BRAIN AND SUBESOPHAGEAL GANGLION EXTRACTS AFFECT JUVENILE-HORMONE BIOSYNTHESIS IN HONEY-BEE LARVAE (APIS-MELLIFERA-CARNICA)

The central nervous system of honey bee larvae contains several factor s that activate or inhibit juvenile hormone biosynthesis in vitro. A h eat-stable, allatotropic factor was found in extracts prepared from br ains and suboesophageal ganglia of worker prepupae. Its stimulatory ac tion on in vitro juvenile hormone production by corpora allata could n ot be reversed by washing out the active extract. Based on its sensiti vity to trypsin, this factor appears to be a peptide. Partial purifica tion by SEP-PAK C-18 fractionation of methanolic extracts revealed a f urther, possibly heat-sensitive, allatotropic component in the optic l obes. The optic lobe factor was insensitive to trypsin, and its action on juvenile hormone production was reversible. A substance having all atostatic activity was also detected but only from the suboesophageal ganglion. Its inhibitory action on corpora allata activity was insensi tive to trypsin and was not reversible. The role of regulators of the corpora allata function in triggering polymorphic pathways during cast e-specific morphogenesis is discussed.