The effects of long-term laboratory rearing on the performance of Telenomus remus Nixon (Hymenoptera: Platygastridae), an egg parasitoid of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), were investigated by comparing a laboratory-reared strain with a wild strain of the parasitoid. Restriction fragment length polymorphism revealed no genetic variation between the two strains. The wild strain exhibited a higher level of egg parasitism, a longer reproductive period, and a higher level of fecundity than did the laboratory-reared strain while developmental time and female longevity did not differ between the strains. Furthermore, host search efficiency and flight ability were superior in the wild strain compared to the laboratory strain, but oviposition behavior did not differ. Our results indicate that, over time, laboratory rearing may select for individuals that are less fertile, less aggressive, and have lower flight activity than their wild counterparts, which also exhibit a higher parasitism performance and superior potential for population increase in a shorter period of time. Implications for biological control using T. remus and strategies to avoid losses of parasitism efficiency are discussed.