ALLATOTROPIC ACTIVITY IN THE SUBESOPHAGEAL GANGLIA OF CRICKETS, GRYLLUS-BIMACULATUS AND ACHETA-DOMESTICUS (ENSIFERA, GRYLLIDAE)

Corpora allata from young male Gryllus bimaculatus were tested for their ability to synthesize juvenile hormone III and to respond to stimulating suboesophageal ganglia extracts in vitro. Corpora allata from day-0 males (3-12 h after ecdysis) exhibit a low basal juvenile hormone III biosynthetic activity and respond consistently and very well to allatotropic stimulation. The stimulatory action is rapid and dose-dependent. A maximum allatotropic activity is present in the suboesophageal ganglia of 3-day-old females, at the time when juvenile hormone III biosynthesis is also highest. Suboesophageal ganglia extracts prepared from males are almost equally effective during the first 5 days after the imaginal moult. A calcium ion concentration of 2.5 mM in the incubation medium supports the allatotropic activity of the suboesophageal ganglia extract in an additive way, Based on its proteinase K sensitivity and heat stability, the allatotropic factor is most likely a peptide. The allatotropin has been partly purified by Sep-Pak C-18 fractionation and reversed-phase HPLC. Extracts prepared from the suboesophageal ganglia of the house cricket, Acheta domesticus, stimulate juvenile hormone III biosynthesis in corpora allata of G. bimaculatus and vice versa.