Role of the brain in photoperiodic regulation of juvenile hormone biosynthesis in the brown-winged green bug Plautia stali

► We measured JH biosynthetic activity by CA from females of Plautia stali. ► JH biosynthetic activity under long-days (LD) was higher than under short-days (SD). ► Middle part of brain (mBr) inhibited JH biosynthesis. ► Neurons with somata in PI, in PL and on NCC in mBr extended fibers to CC-CA. ► These neurons may produce allatostatic factors and change release by photoperiod.