Co-Authors:
Feldlaufer, M.F., Insect Neurobiology and Hormone Laboratory, USDA, Agricultural Research Service, Beltsville, Maryland, United States
Weirich, G.F., Insect Neurobiology and Hormone Laboratory, USDA, Agricultural Research Service, Beltsville, Maryland, United States
Lusby, W.R., Insect Neurobiology and Hormone Laboratory, USDA, Agricultural Research Service, Beltsville, Maryland, United States
Svoboda, J.A., Insect Neurobiology and Hormone Laboratory, USDA, Agricultural Research Service, Beltsville, Maryland, United States
Abstract:
An ecdysteroid RIA was used to determine the ecdysteroid titer in developing embryos of Dysdercus fasciatus and revealed that peak titer occurred approximately 120 h post‐oviposition. Analysis of neutral sterols at this time indicated sitosterol to be the predominant neutral sterol with lesser amounts of campesterol. Embryonic sterols were highly reflective of the sterols found in the cotton seed diet upon which previous generations of the bugs had fed. Analysis of the embryonic extract for ecdysteroids indicated the presence of both makisterone A and the 29‐carbon ecdysteroid makisterone C. Isolation of these compounds was accomplished by reversed‐phase and silica HPLC in conjunction with RIA, and the identification of both compounds was confirmed by mass spectrometry. No ecdysone or 20‐hydroxyecdysone was detected in the embryonic sample. Copyright © 1991 Wiley‐Liss, Inc.