Screening Sugars Can Benefit the Parasitoid Cotesia chilonis (Hymenoptera: Braconidae) Without Benefiting Its Host, Chilo suppressalis (Lepidoptera: Crambidae).

Most adult parasitoids depend on carbohydrate-rich food as an energy source for longevity, fecundity, and mobility. Thus, providing sugars has been proposed as a technique to maximize the biological control efficacy of parasitoids. However, the sugars provided for parasitoids need to be carefully selected because herbivore hosts might also benefit. Here we explore the effects of 12 naturally occurring sugars on the longevity and fecundity of the rice pest, Chilo suppressalis, and the longevity of its parasitoid, Cotesia chilonis, as well as the effect of sugars on sugar consumption of C. chilonis. Results showed that none of the tested sugars significantly impacted the longevity of C. suppressalis, but fructose, glucose, maltose, and sucrose significantly increased its fecundity. The longevity of C. chilonis was significantly increased when fed fructose, glucose, sucrose, maltose, trehalose, and melezitose. Our data suggest that C. chilonis consumed larger quantities of glucose, fructose, and sucrose followed by maltose, melezitose, and trehalose and the longevity of C. chilonis was positively correlated to sugar consumption. Our data also suggest that the herbivore C. suppressalis and its parasitoid C. chilonis responded differently to trehalose and melezitose. Although additional studies are needed, our data suggest that these sugars could be considered as candidate components for sugar sprays to enhance the activity and efficacy of C. chilonis, but without benefiting its pest host.
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