A SIMPLE METHOD FOR IN-VIVO TESTING OF GLANDULAR ENZYMATIC-ACTIVITY ON POTENTIAL PRECURSORS OF LARVAL DEFENSIVE COMPOUNDS IN PHRATORA-SPECIES (COLEOPTERA, CHRYSOMELINAE)

The presence of glandular beta-glucosidase and oxidase-specific activities, and the Possible role of phenol-glucosides and related compounds as precursors for larval defensive compounds, were directly demonstrated by introducing salicin, saligenin and helicin into the defensive glands of Phratora species. Ph. tibialis and Ph. laticollis that normally secrete endogenously-produced iridoid monoterpenes and do not use phenolglucosides from their food sources as precursors, were able to produce salicylaldehyde from helicin when the latter was introduced into the defensive glands.