Identification of juvenile hormone III bisepoxide (JHB 3), juvenile hormone III and methyl farnesoate secreted by the corpus allatum of Phormia regina (Meigen), in vitro and function of JHB 3 either applied alone or as a part of a juvenoid blend

Abstract

The corpus allatum of both male and female adult black blow fly, Phormia regina (Meigen), produced radioisotope-labeled juvenoids when incubated in vitro following a radiochemical assay. The production of juvenoids was greatly enhanced after the flies were fed a protein (liver) meal. These juvenoids were determined as juvenile hormone III bisepoxide (JHB 3), juvenile hormone III (JH III) and methyl farnesoate (MF). These three juvenoids were separated and identified by chromatography (TLC and HPLC) using synthesized standards, respectively. Then, JHB 3 standard and the biological samples of JHB 3 were further identified with PCI GS-MS using published spectrum data. Bioassay of synthetic JHB 3 revealed its ability to restore oögenesis in allatectomized, liver-fed female blow flies. The ability of these three juvenoids and their blends to restore oögenesis was the rational juvenoid blend (i.e. a mixture of JHB 3, JH III and MF according to the percent ratio secreted by the isolated CA of liver-fed females) > JHB 3 = JH III > MF = the irrational juvenoid blend (i.e. a mixture of an arbitrary ratio of JHB 3, JH III and MF). This is the first evidence suggesting that multiple juvenoid production and reception may be a normal event for insects.