JUVENILE-HORMONE ESTERASE-ACTIVITY DURING THE REPRODUCTIVE-CYCLE OF THE RING-LEGGED EARWIG

Corpora allata of the ring-legged earwig, Euborellia annulipes, produc e and secrete juvenile hormone III (JH III). The primary degradation p roduct of JH III in vitro by diluted hemolymph was juvenile hormone ac id, as assessed by thin-layer and high-performance liquid chromatograp hy. This result was confirmed by derivatization of the degradation pro duct using diazomethane. Conversion of JH III to JH acid by E. annulip es hemolymph in vitro occurred at a constant rate for at least 4 hr. T he addition of 10(-6) M O-ethyl-S-phenyl phosphoamidothiolate or, alte rnatively, 3-octyl thio-1,1,1-trifluoropropan-2-one inhibited hemolymp h esterase activity; O,O-diisopropylphosphorofluoridate and ethanol al one 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 r elative to ethanol-treated and untreated controls. JH esterase activit y of diluted hemolymph was relatively high in females with basal folli cles < 0.2 mm and low in those with larger basal follicles. The change in JH esterase activity of the hemolymph was not correlated with chan ges in hemolymph protein content; hemolymph protein content was genera lly 50-100 mu g/mu l and did not change significantly with either age or basal follicle length.