A JUVENILE-HORMONE ANALOG AFFECTS THE PROTEIN PATTERN OF THE HEMOLYMPH IN LAST-INSTAR LARVAE OF LOCUSTA-MIGRATORIA

Pyriproxyfen, a recently developed juvenile hormone analogue, has strong morphogenetic effects when applied topically or by injection to last-instar larvae of Locusta migratoria. A single injection as low as 2-mu-g induced malformation of the wings and green pigmentation, whereas higher doses resulted in supernumerary-stage larvae. Pyriproxyfen repressed the synthesis of two larva-specific haemolymph proteins, but stimulated the synthesis of another high-molecular weight protein. This protein becomes a major protein of the haemolymph and remains so after the adult moult. Its molecular weight is about 500 +/- 13 kDa and it is composed of five subunits, with molecular weights of 110 +/- 8; 101 +/- 6.6; 91 +/- 5.5; 62 +/- 4.0 and 53 +/- 3.5 kDa. This protein was independently identified as vitellogenin.