In vitro rearing of parasitoids: Role of host factors in nutrition

Abstract

AbstractEvidence for the role of host components in the growth and development of parasitoids is briefly reviewed, and implications concerning the development of in vitro culture media are discussed. In vitro development of the entomophagous parasitoids Eucelatoria bryani Sabrosky (Diptera: Tachinidae) and Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) is dependent on low‐molecular‐weight host chemicals. Asparagine, but not aspartic acid, and several other free amino acids are essential dietary ingredients for E. bryani. From insect hemolymph, small, unidentified polar molecules with characteristics similar to sugars are needed for pupation of T. pretiosum. Both adaptive and nonadaptive changes likely are responsible for the dependence of parasitoids on host factors. The genetic changes have no apparent adverse effect unless the parasitoids are fed artificial media devoid of certain chemicals that are obtained in vivo from host insects. The rearing of at least several species of important entomophages to control pest insects of great economic importance is dependent on the identification of constituents from host insects and inclusion of these chemicals in artifical diets.