The activity of five enzymes – amylase, α-glucosidase, cellulase, proteinase and lipase – present in the foregut, midgut and hindgut of the African variegated grasshopper Zonocerus variegatus (L.) was studied in the post-embryonic stages of the insect. The activities of all the enzymes increased with age of the insect, with the adult stage having significantly higher (P < 0.05) activity than the lower instars. The midgut had the highest activity for all the enzymes except for amylase. Proteinase activity was the highest, and cellulase the lowest in the gut regions. These findings indicate that the adult stage of the polyphagous insect has higher digestive capacity than the immature stages.

The measurements of the hind femur and activities of five enzymes (α-glucosidase, amylase, cellulase, proteinase and lipase) were determined in the femoral muscles of all post-embryonic developmental stages of Zonocerus variegatus (Linnaeus). The length, width and weight of the hind femur increased during the post-embryonic developmental stages. The enzymatic activities in the femoral muscles of the adult stage were significantly (P < 0.05) higher than the lower instar stages. Proteinase and lipase activities were higher than the carbohydrases (α-glucosidase, amylase and cellulase), reflecting the nature and composition of the food plants consumed.