Stimulation of embryonic development in Microplitis croceipes (Braconidae) in cell culture media preconditioned with a fat body cell line derived from a nonpermissive host, gypsy moth, Lymantria dispar

A cell culture medium, IPL-52B, was preconditioned with host fat body and two insect cell lines to determine if they would support embryonic development of Microplitis croceipes in vitro. The medium was preconditioned with the cell line IPL-LdFB, derived from fat body of the gypsy moth, Lymantria dispar, cell line IAL-TND1, derived from imaginal discs of the cabbage looper, Trichoplusia ni, and whole fat body tissue from host Helicoverpa zea. A second cell culture medium, Excell 400, was preconditioned with only the cell line, IPL-LdFB. Pregerm band eggs were dissected from third instar host larvae and incubated in the conditioned medium for 20 h. Newly laid parasitoid eggs did not develop in unconditioned IPL-52B, but did develop to germ band stage in unconditioned Excell 400. The IPL-52B medium conditioned with both cell lines induced germ band formation, but only the L. dispar cell line (IPL-LdFB) promoted significant development to eclosion comparable to host far body tissue. Excell 400 medium preconditioned with the cell line, IPL-LdFB also supported development to eclosion.