropeptides with known allatotropic or allatostatic activity in othe r insect species were examined for their effects on honey bee corpora allat a. Using an in vitro radiochemical assay, we assessed the ability of these peptides to affect the biosynthesis of juvenile hormone III and its immedia te precursor methyl farnesoate, as well as their effects on the conversion of methyl farnesoate into juvenile hormone. None of the allatostatins teste d affected JH biosynthesis during the last larval instar of honey bee worke rs. Manduca sexta allatotropin, however, stimulated JH biosynthesis in a st age-specific and dose-dependent manner. Analysis of intraglandular contents of juvenile hormone and its precursor revealed that the allatotropin signi ficantly increased JH precursor but did not overcome the stage-specific blo ck in the terminal step of JH biosynthesis that is typical for early fifth- instar worker larvae. Studies also indicated that the allatotropic effect w as reversible at the level of methyl farnesoate production. (C) 1999 Elsevi er Science Ltd. All rights reserved.