In vitro rearing of Edovum puttleri, an egg parasitoid of the Colorado potato beetle – development from egg through the pupal stage

Abstract

A variety of semi-defined artificial diets were developed and tested for their ability to support the in vitro development of Edovum puttleri. In the most effective diet, 2.6% of E. puttleri pupated. This diet contained high levels of hen egg yolk combined with Manduca sexta larval hemolymph, or with a mixture of M. sexta egg homogenate and larval hemolymph. Egg homogenate alone (without the addition of hemolymph) was not capable of supporting the parasitoid's development. Thus, hemolymph appears to contain unidentified factor(s) important for inducing pupation of the wasp. Addition of M. sexta pupal fat body tissue extract (in place of hemolymph) also promoted pupation of E. puttleri. Gypsy moth (Lymantria dispar) larval hemolymph could not replace M. sexta larval hemolymph. Fractionation irreversibly reduced the growth-promoting effects of M. sexta larval hemolymph. However, the most effective fraction contained components whose molecular weights were ≥1000 kd. In diets that were devoid of insect materials, the best results were achieved when hen egg yolk, FreAmine, yeast extract, lactalbumin, trehalose, fetal bovine serum and bovine milk were included. This is the first report of an artificial diet for in vitro rearing an eulophid parasitoid from the egg through the pupal stage.