MIXED‐FUNCTION OXIDASE ACTIVITY IN LARVAE OF HELIOTHIS PUNCTIGER WALLENGREN (LEPIDOPTERA: NOCTUIDAE)

Abstract

AbstractThe O‐demethylation of 4‐nitroanisole was used to evaluate mixed‐function oxidase (MFO) activity in last and penultimate instar larvae of H. punctiger. The specific activity of tissues of early fifth instar larvae in decreasing order were midgut, integument, fatbody, head capsule, and whole larva. Specific activity of the midgut rose rapidly from the beginning of the instar and then returned to a relatively low level when the insect stopped feeding. Fatbody specific activity increased until early in the last instar and remained at about this level until pupation. Specific activity of the integument was highest at the beginning and end of the instar and lowest in the middle. O‐demethylase activity per larva revealed that although midgut activity was low late in the fifth instar, the insect still possessed relatively high levels of MFO's in the integument and particularly the fatbody.