FEEDING AND ACTIVATION OF CORPORA ALLATA IN THE COCKROACH BLATTELLA-GERMANICA (L.) (DICTYOPTERA, BLATTELLIDAE)

Adult females of the cockroach Blattella germanica have clearly-define d feeding cycles related to oogenesis, In the first cycle, food ingest ion precedes volumetric increase in the corpora allata, which in turn precedes juvenile hormone production, whereas starved females do not d evelop the corpora allata and produce very low amounts of juvenile hor mone, When the second gonadotropic cycle is provoked by removing the o otheca, the first event observed is an increase in food consumption, f ollowed by an increase in corpora allata volume and activity, However, this increase in corpora allata volume (and activity) does not occur if females are starved, thus indicating that the ootheca in the genita l chamber inhibits primarily feeding, and indirectly corpora allata de velopment and activity, Corpora allata volume in isolated heads from s tarved and decapitated females was able to increase to levels similar to fed controls, but this increase was abolished by allatostatin treat ment, We suggest that a factor produced in the thoracico-abdominal com partment, which reaches the head mainly through a nervous pathway, is released during starvation and inhibits corpora allata development, Th is factor may stimulate allatostatin production or release, or may wel l be allatostatin itself. (C) 1997 Elsevier Science Ltd. All rights re served.