REGULATION OF VITELLOGENIN PRODUCTION IN ARMYWORM MOTHS, PSEUDALETIA-UNIPUNCTA

The vitellogenin (Vg) of Pseudaletia unipuncta was identified by SDS-P AGE of egg extracts and male and female hemolymph. It dissociated into two apoproteins of 164 and 40 kDa, the larger of which reacted specif ically with a polyclonal antibody raised against the native Vg. An enz yme-linked immunosorbant assay (ELISA) was used to examine Vg producti on in virgin and mated P. unipuncta females, as well as in neck-ligate d individuals to which juvenile hormone (JH) homologs or analogs were applied, During the 2 days following emergence, Vg titers were low (ca 0.2 mg/ml) in virgin females, but they increased steadily thereafter, reaching values of ca 2.4 mg/ml on day 7. Twenty-four h after mating, Vg titers were significantly higher in mated females than in virgins of the same age, but at 48 h, Vg titers of mated individuals were sign ificantly lower than those of virgins, suggesting that Vg was taken up by the developing oocytes. Females neck-ligated immediately after eme rgence did not produce Vg, but production was restored in a dose-depen dent manner by topical applications of JH homologs or analogs. JH I an d JH II: displayed approx. 10 times more biological activity than JH I II, and two JH analogs were still more active (ED(50), mu g/moth: JH I II, 13.0; JH II, 1.8; JH I, 1.0; methoprene, 0.04; pyriproxyfen, 0.003 ). In a time-course analysis, pyriproxyfen-activated Vg accumulation b egan between day 1 and day 2 and reached a plateau on day 3 after trea tment.