Abstract:

Alkaloids distilled from the weed Sophora alopecuroids was bioassayed with Plagiodera versicolora for their antifeedant effects. The feeding of the insect was strongly inhibited by the total alkaloids and their monomers, with the higher concentrations having stronger antifeedant effects. In choice bioassays, the food intakes of the insect decreased rapidly with the higher concentrations of the total alkaloids. There were no differences among the food intake of non_treated leaves. However, the total food intake decreased significantly with increasing of the alkaloid concentrations. Among the six alkaloids tested, aloperine and sophoramine had stronger antifeedant effects on Plagiodera versicolora. In the non-choice experiments, 99.4% antifeedant rate was observed when the leaves were treated with 5 mg·mL ^-1 aloperine, while in choice bioassays, sophoramine antifeedant showed stronger antifeedant effects with the antifeedant rate 91.7%.

Key words: Sophora alopecuroids, alkaloids, Plagiodera versicolora, antifeedant effect, feeding behavior