Dietary sugars and proline influence biological parameters of adult Trissolcus grandis, an egg parasitoid of Sunn pest, Eurygaster integriceps

• Sugar contents improved the reproductive index in T. grandis.
• Sugar type affected adult longevity, duration of oviposition period and reproductive index.
• Proline levels had significant effects on reproductive index.

Parasitoids are important natural enemies that are used in the biological control of insect herbivore pests. The egg parasitoid Trissolcus grandis Thompson (Hym. Scelionidae) is a major enemy of the Sunn pest, Eurygaster integriceps Puton (Hem. Scutelleridae), which in turn is one of the most destructive pests of wheat in the Middle East. Our objective was to develop an artificial diet to enhance the performance of T. grandis adults in biological control of the Sunn pest on wheat. We studied the combined effects of concentrations and the composition of sugars and proline on several life-history related parameters in T. grandis, including adult longevity, fecundity, fertility, sex ratio, oviposition period, the fecundity to oviposition period ratio, and reproductive index (e.g. intrinsic rate of increase) of T. grandis. Positive effects of sugar compounds and proline were observed on mean longevity in female and male wasps, as well as on offspring sex ratio (more females produced), oviposition period, fecundity, fertility and reproductive index. Our results thus reveal that the type of diet provided to T. grandis adults benefit the mass rearing efficiency of this important biological control agent.