In Vitro Rearing of Edovum puttleri, an Egg Parasitoid of the Colorado Potato Beetle, on Artificial Diets: Effects of Insect Cell Line-Conditioned Medium

Effects of conditioned media prepared from cell lines derived from 11 insect species (six families, three orders) on the in vitro growth and development of the egg parasitoid Edovum puttleri were investigated. The parasitoid exhibited significantly different responses to the various insect cell line-conditioned media that were incorporated into the artificial diets. When cell lines were derived from embryos, higher percentages of 3rd instars and prepupae were observed than when cell lines were derived from fat body or ovaries. Medium conditioned with cell line IPLB-CPB2 derived from the embryos of the Colorado potato beetle produced the best result. Preconditioning time was important. In general, 5 days of preconditioning appeared to be optimal. The growthand development-promoting effect may have resulted from growth factors or growth-supporting factors produced/ released by the insect cell lines into the culture medium. Upon storage at 0–4°C for 7–14 days, the ability of cell line-conditioned medium to promote development beyond the second instar was greatly reduced (approximately 10–55%). Our studies demonstrated that to support the in vitro growth and development of E. puttleri, insect hemolymph could be successfully replaced with insect cell lineconditioned medium. These findings should facilitate the development of a cost-effective mass-rearing system for E. puttleri and/or other parasitoids. Arch. Insect Biochem. Physiol. 40:173–182, 1999. Published 1999 Wiley-Liss, Inc.