Hormonal influence on feeding and digestion in a plant bug, Dysdercus cingulatus, and a caterpillar, Hyblaea puera

ABSTRACT. Allatectomy did not affect either food ingestion or midgut protease and invertase activity in adult female Dysdercus cingulatus Fabr., but ingestion of methoprene (juvenile hormone analogue) stimulated food consumption in the late instar caterpillars of Hyblaea puera Cramer. Implantation of brain to raise the insect's own level of brain neurosecretion also stimulated food ingestion in Hyblaea. Caterpillars which either ingested methoprene or received brain-implants showed higher levels of midgut amylase activity. However, no increase in amylase occurred after ingestion of methoprene or implantation of brain followed by starvation. A probable mechanism of hormonal influence on food ingestion and enzyme activity is discussed in the light of these results.