Juvenile hormone esterase activity during the reproductive cycle of the ring-legged earwig☆

Abstract Corpora allata of the ring-legged earwig, Euborellia annulipes , produce and secrete juvenile hormone III (JH III). The primary degradation product of JH III in vitro by diluted hemolymph was juvenile hormone acid, as assessed by thin-layer and high-performance liquid chromatography. This result was confirmed by derivatization of the degradation product using diazomethane. Conversion of JH III to JH acid by E. annulipes hemolymph in vitro occurred at a constant rate for at least 4 hr. The addition of 10 −6 M O-ethyl-S-phenyl phosphoamidothiolate or, alternatively, 3-octyl thio-1,1,1-trifluoropropan-2-one inhibited hemolymph esterase activity; O,O-diisopropylphosphorofluoridate and ethanol alone had no effect on the conversion of JH III to JH acid. At 10 −4 M, each of the selected inhibitors reduced hemolymph esterase activity relative to ethanol-treated and untreated controls. JH esterase activity of diluted hemolymph was relatively high in females with basal follicles