Does sugar sources enhance the fitness of the olive moth parasitoid Chelonus Elaeaphilus?

Abstract

Chelonus elaeaphilus Silvestri (Hymenoptera: Braconidae) is a specific parasitoid of the olive moth, Prays oleae(Bernard), that in Portugal can cause parasitism rates of about 80%. The objective of this study was to gain insight into the possibilities offered by 18 native plant species from the olive agro-ecosystem in enhancing the fitness of C. elaeaphilus, by providing it with sugars. Four naturally occurring sugars (sucrose, fructose, glucose and maltose) were tested with respect to their effect on the parasitoid longevity. Flowers from the studied plant species were analyzed with respect to their theoretically nectar accessibility, and the sugar composition of the nectars was analyzed. Females longevity was higher when they feed on both sucrose and glucose compared to either maltose or fructose. It was also found that C. elaeaphilusis theoretically able to make use of any of the tested plants, except for the Asteraceae. Nectars mainly contained glucose, fructose and sucrose, although they differed in their relative concentration.