INFLUENCE OF PYRIPROXYFEN ON THE EXPRESSION OF HEMOLYMPH PROTEIN GENES IN THE COLORADO-POTATO BEETLE, LEPTINOTARSA-DECEMLINEATA

Pyriproxyfen, a potent juvenile hormone analogue for the Colorado pota to beetle, Leptinotarsa decemlineata, was applied topically to last-in star larvae and short-day adults at different times after moulting, Th e effect of the hormone analogue on concentration and composition of p rotein in the haemolymph was studied at different intervals after pyri proxyfen application, The hormone analogue had little effect on total protein concentration of the haemolymph, but affected protein composit ion. Diapause protein 1 was prevented from being synthesized if pyripr oxyfen was applied before the gene was activated and disappeared from the haemolymph if applied after the gene had been expressed, It theref ore inactivated the gene for diapause protein in both larvae and adult s, Pyriproxyfen also induced appearance of vitellogenin at both stages , indicating induction of expression of the vitellogenin gene, It also affected the stability of mRNA for diapause protein, The analogue cau sed mRNA for diapause protein 1 to disappear untimely compared to cont rols in last-instar larvae and short-day adults, The response of adult s to the JHA was much more pronounced than that of larvae, although th e analogue had a strong biological effect on last-instar larvae becaus e it prevented metamorphosis at low doses. (C) 1997 Elsevier Science L td.