Comparison between two species of Eretmocerus (Hymenoptera: Aphelinidae): Reproductive performance is one explanation for more effective control in the field

► Eretmocerus hayati lived longer and produced three times as many progeny as E. mundus. ► E. hayati's fecundity is at least twice that reported for other Eretmocerus. ► Sperm limitation can reduce the proportion of female E. hayati progeny.