NEURAL AND HORMONAL-REGULATION OF CALLING BEHAVIOR IN BLATTELLA-GERMANICA FEMALES

Virgin females of the German cockroach, Blattella germanica, exhibit c ycles of calling behavior in relation to the cycles of corpora allata activity and ootheca production. The roles of juvenile hormone, mating , and the ootheca in the regulation of calling behavior were investiga ted. The onset of calling in relation to increasing rates of juvenile hormone synthesis suggested involvement of the corpora allata. Allatec tomy prevented the expression of calling behavior and treatment with t he juvenile hormone analog fenoxycarb restored calling. Corpus allatum denervation through nervi corporis allati transection, which accelera tes the synthesis of juvenile hormone by the corpora allata, also acce lerated the onset of calling. Using castrated males, timed interruptio n of mating and ventral nerve cord transection, we demonstrated that, while insertion of the male genitalia and/or spermatophore in the burs a copulatrix caused an immediate suppression of calling behavior, pres ence of sperm and/or associated seminal fluid in the spermatheca was r equired for the complete inhibition of calling in the first as well as in the second ovarian cycle. Although inhibitory signals from the pre sence of an ootheca in the genital atrium would suppress calling behav ior indirectly by inhibiting corpus allatum activity, treatment of gra vid females with fenoxycarb suggested that signals from the ootheca al so inhibit calling directly. The ventral nerve cord plays a critical r ole in the transmission of inhibitory signals from mating and from the presence of the ootheca.